Request ID	2		Type of the request	High Priority request
Target	Reaction and process	Incident Energy	Secondary energy or angle	Target uncertainty	Covariance
8-O-16	(n,a),(n,abs) SIG	2 MeV-20 MeV		See details	Y
Field	Subfield	Date Request created	Date Request accepted	Ongoing action
Fission	Material recycl, adv. reactors	21-SEP-05	12-SEP-08	Y

Requester: Mr Arnaud COURCELLE at CEA-SACLAY, FR
Email: arnaud.courcelle@cea.fr

Project (context): LWR, Material recycling and NEA WPEC Subgroup 26

Impact:
In light water reactors oxygen is present in UOX, MOX and water. The sensitivity coefficient (dk/k)/(dσ/σ)=-3.5 pcm/%. A 30% uncertainty results in an uncertainty for k_eff of 100 pcm. This important effect was identified by Subgroup 22 of WPEC which investigated the underprediction of the reactivity of light water reactors with the most recent nuclear data evaluations.
A second point concerns helium production which is of importance for the performance of fuel pins and clads. The O-16(n,α) reaction accounts for 25% of the total helium production and contributes 7% to its uncertainty.
A third point concerns the calibration of neutron source strengths using the manganese-sulfate bath technique (NIST). The final requested uncertainty of 1% on neutron source calibrations is very near the 0.5% uncertainty contributed by this reaction.

Design phases of selected reactor and fuel cycle concepts require improved data and methods in order to reduce margins for both economical and safety reasons. A first indicative nuclear data target accuracy assessment was made within WPEC Subgroup 26 (SG-26). The assessment indicated a list of nuclear data priorities for each of the systems considered (ABTR, SFR, EPR, GFR, LFR, ADMAB, VHTR, EPR). These nuclear data priorities should all be addressed to meet target accuracy requirements for the integral parameters characterizing those systems (see the accompanying requests originating from SG-26).

Accuracy:
For (n,a) : 5% in the whole range.
For (n,abs): 9.9 % (2.23 - 6.07 MeV) and 12.1 % (6.07 - 19.6 MeV).

Justification document:
See reference 1 attached: Need for O16(n,alpha) Measurement and Evaluation in the range 2.5 - 10 MeV A. Courcelle et al. (August 2005) and references therein.
See also OECD/NEA WPEC Subgroup 26 Final Report: "Uncertainty and Target Accuracy Assessment for Innovative Systems Using Recent Covariance Data Evaluations" (link to WPEC Subgroup 26 Report in PDF format, 6 Mb), and
And "Nuclear data for improved LEU-LWR reactivity predictions", WPEC Vol. 22 (link to Report).

Comment from requester:
The required accuracy concerns the normalisation of the cross section. A sensitivity analysis is also presented for k_eff in a fast reactor. Considerable differences exist among evaluations and measurements are discrepant. Recent C-13(α,n) and C-13(α,α) measurements are identified that provide detailed knowledge about the inverse reaction. Together with an R-matrix analysis this may be used to improve the evaluation for the O-16(n,α) reaction. Feedback has been obtained from evaluators at ORNL, LANL and KAPL.

Review comment:

A direct measurement is in preparation using an ionisation chamber with the time projection technique. The measurement aims at providing benchmark data for the R-matrix analysis near the main resonance (En ~ 5 MeV).
A poor resolution measurement should be sufficient to check the normalisation of the R-matrix result, since resonance self-shielding is not an issue.
The recent results for the C-13(α,n) correspond to 4.8-12 MeV neutrons. This covers a part of the region of interest, but not the important range from 2.35 to 4.8 MeV.
The status of the IRMM measurements was presented as a poster in the ND2007 conference, by V. Khriatchkov, G. Giorginis, V. Corcalciuc, M. Kievets, "The cross section of the 16O(n,a)13C reaction in the MeV energy range", contribution 481, ND2007, Nice, April 2007.

The achieved accuracy is estimated to be 30%.

The request is well motivated and the response for follow-up is very encouraging.

Entry Status:
Work in progress (as of SG-C review of May 2018)

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

G. Giorginis, et al., The cross section of the 16O(n,a)13C reaction in the MeV energy range, ND2007 proceedings, EXFOR 23040
V.A. Khryachkov, et al., Study of (n,a) Reaction Cross Section on a Set of Light Nuclei, ISINN-18, Sept. 2011, Dubna, Russia, EXFOR 41575
V.A. Khryachkov, et al., (n,a) reaction cross section research at IPPE, CNR*11, EPJ Web of Conferences 21 (2012) 03005, EXFOR 41575
S. Harissopulos et al., Cross section of the 13C(a,n)16O reaction: A background for the measurement of geo-neutrinos, PRC 72 (2005) 062801
P. Mohr, Revised cross section of the 13C(a,n)16O reaction between 5 and 8 MeV, PRC 97 (2018) 064613; W.A. Peters, Comment on "Cross section of the 13C(a,n)16O reaction: A background for the measurement of geo-neutrinos", PRC 96 (2017) 029801
M. Febbraro, et al., New 13C(a,n)16O Cross Section with Implications for Neutrino Mixing and Geoneutrino Measurements, PRL 125 (2020) 062501
Planned measurements at LANL, Demokritos...

Theory/Evaluation

G. Hale and M. Paris, Status and plans for 1H and 16O evaluations by R-matrix analyses of the N-N and 17O systems, NEMEA-7/CIELO, NEA/NSC/DOC(2014)13, page 13,
S. Kunieda, et al., R-matrix Analysis for n +16O Cross-sections up to En = 6.0 MeV with Covariances, NDS 118 (2014) 250-253
L. Leal, et al., Resonance parameter and covariance evaluation for 16O up to 6 MeV, EPJ N 2 (2016) 43
M.B. Chadwick et al., CIELO Collaboration Summary Results: International Evaluations of Neutron Reactions on Uranium, Plutonium, Iron, Oxygen and Hydrogen, NDS 148 (2018) 189
Ongoing evaluation work in the framework of INDEN (CIELO follow-up), see Summary Report of the IAEA CM, 15-17 May 2019, Vienna, Report INDC(NDS)-0788

Validation

M. Salvatores, et al., Methods and Issues for the Combined Use of Integral Experiments and Covariance Data: Results of a NEA International Collaborative Study, Nuclear Data Sheets 118 (2014) 38
G. Palmiotti, et al., Combined Use of Integral Experiments and Covariance Data, Nuclear Data Sheets 118 (2014) 596
A. Shaw, et al., Validation of Continuous-Energy ENDF/B-VIII.0 16O, 56Fe, and 63,65Cu Cross Sections for Nuclear Criticality Safety Applications, Nuclear Science and Engineering 195 (2021) 412

Additional file attached:SG26-report.html
Additional file attached:Need for O16(n,alpha).pdf

Request ID 3 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

94-PU-239 (n,f) prompt g Thermal-Fast Eg=0-10MeV 7.5 Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fission LWR 28-APR-06 12-MAY-06 Y

Requester: Prof. Gerald RIMPAULT at CAD-DER, FR
Email: gerald.rimpault@outlook.fr

Project (context): JEFF, NEA WPEC Subgroup 27

Impact:
The four fast reactor systems of GenIV feature innovative core characteristics for which gamma-ray heating estimates for non-fuel zones require an uncertainty of 7.5% [1]. For the experimental Jules Horowitz Reactor (RJH) at Cadarache a similar requirement appears [2]. Recent studies show evidence of discrepancies on integral measurement in MASURCA, EOLE and MINERVE, from which it is clear that the expectations for GenIV systems and the RJH thermal reactor are not met [3]. Gamma-ray energy release is dominated by Pu-239 and U-235.

Accuracy:
7.5% on the total gamma energy. 7.5% on the multiplicity.
Best accuracy achievable for the gamma spectrum shape.

Justification document:
Reference 1: G. Rimpault, Proc. Workshop on Nuclear Data Needs for Generation IV, April 2005, Antwerp, Belgium
Reference 2: D. Blanchet, Proc. M&C 2005, Int. Topical Meeting on Mathematics and Computation, Supercomputing, Reactor Physics and Nuclear and Biological Applications, Sep. 2005, Avignon, France
Reference 3: 'Needs for accurate measurements of spectrum and multiplicity of prompt gammas emitted in fission', G. Rimpault, A. Courcelle and D. Blanchet, CEA/Cadarache - DEN/DER/SPRC.

Comment from requester:
Forty percent of the total gamma-ray energy release results from prompt decay of fission products. No comprehensive analytic expressions exist and Hauser-Feshbach model calculations are involved and presently lack sufficient knowledge to warrant a solution of the problem. New measurements would be needed to guide new evaluation efforts. Present evaluations are based on measurements from the seventies.

Review comment:
Discrepancies observed for C/E ratios in various benchmarks range from 10 to 28%. The request is well motivated and based on a considerable effort.

Entry Status:
Work in progress (as of SG-C review of May 2018)
Pending new evaluation or validation (as of SG-C review of June 2019)
Pending new evaluation or validation (as of SG-C review of May 2021) with recommendations for priority validation of the latest evaluations
Completed (as of SG-C review of May 2022) - The characteristics of the PFGS have been measured at thermal and fast energies for both U-235 and Pu-239. Experimental data have been combined with model calculations to evaluate the prompt gamma properties as a function of incident neutron energy for JEFF-3.3 and ENDF/B-VIII.0.

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

A. Chyzh, et al., Total prompt g-ray emission in fission of U-235, Pu-239,241, and Cf-252, PRC 90 (2014) 014602, EXFOR 14361
S. Oberstedt, et al., Future research program on prompt g-ray emission in nuclear fission, Eur. Phys. J. A (2015) 51:178
A. Gatera, et al., Prompt-fission g-ray spectral characteristics from 239Pu(nth,f), PRC 95 (2017) 064609

Theory/Evaluation

O. Serot et al., Prompt Fission Gamma Spectra and Multiplicities for JEFF-3.3, JEF/DOC-1828, JEFF Meeting, OECD, Paris (2017)
D. Brown et al., ENDF/B-VIII.0: The 8th Major Release of the Nuclear Reaction Data Library with CIELO-project Cross Sections, New Standards and Thermal Scattering Data, NDS 148 (2018) 1
I. Stetcu et al., Evaluation of the Prompt Fission Gamma Properties for Neutron Induced Fission of U-235,238 and Pu-239, NDS 163 (2020) 261
A. Tudora, Prompt gamma-ray results of two deterministic modelings of prompt emission in fission, Eur. Phys. J. A 56 (2020) 128

Additional file attached:HPRLgammafission.pdf
Additional file attached:

Request ID 4 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

92-U-235 (n,f) prompt g Thermal-Fast Eg=0-10MeV 7.5 Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fission LWR, Gen-IV 10-MAY-06 12-MAY-06 Y

Requester: Prof. Gerald RIMPAULT at CAD-DER, FR
Email: gerald.rimpault@outlook.fr

Project (context): JEFF, NEA WPEC Subgroup 27

Accuracy:
7.5% on the total gamma energy
7.5% on multiplicity
Best accuracy achievable for the gamma spectrum shape

Review comment:
Discrepancies observed for C/E ratios in various benchmarks range from 10 to 28%. The request is well motivated and based on a considerable effort.

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

E. Kwan, et al., Prompt energy distribution of 235U(n,f) gamma at bombarding energies of 1–20 MeV, NIM A 688 (2012) 55, EXFOR 14413
A. Oberstedt et al., Improved values for the characteristics of prompt-fission g-ray spectra from the reaction 235U(nth,f), PRC 87 (2013) 051602(R), EXFOR 31729
A. Chyzh, et al., Total prompt g-ray emission in fission of U-235, Pu-239,241, and Cf-252, PRC 90 (2014) 014602, EXFOR 14361
M. Lebois, et al., Comparative measurement of prompt fission g-ray emission from fast-neutron-induced fission of U-235 and U-238, PRC 92 (2015) 034618, EXFOR 23299
Ongoing work at IRMM-IPNO, S. Oberstedt, et al., Future research program on prompt g-ray emission in nuclear fission, Eur. Phys. J. A (2015) 51:178
Ongoing work at JAEA, see H. Makii et al., Measurement of High-Energy Prompt g-rays from Neutron-Induced Fission of 235U, FIESTA 2017

Theory/Evaluation

O. Serot et al., Prompt Fission Gamma Spectra and Multiplicities for JEFF-3.3, JEF/DOC-1828, JEFF Meeting, OECD, Paris (2017)
D. Brown et al., ENDF/B-VIII.0: The 8th Major Release of the Nuclear Reaction Data Library with CIELO-project Cross Sections, New Standards and Thermal Scattering Data, NDS 148 (2018) 1
I. Stetcu et al., Evaluation of the Prompt Fission Gamma Properties for Neutron Induced Fission of U-235,238 and Pu-239, NDS 163 (2020) 261
A. Tudora, Prompt gamma-ray results of two deterministic modelings of prompt emission in fission, Eur. Phys. J. A 56 (2020) 128

Additional file attached:HPRLgammafission.pdf
Additional file attached:

Request ID 5 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

72-HF-0 (n,g) SIG 0.5 eV-5.0 keV 4 Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fission LWR 28-APR-06 16-APR-07

Requester: Dr Gilles NOGUERE at CAD-DER, FR
Email: gilles.noguere@cea.fr

Project (context): JEFF

Impact:
In nuclear industry hafnium is used as neutron absorbing material to regulate the fission process. Interpretations of critical experiments with UOx fuel conducted by CEA in the AZUR zero-power reactors has shown systematic underestimation of the reactivity worth that may be attributed to an overestimated natural hafnium capture cross section in the epi-thermal energy range [1,2].

Accuracy:
Requested accuracy can be found in the CEA Report "Correlations entre données nucleaires et experiences integrales a plaques, le cas du hafnium", Jean-Marc Palau, CEA-R-5843 (1997). The target accuracy on the effective capture integral has to be lower than 4%

Justification document:
[1] David Bernard, "Determination des incertitudes liés aux grandeurs neutroniques d'interet des reacteurs a eau presurisee a plaques combustibles et application aux etudes de conformite", University Blaise Pascal, Clermont-Ferrand II, France (2001).
[2] G. Noguere, A. Courcelle, J.M. Palau, O.Litaize, "Low neutron energy cross sections of the hafnium isotopes", JEFDOC-1077.pdf, OECD-NEA, Issy-les-Moulineaux, France (2005).
[3] G. Noguere, A. Courcelle, P. Siegler, J.M. Palau, O. Litaize, "Revision of the resolved resonance range of the hafnium isotopes for JEFF-3.1", Technical note CEA Cadarache NT-SPRC/LEPH-05/2001 (2005).

Comment from requester:
Neither the JENDL3.3 nor the JEFF3.1 libraries, that were recently issued, solve the problem. In fact, this was observed for JENDL3.3 before the JEFF3.1 file was constructed. As a result the JEFF3.1 file has been produced with this problem in mind taken into consideration the recent data from Trbovich et al. obtained at RPI [3]. Finally, a 400 pcm underestimation remains that is likely due to interfering isotopic contributions in the resolved energy region. New high resolution measurements appear needed, and would be particularly valuable if they can distinguish the contributions of different isotopes.

Review comment:
Calculations on the AZUR configuration using the JEFF3.1 library give a Hf reactivity worth of about -300 pcm [2].

Entry Status:
Completed (as of SG-C review of May 2018) - The measurements performed at RPI [Trbovich:2009] and JRC-Geel [Ware:2010] allowed to significantly improve the Hf isotopes in JEFF, which now gives satisfactory results for reactivity worth due to Hf data [Noguere:2009].

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

A.K.M. Meaze et al. (G.N. Kim), Measurement of the Total Neutron Cross-Sections and the Resonance Parameters of Natural Hafnium at the Pohang Neutron Facility, J. Korean Phy. Soc. 46 (2005) 401, EXFOR 31689
K. Wisshak, et al., Fast neutron capture on the Hf isotopes: Cross sections, isomer production, and stellar aspects, PRC 73 (2006) 045807, EXFOR 22926
M.J. Trbovich, et al., Hafnium resonance parameter analysis using neutron capture and transmission experiments, NSE 161 (2009) 303, EXFOR 14239
T. Ware, Measurement and analysis of the resolved resonance cross sections of the natural hafnium isotopes, PhD thesis, University of Birmingham (2010); etheses.bham.ac.uk//id/eprint/807
M. Budak, et al., Experimental determination of effective resonance energies for 158Gd(n,g)159Gd and 179Hf(n,g)180mHf reactions, ANE 38 (2011) 2550

Theory/Evaluation

G. Noguere, et al., Average neutron parameters for hafnium, NPA 831 (2009) 106
G. Noguere, et al., Group-average covariance matrices for the hafnium isotopes of interest for light water reactor applications, Annals of Nucl. Energy 36 (2009) 1059
T. Ware et al., Evaluation of Neutron Cross Sections for Hafnium in the Resolved Resonance Range, Journal of the Korean Physical Society 59 (2011) 1884

Additional file attached:JEFDOC-1077.ppt
Additional file attached:NT_Hafnium.pdf

Request ID 8 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

1-H-2 (n,el) DA/DE 0.1 MeV-1 MeV 0-180 Deg 5 Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fission Heavy Water Reactors 25-JUL-06 16-APR-07 Y

Requester: Kenneth KOZIER at CNLCR, CAN
Email:

Project (context): Critical experiments with high enriched uranyl fluoride in heavy water

Impact:
Different representations of the energy-angle neutron elastic scattering probability distributions (at energies <3.2 MeV) used in various releases of the ENDF/B-VI and JENDL-3.3 evaluated data libraries for deuterium cause differences of about: (1) 1000 pcm in simulations [1,2] of critical experiments involving solutions of high enriched uranyl fluoride solutions in heavy water (specifically the HST-004 and HST-020 series of measurements in the NEA ICSBEP handbook), and (2) 60 pcm in the calculation bias observed [2] in simulations of heavy-water coolant void reactivity (CVR) experiments performed in ZED-2. Moreover, both the HST and ZED-2 simulation results show a rising trend with neutron leakage, suggesting that further revision of the deuterium data evaluations may be needed. Modern measurements may help resolve a small positive bias of about 150 pcm in the simulation of ZED-2 heavy-water CVR experiments (corresponding to about 10% of the calculated CVR).

