JRR-4 (Japan Research Reactor No.4)

　JRR-4 is a swimming pool type reactor moderated and cooled with light-water. Since JRR-4 attained its initial criticality in January 1965, it had been operated for about 45 years until December 2010.
　The first purpose of JRR-4 was to carry out experiments for Japanese nuclear ship “MUTSU”, after that, JRR-4 was used for medical irradiation (Boron Neutron Capture Therapy), Activation analysis, Production of silicon semiconductor, Education and Training ,etc.
　After the decommissioning plan of JRR-4 was submitted in 2015, it was approved in 2017. At the present, JRR-4 has been moved to decommissioning.

Facility Outline

Type	Swimming pool type reactor moderated and cooled with light-water
Thermal Output	3,500kW
Purpose	Medical Irradiation (Boron Neutron Capture Therapy), Activation analysis, Production of silicon semiconductor, Education and Training, etc.
Operation	1965 to 2010