| ID | 35 |
|---|---|
| Type | H - High priority request |
| Target | 94-Pu-241 |
| Reaction | (n,f) |
| Quantity | SIG - Cross section |
| Incident energy | 0.5 eV - 1.35 MeV |
| Accuracy | 2-12 % |
| Field(s) | Fission |
| Subfield | Fast and Thermal Reactors |
| 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
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 825/94-pu-242-n-fWPEC 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 recent references
Please report any missing information to hprlinfo@oecd-nea.org
Experiments
Theory/Evaluation
Validation