Accuracy:
About 5%, depending on energy and angle. At 220 keV, existing experimental data have uncertainties of about 16% and differ from the evaluated library values by about 35% at backward angles near 180 degrees. At 500 keV, some experimental data have uncertainties of about 5%, but differ from the library values by up to 50% at 180 degrees. At 1.0 MeV, existing experimental data have uncertainties of about 5%, but differ from the library values by up to 33% near 180 degrees. ENDF/B-VI.8 and JENDL-3.3 differ by about 15% at 180 degrees over this energy range. It is estimated that a 5% uncertainty would correspond to a reactivity uncertainty of about 300 pcm in the context of the HST simulations and about 20 pcm in the ZED-2 CVR simulations, and would be adequate to resolve the current discrepancy between results obtained using the ENDF-B/VI.8 (also VII) and JENDL-3.3 deuterium data files.

Justification document:
The available angular scattering experimental data for deuterium were reviewed [3, attached] and found to be 25 to more than 50 years old, sparse and inconsistent, particularly at backward angles near 180 degrees. The experimental data frequently differ from the evaluated library values by several standard deviations, especially at extreme backward and forward angles. In addition to the HST and ZED-2 simulation results [1,2], the neutronic importance of the deuterium scattering data has been investigated in empirical sensitivity studies of simple systems [4, attached], which suggest that the differences arise at energies up to about 1.0 MeV. A recent TSUNAMI sensitivity analysis of the CVR for an Advanced CANDU Reactor (ACR-700) type lattice cell showed [5] a large sensitivity to the deuterium elastic scattering cross section (34% change in CVR per % change in the cross section), although this methodology does not currently address the angular dependence.
References:
1. R.D. Mosteller, J.M. Campbell and R.C. Little, Reactivity Impact of ENDF/B-VI Cross Sections for Deuterium in Heavy-Water Solution Benchmarks, LA-UR-05-0330, 2005 Annual Meeting of the American Nuclear Society, June 5 - 9, 2005, San Diego, CA.
2. R.D. Mosteller, K.S. Kozier, J.M. Campbell and R.C. Little, ''Reactivity Impact of Deuterium Cross Sections for Heavy-Water Benchmarks'', LA-UR-05-0787, proceedings of the International Topical Meeting on Mathematics and Computation, Supercomputing, Reactor Physics, and Nuclear and Biological Applications, Avignon, France, September 12-15, 2005.
3. L.W. Townsend, ''Neutron-Deuterium Cross Section Evaluation'', Final Technical Report, AECL Purchase Order 217739, March 31, 2006 (copy attached).
4. K.S. Kozier, ''Sensitivity of MCNP5 Calculations for a Spherical Numerical Benchmark Problem to the Angular Scattering Distributions for Deuterium'', proceedings of the PHYSOR-2006 ANS Topical Meeting: Advances in Nuclear Analysis and Simulation, Vancouver, BC, September 10-14, 2006 (copy attached; to be issued).
5. M.L. Williams, J.C. Gehin and K.T. Clarno, ''Sensitivity Analysis of Reactivity Responses Using One-Dimensional Discrete Ordinates and Three-Dimensional Monte Carlo Methods'', proceedings of the PHYSOR-2006 ANS Topical Meeting: Advances in Nuclear Analysis and Simulation, Vancouver, BC, September 10-14, 2006 (to be issued).
6. J.P. Svenne, L. Canton, K. Kozier, and L. Townsend, "Re-evaluating low-energy neutron-deuteron elastic scattering using three-nucleon theory", International Conference on Nuclear Data for Science and Technology 2007, Contrib. #208.
7. K.S. Kozier, "Assessment of evaluated (n,d) energy-angle elastic scattering distributions using MCNP simulations of critical measurements and simplified calculation benchmarks", International Conference on Nuclear Data for Science and Technology 2007, Contrib. #594

Comment from requester:
Additional sensitivity studies are in progress. We are also looking into the possibility of having someone review the theoretical basis for the two distinctly different quantum mechanical formalisms used by ENDF/B & JENDL for the deuterium elastic scattering energy-angle distributions, and potentially undertake some new Faddeev three-body model calculations.

Review comment:
At the ND2007 in Nice two contributions were presented summarising the status at the time of the conference (April 2007, refs. 6 and 7). Theoretical calculations by L. Canton solving the AGS three-body equations using the Bonn-B nuclear potential tend to support the higher degree of backscattering in the ENDF/B-IV.4 evaluation. A 5% experimental accuracy for the differential cross section at 180 degrees would be sufficient to discriminate between ENDF/B-VI.4 and theory on the one hand and ENDF/B versions VI.5 to VII.0 on the other hand. Possibilities for experimental efforts are being investigated in the US and in Europe. Further theoretical efforts are planned to study the impact of three body forces and the use of other nucleon-nucleon potentials on the angular distribution.

Entry Status:
Work in progress (as of SG-C review of May 2018)

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

J.A. Frenje, et al., Measurements of the Differential Cross Sections for the Elastic n-3H and n-2H Scattering at 14.1 MeV by Using an Inertial Confinement Fusion Facility, PRL 107 (2011) 122502, EXFOR 14305
M. Stanoiu, et al., Neutron-Deuteron Elastic Scattering Measurements, Journal of the Korean Physical Society 59 (2011) 1825
N. Nankov, et al., The Angular Distribution of Neutrons Scattered from Deuterium below 2 MeV, ND2013, NDS 119 (2014) 98
R. Nolte, et al., Measurement of the differential neutron-deuteron scattering cross section in the energy range from 100 keV to 600 keV using a proportional counter, ERINDA workshop, CERN Proceedings 2014-002, p.187
G.J. Weisel, et al., Neutron-deuteron analyzing power data at En=22.5 MeV (of interest to theoretical models for evaluations), PRC 89 (2014) 054001, EXFOR 14395
E. Pirovano, et al., Backward-forward reaction asymmetry of neutron elastic scattering on deuterium, PRC 95 (2017) 024601, EXFOR 23335
E. Pirovano, et al., Measurement of the angular distribution of neutrons scattered from deuterium below 3 MeV, EPJ Web of Conferences 239 (2020) 01016

Theory/Evaluation

J.P. Svenne, et al., Re-evaluating low-energy neutron-deuteron elastic scattering using three-nucleon theory, ND2007 proceedings, EDP Sciences p.243
D. Brown et al., ENDF/B-VIII.0: The 8th Major Release of the Nuclear Reaction Data Library with CIELO-project Cross Sections, New Standards and Thermal Scattering Data, NDS 148 (2018) 1

Validation

D. Roubtsov, et al., Reactivity Impact of 2H and 16O Elastic Scattering Nuclear Data on Critical Systems with Heavy Water, ND2013, NDS 118 (2014) 414

Additional file attached:AECL Final Technical Report.pdf
Additional file attached:Full_paper_152003.pdf

Request ID 12 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

92-U-235 (n,g) SIG,RP 100 eV-1 MeV 3 Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fission FBR, Thermal reactors 29-AUG-07 06-NOV-07

Requester: Dr Yasunobu NAGAYA at JAEA, JPN
Email: nagaya.yasunobu@jaea.go.jp

Project (context): JENDL, NEA WPEC Subgroup 29

Impact:
U-235 cross sections are very important not only for major thermal reactors but for FBRs because lots of critical experiments for FBRs have been performed at critical assemblies where UO2 fuels are used as driver fuels. Experimental data obtained at such critical assemblies have a great impact on design work for FBRs. Recent studies show that calculated sodium void reactivity worths for BFS experiments underestimate the experimental results by 30-50% [1].
The significant discrepancies not only exceed the target accuracy of 20% for a FBR design but also deteriorate the design accuracy estimated with the cross-section adjustment and bias factor techniques. Thus such experimental data cannot be employed in these techniques.

Accuracy:
The requested accuracies (relative one standard deviation) are given for energy-averaged cross sections as follows:
Energy interval and accuracy
100eV - 500eV: 5%
500eV - 1keV: 5%
1keV -2.25keV: 5%
2.25keV- 5keV: 8%
5keV - 10keV: 8%
10keV - 20keV: 8%
20keV - 30keV: 8%
30keV - 40keV: 3%
40keV - 90keV: 3%
90keV -200keV: 3%
200keV-400keV: 3%
400keV-900keV: 3%
900keV - 1MeV: 3%
(It is assumed that the resolved resonance region is below 2.25 keV and the unresolved resonance region is between 2.25 keV and 30 keV. The boundaries for the resonance regions are the same as for JENDL-3.3.)

Justification document:
Reference 1: first attached document, O. Iwamoto, "WPEC Subgroup Proposal" JAEA, March 9 (2007).
Reference 2: second attached document, viewgraph for Dr. Iwamoto's proposal at the 19th WPEC meeting.

Comment from requester:
The re-evaluation of U-235 cross sections has been already proposed at the 19th WPEC meeting on 18 - 20 April 2007, at the NEA Headquarters, Issy-les-Moulineaux, France.

Review comment:
The proposal seems well motivated. Concerns were expressed in view of the recent changes to the evaluation that emerged from the activities of NEA/WPEC Subgroup 22 "Nuclear Data for Improved LEU-LWR Reactivity Predictions" and ENDF/B-VII benchmarking. The wider impact that new evaluations of U-235 will have, should be considered and duly accounted for by new efforts. Although, the sensitivity of the cross section for the target application is well argued, the documentation does not reveal if the problem must be uniquely attributed to the capture cross section of U-235 in the specified energy range.

Entry Status:
Work in progress (as of SG-C review of May 2018)
Completed (as of SG-C review of June 2019) - The request was related to an issue in the keV region identified by the JENDL project in the early 2000's. Some preliminary evaluation work was performed in the framework of WPEC/SG29 [Iwamoto:2011]. The new measurements performed at LANSCE [Jandel:2012], RPI [Danon:2017] and n_TOF [Balibrea:2017] have been used in the CIELO evaluation [Capote:2018]. The issue is now solved in all major libraries (JENDL-4.0, JEFF-3.3, ENDF/B-VIII.0).

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

M. Jandel et al., New Precision Measurements of the 235U(n,g) Cross Section, PRL 109 (2012) 202506, EXFOR 14149
A. Wallner et al., Novel Method to Study Neutron Capture of 235U and 238U Simultaneously at keV Energies, Phys. Rev. Lett. 112 (2014) 192501, EXFOR 23170
J. Balibrea et al., Measurement of the neutron capture cross section of the fissile isotope 235U with the CERN n_TOF Total Absorption Calorimeter and a fission tagging based on Micromegas detectors, NDS 119 (2014) 10
Y. Danon, et al., Simultaneous measurement of 235U fission and capture cross sections from 0.01 eV to 3 keV using a gamma multiplicity detector, Nucl. Sci. and Eng. 187 (2017) 191
J. Balibrea et al., Measurement of the neutron capture cross section of the fissile isotope 235U with the CERN n TOF total absorption calorimeter and a fission tagging based on micromegas detectors, EPJ Conferences 146 (2017) 11021

Theory/Evaluation

R. Capote et al., IAEA CIELO Evaluation of Neutron-induced Reactions on 235U and 238U Targets, NDS 148 (2018) 254

Validation

O. Iwamoto et al., Uranium-235 Capture Cross-section in the keV to MeV Energy Region, International evaluation cooperation, Report NEA/WPEC-29, OECD NEA (2011)
M. Salvatores, et al., Methods and Issues for the Combined Use of Integral Experiments and Covariance Data: Results of a NEA International Collaborative Study, Nuclear Data Sheets 118 (2014) 38
G. Palmiotti, et al., Combined Use of Integral Experiments and Covariance Data, Nuclear Data Sheets 118 (2014) 596

Additional file attached:U235proposal.pdf
Additional file attached:Viewgraph.U235proposal.pdf

Request ID 15 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

95-AM-241 (n,g),(n,tot) SIG Thermal-Fast See details

Field Subfield Date Request created Date Request accepted Ongoing action

Fission LWR, Thermal 08-NOV-07 10-SEP-08 Y

Requester: Dr Osamu IWAMOTO at JAEA, JPN
Email: iwamoto.osamu@jaea.go.jp

Project (context): JENDL and WPEC subgroup 26

Impact:
The thermal value for the total cross section is inconsistent with the best value for the capture cross section. This inconsistency should be removed (JENDL). Current inconsistencies in the measured total cross section for the main low energy resonances should be removed and a capture measurement should be made to demonstrate consistency.

Design phases of selected reactor and fuel cycle concepts require improved data and methods in order to reduce margins for both economical and safety reasons. A first indicative nuclear data target accuracy assessment was made within WPEC Subgroup 26 (SG-26). The assessment indicated a list of nuclear data priorities for each of the systems considered (ABTR, SFR, EPR, GFR, LFR, ADMAB, VHTR, EPR). These nuclear data priorities should all be addressed to meet target accuracy requirements for the integral parameters characterizing those systems (see the accompanying requests originating from SG-26).

Accuracy:
For JENDL: A new measurement with a total uncertainty of 5% for the thermal total cross section would be required to resolve the issue.
For SG-26: Target accuracies are specified per system and per energy group when they are not met by the BOLNA estimate of the current (initial) uncertainties.

Energy Range Uncertainty (%)

Initial GFR ADMAB

67.4 -183 keV 7 4 2

24.8 -67.4 keV 8 3 2

9.12 -24.8 keV 7 3 2

2.03 -9.12 keV 7 3 2

0.454-2.03 keV 7 3 3

Justification document:
[1] Toru YAMAMOTO, "Analysis of Core Physics Experiments of High Moderation Full MOX LWR", Proc. of the 2005 Symposium on Nuclear Data, February 2-3, 2006, JAEA, Tokai, Japan, pp.7-13, JAEA-Conf 2006-009 (2006). (See attached document)
OECD/NEA WPEC Subgroup 26 Final Report: "Uncertainty and Target Accuracy Assessment for Innovative Systems Using Recent Covariance Data Evaluations" (Link to WPEC Subgroup 26 Report in PDF format, 6 Mb).

Comment from requester:
Given the present state of knowledge the above target accuracies are very tight. However, any attempt that significantly contributes to reducing the present accuracy for this quantity is strongly encouraged. Any such attempt will significantly enhance the accuracy with which reactor integral parameters may be estimated and will therefore impact economic and safety margins.

Review comment:
New experimental work is ongoing at IRMM in collaboration with CEA. Recent capture measurements have taken place at Los Alamos. There appear to be no large discrepancies in thermal capture measurements dating from 2000 as long as it is clearly distinguished whether the isomer contribution is included or not. Sample material available at IRMM is not compatible with an accurate measurement of the total cross section at thermal energy.

Entry Status:
Work in progress (as of SG-C review of May 2018)
Completed at thermal energies (as of SG-C review of May 2022) - SG41 has reviewed all available data, addressed discrepancies and produced recommendations for Am-241 nuclear data. These data have been incorporated into new evaluations.
Work in progress at fast energies (as of SG-C review of May 2022)

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

S. Nakamura et al., Thermal-Neutron Capture Cross Section and Resonance Integral of Americium-241, JNST 44 (2007) 1500, EXFOR 22998
M. Jandel et al., Neutron capture cross section of 241Am, PRC 78 (2008) 034609, EXFOR 14209
C. Lampoudis et al., Neutron transmission and capture cross section measurements for 241Am at the GELINA facility, Eur. Phys. J. Plus (2013) 128:86, EXFOR 23139
K. Fraval et al., Measurement and analysis of the 241Am(n,g) cross section with liquid scintillator detectors using time-of-flight spectroscopy at the n_TOF facility at CERN, PRC 89 (2014) 044609, EXFOR 23237
H. Harada et al., Capture Cross-section Measurement of 241Am(n,g) at J-PARC/MLF/ANNRI, NDS 119 (2014) 61, EXFOR 23172
K. Terada et al., Measurements of gamma-ray emission probabilities of 241,243Am and 239Np, JNST 53 (2016) 1881
K. Hirose et al., Simultaneous measurement of neutron-induced fission and capture cross sections for 241Am at neutron energies below fission threshold, NIM A 856 (2017) 133, EXFOR 23338
K. Terada et al., Measurements of neutron total and capture cross sections of 241Am with ANNRI at J-PARC, Journal of Nuclear Science and Technology 55 (2018) 1198
E. Mendoza et al., Measurement and analysis of the 241Am neutron capture cross section at the n_TOF facility at CERN, PRC 97 (2018) 054616
New capture measurement performed in 2017 at n_TOF EAR2

Theory/Evaluation

G. Noguere et al., Partial-wave analysis of n+Am-241 reaction cross sections in the resonance region, PRC 92 (2015) 014607
K. Mizuyama et al., Correction of the thermal neutron capture cross section of 241Am obtained by the Westcott convention, JNST 54 (2017) 74
G. Zerovnik et al., Improving nuclear data accuracy of 241Am and 237Np capture cross sections, EPJ Conferences 146 (2017) 11035
H. Harada et al., Improving nuclear data accuracy of the Am-241 capture cross-section, International Evaluation Cooperation, Volume 41, NEA/WPEC-41, report NEA/NSC/R(2020)2, 2020

Additional file attached:Yamamoto_T(MOX-LWR)2006.pdf
Additional file attached:

Request ID 18 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

92-U-238 (n,inl) SIG 65 keV-20 MeV Emis spec. See details Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fission Fast Reactors EFR,SFR,ABTR... 28-MAR-08 11-SEP-08 Y

Requester: Prof. Massimo SALVATORES at CADARACHE, FR
Email:

Project (context): NEA WPEC Subgroup 26

Impact:
Design phases of selected reactor and fuel cycle concepts require improved data and methods in order to reduce margins for both economical and safety reasons. A first indicative nuclear data target accuracy assessment was made within WPEC Subgroup 26 (SG-26). The assessment indicated a list of nuclear data priorities for each of the systems considered (ABTR, SFR, EPR, GFR, LFR, ADMAB, VHTR, EPR). These nuclear data priorities should all be addressed to meet target accuracy requirements for the integral parameters characterizing those systems (see the accompanying requests originating from SG-26).

The request for improved cross sections and emission spectra and their accuracies for ²³⁸U(n,inel) is an important issue that emerges for five of the eight cases studied. The most stringent requirements for this case arise from the GFR and the LFR.
Improvements of the nuclear data for ²³⁸U(n,inel) are important for estimates of k_eff for the GFR, LFR, ABTR and SFR (in order of significance), the peak power of a GFR and the void coefficient of an SFR.

