Maintenance standby system for cooling water system of nuclear power plant

Abstract

The invention relates to a maintenance standby system for a cooling water system of a nuclear power plant, which can solve the maintenance problem of a public main pipe of the cooling water system of the nuclear power plan and a valve connected with the public main pipe. The cooling water system of the nuclear power plant comprises a loop A and a loop B, wherein the loop A is connected with cooling water system users, and the loop A is a cooling water circulation pipeline; the loop A is connected with the loop B through an intermediate heat exchanger, and the loop B is connected with an ultimate hot trap; the loop A and the loop B respectively adopt water supply pipelines of the public main pipe; and at least part of the public main pipe is connected with isolating valves. The maintenance standby system comprises a loop C and a loop D, wherein pipelines of the loop C are directly connected into the cooling water system users connected with the loop. Each cooling water system user is provided with isolating valves in front and back of the loop C side, and the loop C is a cooling water circulation pipeline and is completely independent of the loop A and the loop B. The loop C is connected with the loop D through the intermediate heat exchanger, and the loop D is connected with the ultimate hot trap.

Description

technical field [0001] The invention relates to a standby system for maintenance of a cooling water system of a nuclear power plant. Background technique [0002] During the entire operating life of a nuclear power plant, including shutdown, power operation, or accidental operation, the cooling water system is required to dissipate the core decay heat of the unit, the decay heat of the spent fuel pool, and the heat of other equipment (hereinafter collectively referred to as nuclear power plants) heat) to the ultimate heat sink (such as the atmosphere or the sea, large rivers, etc.). The cooling water system of a general nuclear power plant is divided into two loops, loop A (first loop) and loop B (second loop) (see figure 1 ), the loop A transfers the heat from the nuclear power plant to the loop B through the intermediate heat exchanger 1, and the loop B releases the heat from the nuclear power plant to the final heat sink 14. It should be noted that there are two or more...

AI Technical Summary

Problems solved by technology

The loop A and loop B of some nuclear power plants adopt the water supply mode of common main pipe 3, 5, 11, 12, 13, and 15 (see figure 1 ), while loop A and loop B must maintain continuous operation during the entire operating life of the nuclear power plant, therefore, it will result in failure to control the common main pipe 3, 5, 11, 12, 13, 15, and all isolation valves connected 2, 6, 10, etc. for isolated maintenance or replacement

Once these isolation valves 2 fail, it may cause the relevant cooling water system users 7, 8, 9 (heat exchangers, pumps and other heating equipment) to be unable to isolate and repair or operate, and serious cases may cause loop A or loop B to not operate normally. At this time, the nuclear power plant must be shut down and put into emergency operation

This will reduce the reliability, availability, safety and economics of nuclear power plants

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