A kind of chemical wet maintenance method during shutdown of auxiliary boiler in nuclear power plant

Abstract

The invention belongs to the technical field of auxiliary boiler maintenance in nuclear power plants, and specifically discloses a chemical wet maintenance method during the outage of auxiliary boilers in nuclear power plants. 50‑600ppm, pH (25°C) at 9.5‑11.0 are the maintenance indicators. The chemical wet maintenance method described specifically includes the steps of system water intake, dispensing, dosing, circulation and sampling analysis, and regular monitoring. The invention implements hydrazine wet maintenance on the auxiliary boiler system, and the iron ions in the boiler water are basically stable and less than the control limit during the operation period, effectively solving the problem of equipment corrosion during the auxiliary boiler shutdown process; and clarifying the maintenance scope, maintenance method, and monitoring means , full coverage of the auxiliary boiler system; clear maintenance acceptance criteria, strict process control, to ensure maintenance quality; and simple operation, low cost and low risk.

Description

technical field [0001] The invention belongs to the field of nuclear power plant auxiliary boiler maintenance, and in particular relates to a chemical wet maintenance method during nuclear power plant auxiliary boiler outage. Background technique [0002] The nuclear power plant has a separate auxiliary boiler system designed to generate auxiliary steam to provide auxiliary steam for the steam turbine shaft seal system, deaerator, hot water heating system and laundry room in the site waste treatment facility when the main steam is not available. Most of the equipment in this system is made of carbon steel, which is prone to oxygen absorption corrosion. During the shutdown period of the boiler, if the equipment is not maintained, the corrosion of the equipment will be intensified. Scouring the boiler and related equipment will accelerate corrosion, affect the efficiency of the boiler, and affect the long-term stable operation of the unit. [0003] When the ambient humidity i...

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Problems solved by technology

[0004] Dry maintenance methods mainly include hot air drying method and nitrogen filling method, which have the following disadvantages: hot air drying requires hot air blowers to be arranged on site, and equipment manholes and related exhaust valves need to be opened. Check the temperature and humidity every day, and the daily supervision tasks are relatively heavy; the nitrogen filling method first drains the water inside the equipment before filling the nitrogen, uses the waste heat to dry the inner surface of the equipment, and then fills it with high-purity nitrogen at a certain pressure. High-purity nitrogen needs to be supplemented. Nitrogen maintenance has extremely strict requirements on the airtightness of the system. If there is a leak, the risk of suffocation of personnel in the plant will increase, and the maintenance cost will also increase.

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