NUCLEAR POWER PLANT TEMPERATURE MEASUREMENT SYSTEM AND NUCLEAR POWER PLANT INSTRUMENTATION SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a robust instrumentation system that is free of influence of a severe accident even when the severe accident occurs in an instrumentation system for detecting state quantities of target portions inside a reactor containment vessel of a nuclear power plant.SOLUTION: Sheathed thermocouples 4 and 7 detect temperatures of target portions inside a reactor containment vessel 1. Different kinds of thermocouple wires are built inside metal sheaths of the sheathed thermocouples 4 and 7, and inorganic insulating materials are filled inside the metal sheaths. The sheathed thermocouples 4 and 7 are connected to first metal sheathed inorganic insulation cables 5 and 8 that are protected by sheaths having outer diameters smaller than outer diameters of the sheathed thermocouples 4 and 7, have built-in thermocouple wires having the same configurations and are filled with the inorganic insulating material. The first metal sheathed inorganic insulation cables 5 and 8 are connected to a ceramic terminal block inside a waterproof terminal box 6 inside the reactor containment vessel. Second metal sheathed inorganic insulation cables that have the same configurations and are provided in an electric penetration module 9 of the reactor containment vessel 1 are connected to the first metal sheathed inorganic insulation cables 5 and 8 at the ceramic terminal block. The second metal sheathed inorganic insulation cables are connected to a terminal block inside a terminal box 10 outside the reactor containment vessel 1.