0.5 gpm미만 원자로 냉각재 계통 누설감지 센서 시스템 개발

Abstract

If the size of the crack in the pressure boundary of the pressurized light water reactor coolant system is very small, the coolant is vaporized and spreads into the containment vessel at the beginning of the leakage, and a small amount of condensated coolant steam is accumulated into a sump. In the case of small leakage of 0.5 gpm or less, it is very difficult to recognize leakage occurrences until the time has elapsed and the amount of variation in the internal humidity and temperature of the containment vessel due to the water vaporized leakage water and the rate of change in the water level is very small. In the case of leakage of the reactor coolant pump seal of 1 to 10 gpm or higher, and leakage of the steam generator between the 1<SUP>st</SUP> and 2<SUP>nd</SUP> sides, the level change of the coolant makeup tank or the level of the sump level change can be detected with a meaningful sump level changed up. In the case of a small amount of unidentified leakage, the leakage point occurs at the weld or the location where mechanical or thermal stresses are accumulated, and it is characterized by leakage through unspecified areas. Early detection of small unidentified leakage by multiple measurements can prevent operator error, increase the operator action time for proper operator safety measures, and minimize other radiation leaks. The early detection of small and unidentified leakage can make a very practical contribution to improving the safety of nuclear power plants. The Korea Atomic Energy Research Institute is developing a small amount of unconfirmed leakage detection system that is less than 0.5 gpm. This report introduces a general configuration of the advanced RCS leakage detection system.