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 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)
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 | 6 |
Type of the request | General request |
Target | Reaction and process | Incident Energy | Secondary energy or angle | Target uncertainty | Covariance |
92-U-233 | (n,g) SIG | 10 keV-1.0 MeV | | 9 | Y |
Field | Subfield | Date Request created | Date Request accepted | Ongoing action |
Fission | Fast reactors | 28-APR-06 | 13-MAR-07 | Y |
Requester: Dr Gilles NOGUERE at CAD-DER, FR
Email: gilles.noguere@cea.fr
Project (context): JEFF
Impact:
U-233 is the main isotope of relevance to the Th/U fuel cycle. Its most important cross section is the fission cross section. The direct impact of the U-233 capture cross section is rather limited on most reactor related parameters but breeding. However, reliable capture data are needed for the evaluation work.
Accuracy:
The target accuracy on the capture cross section in the unresolved resonance range should be better than 10%
Justification document:
Interpretations of the Profil and Profil-2 experiments [1] performed in the fast reactor Phenix of the CEA Marcoule have shown an underestimation of 9% the U-233 effective capture cross section available in the latest version of the European library JEFF-3.1. The accuracy of the capture data available in EXFOR is not suitable to perform a new evaluation.
References:
[1] J. Tommasi, E. Dupont and P. Marimbeau., "Analysis of Sample Irradiation Experiments in Phénix for JEFF-3.0 Nuclear Data Validation", Nucl. Sci. Eng. 154 (2006) 119-133
[2] J.C.Hopkins and B.C.Diven, "Neutron capture to fission ratios in U-233, U-235, Pu-239", Nucl. Sci. Eng. 12 (1962)169
[3] G. Noguere, E. Dupont, J. Tommasi and D. Bernard, "Nuclear data needs for actinides by comparison with post irradiation experiments", Technical note CEA Cadarache, NT-SPRC/LEPH-05/204 (2005) (see below).
Comment from requester:
Review comment:
Owing to the difficulty in measuring the U-233(n,g) cross section, new evaluation has to take into account the Profil results [3]. Owing to the integral trend given by the interpretation of PROFIL, the final accuracy on the effective capture cross section should be lower than 9%.
Adrien Bidaud, CENBG, Bordeaux, independently investigated the sensitivity of the regeneration of U-233 to various cross sections. Sensitivities were evaluated considering a molten salt reactor under the constraints of criticality and isotopic equilibrium. Large sensitivities are observed for the capture cross section and for nu-bar. He concludes that "Any effort done to confirm the neutron yields and the capture cross section or at least to confirm their uncertainty would be very much appreciated." The energy range of interest is below that of the current request.
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
- C. Carrapico, E. Berthoumieux, et al., Neutron induced capture and fission discrimination using calorimetric shape decomposition, NIM A 704 (2013) 60-67, EXFOR 23071
- M. Bacak, et al., A compact multi-plate fission chamber for the simultaneous measurement of 233U capture and fission cross-sections, ND2016, EPJ Conferences 146 (2017) 03027
Theory/Evaluation
- A. Trkov, et al., Evaluated nuclear data for nuclides within the Thorium-Uranium fuel cycle, IAEA Report STI/PUB/1435, 2010
Additional file attached:
Additional file attached:NT-Profil.pdf
Request ID | 9 |
Type of the request | General request |
Target | Reaction and process | Incident Energy | Secondary energy or angle | Target uncertainty | Covariance |
92-U-233 | (n,g) nubar,SIG | Thermal-10 keV | | .5 | Y |
Field | Subfield | Date Request created | Date Request accepted | Ongoing action |
Fission | Molten Salt Reactors | 19-APR-07 | 19-APR-07 | Y |
Requester: Dr Adrien BIDAUD at LPSC, FR
Email: bidaud@lpsc.in2p3.fr
Project (context): JEFF
Impact:
U-233 is the main isotope of relevance to the Th/U fuel cycle. The present request concerns the viability of Th/U fueled molten salt reactors which requires that the amount of U-233 generated equals that which is destroyed.
Accuracy:
0.5% in nubar, 5% for the (n,g) cross section
Justification document:
Uncertainties on the predicted regeneration gain inferred from the uncertainties of the nuclear data have been estimated showing a 4200 pcm uncertainty for a regeneration gain designed to be 200 pcm, i.e. very close to a complete balancing of production and destruction of U-233. The main culprits are nubar contributing 2200 pcm and the capture cross section contributing 3260 pcm. A target accuracy of 2000 pcm is required to facilitate defining the reprocessing scheme for a molten salt reactor.
Reference:
A. Bidaud, Impact of Nuclear Data Uncertainties on a GEN IV Thorium Reactor at Equilibrium (attached document).
CEA Technical Note NT-SPRC/LEPH-05/204, G. Noguere et al (attachment 2).
Comment from requester:
Owing to the difficulty in measuring the U-233(n,g) cross section, a new evaluation could be done on the basis of the Profil results (see CEA Technical Note NT-SPRC/LEPH-05/204).