Accuracy:
Target accuracies are specified per system and per energy group when they are not met by the BOLNA estimate of the current (initial) uncertainties.

Energy Range Initial versus target uncertainties (%)

Initial ABTR SFR EFR GFR LFR

6.07-19.6 MeV 29 12 7

2.23-6.07 MeV 20 3 5 4 2 3

1.35-2.23 MeV 21 4 5 4 2 2

0.498-1.35 MeV 12 7 6 5 2 2

67.4-183 keV 11 7 9 7 4

Justification document:
OECD/NEA WPEC Subgroup 26 Final Report: "Uncertainty and Target Accuracy Assessment for Innovative Systems Using Recent Covariance Data Evaluations" (Link to WPEC Subgroup 26 Report in PDF format, 6 Mb).

Review comment:
See appendix A of the attached report. This request is of high priority.

Entry Status:
Work in progress (as of SG-C review of May 2018)

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

M. Kerveno et al., (n,xn gamma) reaction cross section measurements for (n,xn) reaction studies, EPJ Conferences 42 (2013) 01005, EXFOR 22795
A.M. Daskalakis et al., Quasi-differential neutron scattering from 238U from 0.5 to 20 MeV, Annals of Nuclear Energy 73 (2014) 455
M. Kerveno, et al., From gamma emissions to (n,xn) cross sections of interest: the role of GAINS and GRAPhEME in nuclear reaction modelling, Eur. Phys. J. A, 51 12 (2015) 167
M. Kerveno, et al., Measurement of 238U(n,n'γ) cross section data and their impact on reaction models, Phys. Rev. C 104 (2021) 044605

Theory/Evaluation

A. Santamarina et al., Improvement of 238U Inelastic Scattering Cross Section for an Accurate Calculation of Large Commercial Reactors, ND2013, Nuclear Data Sheets 118 (2014) 118-121
R. Capote et al., IAEA CIELO Evaluation of Neutron-induced Reactions on 235U and 238U Targets, NDS 148 (2018) 254

Validation

M. Salvatores, et al., Methods and Issues for the Combined Use of Integral Experiments and Covariance Data: Results of a NEA International Collaborative Study, Nuclear Data Sheets 118 (2014) 38
G. Palmiotti, et al., Combined Use of Integral Experiments and Covariance Data, Nuclear Data Sheets 118 (2014) 596

Additional file attached:SG26-report.html
Additional file attached:

Request ID 19 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

94-PU-238 (n,f) SIG 9 keV-6 MeV See details Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fission Fast Reactors (ADMAB) 31-MAR-08 11-SEP-08 Y

Requester: Prof. Massimo SALVATORES at CADARACHE, FR
Email:

Project (context): NEA WPEC Subgroup 26

Impact:
Design phases of selected reactor and fuel cycle concepts require improved data and methods in order to reduce margins for both economical and safety reasons. A first indicative nuclear data target accuracy assessment was made within WPEC Subgroup 26 (SG-26). The assessment indicated a list of nuclear data priorities for each of the systems considered (ABTR, SFR, EPR, GFR, LFR, ADMAB, VHTR, EPR). These nuclear data priorities should all be addressed to meet target accuracy requirements for the integral parameters characterizing those systems (see the accompanying requests originating from SG-26).

The request for the improved cross section and uncertainties for ²³⁸Pu(n,f) emerges for five of the eight cases studied. The most stringent requirements for this case arise from the SFR, LFR and ADMAB.
Improvements of the nuclear data for ²³⁸Pu(n,f) are important for estimates of k_eff for the SFR, LFR, ADMAB and GFR (in order of significance), the peak power of ADMAB and the void coefficient of an SFR.

Requested accuracy is required to meet target accuracy for burnup for an Accelerator-Driven Minor Actinides Burner (ADMAB). Details are provided in the SG-26 report: "Uncertainty and Target Accuracy Assessment for Innovative Systems Using Recent Covariance Data Evaluations" (link to WPEC Subgroup 26 Report in PDF format, 6 Mb).

Accuracy:
Target accuracies are specified per system and per energy group when they are not met by the BOLNA estimate of the current (initial) uncertainties.

Energy Range Initial versus target uncertainties (%)

Initial SFR EFR GFR LFR ADMAB

2.23 - 6.07 MeV 21 6 7 8 7

1.35 - 2.23 MeV 34 6 24 8 7 6

0.498 - 1.35 MeV 17 3 10 5 3 3

183 - 498 keV 17 4 12 6 3 4

67.4 - 183 keV 9 5 5

24.8 - 67.4 keV 12 6 7 6

9.12 - 24.8 keV 11 7 7 7

Justification document:
OECD/NEA WPEC Subgroup 26 Final Report: "Uncertainty and Target Accuracy Assessment for Innovative Systems Using Recent Covariance Data Evaluations" (link to WPEC Subgroup 26 Report in PDF format, 6 Mb).

Review comment:

Entry Status:
Work in progress (as of SG-C review of May 2018)

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

T. Granier et al., New measurement of the 238Pu(n,f) cross-section, AIP Conf. Proc. 1175 (2009) 227, EXFOR 14273
J.J. Ressler et al., Surrogate measurement of the 238Pu(n,f) cross section, PRC 83 (2011) 054610, EXFOR 14292
R.O. Hughes et al., 236Pu(n,f), 237Pu(n,f), and 238Pu(n,f) cross sections deduced from (p,t), (p,d), and (p,p') surrogate reactions, PRC 90 (2014) 014304, EXFOR 14396
A. Pal et al., Determination of 238Pu(n,f) and 236Np(n,f) cross sections using surrogate reactions, PRC 91 (2015) 054618, EXFOR 33095
Ongoing work by a CENBG-CEA-IPNO+ collaboration on surrogate measurements

Theory/Evaluation

M.B. Chadwick et al., ENDF/B-VII.1 Nuclear Data for Science and Technology: Cross Sections, Covariances, Fission Product Yields and Decay Data, p.2937 in NDS 112 (2011) 2887
Pu-238 evaluation was proposed to be part of INDEN (CIELO follow-up) initial program of work (as of Dec. 2017)

Validation

G. Palmiotti, et al., Combined Use of Integral Experiments and Covariance Data, Nuclear Data Sheets 118 (2014) 596

Additional file attached:SG26-report.html
Additional file attached:

Request ID 21 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

95-AM-241 (n,f) SIG 180 keV-20 MeV See details Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fission Fast Reactors (ADMAB) 31-MAR-08 11-SEP-08 Y

Requester: Prof. Massimo SALVATORES at CADARACHE, FR
Email:

Project (context): NEA WPEC Subgroup 26

Impact:
Design phases of selected reactor and fuel cycle concepts require improved data and methods in order to reduce margins for both economical and safety reasons. A first indicative nuclear data target accuracy assessment was made within WPEC Subgroup 26 (SG-26). The assessment indicated a list of nuclear data priorities for each of the systems considered (ABTR, SFR, EPR, GFR, LFR, ADMAB, VHTR, EPR). These nuclear data priorities should all be addressed to meet target accuracy requirements for the integral parameters characterizing those systems (see the accompanying requests originating from SG-26).

The request for improved cross sections and emission spectra and their accuracies for ²⁴¹Am(n,f) emerges for four of the eight cases studied. The most stringent requirements for this case arises for the ADMAB, while for the SFR and LFR the needs are nearly met.

Requested accuracy is required to meet target accuracy for k_eff for Accelerator-Driven Minor Actinides Burner (ADMAB). Details are provided in the OECD/NEA WPEC Subgroup 26 Final Report: "Uncertainty and Target Accuracy Assessment for Innovative Systems Using Recent Covariance Data Evaluations" (link to WPEC Subgroup 26 Report in PDF format, 6 Mb).

Accuracy:
Target accuracies are specified per system and per energy group when they are not met by the BOLNA estimate of the current (initial) uncertainties.

Energy Range Initial versus target uncertainties (%)

Initial SFR GFR LFR ADMAB

6.07 - 19.6 MeV 13 6

2.23 - 6.07 MeV 12 7 3 2

1.35 - 2.23 MeV 10 6 3 1

0.498 - 1.35 MeV 8 6 3 5 1

183 - 498 keV 8 4

Justification document:
OECD/NEA WPEC Subgroup 26 Final Report: "Uncertainty and Target Accuracy Assessment for Innovative Systems Using Recent Covariance Data Evaluations" (link to WPEC Subgroup 26 Report in PDF format, 6 Mb).

Review comment:
A collaboration between CENBG, IPN-Orsay and CEA have taken data for the reaction ²⁴³Am(³He,af) that may yield the fission probability of ²⁴²Am. ²⁴²Am is the compound nucleus for the ²⁴¹Am(n,f) reaction. A theoretical estimate of the compound nucleus formation cross section for the latter reaction will than allow to infer the fission cross section. The final accuracy may be sufficient for 2-3 of the four systems.

Entry Status:
Work in progress (as of SG-C review of May 2018)
Pending new evaluation or validation (as of SG-C review of June 2019)

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

G. Kessedjian et al., Neutron-induced fission cross sections of short-lived actinides with the surrogate reaction method, Phys. Lett. B 692 (2010) 297, EXFOR 23076
F. Belloni, et al., Measurement of the neutron-induced fission cross-section of 241Am at the time-of-flight facility n_TOF, EPJ A 49 (2013) 2, EXFOR 23148
K. Hirose et al., Simultaneous measurement of neutron-induced fission and capture cross sections for 241Am at neutron energies below fission threshold, NIM A856 (2017) 133, EXFOR 23338
New measurement performed at n_TOF EAR2

Theory/Evaluation

P. Talou et al., Improved Evaluations of Neutron-Induced Reactions on Americium Isotopes, NSE 155 (2007) 84

Validation

G. Palmiotti, et al., Combined Use of Integral Experiments and Covariance Data, Nuclear Data Sheets 118 (2014) 596

Additional file attached:SG26-report.html
Additional file attached:

Request ID 22 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

95-AM-242M (n,f) SIG 0.5 keV-6 MeV See details Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fission Fast Reactors (SFR) 31-MAR-08 11-SEP-08 Y

Requester: Prof. Massimo SALVATORES at CADARACHE, FR
Email:

Project (context): NEA WPEC Subgroup 26

Impact:
Design phases of selected reactor and fuel cycle concepts require improved data and methods in order to reduce margins for both economical and safety reasons. A first indicative nuclear data target accuracy assessment was made within WPEC Subgroup 26 (SG-26). The assessment indicated a list of nuclear data priorities for each of the systems considered (ABTR, SFR, EPR, GFR, LFR, ADMAB, VHTR, EPR). These nuclear data priorities should all be addressed to meet target accuracy requirements for the integral parameters characterizing those systems (see the accompanying requests originating from SG-26).

Requested accuracy is required to meet target accuracy for k_eff for Sodium-cooled Fast Reactor in a TRU burning configuration, i.e., with a Conversion Ratio CR<1 (SFR). Details are provided in the OECD/NEA WPEC Subgroup 26 Final Report: "Uncertainty and Target Accuracy Assessment for Innovative Systems Using Recent Covariance Data Evaluations" (link to WPEC Subgroup 26 Report in PDF format, 6 Mb).

Accuracy:
Target accuracies are specified per system and per energy group when they are not met by the BOLNA estimate of the current (initial) uncertainties.

Energy Range Initial versus target uncertainties (%)

Initial SFR LFR ADMAB

2.23 - 6.07 MeV 23 8

1.35 - 2.23 MeV 20 8

0.498- 1.35 MeV 17 4 6

83 - 498 - keV 17 3 8 5

67.4 - 183 - keV 17 3 5

24.8 - 67.4 keV 14 4 6

9.12 - 24.8 keV 12 4 6

2.03 - 9.12 keV 12 7

0.454- 2.03 keV 12 5

Justification document:
OECD/NEA WPEC Subgroup 26 Final Report: "Uncertainty and Target Accuracy Assessment for Innovative Systems Using Recent Covariance Data Evaluations" (link to WPEC Subgroup 26 Report in PDF format, 6 Mb).

Comment from requester:
SFR: Sodium-cooled Fast Reactor in a TRU burning configuration, i.e., with a Conversion Ratio CR<1
EFR: European Fast Reactor with full recycling of MA and CR~1
GFR: Gas-cooled Fast Reactor also with full recycling of MA
LFR: Lead-cooled Fast Reactor as defined for an IAEA benchmark
ABTR: Advanced Burner Test Reactor Na-cooled core, recently studied within the GNEP initiative
ADMAB: Accelerator-Driven Minor Actinides Burner
PWR: Pressurized Water Reactor

Given the present state of knowledge the above target accuracies are very tight. However, any attempt that significantly contributes to reducing the present accuracy for this quantity is strongly encouraged. Any such attempt will significantly enhance the accuracy with which reactor integral parameters may be estimated and will therefore impact economic and safety margins.

Review comment:

Entry Status:
Work in progress (as of SG-C review of May 2018)

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

T. Kai et al., Measurements of neutron induced fission cross-section for 242mAm from 0.003 eV to 10 keV using lead slowing-down spectrometer, thermal neutron facility and time-of-flight method, Annals of Nuclear Energy 28 (2001) 723, EXFOR 22644
K. Hirose et al., Fission cross-section measurements of 237Np, 242mAm, and 245Cm with lead slowing-down neutron spectrometer, JNST 49 (2012) 1057, EXFOR 23186
M.Q. Buckner et al., Comprehensive 242mAm neutron-induced reaction cross sections and resonance parameters, PRC 95 (2017) 061602(R), EXFOR 14471

Theory/Evaluation

P. Talou et al., Improved Evaluations of Neutron-Induced Reactions on Americium Isotopes, NSE 155 (2007) 84

Validation

G. Palmiotti, et al., Combined Use of Integral Experiments and Covariance Data, Nuclear Data Sheets 118 (2014) 596

Additional file attached:SG26-report.html
Additional file attached:

Request ID 25 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

96-CM-244 (n,f) SIG 65 keV-6 MeV See details Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fission Fast Reactors (ADMAB) 04-APR-08 12-SEP-08 Y

Requester: Prof. Massimo SALVATORES at CADARACHE, FR
Email:

Project (context): NEA WPEC Subgroup 26

Impact:
Requested accuracy is required to meet target accuracies for k_eff, peak power and burnup for the Accelerator-Driven Minor Actinides Burner (ADMAB). Details are provided in the OECD/NEA WPEC Subgroup 26 Final Report: "Uncertainty and Target Accuracy Assessment for Innovative Systems Using Recent Covariance Data Evaluations" (Final Draft attached).

Accuracy:
Target accuracies are specified per system and per energy group when they are not met by the BOLNA estimate of the current (initial) uncertainties.

Energy Range Initial versus target uncertainties (%)

Initial SFR EFR GFR LFR ADMAB

6.07 - 2.23 MeV 31 8 12 3

2.23 - 1.35 MeV 44 8 13 14 3

1.35 - 0.498 MeV 50 5 20 8 6 2

498 - 183 keV 37 12 4

183 - 67.4 keV 48 7

Justification document:
OECD/NEA WPEC Subgroup 26 Final Report: "Uncertainty and Target Accuracy Assessment for Innovative Systems Using Recent Covariance Data Evaluations" (link to WPEC Subgroup 26 Report in PDF format, 6 Mb).

Review comment:
Experimentally the fission probability of the compound nucleus (²⁴⁵Cm) may be studied in detail through the use of a transfer reaction. The fission cross section for n+²⁴⁴Cm may then be inferred from a theoretical estimate of the compound nucleus formation cross section. Probably, this will be adequate for the EFR and GFR requirements and it could be sufficient for the SFR and LFR, as well.

Entry Status:
Work in progress (as of SG-C review of May 2018)

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

B.I. Fursov, Fast neutron induced fission cross sections of some minor actinides, ND1997 Proceedings, p.488 (1997), EXFOR 41343

Theory/Evaluation

K. Shibata et al., JENDL-4.0: A New Library for Nuclear Science and Engineering, J. Nucl. Sci. Technol. 48 (2011) 1

Validation

G. Palmiotti, et al., Combined Use of Integral Experiments and Covariance Data, Nuclear Data Sheets 118 (2014) 596

Additional file attached:SG26-report.html
Additional file attached:

Request ID 27 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

96-CM-245 (n,f) SIG 0.5 keV-6 MeV See details Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fission Fast Reactors (ADMAB) 04-APR-08 12-SEP-08 Y

Requester: Prof. Massimo SALVATORES at CADARACHE, FR
Email:

Project (context): NEA WPEC Subgroup 26

Impact:
Design phases of selected reactor and fuel cycle concepts require improved data and methods in order to reduce margins for both economical and safety reasons. A first indicative nuclear data target accuracy assessment was made within WPEC Subgroup 26 (SG-26). The assessment indicated a list of nuclear data priorities for each of the systems considered (ABTR, SFR, EPR, GFR, LFR, ADMAB, VHTR, EPR). These nuclear data priorities should all be addressed to meet target accuracy requirements for the integral parameters characterizing those systems (see the accompanying requests originating from SG-26).

Requested accuracy is required to meet target accuracies for k_eff, peak power and burnup for the Accelerator-Driven Minor Actinides Burner (ADMAB). Details are provided in the OECD/NEA WPEC Subgroup 26 Final Report: "Uncertainty and Target Accuracy Assessment for Innovative Systems Using Recent Covariance Data Evaluations" (link to WPEC Subgroup 26 Report in PDF format, 6 Mb).

Accuracy:
Target accuracies are specified per system and per energy group when they are not met by the BOLNA estimate of the current (initial) uncertainties.

Energy Range Initial versus target uncertainties (%)

Initial SFR EFR GFR LFR ADMAB

2.23 - 6.07 MeV 31 7

1.35 - 2.23 MeV 44 14 6

0.498 - 1.35 MeV 49 9 43 16 11 3

183 - 498 keV 37 7 13 7 3

67.4 - 183 keV 48 7 42 11 7 3

24.8 - 67.4 keV 27 9 11 9 3

9.12 - 24.8 keV 14 9 3

2.03 - 9.12 keV 13 4

0.454 - 2.03 keV 13 5

Justification document:
OECD/NEA WPEC Subgroup 26 Final Report: "Uncertainty and Target Accuracy Assessment for Innovative Systems Using Recent Covariance Data Evaluations" (link to WPEC Subgroup 26 Report in PDF format, 6 Mb).

