|Type||H - High priority request|
|Quantity||SIG - Cross section|
|Incident energy||0.5 eV - 5.0 keV|
|Latest review date||16-May-2018|
Dr Gilles NOGUERE at CAD-DER, FR
In nuclear industry hafnium is used as neutron absorbing material to regulate the fission process. Interpretations of critical experiments with UOx fuel conducted by CEA in the AZUR zero-power reactors has shown systematic underestimation of the reactivity worth that may be attributed to an overestimated natural hafnium capture cross section in the epi-thermal energy range [1,2].
Requested accuracy can be found in the CEA Report "Correlations entre données nucleaires et experiences integrales a plaques, le cas du hafnium", Jean-Marc Palau, CEA-R-5843 (1997). The target accuracy on the effective capture integral has to be lower than 4%
 David Bernard, "Determination des incertitudes liés aux grandeurs neutroniques d'interet des reacteurs a eau presurisee a plaques combustibles et application aux etudes de conformite", University Blaise Pascal, Clermont-Ferrand II, France (2001).
 G. Noguere, A. Courcelle, J.M. Palau, O.Litaize, "Low neutron energy cross sections of the hafnium isotopes", JEFDOC-1077.pdf, OECD-NEA, Issy-les-Moulineaux, France (2005).
 G. Noguere, A. Courcelle, P. Siegler, J.M. Palau, O. Litaize, "Revision of the resolved resonance range of the hafnium isotopes for JEFF-3.1", Technical note CEA Cadarache NT-SPRC/LEPH-05/2001 (2005).
Comment from requester
Neither the JENDL3.3 nor the JEFF3.1 libraries, that were recently issued, solve the problem. In fact, this was observed for JENDL3.3 before the JEFF3.1 file was constructed. As a result the JEFF3.1 file has been produced with this problem in mind taken into consideration the recent data from Trbovich et al. obtained at RPI . Finally, a 400 pcm underestimation remains that is likely due to interfering isotopic contributions in the resolved energy region. New high resolution measurements appear needed, and would be particularly valuable if they can distinguish the contributions of different isotopes.
Calculations on the AZUR configuration using the JEFF3.1 library give a Hf reactivity worth of about -300 pcm .
Completed (as of SG-C review of May 2018) - The measurements performed at RPI [Trbovich:2009] and JRC-Geel [Ware:2010] allowed to significantly improve the Hf isotopes in JEFF, which now gives satisfactory results for reactivity worth due to Hf data [Noguere:2009].
Main recent references
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