Analysis of MISTRAL Experiments with JENDL-3.2

Abstract

Nuclear Power Engineering Corporation has been analyzing measurement data of MISTRAL, a LWR MOX core physics experimental program, with a deterministic code system of the diffusion and the transport theories, SRAC, and a Monte Carlo transport code, MVP, based on JENDL-3.2. The program consists of one reference U02 core, two homogeneous full MOX cores and one full MOX PWR mock-up core that have higher moderation ratio than the conventional lattice. The measurement parameters cover critical masses, boron concentrations, radial and axial core power distribution, spectrum indexes, conversion factors, effective delayed neutron fractions, iso-thermal temperature coefficients, boron efficiency, single absorber worth, water hole worth, absorber cluster worth and void worth. Critical keff calculations show a slight overestimate for MOX cores and a small systematic trend with aging of MOX fuel. Power distribution calculations show good agreement with the measurements in both homogeneous and mock-up cores. Measured spectrum indexes of fissile isotopes are well reproduced by the calculation. For other measurements, calculated results well reproduce the measurements within one or two times of the experimental error. The analysis verifies the validity of JENDL-3.2 and the analysis methods for the high moderation LWR MOX cores.