26-Fe-56(n,inl)

ID 34
Type H - High priority request
Target 26-Fe-56
Reaction (n,inl)
Quantity SIG - Cross section
Incident energy 0.5 MeV - 20 MeV
Accuracy 2-13 %
Secondary Energy/Angle Emis spec.
Field(s) Fission
Subfield ADMAB and SFR
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).

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 825/94-pu-242-n-fWPEC 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 ABTR SFR EFR LFR ADMAB
    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 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

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

Please report any missing information to hprlinfo@oecd-nea.org

Experiments

  • R.O. Nelson et al., Cross-section standards for neutron-induced gamma-ray production in the MeV energy range, ND2004, AIP Conference Proceedings 769 (2004) 838, EXFOR 14118
  • C.M. Castaneda et al., Gamma ray production cross sections from the bombardment of Mg, Al, Si, Ca and Fe with medium energy neutrons, NIM/B 260 (2007) 508, EXFOR 14151
  • Z. Wang et al., Study on coincidence measurement for 56Fe(n,xng) reaction cross section, Atomic Energy Science and Technology 47 (2013) 2177, EXFOR 32720
  • A. Negret et al., Cross-section measurements for the 56Fe(n,xng) reactions, PRC 90 (2014) 034602, EXFOR 23073
  • R. Beyer et al., Inelastic scattering of fast neutrons from excited states in 56Fe, NP A 927 (2014) 41, EXFOR 23134
  • A.M.Daskalakis et al., Quasi-differential elastic and inelastic neutron scattering from iron in the MeV energy range, Annals of Nuclear Energy 110 (2017) 603
  • Ongoing work at University of Kentucky, cf. J.R. Vanhoy et al., Differential Cross Section Measurements at the University of Kentucky -- Adventures in Analysis, NEMEA-7, NEA Report NEA/NSC/DOC(2014)13 , p.85
  • related measurement by A. Negret, et al., Cross-section measurements for the 57Fe(n,ng)57Fe and 57Fe(n,2ng)56Fe reactions, PRC 96 (2017) 024620 - See section C which discusses the 847keV gamma production cross section in the 57Fe(n,2n) reaction. This contributes (above En=8-9 MeV) to the 847keV gamma production cross section in natFe(n,n') and therefore may represent a source of uncertainty for the 56Fe(n,inl) measurements performed with natFe targets.
  • related measurement by A. Olacel, et al., Neutron inelastic scattering on 54Fe, Eur. Phys. J. A 54 (2018) 183
  • E. Pirovano, et al., Cross section and neutron angular distribution measurements of neutron scattering on natural iron, PRC 99 (2019) 024601

Theory/Evaluation

Validation

  • 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
  • A. Shaw, et al., Validation of Continuous-Energy ENDF/B-VIII.0 16O, 56Fe, and 63,65Cu Cross Sections for Nuclear Criticality Safety Applications, Nuclear Science and Engineering 195 (2021) 412