OVERVIEW

The verification test programs of high burnup BWR and PWR fuels have been carried out by Nuclear Power Engineering Corporation under the sponsorship of Ministry of Economy, Trade and Industry since 1986. BWR and PWR fuel assemblies of high burnup range of up to about 48 GWd/t and 53 GWd/t, respectively were examined by hot cell PIEs and many segment rods of local burnup range of up to more than 60GWd/t were power ramped in test reactors. Though some fuel rods showed minor failure after power ramp tests beyond commercial reactor condition, the results have shown good performance of the high burnup fuels in general. In BWR power ramp tests, the new failure mode of segment rods and the decrease of the failure threshold for higher burnup fuels have been found.

Other than oxide fuel, new type fuels such as metallic, nitride and hydride fuels are under research and development in Japan for fast breeder reactors and, in case of hydride fuel, for both fast reactors and LWRs. Topics on some of these new type fuels will be also presented.