Various types of tanks are used in nuclear power plants, and sludge composed of various organic substances and inorganic oxides contaminated with radioactive materials may be present at the bottom of a tank of a radioactive waste treatment device. In addition, glassy and fixative oxide contamination layers are accumulated on the inner wall of the tank depending on the tank material, usage and degree of oxidation. Such contaminated sludge is the main cause of radiation exposure to workers when dismantling nuclear power plant tanks. In addition, the waste filters generated by filtration of contaminated sludge is treated as secondary radioactive waste, and this radioactive waste not only occupies a lot of disposal space, but also the disposal cost is continuously increasing. Therefore, it is necessary to develop a technology that does not generate waste filters as much as possible. To solve this problem, NILEPLANT Co., Ltd. registered a patent named “Filtering apparatus” based on previous research and manufactured a rotary filtration membrane device through detailed design. The rotary filtration membrane device is composed of three or more multiple rotary filtration membranes, and can remove fine particles in wastewater as well as sludge accumulated inside a radioactive contamination tank. In addition, considering the site characteristics of special conditions such as nuclear power plants, it was designed to show excellent performance in removing fine particles while minimizing the area where the device is installed. The rotary filtration membrane device is designed and manufactured as a double cylinder structure that combines a hydro cyclone filter type body and an inner partition wall, and is equipped with a filter cloth-based rotary cylinder filter to process sludge through the filter cloth in addition to inertial. In addition, the patented principle enables self-backwashing without stopping the filtration process, extending the life of the filter and minimizing waste filters. The filtration performance, self-backwashing function, and sludge behavior of the rotary filtration membrane device manufactured based on the detailed design were evaluated through experiments, and improvements to obtain more effective filtration performance were derived. Accordingly, it is expected that the more improved rotary filtration membrane device can be effectively used to remove sludge generated during the dismantling of nuclear power plants in the future.

PFC 제염기술은 원자력연구시설 핫셀 내부의 바닥이나 장치표면에 부착된 고방사능분진을 제거하기 위한 방법 중의 하나이다. 고가의 PFC 제염용액을 회수 정제후 재사용하고, 2차폐기물발생을 획기적으로 줄일 수 있는 여과장치를 개발하였다. PFC 매질 내 현탁성 방사성입자를 제거하기 위해 오염특성에 적합한 여과장치를 개발하고 입자제거 성능평가시험을 수행하였다. 개발된 PFC 여과장치는 핫셀 내부로 들어갈 수 있게 알맞은 크기와 무게로 제작되었으며 바퀴와 고리를 부착하여 이동이 용이하다. PFC 여과장치의 성능평가결과 모의입자의 농도 증가 시 flux가 감소하였고, Pre-filter()와 final-filter() 두개를 장착하여 여과시간에 따른 flux의 감소를 개선하였다. 개발된 PFC 여과장치는 분당 약 0.2L의 PFC 폐액을 처리 할 수 있다.