| ID | 33 |
|---|---|
| Type | H - High priority request |
| Target | 94-Pu-241 |
| Reaction | (n,g) |
| Quantity | SIG - Cross section |
| Incident energy | 0.1 eV - 1.35 MeV |
| Accuracy | 2-15 % |
| Field(s) | Fission |
| Subfield | Fast Reactors (VHTR) |
| Accepted date | 12-Sep-2008 |
| Status | Work in progress |
| Latest review date | 28-Apr-2022 |
Requester
Prof. Massimo SALVATORES at CADARACHE, 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).
Requested accuracy is required to meet target accuracies for keff 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
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 recent references
Please report any missing information to hprlinfo@oecd-nea.org
Theory/Evaluation
Validation
