92-U-235(n,f)

ID 4
Type
Target 92-U-235
Reaction (n,f)
Quantity prompt g - Prompt gamma production
Incident energy Thermal - Fast
Accuracy 7.5 %
Secondary Energy/Angle Eg=0-10MeV
Field(s) Fission
Subfield LWR, Gen-IV
Accepted date 12-May-2006
Status Work in progress
Latest review date 22-Apr-2022
Requester

Prof. Gerald RIMPAULT at CAD-DER, FR

Project (context)

JEFF, NEA WPEC Subgroup 27

Impact

The four fast reactor systems of GenIV feature innovative core characteristics for which gamma-ray heating estimates for non-fuel zones require an uncertainty of 7.5% [1]. For the experimental Jules Horowitz Reactor (RJH) at Cadarache a similar requirement appears [2]. Recent studies show evidence of discrepancies on integral measurement in MASURCA, EOLE and MINERVE, from which it is clear that the expectations for GenIV systems and the RJH thermal reactor are not met [3]. Gamma-ray energy release is dominated by Pu-239 and U-235.

Accuracy

7.5% on the total gamma energy
7.5% on multiplicity
Best accuracy achievable for the gamma spectrum shape

Justification document

Reference 1: G. Rimpault, Proc. Workshop on Nuclear Data Needs for Generation IV, April 2005, Antwerp, Belgium
Reference 2: D. Blanchet, Proc. M&C 2005, Int. Topical Meeting on Mathematics and Computation, Supercomputing, Reactor Physics and Nuclear and Biological Applications, Sep. 2005, Avignon, France
Reference 3: 'Needs for accurate measurements of spectrum and multiplicity of prompt gammas emitted in fission', G. Rimpault, A. Courcelle and D. Blanchet, CEA/Cadarache – DEN/DER/SPRC.

Comment from requester

Forty percent of the total gamma-ray energy release results from prompt decay of fission products. No comprehensive analytic expressions exist and Hauser-Feshbach model calculations are involved and presently lack sufficient knowledge to warrant a solution of the problem. New measurements would be needed to guide new evaluation efforts. Present evaluations are based on measurements from the seventies.

Review comment

Discrepancies observed for C/E ratios in various benchmarks range from 10 to 28%. The request is well motivated and based on a considerable effort.

Entry status

Work in progress (as of SG-C review of May 2018)
Pending new evaluation or validation (as of SG-C review of June 2019)
Pending new evaluation or validation (as of SG-C review of May 2021) with recommendations for priority validation of the latest evaluations

Main recent references

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

Experiments

  • E. Kwan, et al., Prompt energy distribution of 235U(n,f) gamma at bombarding energies of 1–20 MeV, NIM A 688 (2012) 55, EXFOR 14413
  • A. Oberstedt et al., Improved values for the characteristics of prompt-fission g-ray spectra from the reaction 235U(nth,f), PRC 87 (2013) 051602(R), EXFOR 31729
  • A. Chyzh, et al., Total prompt g-ray emission in fission of U-235, Pu-239,241, and Cf-252, PRC 90 (2014) 014602, EXFOR 14361
  • M. Lebois, et al., Comparative measurement of prompt fission g-ray emission from fast-neutron-induced fission of U-235 and U-238, PRC 92 (2015) 034618, EXFOR 23299
  • Ongoing work at IRMM-IPNO, S. Oberstedt, et al., Future research program on prompt g-ray emission in nuclear fission, Eur. Phys. J. A (2015) 51:178
  • Ongoing work at JAEA, see H. Makii et al., Measurement of High-Energy Prompt g-rays from Neutron-Induced Fission of 235U, FIESTA 2017

Theory/Evaluation

  • O. Serot et al., Prompt Fission Gamma Spectra and Multiplicities for JEFF-3.3, JEF/DOC-1828, JEFF Meeting, OECD, Paris (2017)
  • D. Brown et al., ENDF/B-VIII.0: The 8th Major Release of the Nuclear Reaction Data Library with CIELO-project Cross Sections, New Standards and Thermal Scattering Data, NDS 148 (2018) 1
  • I. Stetcu et al., Evaluation of the Prompt Fission Gamma Properties for Neutron Induced Fission of U-235,238 and Pu-239, NDS 163 (2020) 261
  • A. Tudora, Prompt gamma-ray results of two deterministic modelings of prompt emission in fission, Eur. Phys. J. A 56 (2020) 128