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        검색결과 7

        1.
        2023.05 구독 인증기관·개인회원 무료
        It is important to make a strategy for clearance-level radioactive waste. Sampling and disposal plans should be drawn up with characteristics of target waste. In this paper, a target clearance-level radioactive waste is used in a laboratory for experiments with Cs-137 and Co-60, unsealed radioactive sources with gamma radiation isotopes. Therefore, it is enough to analyze with HPGe to check the contaminant level. The laboratory fume hood combined multiple materials, which means some are volume contamination and others are surface contamination. The wood, plastic, and drywall boards, which are absorbent volume contaminated parts and make up PVC pipes, base cabinet doors, backside baffles, etc., will be sampled with coring methods. The metals and glasses, which are unabsorbent, surface-contaminated parts, are sampled with smear methods. The work surface, baffles, exhaust plenum, and glass sash inside parts have a high possibility of being contaminated. The hood body, flame, base cabinet, PVC pipe (the rare end of the filter), and blower transition case have a low possibility of becoming contaminated. When we checked with HPGe, except for the work surface (which was below clearance level), other parts were less than MDA. The highest radionuclide concentration was in PVC pipe: Cs-137C 3.91E-02 (Bq/g), Co-60 4.54E- 03 (Bq/g). It is less than clearance level. Therefore, the waste was applied for the clearance level radioactive wastes and got permission from the regulatory body.
        2.
        2022.10 구독 인증기관·개인회원 무료
        Following a radioactive waste criterion and clearance level radioactive waste Act Article 2. “The radioactive wastes confirmed by the Commission as having concentration by nuclide not exceeding the value determined by the Commission through incineration, reclamation, recycling, etc”. The combustible clearance level radioactive wastes like lumbers are incinerated and non-combustible wastes like concreted are buried. The metals clearance level radioactive wastes are recycled after being re-molded. However, the clearance level radioactive waste with keeping its original forms is not common. Due to the nature of KAERI, the equipment are brought into the radiation-controlled zone for experiments. Those equipment are conservatively considered contaminated and categorized with radioactive waste following nuclear safety acts. In this case, the spectroscopy device which is clearance level radioactive waste is self-disposed for use in non-controlled areas. The 4 devices are composed of 3 gamma-ray spectroscopy and 1 alpha, beta counting system. Those devices were used for clearance level radioactive waste’s radioisotope analysis in Radioactive Waste Form Test Facility which is used in a separated room for analysis. This room will be released in nonradiation controlled area, therefore those devices will be moved to non-controlled area and keep using. Last April self-disposal was reported to the regulatory body and got acceptance last May. Those devices were moved to non-controlled area last July. This case will be good example for reuse equipment which stop using in radiation controlled area but can keep used.