UO2 펠릿 산화로의 분말 비산 방지를 위한 최종속도 측정
실증용 UO pellet 산화로의 실증을 위한 제한된 핫셀 공간 안에서 사용후 핵 연료를 취급하는 산화로는 소형화 하여야 하고, 사용후 핵 연료 분말은 UO pellet 산화로 장치로부터 비산되지 않아야 한다. 본 연구에서는 분말의 최종속도를 구하기 위하여 Stokes식과 밀도비식을 제안하였다. UO 의 최종속도 SiO 의 최종속도를 사용하여 예측하였고, 비산방지를 할 수 있는 최적유량을 결정하였다. SiO 의 이론 최종속도 식을 검증하고, UO 과 관계식을 예측하기 위하여 아크릴 장치를 만들었다. 목업시설 에 설치 된 산화로에서 제안된 이론최종속도식 인 Stokes식 의 20 L/min과 밀도비식의 14.5 L/min을 적용하여 UO 분말의 필터감지에 의해 검증하였다. 그 결과 밀도비식에 의한 14.5 L/min은 UO 이전혀 검출되지 않았고, Stokes식의 20 L/min에서는 평균 7m 의 입도분말이 검출되었다. 따라서 UO pellet 산화로에서 UO이 비산되지 않는 최적유량은 14.5L/min임을 알 수 있었고, 제안된 밀도비식이 바람직함을 알 수 있었다.
A voloxidizer for a hot cell demonstration, that handles spent fuels of a high radiation level in a limited space should be small and spent fuel powders should not be dispersed out of the equipment involved. In this study a density rate equation as well as the Stokes'equation has been proposed in order to obtain the theoretical terminal velocity of powders. The terminal velocity of UO has been predicted by using the terminal velocity of SiO, and then determination has been the optimum air flow rate which is able to prevent powders from scattering. An equation which has shown a relationship between theoretical terminal velocities of UO and SiO has been derived with the help of the Stokes'equation, and then an experimental verification made for the theoretical Stokes' equation of SiO by means of an experimental device made of acryl. The theoretical terminal velocity based on the proposed density rate equation has been verified by detecting UO powders in a filter installed in the mock-up voloxidizer. As the results, the optimum air flow rates seem to be 20 LPM by the Stokes'equation while they are 14.5 L/min by the density rate equation. At the experiments with the mock-up voloxidizer, a trace amount of UO seems to be detectable at the air flow rate of 14.5 L/min by the density rate equation, but UO powders of 7m diameter seem detectable at the air flow rate of 20 L/min by the Stokes'equation. It is revealed that 14.5 L/min is the optimum air flowe rate which is capable of preventing UO powders from scattering in the UO voloxidizer and the proposed density rate equation is proper to calculate the terminal velocity of UO powders.