PERIODIC INSPECTION FOR KN-12 IN KOREA

According to the atomic energy act, it is need to be issued the certificate of design approval by the Ministry of Science and Technology (MOST) to transport spent nuclear fuel packages in Korea. After design approval, the packaging has to be inspected during manufacture. And the packaging should be undergone the periodic performance inspection in every 5 years. CASTOR KN-12 is the spent nuclear fuel transport cask that was certified as type B(U) package. It can contain 12 pressurized water reactor(PWR) spent fuel assemblies that cooled more than 7 years, enriched up to 5 weight percent, and burnt up to 50 GWD/MTU. There are two KN-12 casks that had been used for 5 years in Kori nuclear power plant of Korea. According to the atomic energy act, two casks had been undergone first periodic performance inspections during late 2006 and early 2007. The periodic performance inspections for the KN-12 cask included visual inspection of the cask surface, and particularly sealing surfaces for defect occurring as the results of use, load inspection for lifting and tie-down structure, gamma and neutron shielding inspection, welding integrity inspection by nondestructive test methods, external surface contamination inspection, maximum operating pressure inspection on the cask cavity, leakage inspection for containment system verification and heat transfer inspection for verification of the heat rejection of the cask. Through the inspection, it had been approved that two KN-12 casks maintained good performances. The results of the inspection will be put to practical use as useful experience in the manufacturing inspection for three additionally manufactured KN-12 casks and in the safety review for other type of developing casks.