Review comment:

Entry Status:
Work in progress (as of SG-C review of May 2018)

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

O. Serot et al., Measurement of the Neutron Induced Fission of 245Cm in the Resolved Resonance Region and Its Resonance Analysis, Journal of the Korean Physical Society 59 (2011) 1896, EXFOR 23120
K. Hirose et al., Fission cross-section measurements of 237Np, 242mAm, and 245Cm with lead slowing-down neutron spectrometer, JNST 49 (2012) 1057, EXFOR 23186
M. Calviani, et al., Neutron-induced fission cross section of 245Cm: New results from data taken at the time-of-flight facility n_TOF, PRC 85 (2012) 034616, EXFOR 23168

Theory/Evaluation

K. Shibata et al., JENDL-4.0: A New Library for Nuclear Science and Engineering, J. Nucl. Sci. Technol. 48 (2011) 1

Validation

G. Palmiotti, et al., Combined Use of Integral Experiments and Covariance Data, Nuclear Data Sheets 118 (2014) 596

Additional file attached:SG26-report.html
Additional file attached:

Request ID 29 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

11-NA-23 (n,inl) SIG 0.5 MeV-1.3 MeV Emis spec. See details Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fission Fast Reactors (SFR) 04-APR-08 12-SEP-08

Requester: Prof. Massimo SALVATORES at CADARACHE, FR
Email:

Project (context): NEA WPEC Subgroup 26

Impact:
Design phases of selected reactor and fuel cycle concepts require improved data and methods in order to reduce margins for both economical and safety reasons. A first indicative nuclear data target accuracy assessment was made within WPEC Subgroup 26 (SG-26). The assessment indicated a list of nuclear data priorities for each of the systems considered (ABTR, SFR, EPR, GFR, LFR, ADMAB, VHTR, EPR). These nuclear data priorities should all be addressed to meet target accuracy requirements for the integral parameters characterizing those systems (see the accompanying requests originating from SG-26).

Requested accuracy is required to meet target accuracy for void coefficient for the Sodium-cooled Fast Reactor in a TRU burning configuration, i.e., with a Conversion Ratio CR<1 (SFR). Details are provided in the OECD/NEA WPEC Subgroup 26 Final Report: "Uncertainty and Target Accuracy Assessment for Innovative Systems Using Recent Covariance Data Evaluations" (link to WPEC Subgroup 26 Report in PDF format, 6 Mb).

Accuracy:
Target accuracies are specified per system and per energy group when they are not met by the BOLNA estimate of the current (initial) uncertainties.

Energy Range Target versus initial uncertainties (%)

Initial ABTR SFR EFR

1.35 - 2.23 MeV 13 9

0.498 - 1.35 MeV 28 10 4 8

Justification document:
OECD/NEA WPEC Subgroup 26 Final Report: "Uncertainty and Target Accuracy Assessment for Innovative Systems Using Recent Covariance Data Evaluations" (link to WPEC Subgroup 26 Report in PDF format, 6 Mb).

Review comment:

Entry Status:
Work in progress (as of SG-C review of May 2018)
Pending new evaluation or validation (as of SG-C review of June 2019)
Completed (as of SG-C review of May 2021) - The Na-23 inelastic scattering cross section has been accurately measured at JRC-Geel [Rouki, 2012]. In the framework of the ASTRID SFR project a new evaluation based on both differential and integral information has been prepared for JEFF-3.2 [Archier, 2011, 2014] and adopted in JEFF-3.3 with uncertainties matching the request.

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

C. Rouki et al., High resolution measurement of neutron inelastic scattering cross-sections for 23Na, NIM A 672 (2012) 82, EXFOR 23137
J.R. Vanhoy et al., Neutron scattering differential cross-sections for 23Na from 1.5 to 4.5 MeV, Nucl. Phys. A 939 (2015) 121, EXFOR 14403

Theory/Evaluation

S. Kopecky and A. Plompen, R-matrix analysis of the total and inelastic scattering cross sections, EUR 25067 EN (2011)
M. Herman et al., COMMARA-2.0 Neutron Cross-Section Covariance Library, Report BNL- 94830-2011, Brookhaven National Laboratory (2011)
P. Archier et al., 23Na evaluation with CONRAD for fast reactor applications, Journal of Korean Physical Society 59 (2011) 915
P. Archier et al., New JEFF-3.2 Sodium Neutron Induced Cross-sections Evaluation for Neutron Fast Reactors Applications: from 0 to 20 MeV, NDS 118 (2014) 140
D. Rochman et al., On the evaluation of 23Na neutron-induced reactions and validations, NIM A 612 (2010) 374
Evaluation work in the framework of INDEN (CIELO follow-up), see Summary Report of the IAEA CM, 15-17 May 2019, Vienna, Report INDC(NDS)-0788
P. Tamagno, et al., New 23Na evaluation in the resolved resonance range taking into account both differential and double differential experiments, EPJ Conf. 239 (2020) 11006

Validation

M. Salvatores, et al., Methods and Issues for the Combined Use of Integral Experiments and Covariance Data: Results of a NEA International Collaborative Study, Nuclear Data Sheets 118 (2014) 38
G. Palmiotti, et al., Combined Use of Integral Experiments and Covariance Data, Nuclear Data Sheets 118 (2014) 596
Y.-K. Lee, E. Brun, Investigation of Nuclear Data Libraries with TRIPOLI-4 Monte Carlo Code for Sodium-cooled Fast Reactors, Nuclear Data Sheets 118 (2014) 433

Additional file attached:SG26-report.html
Additional file attached:

Request ID 32 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

94-PU-239 (n,g) SIG 0.1 eV-1.35 MeV See details Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fission Fast Reactors (VHTR) 04-APR-08 12-SEP-08 Y

Requester: Prof. Massimo SALVATORES at CADARACHE, FR
Email:

Project (context): NEA WPEC Subgroup 26

Impact:
Design phases of selected reactor and fuel cycle concepts require improved data and methods in order to reduce margins for both economical and safety reasons. A first indicative nuclear data target accuracy assessment was made within WPEC Subgroup 26 (SG-26). The assessment indicated a list of nuclear data priorities for each of the systems considered (ABTR, SFR, EPR, GFR, LFR, ADMAB, VHTR, EPR). These nuclear data priorities should all be addressed to meet target accuracy requirements for the integral parameters characterizing those systems (see the accompanying requests originating from SG-26).

Requested accuracy is required to meet target accuracy for k-eff for all fast reactors and the VHTR. Requirements become more stringent when inelastic cross sections would be allowed less stringent target accuracies (eg for inelastic of 243Am, 238U, but also 239Pu) Details are provided in the OECD/NEA WPEC Subgroup 26 Final Report: "Uncertainty and Target Accuracy Assessment for Innovative Systems Using Recent Covariance Data Evaluations" (link to WPEC Subgroup 26 Report in PDF format, 6 Mb).

Accuracy:

Energy Range Initial versus target uncertainties (%)

Initial ABTR SFR EFR GFR LFR ADMAB VHTR

λ=1 λ≠1,a λ≠1,b λ=1 λ≠1,a λ≠1,b λ=1 λ≠1,a λ=1 λ≠1,a λ=1 λ≠1,a λ=1 λ≠1,a λ=1 λ≠1,a

0.498 - 1.35 MeV 18 10 7 5 11 8 7 7 5 7 5 7 5

183 - 498 keV 12 6 4 3 7 5 4 5 4 4 3 5 4

67.4 - 183 keV 9 5 4 3 6 4 4 5 3 6 4 4 3 5 3

24.8 - 67.4 keV 10 6 4 3 7 5 4 5 4 5 4 5 3 5 4

9.12 - 24.8 keV 7 6 4 3 6 4 4 5 3 4 3 5 3 5 3

2.03 - 9.12 keV 16 7 5 4 7 5 4 4 3 3 2 6 4 4 3

0.10 - 0.54 eV 1.4 0.8 0.7

Justification document:
OECD/NEA WPEC Subgroup 26 Final Report: "Uncertainty and Target Accuracy Assessment for Innovative Systems Using Recent Covariance Data Evaluations" (link to WPEC Subgroup 26 Report in PDF format, 6 Mb).

Review comment:
See appendix A of the attached report.

Entry Status:
Work in progress (as of SG-C review of May 2018)

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

S. Mosby et al., Improved neutron capture cross section of Pu-239, PRC 89 (2014) 034610, EXFOR 14383
S. Mosby et al., 239Pu(n,g) from 10 eV to 1.3 MeV, NDS 148 (2018) 312
S. Mosby et al., Unifying measurement of 239Pu(n,g) in the keV to MeV energy regime, PRC 97 (2018) 041601
R. Perez Sanchez et al., Simultaneous Determination of Neutron-Induced Fission and Radiative Capture Cross Sections from Decay Probabilities Obtained with a Surrogate Reaction (to infer the neutron-induced fission and radiative capture cross sections of 239Pu), Phys. Rev. Lett. 125 (2020) 122502

Theory/Evaluation

C. De Saint Jean et al., Coordinated Evaluation of Plutonium-239 in the Resonance Region, International Evaluation Cooperation, Volume 34, NEA/WPEC-34, OECD (2014)
M.B. Chadwick et al., CIELO Collaboration Summary Results: International Evaluations of Neutron Reactions on Uranium, Plutonium, Iron, Oxygen and Hydrogen, NDS 148 (2018) 189

Validation

M. Salvatores, et al., Methods and Issues for the Combined Use of Integral Experiments and Covariance Data: Results of a NEA International Collaborative Study, Nuclear Data Sheets 118 (2014) 38
G. Palmiotti, et al., Combined Use of Integral Experiments and Covariance Data, Nuclear Data Sheets 118 (2014) 596

Additional file attached:SG26-report.html
Additional file attached:

Request ID 33 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

94-PU-241 (n,g) SIG 0.1 eV-1.35 MeV See details Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fission Fast Reactors (VHTR) 04-APR-08 12-SEP-08 Y

Requester: Prof. Massimo SALVATORES at CADARACHE, FR
Email:

Project (context): NEA WPEC Subgroup 26

Impact:
Design phases of selected reactor and fuel cycle concepts require improved data and methods in order to reduce margins for both economical and safety reasons. A first indicative nuclear data target accuracy assessment was made within WPEC Subgroup 26 (SG-26). The assessment indicated a list of nuclear data priorities for each of the systems considered (ABTR, SFR, EPR, GFR, LFR, ADMAB, VHTR, EPR). These nuclear data priorities should all be addressed to meet target accuracy requirements for the integral parameters characterizing those systems (see the accompanying requests originating from SG-26).

Requested accuracy is required to meet target accuracies for k_eff and burnup for the Very High Temperature Reactor (VHTR). Details are provided in the OECD/NEA WPEC Subgroup 26 Final Report: "Uncertainty and Target Accuracy Assessment for Innovative Systems Using Recent Covariance Data Evaluations" (link to WPEC Subgroup 26 Report in PDF format, 6 Mb).

Accuracy:
Target accuracies are specified per system and per energy group when they are not met by the BOLNA estimate of the current (initial) uncertainties. The weighting factor λ is explained in detail in the accompanying document. Changes from the reference value of λ=1 show the the possible allowance for other target uncertainties. Two cases (A and B) are distinguished for λ≠1 (see Table 24 of the report).

Energy Range Initial versus target uncertainties (%)

Initial SFR ADMAB VHTR PWR

λ=1 λ≠1,a λ≠1,b λ=1 λ=1 λ≠1,a λ=1 λ≠1,a

0.498 - 1.35 MeV 32 14 15 13 8

183 - 498 keV 21 11 11 10 7

0.10 - 0.54 eV 7 2 3 3 4

Justification document:
OECD/NEA WPEC Subgroup 26 Final Report: "Uncertainty and Target Accuracy Assessment for Innovative Systems Using Recent Covariance Data Evaluations" (link to WPEC Subgroup 26 Report in PDF format, 6 Mb).

Review comment:
See appendix A of the attached report.

Entry Status:
Work in progress (as of SG-C review of May 2018)

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Theory/Evaluation

H. Derrien et al., Reevaluation and Validation of the 241Pu Resonance Parameters in the Energy Range Thermal to 20 eV, NSE 150 (2005) 109
Pu-241 evaluation was proposed to be part of INDEN (CIELO follow-up) initial program of work (as of Dec. 2017)

Validation

M. Salvatores, et al., Methods and Issues for the Combined Use of Integral Experiments and Covariance Data: Results of a NEA International Collaborative Study, Nuclear Data Sheets 118 (2014) 38
G. Palmiotti, et al., Combined Use of Integral Experiments and Covariance Data, Nuclear Data Sheets 118 (2014) 596

Additional file attached:SG26-report.html
Additional file attached:

Request ID 34 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

26-FE-56 (n,inl) SIG 0.5 MeV-20 MeV Emis spec. See details Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fission ADMAB and SFR 04-APR-08 12-SEP-08 Y

Requester: Prof. Massimo SALVATORES at CADARACHE, FR
Email:

Project (context): NEA WPEC Subgroup 26

Impact:
Design phases of selected reactor and fuel cycle concepts require improved data and methods in order to reduce margins for both economical and safety reasons. A first indicative nuclear data target accuracy assessment was made within WPEC Subgroup 26 (SG-26). The assessment indicated a list of nuclear data priorities for each of the systems considered (ABTR, SFR, EPR, GFR, LFR, ADMAB, VHTR, EPR). These nuclear data priorities should all be addressed to meet target accuracy requirements for the integral parameters characterizing those systems (see the accompanying requests originating from SG-26).

Somewhat different requested accuracy is required to meet target accuracies for k_eff, peak power and void coefficient for the Accelerator-Driven Minor Actinides Burner (ADMAB) and for k_eff for the Sodium-cooled Fast Reactor in a TRU burning configuration, i.e., with a Conversion Ratio CR<1 (SFR). Details are provided in the OECD/NEA WPEC Subgroup 26 Final Report: "Uncertainty and Target Accuracy Assessment for Innovative Systems Using Recent Covariance Data Evaluations" (link to WPEC Subgroup 26 Report in PDF format, 6 Mb).

Accuracy:
Target accuracies are specified per system and per energy group when they are not met by the BOLNA estimate of the current (initial) uncertainties. The weighting factor λ is explained in detail in the accompanying document. Changes from the reference value of λ=1 show the the possible allowance for other target uncertainties. Two cases (A and B) are distinguished for λ≠1 (see Table 24 of the report).

Energy Range Initial versus target uncertainties (%)

Initial ABTR SFR EFR LFR ADMAB

λ=1 λ≠1,a λ≠1,b λ=1 λ≠1,a λ≠1,b λ=1 λ≠1,a λ=1 λ≠1,a λ=1 λ≠1,a

6.07 - 19.6 MeV 13 9 11 13

2.23 - 6.07 MeV 7 4 5 7 3 3

1.35 - 2.23 MeV 25 6 7 10 3 4 7 7 7 4 6 2 2

0.498 - 1.35 MeV 16 8 9 13 3 4 6 8 9 4 5 2 2

Justification document:
OECD/NEA WPEC Subgroup 26 Final Report: "Uncertainty and Target Accuracy Assessment for Innovative Systems Using Recent Covariance Data Evaluations" (link to WPEC Subgroup 26 Report in PDF format, 6 Mb).

Review comment:
Experimental work was recently completed at IRMM. The impact of the new experimental results is studied at CEA/Cadarache. Uncertainties below 5% will require a major further improvement.

Entry Status:
Work in progress (as of SG-C review of May 2018)

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

R.O. Nelson et al., Cross-section standards for neutron-induced gamma-ray production in the MeV energy range, ND2004, AIP Conference Proceedings 769 (2004) 838, EXFOR 14118
C.M. Castaneda et al., Gamma ray production cross sections from the bombardment of Mg, Al, Si, Ca and Fe with medium energy neutrons, NIM/B 260 (2007) 508, EXFOR 14151
Z. Wang et al., Study on coincidence measurement for 56Fe(n,xng) reaction cross section, Atomic Energy Science and Technology 47 (2013) 2177, EXFOR 32720
A. Negret et al., Cross-section measurements for the 56Fe(n,xng) reactions, PRC 90 (2014) 034602, EXFOR 23073
R. Beyer et al., Inelastic scattering of fast neutrons from excited states in 56Fe, NP A 927 (2014) 41, EXFOR 23134
A.M.Daskalakis et al., Quasi-differential elastic and inelastic neutron scattering from iron in the MeV energy range, Annals of Nuclear Energy 110 (2017) 603
Ongoing work at University of Kentucky, cf. J.R. Vanhoy et al., Differential Cross Section Measurements at the University of Kentucky -- Adventures in Analysis, NEMEA-7, NEA Report NEA/NSC/DOC(2014)13, p.85
related measurement by A. Negret, et al., Cross-section measurements for the 57Fe(n,ng)57Fe and 57Fe(n,2ng)56Fe reactions, PRC 96 (2017) 024620 - See section C which discusses the 847keV gamma production cross section in the 57Fe(n,2n) reaction. This contributes (above En=8-9 MeV) to the 847keV gamma production cross section in natFe(n,n') and therefore may represent a source of uncertainty for the 56Fe(n,inl) measurements performed with natFe targets.
related measurement by A. Olacel, et al., Neutron inelastic scattering on 54Fe, Eur. Phys. J. A 54 (2018) 183
E. Pirovano, et al., Cross section and neutron angular distribution measurements of neutron scattering on natural iron, PRC 99 (2019) 024601

Theory/Evaluation

M. Herman et al., Evaluation of Neutron Reactions on Iron Isotopes for CIELO and ENDF/B-VIII.0, NDS 148 (2018) 214
Ongoing work in the INDEN framework

Validation

C. Jouanne, Sensitivity of the Shielding Benchmarks on Variance-covariance Data for Scattering Angular Distributions, Nuclear Data Sheets 118 (2014) 384
I. Kodeli, A. Trkov, G. Zerovnik, Benchmark analysis of iron neutron cross-sections, Jozef Stefan Institute, Ljubljana, Slovenia, Report IJS-DP-11544 (2014)
M. Salvatores, et al., Methods and Issues for the Combined Use of Integral Experiments and Covariance Data: Results of a NEA International Collaborative Study, Nuclear Data Sheets 118 (2014) 38
G. Palmiotti, et al., Combined Use of Integral Experiments and Covariance Data, Nuclear Data Sheets 118 (2014) 596
A. Shaw, et al., Validation of Continuous-Energy ENDF/B-VIII.0 16O, 56Fe, and 63,65Cu Cross Sections for Nuclear Criticality Safety Applications, Nuclear Science and Engineering 195 (2021) 412

Additional file attached:SG26-report.html
Additional file attached:

Request ID 35 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

94-PU-241 (n,f) SIG 0.5 eV-1.35 MeV See details Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fission Fast and Thermal Reactors 04-APR-08 12-SEP-08 Y

Requester: Prof. Massimo SALVATORES at CADARACHE, FR
Email:

Project (context): NEA WPEC Subgroup 26

Impact:
Distinct requests for this fission cross section are made at higher energies for fast reactor applications and also at lower energies for thermal reactor applications. Requested accuracy is required to meet target accuracy for k-eff for the GFR, SFR, LFR and ABTR and to meet k-eff and burnup for EFR. Requested accuracy is also required to meet target accuracy for k-eff for the VHTR and k-eff and burnup for the PWR. Details are provided in the OECD/NEA WPEC Subgroup 26 Final Report: "Uncertainty and Target Accuracy Assessment for Innovative Systems Using Recent Covariance Data Evaluations" (Final Draft attached).

