NEA Nuclear Data High Priority Request List, HPRL


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Request ID34 Type of the request High Priority request
TargetReaction and processIncident EnergySecondary energy or angleTarget uncertaintyCovariance
 26-FE-56 (n,inl) SIG  0.5 MeV-20 MeV Emis spec. See details Y
FieldSubfieldDate Request createdDate Request acceptedOngoing action
 Fission ADMAB and SFR 04-APR-08 12-SEP-08 Y

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Requester: Prof. Massimo SALVATORES at CADARACHE, FR

Project (context): NEA WPEC Subgroup 26

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).

Somewhat different requested accuracy is required to meet target accuracies for keff, peak power and void coefficient for the Accelerator-Driven Minor Actinides Burner (ADMAB) and for keff for the Sodium-cooled Fast Reactor in a TRU burning configuration, i.e., with a Conversion Ratio CR<1 (SFR). 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).

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,b λ=1 λ≠1,a λ≠1,b λ=1 λ≠1,a λ=1 λ≠1,a λ=1 λ≠1,a
6.07 - 19.6 MeV 13 9 11 13
2.23 - 6.07 MeV 7 4 5 7 3 3
1.35 - 2.23 MeV 25 6 7 10 3 4 7 7 7 4 6 2 2
0.498 - 1.35 MeV 16 8 9 13 3 4 6 8 9 4 5 2 2

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:
Experimental work was recently completed at IRMM. The impact of the new experimental results is studied at CEA/Cadarache. Uncertainties below 5% will require a major further improvement.

Entry Status:
Work in progress (as of SG-C review of May 2018)

Main recent references:
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  • M. Herman et al., Evaluation of Neutron Reactions on Iron Isotopes for CIELO and ENDF/B-VIII.0, NDS 148 (2018) 214


  • C. Jouanne, Sensitivity of the Shielding Benchmarks on Variance-covariance Data for Scattering Angular Distributions, Nuclear Data Sheets 118 (2014) 384
  • I. Kodeli, A. Trkov, G. Zerovnik, Benchmark analysis of iron neutron cross-sections, Jozef Stefan Institute, Ljubljana, Slovenia, Report IJS-DP-11544 (2014)
  • M. Salvatores, et al., Methods and Issues for the Combined Use of Integral Experiments and Covariance Data: Results of a NEA International Collaborative Study, Nuclear Data Sheets 118 (2014) 38
  • G. Palmiotti, et al., Combined Use of Integral Experiments and Covariance Data, Nuclear Data Sheets 118 (2014) 596