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Request ID6 Status of the request General request
TargetReaction and processIncident EnergySecondary energy or angleTarget uncertaintyCovariance
 92-U-233 (n,g) SIG  10 keV-1.0 MeV  9 Y
FieldSubfieldDate Request createdDate Request acceptedOngoing action
 Fission Fast reactors 28-APR-06 13-MAR-07 

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Requester: Dr Gilles NOGUERE at CAD-DER, FR

Project (context): JEFF

U-233 is the main isotope of relevance to the Th/U fuel cycle. Its most important cross section is the fission cross section. The direct impact of the U-233 capture cross section is rather limited on most reactor related parameters but breeding. However, reliable capture data are needed for the evaluation work.

The target accuracy on the capture cross section in the unresolved resonance range should be better than 10%

Justification document:
Interpretations of the Profil and Profil-2 experiments [1] performed in the fast reactor Phenix of the CEA Marcoule have shown an underestimation of 9% the U-233 effective capture cross section available in the latest version of the European library JEFF-3.1. The accuracy of the capture data available in EXFOR is not suitable to perform a new evaluation.
[1] J. Tommasi, E. Dupont and P. Marimbeau., "Analysis of Sample Irradiation Experiments in Phénix for JEFF-3.0 Nuclear Data Validation", Nucl. Sci. Eng. 154 (2006) 119-133
[2] J.C.Hopkins and B.C.Diven, "Neutron capture to fission ratios in U-233, U-235, Pu-239", Nucl. Sci. Eng. 12 (1962)169
[3] G. Noguere, E. Dupont, J. Tommasi and D. Bernard, "Nuclear data needs for actinides by comparison with post irradiation experiments", Technical note CEA Cadarache, NT-SPRC/LEPH-05/204 (2005) (see below).

Comment from requester:

Comments from evaluator/experimentalist:
Owing to the difficulty in measuring the U-233(n,g) cross section, new evaluation has to take into account the Profil results [3] (see below).
CENBG has proposed an experiment to study the ratio of the capture to the fission cross section at IRMM in the frame of the NUDAME transnational access scheme (

Comments for achieved accuracy:
Owing to the integral trend given by the interpretation of PROFIL, the final accuracy on the effective capture cross section should be lower than 9%.

Review comment:
Adrien Bidaud, CENBG, Bordeaux, independently investigated the sensitivity of the regeneration of U-233 to various cross sections. Sensitivities were evaluated considering a molten salt reactor under the constraints of criticality and isotopic equilibrium. Large sensitivities are observed for the capture cross section and for nu-bar. He concludes that "Any effort done to confirm the neutron yields and the capture cross section or at least to confirm their uncertainty would be very much appreciated." The energy range of interest is below that of the current request.

Additional file attached:
Additional file attached: NT-Profil.pdf