Accuracy:
Target accuracies are specified per system and per energy group when they are not met by the BOLNA estimate of the current (initial) uncertainties. The weighting factor λ is explained in detail in the accompanying document. Changes from the reference value of λ=1 show the the possible allowance for other target uncertainties. Two cases (A and B) are distinguished for λ≠1 (see Table 24 of the report).

Energy Range Initial versus target uncertainties (%)

Initial ABTR SFR EFR GFR LFR ADMAB VHTR EPR

λ=1 λ≠1,b λ=1 λ≠1,b λ=1 λ≠1,a λ=1 λ=1 λ=1 λ=1 λ≠1,a λ=1 λ≠1,a

0.498 - 1.35 MeV 17 12 9 3 3 8 7 4 4 2

183 - 498 keV 14 9 7 3 2 7 6 3 3 2

67.4 - 183 keV 20 9 7 3 2 6 5 3 3 2

24.8 - 67.4 keV 9 3 3 6 6 3 3 2

9.12 - 24.8 keV 11 4 3 7 6 3 4 2

2.03 - 9.12 keV 10 5 5 8 7 2 5 2

0.454 - 2.03 keV 13 4 4 7 6 3 3

22.6 - 454 eV 19 9 8 5 7 6 8 5 6

0.54 - 4.00 eV 27 9 12 8 10

Justification document:
OECD/NEA WPEC Subgroup 26 Final Report: "Uncertainty and Target Accuracy Assessment for Innovative Systems Using Recent Covariance Data Evaluations" (link to WPEC Subgroup 26 Report in PDF format, 6 Mb).

Review comment:
See appendix A of the attached report.

Entry Status:
Work in progress (as of SG-C review of May 2018)

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

F. Tovesson, T.S. Hill, Cross Sections for 239Pu(n,f) and 241Pu(n,f) in the Range En = 0.01 eV to 200 MeV, Nuclear Science and Engineering 165 (2010) 224, EXFOR 14271
V.V. Desai, Determination of 241Pu(n,f) cross sections by the surrogate-ratio method, PRC 87 (2013) 034604, EXFOR 33053

Theory/Evaluation

H. Derrien et al., Reevaluation and Validation of the 241Pu Resonance Parameters in the Energy Range Thermal to 20 eV, NSE 150 (2005) 109
Pu-241 evaluation was proposed to be part of INDEN (CIELO follow-up) initial program of work (as of Dec. 2017)

Validation

M. Salvatores, et al., Methods and Issues for the Combined Use of Integral Experiments and Covariance Data: Results of a NEA International Collaborative Study, Nuclear Data Sheets 118 (2014) 38
G. Palmiotti, et al., Combined Use of Integral Experiments and Covariance Data, Nuclear Data Sheets 118 (2014) 596

Additional file attached:SG26-report.html
Additional file attached:

Request ID 36 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

92-U-238 (n,g) SIG 20 eV-25 keV See details Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fission Fast and Thermal Reactors 15-SEP-08 15-SEP-08

Requester: Prof. Massimo SALVATORES at CADARACHE, FR
Email:

Project (context): CEA Cadarache

Accuracy:
Target accuracies are specified per system and per energy group when they are not met by the BOLNA estimate of the current (initial) uncertainties. The weighting factor λ is explained in detail in the accompanying document. Changes from the reference value of λ=1 show the the possible allowance for other target uncertainties. Two cases (A and B) are distinguished for λ≠1 (see Table 24 of the report).

Energy Range Initial versus target uncertainties (%)

Initial ABTR SFR EFR GFR LFR VHTR EPR

λ=1 λ≠1,a λ≠1,b λ=1 λ≠1,a λ≠1,b λ=1 λ≠1,a λ=1 λ≠1,a λ=1 λ≠1,a λ=1 λ≠1,a λ=1 λ≠1,a

9.12 - 24.8 keV 9 3 2 2 4 3 3 3 2 2 1 2 2 5 4

2.03 - 9.12 keV 3 1 1

22.6 - 454 eV 2 1 1 1 1

Justification document:
1. OECD/NEA WPEC Subgroup 26 Final Report: "Uncertainty and Target Accuracy Assessment for Innovative Systems Using Recent Covariance Data Evaluations" (link to WPEC Subgroup 26 Report in PDF format, 6 Mb).
2. OECD/NEA WPEC Subgroup 7 (SG-7) Final Report: "Nuclear data standards" (link to WPEC Subgroup 7 Report in PDF format, 450kb).

Review comment:
In this particular case high accuracy is required throughout the energy range. Only the groups shown above have initial uncertainties larger than the target uncertainties. The low initial uncertainty is a result of the standards evaluation (see SG-7 report above). Concerns have been raised that despite the excellent efforts of this subgroup an independent check is in order to verify the present view on required corrections to experimental work for the unresolved resonance range.

Entry Status:
Completed (as of SG-C review of May 2018) - New time-of-flight measurements have been performed worldwide, e.g., at LANSCE [Ullmann:2014], JRC-Geel [Kim:2016] and n_TOF [Mingrone:2017;Wright:2017]. These experimental data have been used in the CIELO evaluation [Sirakov:2017,Capote:2018] and for the evaluation of the standards [Carlson:2018]. The CIELO evaluated data have been adopted in ENDF/B-VIII.0 and JEFF-3.3; the evaluated uncertainties match the requested accuracy.

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

A. Wallner et al., Novel Method to Study Neutron Capture of 235U and 238U Simultaneously at keV Energies, PRL 112 (2014) 192501, EXFOR 23170
J.L. Ullmann, et al., Cross section and g-ray spectra for 238U(n,g) measured with the DANCE detector array at the Los Alamos Neutron Science Center, PRC 89 (2014) 034603, EXFOR 14310
H.I. Kim et al., Neutron capture cross section measurements for 238U in the resonance region at GELINA, EPJ A 52 (2016) 170, EXFOR 23302
F. Mingrone et al., Neutron capture cross section measurement of 238U at the CERN n_TOF facility in the energy region from 1 eV to 700 keV, PRC 95 (2017) 034604, EXFOR 23234
T. Wright et al., Measurement of the 238U(n,g) cross section up to 80 keV with the Total Absorption Calorimeter at the CERN n_TOF facility, PRC 96 (2017) 064601

Theory/Evaluation

H. Derrien et al., R-Matrix Analysis of 238U High-Resolution Neutron Transmissions and Capture Cross Sections in the Energy Range 0 to 20 keV, NSE 161 (2009) 131
R. Dagan et al., Impact of the Doppler Broadened Double Differential Cross Section on Observed Resonance Profiles, ND2013, NDS 118 (2014) 179
Kopecky et al., Status of Evaluated Data Files for 238U in the Resonance region, JRC Technical Report, EUR 27504 EN (2015)
I. Sirakov et al., Evaluation of cross sections for neutron interactions with 238U in the energy region between 5 keV and 150 keV, EPJ A 53 (2017) 199
R. Capote et al., IAEA CIELO Evaluation of Neutron-induced Reactions on 235U and 238U Targets, NDS 148 (2018) 254
A.D. Carlson et al., Evaluation of the Neutron Data Standards, NDS 148 (2018) 143

Validation

M. Salvatores, et al., Methods and Issues for the Combined Use of Integral Experiments and Covariance Data: Results of a NEA International Collaborative Study, Nuclear Data Sheets 118 (2014) 38
G. Palmiotti, et al., Combined Use of Integral Experiments and Covariance Data, Nuclear Data Sheets 118 (2014) 596

Additional file attached:SG26-report.html
Additional file attached:

Request ID 37 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

94-PU-240 (n,f) SIG 0.5 keV-5 MeV See details Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fission Fast Reactors 15-SEP-08 15-SEP-08 Y

Requester: Prof. Massimo SALVATORES at CADARACHE, FR
Email:

Project (context): CEA Cadarache

Accuracy:
Target accuracies are specified per system and per energy group when they are not met by the BOLNA estimate of the current (initial) uncertainties. The weighting factor λ is explained in detail in the accompanying document. Changes from the reference value of λ=1 show the the possible allowance for other target uncertainties. Two cases (A and B) are distinguished for λ≠1 (see Table 24 of the report).

Energy Range Initial versus target uncertainties (%)

Initial SFR EFR GFR LFR ADMAB

λ=1 λ≠1,a λ≠1,b λ=1 λ≠1,a λ=1 λ≠1,a λ=1 λ≠1,a λ=1 λ≠1,a

2.23 - 6.07 MeV 5 3 3 3 3 3 3 3

1.35 - 2.23 MeV 6 3 3 2 3 3 3 3 3 3

0.498 - 1.35 MeV 6 2 2 2 4 3 2 3 2 2 2 2

0.454 - 2.03 keV 22 13 13 11 9 10

Justification document:
OECD/NEA WPEC Subgroup 26 Final Report: "Uncertainty and Target Accuracy Assessment for Innovative Systems Using Recent Covariance Data Evaluations" (link to WPEC Subgroup 26 Report in PDF format, 6 Mb).

Review comment:

Entry Status:
Work in progress (as of SG-C review of May 2018)
Pending new evaluation or validation (as of SG-C review of May 2021)

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

A.B. Laptev et al., Int. Conf. on Fission and Properties of Neutron-Rich Nuclei, Sanibel Island, USA, p.462, 2007, EXFOR 41487
F. Tovesson et al., Neutron induced fission of 240,242Pu from 1 eV to 200 MeV, PRC 79 (2009) 014613, EXFOR 14223
P. Salvador et al., Neutron-induced fission cross section of 240Pu from 0.5 MeV to 3 MeV, PRC 92 (2015) 014620, EXFOR 23281
F. Belloni et al., Neutron induced fission cross section measurements of 240Pu and 242Pu, EPJ Conf. 146 (2017) 04062
A. Stamatopoulos et al., Investigation of the 240Pu(n,f) reaction at the n_TOF/EAR2 facility in the 9 meV-6 MeV range, PRC 102 (2020) 014616, EXFOR 23458
Ongoing work from a JRC-PTB-NPL collaboration and from a CENBG-CEA-JRC collaboration (ANDES and EMRP projects)

Theory/Evaluation

D. Brown et al., ENDF/B-VIII.0: The 8th Major Release of the Nuclear Reaction Data Library with CIELO-project Cross Sections, New Standards and Thermal Scattering Data, NDS 148 (2018) 1
Pu-240 evaluation was proposed to be part of INDEN (CIELO follow-up) initial program of work (as of Dec. 2017)

Validation

M. Salvatores, et al., Methods and Issues for the Combined Use of Integral Experiments and Covariance Data: Results of a NEA International Collaborative Study, Nuclear Data Sheets 118 (2014) 38
G. Palmiotti, et al., Combined Use of Integral Experiments and Covariance Data, Nuclear Data Sheets 118 (2014) 596

Additional file attached:SG26-report.html
Additional file attached:

Request ID 38 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

94-PU-240 (n,f) nubar 200 keV-2 MeV See details Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fission Fast Reactors 15-SEP-08 15-SEP-08 Y

Requester: Prof. Massimo SALVATORES at CADARACHE, FR
Email:

Project (context): CEA Cadarache

Accuracy:
Target accuracies are specified per system and per energy group when they are not met by the BOLNA estimate of the current (initial) uncertainties. The weighting factor λ is explained in detail in the accompanying document. Changes from the reference value of λ=1 show the the possible allowance for other target uncertainties. Two cases (A and B) are distinguished for λ≠1 (see Table 24 of the report).

Energy Range Initial versus target uncertainties (%)

Initial SFR EFR GFR LFR ADMAB

λ=1 λ≠1,a λ≠1,b λ=1 λ≠1,a λ=1 λ≠1,a λ=1 λ≠1,a λ=1 λ≠1,a

1.35 - 2.23 MeV 3 2 2 2

0.498 - 1.35 MeV 4 2 2 1 3 2 2 2 1 1 2 2

183 - 498 keV 5 3 3 3 3 3

Justification document:
OECD/NEA WPEC Subgroup 26 Final Report: "Uncertainty and Target Accuracy Assessment for Innovative Systems Using Recent Covariance Data Evaluations" (link to WPEC Subgroup 26 Report in PDF format, 6 Mb).

Review comment:

Entry Status:
Work in progress (as of SG-C review of May 2018)

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Theory/Evaluation

Pu-240 evaluation was proposed to be part of INDEN (CIELO follow-up) initial program of work (as of Dec. 2017)

Validation

M. Salvatores, et al., Methods and Issues for the Combined Use of Integral Experiments and Covariance Data: Results of a NEA International Collaborative Study, Nuclear Data Sheets 118 (2014) 38
G. Palmiotti, et al., Combined Use of Integral Experiments and Covariance Data, Nuclear Data Sheets 118 (2014) 596

Additional file attached:SG26-report.html
Additional file attached:

Request ID 39 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

94-PU-242 (n,f) SIG 200 keV-20 MeV See details Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fission Fast Reactors 15-SEP-08 15-SEP-08 Y

Requester: Prof. Massimo SALVATORES at CADARACHE, FR
Email:

Project (context): CEA Cadarache

Accuracy:
Target accuracies are specified per system and per energy group when they are not met by the BOLNA estimate of the current (initial) uncertainties. The weighting factor λ is explained in detail in the accompanying document. Changes from the reference value of λ=1 show the the possible allowance for other target uncertainties. Two cases (A and B) are distinguished for λ≠1 (see Table 24 of the report).

Energy Range Initial versus target uncertainties (%)

Initial SFR EFR GFR LFR ADMAB

λ=1 λ≠1,b λ=1 λ≠1,a λ=1 λ≠1,a λ=1 λ≠1,a λ=1

6.07 - 19.6 MeV 37 15 14

2.23 - 6.07 MeV 15 5 5 6 6 7 8 7

1.35 - 2.23 MeV 21 5 4 5 6 7 7 5

0.498 - 1.35 MeV 19 4 3 11 9 4 4 4 4 4

183 - 498 keV 19 9 8

Justification document:
OECD/NEA WPEC Subgroup 26 Final Report: "Uncertainty and Target Accuracy Assessment for Innovative Systems Using Recent Covariance Data Evaluations" (link to WPEC Subgroup 26 Report in PDF format, 6 Mb).

Review comment:

Entry Status:
Work in progress (as of SG-C review of May 2018)

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

F. Tovesson et al., Neutron induced fission of 240,242Pu from 1 eV to 200 MeV, PRC 79 (2009) 014613, EXFOR 14223
A. Tsinganis, et al., Measurement of the 242Pu(n,f) Cross Section at the CERN n_TOF Facility, NDS 119 (2014) 58-60
P. Salvador-Castineira, Neutron-induced fission cross sections of Pu242 from 0.3 MeV to 3 MeV, PRC 92 (2015) 044606, EXFOR 23280
C. Matei, et al., Absolute cross section measurements of neutron-induced fission of 242Pu from 1 to 2.5 MeV, PRC 95 (2017) 024606, EXFOR 23334
P. Marini, et al., 242Pu neutron-induced fission cross-section measurement from 1 to 2 MeV neutron energy, PRC 96 (2017) 054604
F. Belloni et al., Neutron induced fission cross section measurements of 240Pu and 242Pu, EPJ Conf. 146 (2017) 04062
T. Koegler et al., Fast-neutron-induced fission cross section of 242Pu measured at the neutron time-of-flight facility nELBE, PRC 99 (2019) 024604

Theory/Evaluation

M. Herman et al., COMMARA-2.0 Neutron Cross Section Covariance Library, Report BNL-94830-2011, Brookhaven National Laboratory (2011)
Pu-242 evaluation was proposed to be part of INDEN (CIELO follow-up) initial program of work (as of Dec. 2017)

Validation

G. Palmiotti, et al., Combined Use of Integral Experiments and Covariance Data, Nuclear Data Sheets 118 (2014) 596

Additional file attached:SG26-report.html
Additional file attached:

Request ID 40 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

14-SI-28 (n,inl) SIG 1.4 MeV-6 MeV See details Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fission Fast Reactors 15-SEP-08 15-SEP-08

Requester: Prof. Massimo SALVATORES at CADARACHE, FR
Email:

Project (context): CEA Cadarache

Justification document:
OECD/NEA WPEC Subgroup 26 Final Report: "Uncertainty and Target Accuracy Assessment for Innovative Systems Using Recent Covariance Data Evaluations" (link to WPEC Subgroup 26 Report in PDF format, 6 Mb).

Review comment:

Entry Status:
Completed (as of SG-C review of May 2018) - The measurement performed at JRC-Geel [Negret:2013] and the latest evaluations (JEFF-3.3, ENDF/B-VIII.0) all match the requested accuracy.

