The Remodeling and Basic Characteristics of the Heavy Water Neutron Irradiation Facility of the Kyoto Univesity Research Reactor, Mainly for Neutron Capture Therapy

The Heavy Water Thermal Neutron Facility of the Kyoto University Research Reactor (KUR) was wholly updated in March 1996 mainly for neutron capture therapy. The performance as a neutron irradiation facility was improved using the epithermal neutron moderator of the aluminum-heavy water mixture (Al/D2O = 80/20 vol%), the neutron energy spectrum shifter of heavy water, and the thermal neutron filters of cadmium and boral plates. The clinical irradiation utilization under the full-power (5-MW) continuous KUR operation was realized employing both the radiation shielding system, consisting of the shielding door and irradiation room, and the remote carrying system for a patient. The safety and utility of the facility were improved due to the safety observation system.