Current status of irradiation facilities in JRR-3, JRR-4 and NSRR

Kishi, Toshiaki ; Ichimura, Shigeju; Kinase, Masami ; Wada, Shigeru

The Department of Research Reactor and Tandem Accelerator operates three research reactors, JRR-3, JRR-4 and NSRR. JRR-3 was operated for 180 days in Japanese Fiscal Year 2007. The neutron bender system was installed on the cold neutron guide tube. As a result, the cold beam intensity has increased by about 10 times. JRR-4 was operated for 93 days in Japanese Fiscal Year 2007. Boron neutron capture therapy was carried out 25 times. The trouble of reflector occurred in December 2007. At present, the reactor has stopped to replace the reflectors. NSRR has been built for the investigation of light water reactor fuel behavior during off-normal conditions such as reactivity-initiated accident. Recently the investigation is performed for the behavior of high burnup fuel and mixed oxide fuel. At present, the NSRR experiments with the new capsule are continuing for high burnup fuels of 59, 67 and 71 GWd/t.