COOLANT TEMPERATURE MEASURING INSTRUMENT FOR BOILING WATER NUCLEAR REACTOR AND ITS MEASUREMENT METHOD

摘要

PPROBLEM TO BE SOLVED: To rationally and accurately measure coolant temperature and its temperature distribution at a downcomer part or a core inlet part to accurately perform core-portion flow measurement and core performance monitoring with satisfactory precision based on the measured coolant temperature distribution. PSOLUTION: This coolant temperature measuring instrument for a boiling water reactor 10 is made by housing a reactor core 12 in a reactor pressure vessel 11, forming the core inlet part 24 in a lower part of the reactor core 12 while surrounding the reactor core 12 with a core shroud 14, and providing the downcomer part 21 between the core shroud 14 and the pressure vessel 11. The reactor 10 is provided with a plurality of thermometers 31 at radially middle positions from the center of the pressure vessel 11 down to the core shroud 14, and in the inlet part 24 at a circumferential position corresponding to feed water nozzles 30 from a reactor feed water system, and the coolant temperature and its temperature distribution at the inlet part 24 are measured by means of the respective thermometers 31. PCOPYRIGHT: (C)2007,JPO&INPIT