Present status of operation and maintenance of JRR-3

Ichimura, Toshiyuki ; Suwa, Masayuki ; Fukushima, Manabu; Oba, Toshinobu ; Nemoto, Yoshinori; Terakado, Yoshibumi

The JRR-3 (Japan Research Reactor No. 3) was constructed as the first domestic reactor in 1962. The large-scale modification such as removal and re-installation of the core was carried out from 1985 to 1990. It reached integrated output of 59.9 GWd in July, 2009. JRR-3 has continued the stable operation with several maintenance. Three topics are picked up as major maintenances; modification of fuel elements from aluminide to silicide, replacement of a process control computer system, replacement of a helium compressor of the helium gas system which is part of the heavy water cooling system.