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

A. Negret et al., Cross sections for inelastic scattering of neutrons on 28Si and comparison with the 25Mg(a,n)28Si reaction, PRC 88 (2013) 034604, EXFOR 23173
A. Negret et al., Neutron inelastic scattering measurements for background assessment in neutrinoless double beta decay experiments, PRC 88 (2014) 027601

Theory/Evaluation

M. Herman et al., COMMARA-2.0 Neutron Cross Section Covariance Library, Report BNL-94830-2011, Brookhaven National Laboratory (2011)

Additional file attached:SG26-report.html
Additional file attached:

Request ID 41 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

82-PB-206 (n,inl) SIG 0.5 MeV-6 MeV See details Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fission Fast Reactors 15-SEP-08 15-SEP-08 Y

Requester: Prof. Massimo SALVATORES at CADARACHE, FR
Email:

Project (context): CEA Cadarache

Justification document:
OECD/NEA WPEC Subgroup 26 Final Report: "Uncertainty and Target Accuracy Assessment for Innovative Systems Using Recent Covariance Data Evaluations" (link to WPEC Subgroup 26 Report in PDF format, 6 Mb).

Review comment:
Data have been taken at IRMM for using the (n,n’g)-technique. Experimental results have been included in a new evaluation. The experimental uncertainties are better than 5% in most of the energy range of interest and therefore the request is nearly met. Complementary data for the neutron emission spectrum (angular distribution) would be of interest.

Entry Status:
Pending new evaluation or validation (as of SG-C review of May 2018)

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

L.C. Mihailescu et al., Neutron (n,xng) cross-section measurements for 52Cr, 209Bi, 206,207,208Pb from threshold up to 20 MeV, PhD thesis, Report EUR 22343 EN, European Communities (2006), EXFOR 23286
V.E. Guiseppe et al., Neutron inelastic scattering and reactions in natural Pb as a background in neutrinoless double-beta-decay experiments, PRC 79 (2009) 054604, EXFOR 14231
A. Negret, L.C. Mihailescu et al., Cross section measurements for neutron inelastic scattering and the (n, 2n gamma) reaction on 206Pb, PRC 91 (2015) 064618, EXFOR 23292
M. Kerveno et al., From gamma emissions to (n,xn) cross sections of interest: The role of GAINS and GRAPhEME in nuclear reaction modeling, EPJA 51 (2015) 167

Theory/Evaluation

D. Rochman and A. Koning, Pb and Bi neutron data libraries with full covariance evaluation and improved integral tests, NIM A 589 (2008) 85

Additional file attached:SG26-report.html
Additional file attached:

Request ID 42 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

82-PB-207 (n,inl) SIG 0.5 MeV-6 MeV See details Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fission Fast Reactors 15-SEP-08 15-SEP-08 Y

Requester: Prof. Massimo SALVATORES at CADARACHE, FR
Email:

Project (context): CEA Cadarache

Justification document:
OECD/NEA WPEC Subgroup 26 Final Report: "Uncertainty and Target Accuracy Assessment for Innovative Systems Using Recent Covariance Data Evaluations" (link to WPEC Subgroup 26 Report in PDF format, 6 Mb).

Entry Status:
Pending new evaluation or validation (as of SG-C review of May 2018)

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

L.C. Mihailescu et al., Neutron (n,xng) cross-section measurements for 52Cr, 209Bi, 206,207,208Pb from threshold up to 20 MeV, PhD thesis, Report EUR 22343 EN, European Communities (2006), EXFOR 23286
V.E. Guiseppe et al., Neutron inelastic scattering and reactions in natural Pb as a background in neutrinoless double-beta-decay experiments, PRC 79 (2009) 054604, EXFOR 14231
A. Plompen and A. Negret (Eds), Uncertainties and covariances for inelastic scattering data, Report EUR 25208 EN, European Union, 2011
M. Kerveno et al., From gamma emissions to (n,xn) cross sections of interest: The role of GAINS and GRAPhEME in nuclear reaction modeling, EPJA 51 (2015) 167

Theory/Evaluation

D. Rochman and A. Koning, Pb and Bi neutron data libraries with full covariance evaluation and improved integral tests, NIM A 589 (2008) 85

Additional file attached:SG26-report.html
Additional file attached:

Request ID 44 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

93-NP-237 (n,f) SIG 200 keV-20 MeV 2-3 Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fission fast reactors 11-MAY-15 18-MAY-15

Requester: Dr Fredrik TOVESSON at LANL, USA
Email: tovesson@lanl.gov

Project (context): Los Alamos National Laboratory

Impact:

The Np-237 fission cross section has impact for certain fast nuclear reactor designs. A sensitivity study by Aliberti et al. [1] pointed to a target accuracy of 8% for this cross section for Sodium-cooled Fast Reactor of the Gen-IV type (high level waste recycling).

WPEC Subgroup-26 [2]: Present uncertainty (BOLNA) 6-8% from 0.5-6 MeV. Required uncertainty for an Accelerator Driven Minor Actinide Burner (ADMAB): 1.5-4 %.

For many measurements the 237Np(n,f) is a reference cross section that is valuable on account of its low fission threshold and moderate activity.

Accuracy:
Uncertainties of 2-3%

Justification document:
There is a discrepancy of about 6-9% between a recent measurement performed by the n_TOF collaboration and ENDF/B-VII (C. Paradela et al. [3]).
The higher n_TOF values are supported by a validation exercise by Leong et al. [4].
A recent independent result in the energy range from 4.8 to 5.6 MeV yields cross sections that in function of energy first agree with ENDF/B-VII and then with the n_TOF result (M. Diakaki et al. [5]).
Independently an issue was recently found when cross sections for Pu-isotopes referred to the 238U(n,f) cross section were compared to the same cross sections referred to the 237Np(n,f) cross section in the same measurement arrangement (P. Salvador et al. [6]).

Comment from requester:

The request is well motivated and of some concern also to reactor dosimetry when using spectral indices and/or reaction rates of 237Np fission chambers (IRDFF [7]).

References:

[1] G. Aliberti et al., Annals of Nuclear Energy 33 (2006) 700-733.
[2] M. Salvatores et al., Nuclear Science NEA/WPEC-26, www.oecd.org.
[3] C. Paradela et al., Phys. Rev. C 82 (2010) 034601; Korean Physical Society 59 (2011) 1519.
[4] L.S. Leong et al., Annals of Nuclear Energy 54 (2013) 36

Review comment:

Entry Status:
Completed (as of SG-C review of May 2018) - The request was related to a discrepancy between measurements performed at LANSCE [Tovesson:2007] and n_TOF [Paradela:2010]. New measurements using improved PPAC detectors have shown that the overestimation of the n_TOF data was caused by different roughness of the surface of the Np and U samples [Tassan-Got:2019].

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

O. Shcherbakov et al., Neutron-Induced Fission of 233U, 238U, 232Th, 239Pu, 237Np, natPb and 209Bi Relative to 235U in the Energy Range 1-200 MeV, Jour. of Nuclear Science and Technology Suppl. 2 (2002) 230, EXFOR 41455
F. Tovesson and T. Hill, Neutron induced fission cross section of 237Np from 100 keV to 200 MeV, PRC 75 (2007) 034610, EXFOR 14130
M.S. Basunia, The (3He, t f) as a surrogate reaction to determine (n,f) cross sections in the 10-20 MeV energy range, NIM B 267 (2009) 1899, EXFOR 31673
C. Paradela, et al., Neutron-induced fission cross section of 234U and 237Np measured at the CERN Neutron Time-of-Flight (n_TOF) facility, PRC 82 (2010) 034601, EXFOR 23126
M. Diakaki et al., Determination of the 237Np(n,f) reaction cross section for En = 4.5-5.3 MeV using a MicroMegas detector assembly, EPJA 49 (2013) 62, EXFOR 23189
M. Diakaki et al., Neutron-induced fission cross section of 237Np in the keV to MeV range at the CERN n_TOF facility, PRC 93 (2016) 034614, EXFOR 22742
L. Tassan-Got et al., Fission program at n_TOF, EPJ Web of Conferences 211, 03006 (2019)

Theory/Evaluation

M.B. Chadwick et al., ENDF/B-VII.0: Next Generation Evaluated Nuclear Data Library for Nuclear Science and Technology, NDS 107 (2006) 2931

Validation

G. Palmiotti, et al., Combined Use of Integral Experiments and Covariance Data, Nuclear Data Sheets 118 (2014) 596

Additional file attached:1-s2.0-S0306454906000296-main.pdf
Additional file attached:

Request ID 45 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

19-K-39 (n,p),(n,np) SIG 10 MeV-20 MeV 10 Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fusion 17-MAY-17 11-JUL-17 Y

Requester: Dr Stanislav SIMAKOV at KIT, GER
Email: intersurfen@gmail.com

Project (context): IFMIF and DONES material test facilities, and fusion power plants

Impact:
The 39K(n,p) reaction produces 39Ar with decay half-life of 269 years and makes the dominant contribution to the long-lived radioactive inventories in NaK. The latter is considered as a coolant of specimens in the accelerator driven irradiation facilities that are designed now for the fusion material testing (IFMIF [1], DONES [2] ...). Together with the competing reaction 39K(n,np)38Ar they also determine the total amount of Argon gas which impact on the thermal and mechanical properties of sealed specimens containers [3]. The current poor knowledge of these two reactions questions whether NaK could be used in the IFMIF and DONES design. Additionally, since potassium is present in cement and concrete, the 39K(n,p)39Ar reaction impacts on the long-term radioprotection and shielding issues in IFMIF/DONES testing vaults and future fusion power plants.

Accuracy:
The continuous Argon gas leakage through cracks in the welding of sealed containers or their accidental rupture is a complex process. Because of this complexity, the sensitivity analyses quantifying the required accuracy of the cross sections have never been done. However, considering the potentially high impact and the poor knowledge of these cross sections, a request for 10% accuracy is a reasonable requirement that will be practically achievable by utilizing the current techniques. This requirement is supported by the fusion and general nuclear data users.

Justification document:

At 14 MeV neutron energy 3 measurements by proton spectroscopy and activation [4-6] reported 3 times larger value for 39K(n,p)39Ar reaction cross section than measurement by AMS [7]. For competing reaction 39K(n,np)38Ar the situation is vice versa. See Ref. [3] for more information.

The main evaluated libraries are similarly discrepant depending on which experiment they follow.

The new measurement is needed first at 14 MeV to resolve this contradiction.

References

[1] F. Arbeiter et al., Nuclear Materials and Energy 9 (2016)59.
[2] A. Ibarra et al., Fusion Science and Technology 66 (2014) 252.
[3] S.P. Simakov, Y. Qiu, U. Fischer, EFFDOC-1318, JEFF Meeting, OECD, Paris, April 24-27, 2017.
[4] M. Bormann et al., Zeitschrift fuer Naturforschung A 15 (1960) 200.
[5] D.V. Aleksandrov, L.I. Klochkova, B.S. Kovrigin, Soviet Atomic Energy 39 (1975) 736 (translated from Atomnaya Energiya 39 (1975) 137).
[6] W. Schantl, PhD thesis, Institut für Radiumforschung und Kernphysik, University of Vienna, 1970.
[7] K.A. Foland, R.J. Borg, M.G. Mustafa, Nuclear Science and Engineering 95 (1987) 128.

Comment from requester:

Review comment:

Entry Status:
Work in progress (as of SG-C review of May 2018)

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Additional file attached:effdoc-1318.pdf
Additional file attached:

Request ID 97 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

24-CR-50 (n,g) SIG 1 keV-100 keV 8-10 Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fission 20-JAN-18 05-FEB-18 Y

Requester: Dr Roberto CAPOTE NOY at IAEA, AUT
Email: roberto.capotenoy@iaea.org

Project (context):

Impact:

Neutron absorption in the Cr isotopes of structural materials affects the criticality of fast reactor assemblies [Koscheev2017]. These cross sections are also of interest for stellar nucleosynthesis [Kadonis10].

Accuracy:

8-10% in average cross-sections and calculated MACS at 10, 30, 100 keV.

Selected criticality benchmarks with large amounts of Cr (e.g., PU-MET-INTER-002, and HEU-COMP-INTER-005/4=KBR-15/Cr) show large criticality changes of the order of 1000 pcm due to 30% change in Cr-53 capture in the region from 1 keV up to 100 keV [Trkov2018]. On the other side different evaluations (e.g., BROND-3.1, ENDF/B-VII.1, ENDF/B-VIII.0 and JEFF-3.3) for Cr-53(n,g) are discrepant by 30% in the same energy region. For Cr-50, evaluated files show better agreement at those energies but they are lower than Mughabghab evaluation of the resonance integral by 35%. These discrepancies are not reflected in estimated uncertainty of the evaluated files (e.g., JEFF-3.3 uncertainty is around 10% which is inconsistent with the observed spread in evaluations). Due to these differences we request new capture data with 8-10% uncertainty to discriminate between different evaluations and improve the C/E for benchmarks containing Chromium and/or SS.

Justification document:

Criticality benchmarks can test different components of stainless steel (SS), including Cr which is a large component of some SS. Currently, a large part of the uncertainty in SS capture seems to be driven by uncertainty in Cr capture [Koscheev2017]. Indeed, some benchmarks highly sensitive to Cr (as a component of SS) indicate a need for much higher capture in Cr for both Pu and U fueled critical assemblies (e.g., HEU-COMP-INTER-005/4=KBR-15/Cr and PU-MET-INTER-002=ZPR-6/10).

Capture in natural Cr is driven by capture on Cr-50 and especially in odd Cr-53.

For Cr-53(n,g) there is a very large spread in MACS(30) values in different libraries compared to recommended KADoNiS 1.0 [Kadonis10] value of 41 +/- 10 mb (the latter is 25% larger). Existing measurements from the 70s are even larger being close to 60 mb with 30% uncertainty.

Note also discrepancies in resonance integrals (in barns) between evaluated libraries and ATLAS [Mughabghab2006] for both Cr-50(n,g) and Cr-53(n,g)

Reaction	ENDF/B-VII.1	BROND-3.1	ATLAS 2006
Cr-50(n,g)	7.21	7.21	11.7 +/- 0.2
Cr-53(n,g)	8.42	11.2	12.3

Finally, the re-evaluation for ENDF/B-VIII.0 of the ORNL TOF measurement on enriched Cr-53 target [Guber2011] contradicts the increase suggested in Ref. [Koscheev2017] where preliminary data have been used.

Such contradictions need to be resolved thanks to new measurements and evaluation.

References

[Guber2011] K.H. Guber, et al., Journal of the Korean Physical Society 59(2), 1685-1688, 2011
[Kadonis10] KADoNiS 1.0 (http://exp-astro.physik.uni-frankfurt.de/kadonis1.0)
[Koscheev2017] V. Koscheev, et al., EPJ Conf. 146, 06025, 2017
[Mughabghab2006] S.F. Mughabghab, Atlas of Neutron Resonances, 5th Edition, Elsevier, 2006
[Trkov2018] A. Trkov, O. Cabellos and R. Capote, Sensitivity of selected benchmarks to Cr-53 and Cr-50 capture, January 2018

Comment from requester:

- Cr-50(n,g) may be measured by activation or TOF. An accurate activation measurement at 5 and 25 keV may help in solving the puzzle of Cr capture.
- Cr-53(n,g) can only be measured by TOF. There is no publication of the final analysis of the ORNL TOF measurement using enriched Cr-53 sample.
- Lead Slowing Down Spectrometer (LSDS) measurements of Cr-50, Cr-53 and Cr-52 enriched samples and of Cr-nat sample could be extremely important to validate and select a proper evaluation of Cr capture cross section below 100 keV. These measurements are strongly encouraged as complementary to TOF and feasible activation measurements.

Review comment:

Entry Status:
Work in progress (as of SG-C review of May 2018)

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

Yijun Xia et al., Measurement of neutron capture cross section of Cr-50 in the energy range from 50 to 1052 keV, Communication of Nuclear Data Progress 28 (2002) 1, Report INDC(CPR)-059/L, EXFOR 32648
K.H. Guber et al., Neutron Cross-Section Measurements on Structural Materials at ORELA, Journal of the Korean Physical Society 59 (2011) 1685, EXFOR 14324

Theory/Evaluation

L. Leal et al., Evaluation of the Chromium Resonance Parameters Including Resonance Parameter Covariance, Journal of the Korean Physical Society 59 (2011) 1644
G.P.A. Nobre, et al., Newly Evaluated Neutron Reaction Data on Chromium Isotopes, Nuclear Data Sheets 173 (2021) 1

Validation

V. Koscheev et al., Use the results of measurements on KBR facility for testing of neutron data of main structural materials for fast reactors, EPJ Conferences 146 (2007) 06025

Additional file attached:Trkov2018.pdf
Additional file attached:

Request ID 98 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

24-CR-53 (n,g) SIG 1 keV-100 keV 8-10 Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fission 20-JAN-18 05-FEB-18 Y

Requester: Dr Roberto CAPOTE NOY at IAEA, AUT
Email: roberto.capotenoy@iaea.org

Project (context):

Impact:

Accuracy:

8-10% in average cross-sections and calculated MACS at 10, 30, 100 keV.

Justification document:

Capture in natural Cr is driven by capture on Cr-50 and especially in odd Cr-53.

Note also discrepancies in resonance integrals (in barns) between evaluated libraries and ATLAS [Mughabghab2006] for both Cr-50(n,g) and Cr-53(n,g)

Reaction	ENDF/B-VII.1	BROND-3.1	ATLAS 2006
Cr-50(n,g)	7.21	7.21	11.7 +/- 0.2
Cr-53(n,g)	8.42	11.2	12.3

Such contradictions need to be resolved thanks to new measurements and evaluation.

References

[Guber2011] K.H. Guber, et al., Journal of the Korean Physical Society 59(2), 1685-1688, 2011
[Kadonis10] KADoNiS 1.0 (http://exp-astro.physik.uni-frankfurt.de/kadonis1.0)
[Koscheev2017] V. Koscheev, et al., EPJ Conf. 146, 06025, 2017
[Mughabghab2006] S.F. Mughabghab, Atlas of Neutron Resonances, 5th Edition, Elsevier, 2006
[Trkov2018] A. Trkov, O. Cabellos and R. Capote, Sensitivity of selected benchmarks to Cr-53 and Cr-50 capture, January 2018

Comment from requester:

Review comment:

Entry Status:
Work in progress (as of SG-C review of May 2018)

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

Yijun Xia et al., Measurement of neutron capture cross section of Cr-50 in the energy range from 50 to 1052 keV, Communication of Nuclear Data Progress 28 (2002) 1, Report INDC(CPR)-059/L, EXFOR 32648
K.H. Guber et al., Neutron Cross-Section Measurements on Structural Materials at ORELA, Journal of the Korean Physical Society 59 (2011) 1685, EXFOR 14324

Theory/Evaluation

L. Leal et al., Evaluation of the Chromium Resonance Parameters Including Resonance Parameter Covariance, Journal of the Korean Physical Society 59 (2011) 1644
G.P.A. Nobre, et al., Newly Evaluated Neutron Reaction Data on Chromium Isotopes, Nuclear Data Sheets 173 (2021) 1

Validation

V. Koscheev et al., Use the results of measurements on KBR facility for testing of neutron data of main structural materials for fast reactors, EPJ Conferences 146 (2007) 06025

Additional file attached:Trkov2018.pdf
Additional file attached:

Request ID 99 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

94-PU-239 (n,f) nubar Thermal-5 eV 1 Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fission 23-MAR-18 12-APR-18 Y

Requester: Dr Roberto CAPOTE NOY at IAEA, AUT
Email: roberto.capotenoy@iaea.org

Project (context):

Impact:

Cf. Ref. [1,2]. A similar, but stronger than in U-235, resonance nubar effect is expected for Pu-239 due to the 1/2 GS spin.

