NEA Nuclear Data High Priority Request List, HPRL

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Request ID19 Status of the request High Priority request
TargetReaction and processIncident EnergySecondary energy or angleTarget uncertaintyCovariance
 94-PU-238 (n,f) SIG  9 keV-6 MeV  See details Y
FieldSubfieldDate Request createdDate Request acceptedOngoing action
 Fission Fast Reactors (ADMAB) 31-MAR-08 11-SEP-08 

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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 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 RangeInitial versus target uncertainties (%)
InitialSFREFRGFRLFRADMAB
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.

Comments from evaluator/experimentalist:

Comments for achieved accuracy:
See accuracy table

Review comment:

Additional file attached: SG26-report.html