KFK Iron Sphere Neutron and Gamma Benchmark Sensitivity/uncertainty Analysis to n/g Nuclear Data and Potential Use for ND Improvement
The SUSD3D computer code has been recently updated with new features including the extension of the nuclear data sensitivity and uncertainty (S/U) analysis to gammaray quantities such as gamma flux and heating. Gamma relevant nuclear data can be processed allowing S/U for coupled neutron/gamma problems. The code is available from the NEA data Bank as part of the new version of the XSUN-2023 computer code package which includes also the latest updates of the cross section and covariance matrix libraries based on the JEFF-3.3, ENDF/B-VIII.0 and FENDL-3.2 evaluations. The code was applied to the S/U analysis of the KFK neutron and g-ray leakage benchmark to evaluate the sensitivities to iron neutron and gamma cross sections. Sensitivity of neutron and gamma flux to the iron inelastic, elastic and capture cross sections was found to depend in an interesting way on iron shell thickness, even changing from positive to negative, which suggests that these type of measurements (in particular if repeated using more modern measurement techniques) can be powerful for the validation of iron cross section in the high energy ranges. The need for the evaluation of gamma ray covariances is raised.