Management of wastes from decommissioning of hot cells and laboratories of KRR-2

It was concluded that the Korea research reactors, KRR-1 and KRR-2, would be shut down and decommissioned and a project was launched for their decommissioning from January of 1997. The final goal of the project was the release of the site and buildings for unrestricted use and it was planned to achieve it by 2008. As the first step of the project, the hot cells and laboratories of KRR-2 were dismantled by the end of 2002. The concept of the management of radioactive wastes from it's dismantling was reviewed as a task of the evaluation program of the project, together with manpowers, technologies and so on. The wastes from the decommissioning were categorized into three groups; not contaminated, releasable and radioactive. The not contaminated waste will be sent to the industrial disposal site and the releasable waste was stored for future disposal after the assessment for environmental impacts and the individual dose rate to the public. The radioactive waste was packed in containers, and will be stored in the reactor room of KRR-2 and sent to the national repository site, planned by KHNP. The minimization of radioactive wastes, one of the strategies of the project, could be achieved by the repeated decontamination. On dismantling of the underframe structures of lead hot cells, only 184 kg among the total 24 tons of concrete waste was classified as the radioactive waste and 1851 kg as releasable waste after the decontamination was repeated several times. For the works related to the decontamination, the manpower of 358 man-days were consumed and the reason for the higher manpower requirement was the time for measurement and assessment of the contamination because very low radioactivity should be measured. In spite of this higher manpower consumption, the total cost of the project can be reduced with reduction of the repository cost. (orig.)