Review comment:
Any effort done to reduce the uncertainties on neutron yields and capture cross section down to less than 1% and about 5% respectively or at least to confirm their uncertainty would be very much appreciated. If the uncertainty on RG could be reduced down to 2000pcm, the needed reprocessing scheme could be designed with more confidence, and then the research on specific goals such as minor actinide and protactinium extraction could be prioritized.
Nubar is currently known to 1%, the capture cross section to 10%. The above mentioned target uncertainties implies that the desired accuracies for improved data are approximately half these numbers.
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.E. Escher and F.S. Dietrich, Cross sections for neutron capture from surrogate measurements: An examination of Weisskopf-Ewing and ratio approximations, PRC 81 (2010) 024612
- C. Carrapico, E. Berthoumieux, et al., NIM A 704 (2013) 60-67, EXFOR 23071
- M. Bacak, et al., A compact multi-plate fission chamber for the simultaneous measurement of 233U capture and fission cross-sections, ND2016, EPJ Conferences 146 (2017) 03027
Theory/Evaluation
- A. Trkov, et al., Evaluated nuclear data for nuclides within the Thorium-Uranium fuel cycle, IAEA Report STI/PUB/1435, 2010
Additional file attached:U233_MSR_Impact.pdf
Additional file attached:NT-Profil.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 | 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: massimo.salvatores@cea.fr
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 keff 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).
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:
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
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
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: massimo.salvatores@cea.fr
Project (context): CEA Cadarache
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).
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).
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:
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
Additional file attached:SG26-report.html
Additional file attached:
Request ID | 55 |
Type of the request | Special Purpose Quantity |
Target | Reaction and process | Incident Energy | Secondary energy or angle | Target uncertainty | Covariance |
92-U-238 | (n,g) SIG,SPA | 235U(n,f) | | 2-5 | Y |
Field | Subfield | Date Request created | Date Request accepted | Ongoing action |
Dosimetry | Fast fission, D-T fusion | 06-OCT-17 | 06-OCT-17 | |
Requester: Dr Stanislav SIMAKOV at KARLSRUHE, GER
Email: stanislav.simakov@partner.kit.edu
Project (context): IRDFF project
Impact:
The International Reactor Dosimetry and Fusion File (IRDFF) aims at providing evaluated neutron dosimetry reactions validated for all applications related to fission reactors and fusion technology development [IAEA2017].
Accuracy:
2%-5%
Justification document:
Accurate cross sections as well as spectrum-averaged cross sections (SACS) in relevant and well-characterized neutron fields are essential for improvement and validation of the evaluated data [Simakov2017].
Comment from requester:
New measurements of the spectrum-averaged cross section are requested to solve C/E discrepancy. See SPA_CE_U235.pdf below.
References
- [IAEA2017] IAEA CRP on Testing and Improving the International Reactor Dosimetry and Fusion File (IRDFF),
http://www-nds.iaea.org/IRDFFtest/.
- [Simakov2017] S. Simakov, et al., “Proposals for new measurements for IRDFF community and HPRL”, September 2017.
Review comment:
Non-threshold reactions measured in fast spectra such as the 252Cf(sf) and 235U(nth,f) spectrum tend to have their spectrum averaged cross section dominated by scattering contributions and ‘room-return’ neutrons. Experiments should be designed to minimize these contributions and maximize the reaction rate from the primary source. For new experiments best estimates must be provided by detailed Monte Carlo calculation of the spectrum realized in the experiment and the Monte Carlo model must be made available to IRDFF to facilitate validation of new proposals for the cross section. In all cases it is advised to publish both the fully corrected SACS and the measured reaction rates of the primary reaction and the monitor reactions used for normalization and validation of the model. The measured reaction rates must be provided with a full covariance matrix.
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
Additional file attached:Simakov2017.pdf
Additional file attached:SPA_CE_U235.pdf
Request ID | 65 |
Type of the request | Special Purpose Quantity |
Target | Reaction and process | Incident Energy | Secondary energy or angle | Target uncertainty | Covariance |
92-U-238 | (n,2n) SIG,SPA | 252Cf(sf)-235U(n,f) | | 2-5 | Y |
Field | Subfield | Date Request created | Date Request accepted | Ongoing action |
Dosimetry | Fast fission, D-T fusion | 06-OCT-17 | 06-OCT-17 | |
Requester: Dr Stanislav SIMAKOV at KARLSRUHE, GER
Email: stanislav.simakov@partner.kit.edu
Project (context): IRDFF project
Impact:
The International Reactor Dosimetry and Fusion File (IRDFF) aims at providing evaluated neutron dosimetry reactions validated for all applications related to fission reactors and fusion technology development [IAEA2017].
Accuracy:
2%-5%
Justification document:
Accurate cross sections as well as spectrum-averaged cross sections (SACS) in relevant and well-characterized neutron fields are essential for improvement and validation of the evaluated data [Simakov2017].
Comment from requester:
New measurements of the spectrum-averaged cross section are requested to solve C/E discrepancy and for improvement of the prompt fission neutron spectrum at high energy. See CE_Cf252U235_and_HighThreshold.pdf below.
