Design Overview for Process System of Chlorine Production by Electrolyzing Saline in the Nuclear Power Plant

A nuclear power plant adopts electrolyzing saline to prepare sodium hypochlorite solution with the effective chlorine concentration no less than 8000 mg/L, which is provided to the circulating water system, essential service water system, industrial water system, potable water system, and demineralized water production system as biocide. The system name of sodium hypochlorite solution production by electrolyzing saline is the circulating water treatment system, which includes salt storage, dilute saline preparation, sodium hypochlorite solution production, sodium hypochlorite solution storage and dosing, etc. In system process design, the system automatic operation is realized by optimizing the system design and operation control scheme, and setting online monitoring instruments, automatic valves and control system to reduce the intervention of operators. In addition, the hydrogen exhaust fans are set next to the outdoor sodium hypochlorite storage tanks for mechanical hydrogen exhaust, so that the hydrogen can be quickly diluted and discharged to the atmosphere to ensure the safety of system operation. Combined with the engineering practice, this paper expounds the design overview of circulating water treatment system from the aspects of user requirements, optimization design of each process link and process equipment configuration, which can provide reference for the process design of circulating water treatment system in subsequent nuclear power plants.