Fast Determination of Containment Leakage Rate Based on Pressure Rise Monitoring

In this paper, a qualitative and quantitative method for fast determination of containment leakage at the start-up stage of the unit is proposed. Based on the rising trend of containment pressure within 24 h during the unit start-up, the set leakage rate limit is taken as the assumed leakage rate, and the calculated pressure rise is obtained according to the ideal gas state equation and the gas mass balance relationship in the containment, and the leakage situation is qualitatively determined by comparing the calculated pressure rise with the monitored pressure rise. According to the gas mass balance relationship in the containment, the quantitative method can reversely solve the containment leakage rate matching with the monitoring pressure rise. Using the above method, the containment leakage rate of five units in a nuclear power plant is analyzed. The qualitative determination results show that the leakage rate of only one unit exceeds the limit of 5 Nm³/h (Nm³ is the gas volume at 0℃ and 1 standard atmospheric pressure). The quantitative calculation results show that the leakage rate of the unit is 5.11 Nm³/h, which is close to the first daily leakage rate of 4.98 Nm³/h, indicating that the method proposed in this paper has good accuracy.