Core characteristics of JRR-4 using low-enriched-uranium-silicied fuel; Initial core and burn-up core

Ishikuro, Yasuhiro 

JRR-4, a light-water-moderated and cooled, swimming pool type research reactor using high-enriched uranium plate-type fuels had been operated from 1965 to 1996. In order to convert to low-enriched -uranium-silicied fuels, modification work had been carried out for 2 years, from 1996 to 1998. After the modification, the first criticality of low-enriched-uranium-silicied core was achieved on 14th July 1998, and the operation has been carried out since 6th October 1998. In this report, the core characteristics have been analyzed with SRAC code system. SRAC was verified compared with the experiment value. The core characteristics were analyzed such as excess reactivity, control rod worth, neutron flux distribution, the peaking factor of initial core, as well as excess reactivity of burn -up core. As a result, in the initial core, against the experiment value, excess reactivity was an error of about 1%k/k, the peaking factor was an error of about 1%, control rod worth was an error of about 14%. SRAC code was confirmed that it was able to evaluate with accuracy in low-enriched-uranium-silicied fuel.