Experience of Maintenance of the HZ-75T Cask in Japan

The HZ-75T spent fuel shipping cask has been used in domestic transportation of LWR spent fuel and ATR spent fuel from lO(ten) nuclear power plants to the Tokai Reprocessing Plant of Power Reactor and Nuclear Fuel Development Corporation. The details of design. fabrication and experience of operation were presented at previous meetings of the PATRAM (Onodera et al 1978. Niomura et al 1980 and Ozaki et al 1983) . As of March 1992. 104 shipments in total(number of casks:208. about 600 MTU) have been made. The HZ-75T casks are strictly controlled in aecordance with the proper quality assurance program for long term use. jy application of the appropriate periodic inspections and maintenances, the soundness of casks have been kept perfectly at any time. The periodic inspections and maintenances of HZ-75T cask are specified as 4(four) categories in the essential maintenance program. They are each shipment, annually, 5(five) yearly and lO(ten) yearly. By continuing these activities. it is planned to use HZ-75T Casks for the domestic transportation of spent fuel for a long time.