References
- [IAEA2017] IAEA CRP on Testing and Improving the International Reactor Dosimetry and Fusion File (IRDFF),
http://www-nds.iaea.org/IRDFFtest/.
- [Simakov2017] S. Simakov, et al., “Proposals for new measurements for IRDFF community and HPRL”, September 2017.
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
Additional file attached:Simakov2017.pdf
Additional file attached:CE_Cf252U235_and_HighThreshold.pdf
Request ID | 100 |
Type of the request | Special Purpose Quantity |
Target | Reaction and process | Incident Energy | Secondary energy or angle | Target uncertainty | Covariance |
92-U-235 | (n,f),(p,f) SIG | 100 MeV-500 MeV | | 5 | Y |
Field | Subfield | Date Request created | Date Request accepted | Ongoing action |
Standard | ADS | 23-MAR-18 | 11-APR-18 | Y |
Requester: Dr Roberto CAPOTE NOY at IAEA, AUT
Email: roberto.capotenoy@iaea.org
Project (context):
Impact:
Improvements in the standard cause all measurements relative to that standard to be improved. See Ref. [1].
Accuracy:
5% of the cross-section
Justification document:
There are discrepancies (see Fig. 24 in section III.E, pp.161-162 of Ref. [1]) between different theoretical calculations, data estimated from the (p,f) reaction, and the only measured data set of U-238(n,f) cross section at those energies [2]. New measurements of absolute cross sections of U-235 or U-238 (n,f) and/or U-235 or U-238 (p,f) reactions in the energy range where pion channels begin to play an important role (100-500 MeV) are needed to solve the discrepancies and to reduce the uncertainties of the Neutron Standards in that energy range.
References
- A.D. Carlson, et al., Evaluation of the Neutron Data Standards, Nuclear Data Sheets 148, 143-188 (2018)
- Z.W. Miller, A Measurement of the Prompt Fission Neutron Energy Spectrum for 235U(n,f) and the Neutron-induced Fission Cross Section for 238U(n,f), PhD Thesis, University of Kentucky (2015); https://uknowledge.uky.edu/physastron_etds/29/
Comment from requester:
At high-energy the (n,f) cross-section can be inferred with rather low uncertainty from (p,f) cross-section measurements, and thanks to this can be used in the neutron standards evaluation.
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
- U-235 measurement performed at n_TOF in 2018
Theory/Evaluation
- B. Marcinkevicius, S. Simakov, V. Pronyaev, 209Bi(n,f) and natPb(n,f) cross sections as a new reference and extension of the 235U, 238U and 239Pu(n,f) standards up to 1 GeV, IAEA Report INDC(NDS)-0681
- A.D. Carlson et al., Evaluation of the Neutron Data Standards, NDS 148 (2018) 143
Additional file attached:
Additional file attached:
Request ID | 101 |
Type of the request | Special Purpose Quantity |
Target | Reaction and process | Incident Energy | Secondary energy or angle | Target uncertainty | Covariance |
92-U-238 | (n,f),(p,f) SIG | 100 MeV-500 MeV | | 5 | Y |
Field | Subfield | Date Request created | Date Request accepted | Ongoing action |
Standard | ADS | 23-MAR-18 | 11-APR-18 | Y |
Requester: Dr Roberto CAPOTE NOY at IAEA, AUT
Email: roberto.capotenoy@iaea.org
Project (context):
Impact:
Improvements in the standard cause all measurements relative to that standard to be improved. See Ref. [1].
Accuracy:
5% of the cross-section
Justification document:
There are discrepancies (see Fig. 24 in section III.E, pp.161-162 of Ref. [1]) between different theoretical calculations, data estimated from the (p,f) reaction, and the only measured data set of U-238(n,f) cross section at those energies [2]. New measurements of absolute cross sections of U-235 or U-238 (n,f) and/or U-235 or U-238 (p,f) reactions in the energy range where pion channels begin to play an important role (100-500 MeV) are needed to solve the discrepancies and to reduce the uncertainties of the Neutron Standards in that energy range.
References
- A.D. Carlson, et al., Evaluation of the Neutron Data Standards, Nuclear Data Sheets 148, 143-188 (2018)
- Z.W. Miller, A Measurement of the Prompt Fission Neutron Energy Spectrum for 235U(n,f) and the Neutron-induced Fission Cross Section for 238U(n,f), PhD Thesis, University of Kentucky (2015); https://uknowledge.uky.edu/physastron_etds/29/
Comment from requester:
At high-energy the (n,f) cross-section can be inferred with rather low uncertainty from (p,f) cross-section measurements, and thanks to this can be used in the neutron standards evaluation.
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
- B. Marcinkevicius, S. Simakov, V. Pronyaev, 209Bi(n,f) and natPb(n,f) cross sections as a new reference and extension of the 235U, 238U and 239Pu(n,f) standards up to 1 GeV, IAEA Report INDC(NDS)-0681
- A.D. Carlson et al., Evaluation of the Neutron Data Standards, NDS 148 (2018) 143
Additional file attached:
Additional file attached: