A chemical control method during the flushing of the secondary loop during start-up of a nuclear power plant

Abstract

A chemical control method during the flushing period of the start-up secondary circuit of a nuclear power plant. Additives are added to flushing water to reduce the corrosion rate of equipment during flushing. ; And during the dosing process, sampling is carried out for concentration analysis, and the dosing amount and dosing time of the additive are adjusted according to the concentration of the additive. The invention specifies a complete set of chemical control methods during the flushing of the secondary circuit system, and clarifies the dosing concentration and monitoring means of the drugs in different stages, so as to inhibit equipment corrosion in the flushing process, improve the flushing effect, and shorten the flushing construction period.

Description

technical field [0001] The invention belongs to the technical field of nuclear power engineering construction and debugging, and in particular relates to a chemical control method during the flushing of a secondary circuit of a nuclear power plant. Background technique [0002] Before the start-up of the secondary circuit, the nuclear power plant needs to flush the system pipeline and equipment to remove foreign matter, impurities and corrosion products introduced into the system equipment during the process of equipment manufacturing, installation and commissioning, so as to ensure the water quality of downstream users (steam generators) Meet the specification requirements as soon as possible, maintain a good water chemical environment of the steam generator, and inhibit or delay the corrosion of the steam generator. [0003] The equipment of the secondary circuit system is mostly made of carbon steel, which is prone to oxygen absorption corrosion. Oxygen is a depolarizer, ...

AI Technical Summary

Problems solved by technology

[0007] The flushing of the secondary circuit of most domestic nuclear power plants in the start-up phase adopts the method of overall water intake and circular flushing. No chemicals are added during the flushing period. In the environment of saturated dissolved oxygen and neutral flushing water, the corrosion of equipment pipelines cannot be effectively inhibited, and the flushing time is increased.

According to the actual verification results on site, during the system flushing period, the system turbidity is flushed to 1ppm and then the filling and discharge are stopped. During this period, no medicine is added. After 8 hours, the system turbidity is measured again, and it will rise to about 2ppm, which needs to be executed again. Filling and draining will increase the consumption of flushing water, which will affect the flushing period of the secondary circuit; even if hydrazine is used as an additive, the application of hydrazine solution is relatively shallow. During the flushing process of the secondary loop system, the hydrazine The addition amount of the solution has not been clearly regulated, the standard for the use of hydrazine is not clear, and the passivation effect on the system piping equipment is not good

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