TRIGA Mark-II, the first Korean research reactor (KRR-1), started opera­tion in 1962, and the second, TRIGA Mark-III (KRR-2) located in Seoul, has been operational since 1972. These two research reactors, located at the former KAERI site in Seoul, were permanently shut down at the end of 1995. As a replacement for the TRIGA research reactors, the 30 MWth multipurpose HANARO research reactor was constructed in 1995 located at KAERI in Daejeon and has operated successfully since then. The D&D of KRR-1 and 2 research reactors was started in January 1997. The decommissioning plan, environmental impact assessment and decommis­sioning design were carried out in 1998. In July 1998, all SF from the TRIGA Mark-II and III reactors was safely transported to the US. At the end of 1998, the decommissioning plan was submitted to the Ministry of Educa­tion, Science, and Technology for licensing, and the Korea Institute of Nuclear Safety (KINS) reviewed it in 1999. The report of their review was considered in January 2000 by the Expert Group for Environmental Radia­tion, one of the four groups of the Nuclear Safety Commission, and the recommendation made by that Expert Group was submitted to the Com­mission for its final approval. At the moment, KRR-2 has been completely dismantled, whereas the decommissioning of KRR-1 was started in 2011 and will be completed by the end of 2014.

Radioactive wastes from the decommissioning of KRR-1 and 2 were classified according to their characteristics and radioactivity levels, packed into 200 L drums or 4 m3 containers and stored in the reactor hall of the KRR-2 according to the process scheme of radioactive waste treatment from decommissioning sites, shown in Fig. 21.12 Radioactive waste gener­ated from KRR-1 and 2 contains 60Co and 152Eu as major radionuclides in the activated waste and 60Co and 137Cs in the case of the contaminated waste. The current status of KRR-1 and 2 is shown in Fig. 21.13, and complete D&D of both will be performed within a few years later.