TRANSIENT-BEHAVIOR OF LOW ENRICHED URANIUM SILICIDE AND ALUMINIDE MINIPLATE FUEL FOR RESEARCH REACTORS

This paper describes the results of transient experiments using a low enriched uranium silicide (density, 4.0 g U/cm(3)) and aluminide (dens ity, 2.2 g U/cm(3)) miniplate fuels prepared for the Japan Research Re actor-3 (JRR-3). The transient irradiation was performed in the Nuclea r Safety Research Reactor (NSRR) at the Japan Atomic Energy Research I nstitute (JAERI). The results obtained are summarized below. (1) The t ested silicide miniplate fuel, which will be a candidate for a future low enriched fuel in the JRR-3 core, did not fail with an energy depos ition of 106 cal/g . fuel at a peak cladding surface temperature (PCST ) of 508 degrees C. This condition simulated a transient causing blist er failure, which was assumed to occur above the PCST of 400 degrees C . Accordingly, the tested silicide miniplate fuel had a strong resista nce against blistering up to 508 degrees C. (2) The tested aluminide m iniplate fuel did not fail with an energy deposition of 55 cal/g . fue l at a PCST of 230 degrees C. This condition simulated an accidental m ater channel closure, which was assumed in the safety analysis of JRR- 3. The predicted PCST by using the EUREKA-2 code was about 150 degrees C. Accordingly the conventional aluminide fuel used in JRR-3 was foun d to be intact under a simulated mater channel closure accident.