Korea Research Reactor 1 (KRR-1), the first research reactor in Korea, has been operated since 1962, and the second one, Korea Research Reactor 2 (KRR-2) since 1972. The operation of both of them was phased out in 1995 due to their lifetime and operation of the new and more powerful research reactor, HANARO (High-flux Advanced Neutron Application Reactor; 30MW). Both are TRIGA Pool type reactors in which the cores are small self-contained units sitting in tanks filled with cooling water. The KRR-1 is a TRIGA Mark Ⅱ, which could operate at a level of up to 250 kW. The second one, the KRR-2 is a TRIGA Mark Ⅲ, which could operate at a level of up to 2,000 kW. The decontamination and decommissioning (D & D) project of these two research reactors, the first D & D project in Korea, was started in January 1997 and will be completed to stage 3 by 2008. The aim of this decommissioning program is to decommission the KRR-1 & 2 reactors and to decontaminate the residual building structures and the site to release them as unrestricted areas. KAERI (Korea Atomic Energy Research Institute) submitted the decommissioning plan and the environmental impact assessment reports to the Ministry of Science and Technology (MOST) for the license in December 1998, and was approved in November 2000. In June 1998, All 299 rods of spent fuels from the two research reactors were safely transported to the US, according to the US originated fuel management policy. Therefore, this project doesn't include the handling of fuel and any potential criticality hazards. Until now, the radioactivity measurement results of the contaminated area show that the radiation levels do not exceed more that 3 times the natural radiation level. The free release level of these areas is fixed 0.4 Bq/g (or Bq/cm 2 ) for β -γ emitters and 0.04 Bq/g (or Bq/cm 2 ) for α emitters. The occupational dose target was established at 15 mSv/y. This target was kept in establishing the ALARA strategy. All the dismantled materials are classified by the 3 following categorises; non-contaminated, radioactive material lower than the free release level and material higher than this. The non-contaminated wastes will be disposed of like industrial waste. The second one will be temporarily stored on the site then disposed of after permission from the Ministry of Science and Technology. The radioactive wastes will be further volume reduced by decontamination by proper techniques such as chemical and ultrasonic washing, cutting, compacting etc., and putting them into a 4m 3 containers for temporary storage on the site. These will then be transported to the national LILW repository when it is operational, probably in 2008. According to the decommissioning program, the practical D & D activities were started in August 2001 by decommissioning the radioisotope production facility, hot cells, equipment and experimental laboratories in the KRR-2. These objects are currently being decontaminated and dismantled. The two reactor halls, the reactor themselves and the auxiliary facilities will be dismantled starting in 2003.
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