Current status of JRR-3, 1; Outline and recovery works after the Great East Japan Earthquake

Kawamura, Sho; Wada, Shigeru; Murayama, Yoji

JRR-3 (Japan Research Reactor No.3) at Tokai site of JAEA is a light water cooled and moderated swimming pool type research reactor with nominal thermal power of 20 MW. JRR-3 is utilized from academic research to industrial use as neutron beam experiments, irradiation tests of the reactor material, and manufacturing radio isotopes for medicine use and the silicon semiconductor by neutron transmutation doping (NTD). Reactor reached first critical state in 1990 and it was continued operating for 20 years till the Great East Japan Earthquake on 2011. JRR-3 was in this regular maintenance period, when the Great East Japan Earthquake took place on 11th March 2011. The Great East Earthquake's acceleration was measured larger seismic acceleration than that of seismic design of JRR-3. The ground around rhe buildings was sunk about 40 cm. Therefore, some facilities were damaged such as exhaust duct led to a stack and electric transformers in secondary cooling tower. However, the reactor building with the solid foundations and the safety-related facilities survived the earthquake without serious damage, and no radioactive leakage has been occurred. To confirm soundness, checking and testing of the integrity for every components of JRR-3 have been carried out without delay.