Accuracy:

Accuracy below 1% is required on the evaluated data. New measurements must strive to achieve a relative uncertainty below about 1% on the ratio to Cf-252(sf) nubar, as done in the best past experiments [3].

Statistical precision below about 1% at the resonances is required in order to unambiguously identify resonant fluctuations.

Justification document:

A new evaluation of the PFNS [4] in the thermal energy range has determined a lower value of the average neutron energy than that reported in the existing evaluated nuclear data libraries. This value is in agreement with Rising et al and Neudecker independent evaluations. However, a number of thermal-solution benchmarks has shown that the combined use of the new Thermal Neutron Constants and a softer prompt fission neutron spectrum at thermal energy yields k-eff values that are larger than measurements by a margin that increases as the above-thermal-leakage fraction (ATLF) increases (see Ref. [5]). Therefore a reduced criticality is needed for high-leakages solutions. Such reduced criticality may arises due to the (n,gf) process in Pu-239 resonance nubar.

Unfortunately, only measurements from the 70s and 80s are available, a critical region below 5 eV needs to be remeasured with higher incident-energy resolution and higher accuracy and precision to improve existing evaluated data files.

References

M.T. Pigni, et al., n+235U resonance parameters and neutron multiplicities in the energy region below 100 eV, EPJ Web of Conferences 146, 02011 (2017)
E. Fort et al., Evaluation of prompt nubar for 239Pu: Impact for applications of the fluctuations at low energy, Nuclear Science and Engineering 99, 375 (1988)
Gwin et al., Measurements of the energy dependence of prompt neutron emission from 233U, 235U, 239Pu, and 241Pu for En = 0.005 to 10 eV relative to emission from spontaneous fission of 252Cf, Nuclear Science and Engineering 87, 381 (1984)
R. Capote, et al., Prompt Fission Neutron Spectra of Actinides, Nuclear Data Sheets 131, 1-106 (2016)
C. De Saint Jean (coordinator), Co-ordinated Evaluation of Plutonium-239 in the Resonance Region, Nuclear Energy Agency, International Evaluation Cooperation, NEA/WPEC-34, Report NEA/NSC/WPEC/DOC(2014)447 (2014)

Comment from requester:

Additionally to changes in nubar changes in resonance parameters may be required. We cannot split those effects on studied criticality benchmarks.

Review comment:

Entry Status:
Work in progress (as of SG-C review of May 2018)

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

F.J. Hambsch, et al., Prompt fission neutron emission in resonance fission of 239Pu, ND2004, Santa Fe (NM), USA, September 2004, AIP 769 (2005) 644

Theory/Evaluation

J.E. Lynn, P. Talou and O. Bouland, Reexamining the role of the (n,gf) process in the low-energy fission of 235U and 239Pu, PRC 97 (2018) 064601

Additional file attached:
Additional file attached:

Request ID 102 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

64-GD-155 (n,g),(n,tot) SIG Thermal-100 eV 4 Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fission LWR 07-FEB-18 09-MAY-18 Y

Requester: Mr Cristian MASSIMI at UBOLOGNA, ITY
Email: cristian.massimi@unibo.it

Project (context):

Impact:
In nuclear industry gadolinium is used as neutron absorber having the highest thermal absorption cross section among all stable elements thanks to Gd-155 and especially Gd-157 isotopes. It is commonly used, in PWR or BWR, as burnable absorber in fresh fuel to compensate an excess of reactivity or as emergency shutdown poison in CANDU reactors. RPI measurements of the Gd-157 thermal capture cross-section [1] differ by 10% from the ENDF/B-VI.8 value and, thus, in ENDF/B-VII.1 [2] the low energy cross section uncertainty was increased by up to a factor 2, i.e. from about 2-4% to 4-6%. There is no significant change in the latest ENDF/B-VIII.0 evaluation of these two isotopes. A sensitivity and uncertainty analysis was performed by ENEA to quantify the maximum impact of the uncertainty of the gadolinium isotopes cross sections on the criticality of a LWR system [3-5]. It showed that, in systems with a high number of gadolinium fuel pins, neutron capture of odd gadolinium isotopes contribution to keff uncertainty ranks high, just after the major U-235 and U-238 contributions.

Accuracy:
Sensitivity and uncertainty analyses show that keeping the cross section uncertainty below 4% mitigates the impact on keff uncertainty at high-burnup, which is important for a good estimation of the residual reactivity penalty of a fuel assembly at the end of life.

Justification document:
Despite their importance, the capture cross sections of the odd Gd isotopes have not been extensively studied and are not known with the accuracy required by present-day nuclear industry. In the thermal energy range these cross sections contribute more than 99% to the total cross section. Complementary accurate transmission measurements are also required to constrain the capture cross section. Table 1 in Ref. [4] illustrates current discrepancies for 157Gd capture cross-section at thermal energy. Such contradictions should be clarified thanks to new measurements and evaluation.

References

G. Leinweber, et al., Nuclear Science and Engineering 154, 261-279 (2006)
M. B. Chadwick et al., ENDF/B-VII.1 Nuclear Data for Science and Technology: Cross Sections, Covariances, Fission Product Yields and Decay Data, Nuclear Data Sheets 112, 2887-2996 (2011)
F. Rocchi, 157Gd and 155Gd (n,g) cross section project, JEF/DOC-1835 (2017)
F. Rocchi, A. Guglielmelli, D.M. Castelluccio and C. Massimi, Reassessment of gadolinium odd isotopes neutron cross sections: scientific motivations and sensitivity-uncertainty analysis on LWR fuel assembly criticality calculations, EPJ Nuclear Sci. Technol. 3, 21 (2017)
F. Rocchi, A. Guglielmelli, S. Lo Meo, Implementation of a Cross Section Evaluation Methodology for Safety Margin Analysis: Application to Gadolinium Odd Isotopes, ENEA Report RdS/PAR2015/078 (2016)

Comment from requester:
Beyond nuclear industry, nuclear astrophysics can benefit from the accurate knowledge of 155- and 157-Gd(n,g) cross section up to a few keV, as the even-Gd isotopes play an important role in the s-process nucleosynthesis. Therefore a consistent analysis of all Gd-nat isotopes from thermal up to a few keV is of high interest for both astrophysics and nuclear data evaluation purpose.

Review comment:

Entry Status:
Pending new evaluation or validation (as of SG-C review of May 2018)

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

G. Leinweber et al., Neutron capture and total cross-section measurements and resonance parameters of gadolinium, Nuclear Science and Engineering 154 (2006) 261
B. Baramsai et al., Neutron resonance parameters in 155Gd measured with the DANCE g-ray calorimeter array, Phys. Rev. C 85 (2012) 024622
H.D. Choi et al., Radiative capture cross sections of 155,157Gd for thermal neutrons, Nucl. Science and Eng. 177 (2014) 219
Y.-R. Kang et al., Neutron capture measurements and resonance parameters of gadolinium, Nucl. Science and Eng. 180 (2015) 86
M. Mastromarco, et al., Cross section measurements of 155,157Gd(n,g) induced by thermal and epithermal neutrons, Eur. Phys. J. A 55 (2019) 9
Yong-uk Kye, et al., Resonance parameters of Gd isotopes derived from capture measurements at GELINA, Eur. Phys. J. A 56 (2020) 30
R. Mucciola, et al., Results of time-of-flight transmission measurements for 155,157Gd at a 10m station of GELINA, IAEA INDC Report, INDC(EUR)-0037 (2020)
A. Kimura, et al., Neutron capture and total cross-section measurements of 155Gd and 157Gd at ANNRI in J-PARC, EPJ Conf. 239 (2020) 01012

Theory/Evaluation

L. Leal, et al., Resonance evaluation of Gadolinium isotopes, EPJ Conf. 239 (2020) 11004

Validation

F. Rocchi et al., Reassessment of gadolinium odd isotopes neutron cross sections: scientific motivations and sensitivity-uncertainty analysis on LWR fuel assembly criticality calculations, EPJ N 3 (2017) 21
F. Rocchi et al., Sensitivity uncertainty analysis and new neutron capture cross-sections for gadolinium odd-isotopes to support nuclear safety, Annals of Nuclear Energy 132 (2019) 537

Additional file attached:ENEA_RdS_PAR2015_078.pdf
Additional file attached:jefdoc-1835.pdf

Request ID 103 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

64-GD-157 (n,g),(n,tot) SIG Thermal-100 eV 4 Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fission LWR 07-FEB-18 09-MAY-18 Y

Requester: Mr Cristian MASSIMI at UBOLOGNA, ITY
Email: cristian.massimi@unibo.it

Project (context):

References

G. Leinweber, et al., Nuclear Science and Engineering 154, 261-279 (2006)
M. B. Chadwick et al., ENDF/B-VII.1 Nuclear Data for Science and Technology: Cross Sections, Covariances, Fission Product Yields and Decay Data, Nuclear Data Sheets 112, 2887-2996 (2011)
F. Rocchi, 157Gd and 155Gd (n,g) cross section project, JEF/DOC-1835 (2017)
F. Rocchi, A. Guglielmelli, D.M. Castelluccio and C. Massimi, Reassessment of gadolinium odd isotopes neutron cross sections: scientific motivations and sensitivity-uncertainty analysis on LWR fuel assembly criticality calculations, EPJ Nuclear Sci. Technol. 3, 21 (2017)
F. Rocchi, A. Guglielmelli, S. Lo Meo, Implementation of a Cross Section Evaluation Methodology for Safety Margin Analysis: Application to Gadolinium Odd Isotopes, ENEA Report RdS/PAR2015/078 (2016)

Review comment:

Entry Status:
Pending new evaluation or validation (as of SG-C review of May 2018)

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

G. Leinweber et al., Neutron capture and total cross-section measurements and resonance parameters of gadolinium, Nuclear Science and Engineering 154 (2006) 261
H.D. Choi et al., Radiative capture cross sections of 155,157Gd for thermal neutrons, Nucl. Science and Eng. 177 (2014) 219
Y.-R. Kang et al., Neutron capture measurements and resonance parameters of gadolinium, Nucl. Science and Eng. 180 (2015) 86
M. Mastromarco, et al., Cross section measurements of 155,157Gd(n,g) induced by thermal and epithermal neutrons, Eur. Phys. J. A 55 (2019) 9
Yong-uk Kye, et al., Resonance parameters of Gd isotopes derived from capture measurements at GELINA, Eur. Phys. J. A 56 (2020) 30
R. Mucciola, et al., Results of time-of-flight transmission measurements for 155,157Gd at a 10m station of GELINA, IAEA INDC Report, INDC(EUR)-0037 (2020)
A. Kimura, et al., Neutron capture and total cross-section measurements of 155Gd and 157Gd at ANNRI in J-PARC, EPJ Conf. 239 (2020) 01012

Theory/Evaluation

L. Leal, et al., Resonance evaluation of Gadolinium isotopes, EPJ Conf. 239 (2020) 11004

Validation

F. Rocchi et al., Reassessment of gadolinium odd isotopes neutron cross sections: scientific motivations and sensitivity-uncertainty analysis on LWR fuel assembly criticality calculations, EPJ N 3 (2017) 21
F. Rocchi et al., Sensitivity uncertainty analysis and new neutron capture cross-sections for gadolinium odd-isotopes to support nuclear safety, Annals of Nuclear Energy 132 (2019) 537

Additional file attached:ENEA_RdS_PAR2015_078.pdf
Additional file attached:jefdoc-1835.pdf

Request ID 114 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

83-BI-209 (n,g)Bi-210g,m BR 500 eV-300 keV 10 Y

Field Subfield Date Request created Date Request accepted Ongoing action

ADS,Fission 26-OCT-18 09-NOV-18 Y

Requester: Dr Alexey STANKOVSKIY at SCK-CEN, BLG
Email: alexey.stankovskiy@sckcen.be

Project (context): MYRRHA and Gen-IV reactors with lead-bismuth coolants

Impact:

Polonium-210, a rather short-lived alpha emitter (half-life 138.4 days), determines the radiological burden associated with the use of lead-bismuth heavy metal coolants of fast reactors, MYRRHA accelerator-driven system currently designed at SCK•CEN, Belgium is one of the examples. It is produced via neutron capture on 209Bi forming the ground state of 210Bi (half-live 5 days) which rapidly decays into 210Po. 210Bi has also long-lived (3 My) metastable state that can also be produced via neutron capture and that decays to 206Tl. Thus the knowledge of branching ratio between these two neutron capture channels is important to accurately predict the inventory of Polonium-210.

Accuracy:

10% on the capture cross sections both to ground and metastable states of 210Bi.

The analysis performed in [Fiorito2018] reveals high sensitivity of 210Po production to the neutron capture cross section at first (801.6 eV) and neighbouring resonances up to 10 keV, as well as to the data around 100-300 keV where the neutron spectrum is peaked. The spread in prediction of 210Po concentration between nuclear data libraries reaches 40% while the propagation of existing covariance data for the capture cross section results in uncertainties between 5 and 20%. Furthermore, the covariance data on the branching ratio are not provided in the evaluated data files although they are likely to contribute significantly to the final 210Po concentration uncertainty.

Justification document:

Significant differences between evaluations were observed in the neutron capture cross section and branching ratio, which were proved to pose a severe constraint for the correct 210Po content prediction in MYRRHA and other lead-bismuth cooled reactor concepts. The covariance matrices found in the 209Bi evaluations result in different uncertainty profiles and energy correlations. The 210Po concentration uncertainty (intended as one standard deviation) after one irradiation cycle of MYRRHA is ranging between 5% and 20%. This level of uncertainty does not cover the deviation between 210Po concentration values assessed with the evaluated files coming from different libraries, even when three standard deviations are considered. Furthermore, branching ratio covariances were not propagated since they are not provided in the evaluated files, although they are likely to add a significant uncertainty contribution to the polonium content.

Significant efforts are necessary to reduce the discrepancies between evaluated data. In particular, accurate measurements should be carried out to obtain the reliable branching ratio not only at thermal energies and for the first resonance at about 800 eV, but also in the energy ranges of interest for lead-bismuth-cooled reactors such as MYRRHA, as made clear by the sensitivity plots in [Fiorito2018].

Because of the disagreement between libraries, a consistent evaluation for the branching ratios should be elaborated that also includes the energy-dependent behaviour in the resonance region and above. Although the BROND-3.1 [Blokhin2016] evaluation seems providing most accurate branching ratio among evaluated libraries, it also relies only on few experimental energy points [Saito2003, Saito2004, Borella2008, Borella2011] in the range 800 eV – 10 keV. The future evaluation thus should be supported by additional experimental measurements.

References

[Saito2003] K. Saito, M. Igashira, T. Ohsaki, T. Obara, H. Sekimoto, Measurement of cross sections of the 210-Po production reaction by keV-neutron capture of 209-Bi, in JAERI Conf. Proc., Vol. 6, p. 133, 2003
[Saito2004] K. Saito, M. Igashira, J. Kawakami, T. Ohsaki, T. Obara, H. Sekimoto, Measurement of keV-Neutron Capture Cross Sections and Capture Gamma-Ray Spectra of 209Bi, J. Nucl. Sci. Technol. 41, 406 (2004)
[Borella2008] A. Borella, T. Belgya, E. Berthoumieux, N. Colonna, C. Domingo-Pardo, J.C. Drohe, F. Gunsing, S. Marrone, T. Martinez, C. Massimi, P. Mastinu, P.M. Milazzo, P. Schillebeeckx, G. Tagliente, J. Tain, R. Terlizzi, R. Wynants, Measurements of the branching ratio of the 209Bi (n,g) 210gBi/210mBi reactions at GELINA, Proc. Int. Conf. on Nuclear Data for Science and Technology ND-2007, Nice, France, EDP Sciences (2008), DOI: 10.1051/ndata:07431
[Borella2011] A. Borella, T. Belgya, S. Kopecky, F. Gunsing, M. Moxon, M. Rejmund, P. Schillebeeckx, L. Szentmiklosi, Determination of the 209Bi (n,g) 210Bi and 209Bi (n,g) 210m,g Bi reaction cross sections in a cold neutron beam, Nucl. Phys. A 850, 1 (2011)
[Blokhin2016] A.I. Blokhin, E.V. Gai, A.V. Ignatyuk, I.I. Koba, V.N. Manokhin, V.G. Pronyaev, New version of neutron evaluated data library BROND-3.1, Technical Report Yad. Reak. Konst. No.2, p.62, A.I. Leypunsky Institute for Physics and Power Engineering, Obninsk, Russia, 2016
[Fiorito2018] L. Fiorito, A. Stankovskiy, A. Hernandez-Solis, G. van den Eynde and G. Zerovnik, Nuclear data uncertainty analysis for the Po-210 production in MYRRHA, EPJ Nuclear Sci. Technol. 4, 48 (2018)

Comment from requester:

Review comment:
In addition to 209Bi(n,g) branching ratio or activation measurements, complementary transmission measurements may be needed to fix the resonance parameters in the re-evaluation of the 209Bi capture cross section. Moreover, integral benchmarks dedicated to 209Bi activation/cooling in representative spectra are required to better assess the performance of evaluated data.

