NSRR experiments on LWR fuel behaviour under reactivity initiated accident conditions

JAERI has utilized the NSRR to perform accident simulating experiments of light water reactor fuels since 1975. Over 1200 experiments have successfully been carried out with fresh fuel rods to clarify fuel behaviour under RIA conditions and to obtain fuel failure limit. The results have been reflected in safety evaluation guidelines for the RIA in some other countries as well as in Japan. The NSRR facilities were modified to test high burnup fuels, and more than 70 experiments have been performed with irradiated fuel rods since 1989. These experiments have provided necessary information for the safety assurance of high burnup LWR fuels. Further safety research using the NSRR is expected to support fuel burnup extension and MOX fuel introduction. In order to meet the requirements, the capability of the NSRR facilities is being extended