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Request ID42 Type of the request High Priority request
TargetReaction and processIncident EnergySecondary energy or angleTarget uncertaintyCovariance
 82-PB-207 (n,inl) SIG  0.5 MeV-6 MeV  See details Y
FieldSubfieldCreated dateAccepted dateOngoing actionArchived Date
 Fission Fast Reactors 15-SEP-08 15-SEP-08 Y

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Requester: Prof. Massimo SALVATORES at CADARACHE, FR

Project (context): CEA Cadarache

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).
This request is specific to the SFR and ADMAB lead-cooled systems.

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 RangeInitial versus target uncertainties (%)
   λ=1 λ≠1,a λ=1 λ≠1,a
6.07 - 19.6 MeV 18 7 9
2.23 - 6.07 MeV 5 3 4
1.35 - 2.23 MeV 14 5 7
0.498- 1.35 MeV 11 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 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.

Additional file attached: SG26-report.html

Review comment:
Data have been taken at IRMM for using the (n,n’g)-technique. Experimental results have been included in a new evaluation. The experimental uncertainties are better than 5% in most of the energy range of interest and therefore the request is nearly met. Complementary data for the neutron emission spectrum (angular distribution) would be of interest.

Entry Status:
Pending new evaluation or validation (as of SG-C review of May 2018)

Main recent references:
Please report any missing information to


  • L.C. Mihailescu et al., Neutron (n,xng) cross-section measurements for 52Cr, 209Bi, 206,207,208Pb from threshold up to 20 MeV, PhD thesis, Report EUR 22343 EN, European Communities (2006), EXFOR 23286
  • V.E. Guiseppe et al., Neutron inelastic scattering and reactions in natural Pb as a background in neutrinoless double-beta-decay experiments, PRC 79 (2009) 054604, EXFOR 14231
  • A. Plompen and A. Negret (Eds), Uncertainties and covariances for inelastic scattering data, Report EUR 25208 EN, European Union, 2011
  • M. Kerveno et al., From gamma emissions to (n,xn) cross sections of interest: The role of GAINS and GRAPhEME in nuclear reaction modeling, EPJA 51 (2015) 167


  • D. Rochman and A. Koning, Pb and Bi neutron data libraries with full covariance evaluation and improved integral tests, NIM A 589 (2008) 85