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 keff 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).
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:
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
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 keff 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).
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
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
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 keff 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
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 keff, 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).
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
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
Validation
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 keff, 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).
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:
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
Validation
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).
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.
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
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
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 | 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).
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:
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
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
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 | 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).
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:
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
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
Additional file attached:1-s2.0-S0306454906000296-main.pdf
Additional file attached: