PRESSURIZED WATER NUCLEAR REACTOR WITH WATER LEVEL GAUGE FOR PRIMARY CIRCULATION LOOP

摘要

PURPOSE:To obtain an improved reliability of a volume detection of a held water by providing water level gauges between upper ends of outlet plenums and lower ends of loop seals of steam generators in all primary loops. CONSTITUTION:A temperature compensated pressure difference typed water level gauge 9 is provided at a part which is located between an outlet plenum of a steam generator 4 containing a vertical portion of a primary circulating loop which is located underneath a pressurizer water level gauge 10 and above a lower end of a reactor core 2, and a lower end of a loop seal, and moreover the same typed water level gauges are provided to all loops of the primary circulation systems. A volume of the primary system corresponding to a 2.2m range above a lower end of a primary system horizontal piping of the water level gauge 9 stays within a range of 27 to 60% of the whole volume. As one third of the whole volume is concentrated to this measuring range, a level change in this range is the slowest change with an elapsing time, as compared with other parts within the primary system. Also, a primary system volume corresponding to a 3.7m portion underneath the primary system horizontal piping is 15% of the whole volume and around 1/2 of the whole primary system volume, in total, corresponding to a whole measuring range of the water level gauge 9.