Entry Status:
Work in progress (as of SG-C review of June 2019)

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

A. Shor, et al., Bismuth activation with quasi-Maxwellian neutrons at kT ∼ 30 keV, Phys. Rev. C 96 (2017) 055805
A. Shor, et al., Branching ratio to the 803 keV level in 210Po α decay, Phys. Rev. C 97 (2018) 034303
K. Al-Khasawneh, et al., Determination of the 209Bi(n,γ)210gBi cross section using the NICE detector, Phys. Rev. C 103 (2021) 065805
A. Shor, et al., Measurements of the 210gBi to 210mBi activation ratio for the 209Bi(n,γ) reaction with thermal and epithermal neutrons at the Soreq IRR1 reactor, Phys. Rev. C 105 (2022) 025802

Additional file attached:
Additional file attached:

Request ID 115 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

94-PU-239 (n,tot) SIG Thermal-5 eV 1 Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fission Thermal reactors 22-MAR-19 08-APR-19 Y

Requester: Dr Gilles NOGUERE at CAD-DER, FR
Email: gilles.noguere@cea.fr

Project (context):

Impact:

The use of new high-accuracy transmission data in the evaluation procedure will affect the partial cross sections and their uncertainties, whose impact on neutronic calculations may be significant. For the first resonance the uncertainty on capture is 2.5% in JEFF-3.3 and 4% in ENDF/B-VIII.0, whereas the sensitivity of keff to capture is close to 200 pcm/% for MOX fuel. Hence, any modifications of the resonance parameters and their uncertainties will have a sizeable impact on reactor applications.

Accuracy:

Accuracy and precision better than 1% are required for the first resonance.

Justification document:

New experimental setups are developed to measure the capture cross sections of actinides in the resolved resonance range. However, total cross sections are also important quantities for evaluation purposes.

The transmission data of the first resonance have all been measured in the 1950's (see attached figure).

Uncertainty information on these old measurements are scarce or lacking and does not help much to constrain the resonance parameters in the evaluation process, which is a pity given the high accuracy that can be reached on a transmission measurement (compared to capture). The attached figure illustrates how ENDF/B-VIII.0 and JEFF-3.3 differs, partly because of evaluators' choices, but also because of poor uncertainty information.

New high-accuracy transmission measurements of the first resonance will help improve the resonance parameters and reduce the uncertainty on the capture cross section.

Comment from requester:

Review comment:

Entry Status:
Work in progress (as of SG-C review of June 2019)

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

C. de Saint Jean (coordinator), Co-ordinated Evaluation of Plutonium-239 in the Resonance Region, Nuclear Energy Agency, International Evaluation Cooperation, NEA/WPEC-34, Report NEA/NSC/WPEC/DOC(2014)447 (2014)

Additional file attached:HPRL_Request_Pu239_ntot_1stRes.png
Additional file attached:

Request ID 116 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

3-LI-0 (d,x)Be-7 SIG 10 MeV-40 MeV 10 Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fusion DONES, IFMIF 15-MAY-21 31-MAY-21 Y

Requester: Dr Stanislav SIMAKOV at KIT, GER
Email: intersurfen@gmail.com

Project (context): Fusion (DONES, IFMIF) and Accelerator driven neutron sources (e.g., SARAF-II)

Impact:

The Li(d,x)7Be reactions will produce 100% of radioactive isotope 7Be in the IFMIF Li loop [1]. Consequently the accuracy of the Li(d,x)7Be cross sections will solely impact on the efficiency, design and cost of the IFMIF radio-protection measures which should guarantee the safe accumulation of 7Be in the lithium loop Heat Exchanger and cold inventory traps [2,3].

[1] S. Simakov et al., “Assessment of the 3H and 7Be generation in the IFMIF lithium loop”, J. Nucl. Mat. 329 (2004) 213
[2] A. Ibarra et al., “The European approach to the fusion-like neutron source: the IFMIF-DONES project”, Nuclear Fusion 59 (2019) 065002
[3] F. Martín-Fuertes et al., “Integration of Safety in IFMIF-DONES Design”, Safety 5 (2019) 74

Accuracy:

Uncertainties below 10% as a reasonable compromise between application needs and what is practically achievable using standard techniques.

Justification document:

In the requested deuteron energy range from 10 MeV to 40 MeV (the latter is DONES working energy) there are no experimental data for the 6,7Li(d,x)7Be reaction cross sections. Moreover, the evaluated major deuteron libraries (ENDF, JEFF, FENDL, TENDL) including the just-released JENDL/DEU disagree from the existing measurements below 10 MeV.

More details on the status of the cross section data are available in the following documents:
S. Simakov et al., “Status and benchmarking of the deuteron induced Tritium and Beryllium-7 production cross sections in Lithium”, KIT Scientific Working Papers 147, KIT, June 2020; EFFDOC-1438, JEFF Meetings, NEA, November 2020; Presentation at EG HRPL, WPEC Meetings, NEA, 12 May 2021 (see attached file below).

Comment from requester:

Review comment:

Entry Status:
Work in progress (as of SG-C review of May 2021)

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Additional file attached:Simakov_EGHPRL_2021May.pdf
Additional file attached:

Request ID 117 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

3-LI-0 (d,x)H-3 SIG,TTY 5 MeV-40 MeV 10 Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fusion DONES, IFMIF 15-MAY-21 31-MAY-21 Y

Requester: Dr Stanislav SIMAKOV at KIT, GER
Email: intersurfen@gmail.com

Project (context): Fusion (DONES, IFMIF) and Accelerator driven neutron sources (e.g., SARAF-II)

Impact:

The Li(d,x)t reactions will produce 80% of tritium in the IFMIF Li loop [1]. Consequently the accuracy of the Li(d,x)t cross section will impact on the efficiency, design and cost of the planned IFMIF radio-protection measures such as replacement of the yttrium and cold traps for the long tritium retaining, prevention of its permeation in atmosphere, etc. [2,3].

Accuracy:

Uncertainties below 10% as a reasonable compromise between application needs and what is practically achievable using standard techniques.

Justification document:

At the requested deuteron energies from 5 MeV up to 40 MeV there are no experimental data for the 6,7Li(d,x)t reaction cross sections; whereas Tritium TTY was measured only once at 40 MeV. The evaluated major deuteron libraries (ENDF, JEFF, FENDL, TENDL) including the just-released JENDL/DEU disagree with known measurements by a factor 2-3.

More details on the status of cross sections and TTY are available in the following documents:
S. Simakov et al., “Status and benchmarking of the deuteron induced Tritium and Beryllium-7 production cross sections in Lithium”, KIT Scientific Working Papers 147, KIT, June 2020; EFFDOC-1438, JEFF Meetings, NEA, November 2020; Presentation at EG HRPL, WPEC Meetings, NEA, 12 May 2021 (see attached file below).

Comment from requester:

In the case of the tritium spectroscopy experiments, the tritium double-differential data (DDX) for reaction (d,x)H-3 are desirable to measure in the maximum t-energy range and for the representative emission angles to allow integration of DDX and thus obtaining the production cross section σ(d,x)t. However, an activation experiment measuring tritium by its decay or by other direct means is sufficient.

Review comment:

Entry Status:
Work in progress (as of SG-C review of May 2021)

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Additional file attached:Simakov_EGHPRL_2021May.pdf
Additional file attached:

Request ID 118 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

68-ER-167 (n,g) SIG,RP 0.01 eV-100 eV 2 Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fission LWR, innovative fuel 09-JUL-21 30-AUG-21 Y

Requester: Dr Antonio GUGLIELMELLI at ENEA-BOLO, ITY
Email: antonio.guglielmelli@enea.it

Project (context):

Impact:

A more precise knowledge of the erbium capture cross section in the most important energy region for LWR technology would reduce the criticality uncertainty margin in the erbia-credit super high burnup (Er-SHB) fuel concept. The Er-SHB concept is a system constituted of LWR fuel assemblies in which all fuel pins are erbia-doped. This system has already been subject to a research phase, and it has been verified that its application on large-scale commercial reactors would allow both to extend the fuel life cycle and to obtain several physical enhancements (i.e., less downgrade of the flux distribution, improving the intrinsic reactor safety parameters, better control of the transient power phase). The adoption of a Er-SHB fuel also allows to manufacture fuel with an enrichment greater than 5 wt% without modifying the current fuel manufacturing facilities that should be handling more enriched (> 5 wt%) uranium fuel, but whose criticality is hold-down by the erbia absorbers. In turn, the improvement of the erbia – especially Er-167(n,g) – capture cross sections, would make possible to assess better the criticality safety of the manufacturing facilities of an erbia-doped highly enriched uranium (Er-HEU) fuel. The erbia cross sections improvement will also allow to significantly reduce the uranium fuel cost because the code used to perform core neutronic design calculations will be able to optimize the uranium mass necessary to reach criticality conditions of an erbia-doped core system with less uncertainty.

Accuracy:

< 2% in all the energetic range below 100 eV

The target uncertainty for the Er-167(n,g) cross section is proposed to be less than 2% in order to reach the same level of uncertainty attributable to U-235(n,f) on the integral parameter (criticality coefficient) of a erbia-doped LWR system.

The Sensitivity and Uncertainty (S&U) analysis performed on an erbia-doped LWR system showed that the relevant region should be extended up to 100 eV because of minor but not-negligible contributions beyond 10 eV.

Justification document:

A Sensitivity and Uncertainty study (S&U) has been performed to evaluate the criticality uncertainty contribution of the erbium isotopes on an Er-SHB system. The analysis was performed with the TSUNAMI-2D code of SCALE 6.2.3 tool. The data library used (v7-252) is a 252-energy group library based on ENDF/B-VII.1 evaluation, the covariance data used is a 56-energy group collapsed data based on ENDF/B-VII.1 data. The results showed that Er-167(n,g) is the largest contributor to criticality uncertainty after the U-235 and U-238 cross section reactions. The contribution of Er-167(n,g) to the criticality uncertainty was found equal to 123 pcm, this value has to be considered not negligible for core design purpose and equal to 18% of the total evaluated uncertainty. The uncertainty on the criticality due to the overall erbium isotopes (Er-166, Er-167 and to a lesser extent Er-168 and Er-170) was found equal to 166 pcm. A review of the historical experimental data values at thermal point present in the EXFOR database of the most uncertainty-related important erbium isotopes (i.e., Er-167) showed that the Er-167(n,g) data are inconsistent because they show a standard deviation with respect to the average value equal to 8.4%. An intercomparison between the most recent Er-167(n, g) measures at thermal point also revealed a relative difference roughly equal to 12%. The Er-167(n,g) ENDF/B-VII.1 and B-VIII.0 evaluated uncertainty at thermal energy and in the high-sensitivity region (0.5 - 5 eV) are set to 1.23% and 2.35%, respectively, on the basis of a pragmatic "low-fidelity" approach that would benefit from additional measurements. A data analysis of the experimental and calculated results provided by all criticality facilities of the International Criticality Safety Benchmark Evaluation Project (ICSBEP) that contain erbia in solid form confirmed that the declared evaluated uncertainty data (i.e., 2.35 %) of the ENDF evaluation would be considered an underestimation of the real uncertainty to be associated with the thermal range of the current Er-167(n,g) nuclear cross section data.

Comment from requester:

The request is on capture, but complementary transmission measurements would help extract more accurate resonance parameters for both neutron and radiative widths.

Depending on the Er-167 sample enrichment used in the experiments, complementary measurements on other major natural erbium isotopes (Er-166, 168, 170) may be necessary to accurately determine the Er-167 cross section and resonance parameters. In addition, Er-166 capture cross section has a slight neutronic impact because of its relatively large evaluated uncertainty (about 8% in the energy range of interest for ENDF/B-VIII.0).

Review comment:

The request is well justified, but the target accuracy of less than 2% is very demanding even if focusing the efforts on the thermal region and the low energy resonances. In order to achieve such an accuracy the experimental results should be provided in the form of capture yields for optimal assimilation of the data in the evaluation process, and complementary information from integral measurements might be necessary.

Entry Status:
Work in progress (as of SG-C review of May 2022)

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Experiments

Y. Danon, et al., Neutron total cross-section measurements and resonance parameter analysis of holmium, thulium, and erbium from 0.001 to 20 eV, Nuclear Science and Engineering 128 (1998) 61

Additional file attached:
Additional file attached:

Request ID 119 Type of the request High Priority request

Target Reaction and process Incident Energy Secondary energy or angle Target uncertainty Covariance

17-CL-35 (n,p) SIG 100 keV-5 MeV 5-8 Y

Field Subfield Date Request created Date Request accepted Ongoing action

Fission Gen-IV 09-MAR-22 17-APR-22 Y

Requester: at ,
Email:

Project (context): Gen-IV (fast chloride molten salt reactor design)

Impact:

Requester: Tom Taylor (Moltex Energy) and Tommy Cisneros (TerraPower)

There is currently large uncertainty in reactivity for chloride fast reactors, due mainly to the uncertainty in the Cl-35 (n,p) cross section at high energies. This is a difficulty for chloride fast reactor design because the required fissile loading has large uncertainty, and this uncertainty also propagates to other parameters important to safety, such as reactivity coefficients. Production of S-35 via this reaction is also important for corrosion.

Additionally, above 1.2 MeV there is no uncertainty available for Cl-35 (n,p) in any evaluated library, except TENDL. This makes it difficult to justify a reasonable total uncertainty.

A number of organisations are designing or studying chloride fast reactors and are therefore sensitive to this nuclear data. In addition to Moltex Energy and TerraPower (MCRE and MCFR) the CEA is performing chloride fast reactor R&D. Previous work led by EDF R&D on the REBUS-3700 fast chloride reactor also concluded that more accurate nuclear data for Cl was needed (Mourogov & Bokov, 2006).

It is also worth noting that other Cl nuclear data is important for chloride fast reactors, particularly Cl-35 (n,gamma) and Cl-36 capture, for Cl-36 waste considerations.

Accuracy:

To achieve a target k-eff uncertainty < 300 pcm, the table below suggests uncertainties < 2% would be required above ~100 keV. However, such a low uncertainty is unlikely to be achievable using differential measurements. k-eff uncertainty > 300 pcm would be tolerable, given the uncertainty is currently estimated to be at least ~1000 pcm. On this basis a target of 5 – 8 % is suggested.

It is realised that it may be challenging to achieve even this uncertainty. Any reduction in uncertainty, and/or improved covariances, would be valuable. Integral experiments would likely be needed to reduce uncertainties to a level of 2 – 3 %.

Justification document:

33 group sensitivity coefficients have been generated for the main output parameters, as part of a collaboration with ANL (using the PERSENT code and ENDF/B-VII.0 data). Those for Cl-35 (n,p) are large, as expected, see attached Figure 1.

Uncertainties and target uncertainties have then been derived by UPM through WPEC SG46, using this sensitivity data. Using the TENDL-2021 evaluation for Cl-35, and ENDF/B-VII.1 otherwise, gives a total uncertainty of 836 pcm, with 631 pcm from Cl-35 alone, and dominated by the (n,p) cross section (595 pcm, next largest 173 pcm from (n,alpha)). Below is a table showing target accuracy requirements for the top 10 most important reactions for the Moltex SSR-W.

Recent measurements in the US (Batchelder et al., 2019) and (Kuvin et al., 2020) also indicate that the cross section in all libraries could be too high above ~1.2 MeV. Direct perturbation of the Cl-35 (n,p) reaction in this energy range shows large sensitivity (increase of ~1000 pcm for reduction by 50% between 2.23 and 3.68 MeV).

TerraPower indicates also that very recent measurements (Warren, 2021) of the 35Cl(n,p) cross section have significantly disagree with the evaluated nuclear data in ENDF/B-VIII.0 that was not updated in the last update of chlorine nuclear data – ENDF/B-VII.1. The attached Figure 2 presents the discrepancy between evaluated data and recent measurements.

Comment from requester:

The tables below are reproduced, with permission, from A Review of the Nuclear Data Adjustment Activities within WPEC Sub-groups, O. Cabellos, WANDA 2022, March 2022.

Target accuracy requirements for total k-eff uncertainty < 300 pcm, with nuclear data from ENDF/B-VII.1 (Cl-35 uncertainty from TENDL-2021).

Rank#	Reaction	Energy group	Current (%)	Target (%)	Rel. unc. reduction (%)
1	Cl35 (n,p)	2	6.6	0.9	37.4
2	Cl35 (n,p)	3	12	1.6	14.9
3	Pu239(n,gamma)	4	8.4	1.3	12
4	Cl35 (n,p)	1	8.4	1.2	8.9
5	Pu239(n,gamma)	3	10.4	2.0	4.6
6	Fe56(n,elastic)	3	9.2	1.9	4.3
7	Fe56(n,gamma)	3	16.8	2.8	1.8
8	Pu240(n,gamma)	2	59.3	4.2	1.8
9	Cl35(n,p)	4	11.1	3.7	1.5
10	Fe56(elastic)	2	5.4	1.9	1.3

Boundaries of energy groups

Group#	Lower energy (eV)	Upper energy (eV)	Description
1	2.23130E+06	1.96403E+07	Above threshold fertile
2	4.97871E+05	2.23130E+06	Above threshold inelastic
3	6.73795E+04	4.97871E+05	Continuum to URR
4	2.03468E+03	6.73795E+04	URR
5	2.26033E+01	2.03468E+03	RRR
6	5.40000E-01	2.26033E+01	Epithermal
7	1.40000E-05	5.40000E-01	Thermal

Review comment:

Entry Status:
Work in progress (as of SG-C review of May 2022)

Main references:
Please report any missing information to hprlinfo@oecd-nea.org

Additional file attached:Fig1_Sensitivity.png
Additional file attached:Fig2_35Cl_np.png

Energy Range	Uncertainty (%)
	Initial	GFR	ADMAB
67.4 -183 keV	7	4	2
24.8 -67.4 keV	8	3	2
9.12 -24.8 keV	7	3	2
2.03 -9.12 keV	7	3	2
0.454-2.03 keV	7	3	3

Energy Range	Initial versus target uncertainties (%)
	Initial	ABTR	SFR	EFR	GFR	LFR
6.07-19.6 MeV	29	12			7
2.23-6.07 MeV	20	3	5	4	2	3
1.35-2.23 MeV	21	4	5	4	2	2
0.498-1.35 MeV	12	7	6	5	2	2
67.4-183 keV	11	7		9	7	4

Energy Range	Target versus initial uncertainties (%)
	Initial	ABTR	SFR	EFR
1.35 - 2.23 MeV	13		9
0.498 - 1.35 MeV	28	10	4	8