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 | Created date | Accepted date | Ongoing action | Archived Date |
Fission | Fast and Thermal Reactors | 04-APR-08 | 12-SEP-08 | Y |
Send a comment on this request to NEA.
Requester: Prof. Massimo SALVATORES at CADARACHE, FR
Email:
Project (context): NEA WPEC Subgroup 26
Impact:
Accuracy:
Justification document:
Comment from requester:
Additional file attached: SG26-report.html
Review comment:
Entry Status:
Main recent references: Experiments Theory/Evaluation Validation
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).
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
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).
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.
See appendix A of the attached report.
Work in progress (as of SG-C review of May 2018)
Please report any missing information to hprlinfo@oecd-nea.org