Boron-free single lithium weakly alkaline water quality regulating system and method suitable for small-sized reactor

Abstract

The invention aims to disclose a boron-free single lithium weak alkaline water quality regulating system and method suitable for a small-sized reactor. The system comprises a water replenishing and chemical adding module, a purification desalting module and a sampling analysis module; cooling water is replenished with water or chemicals through the water replenishing and chemical adding module, the cooling water is purified through the purification desalting module, and the cooling water before and after purification is detected and analyzed through the sampling analysis module to realize themeasurement of electrical conductivity and lithium concentration. The system can realize the purpose of adjusting primary circuit alkalescence regulation during reactor power operation so as to reduceprimary circuit equipment corrosion, ensure the integrity of primary circuit pressure boundary and fuel cladding, and reduce the radioactivity level outside a reactor core.

Description

technical field [0001] The invention relates to water quality regulation of a nuclear reactor primary circuit, in particular to a boron-free monolithium weak alkaline water quality regulation system and method suitable for small reactors, belonging to the application field of small nuclear reactors. Background technique [0002] According to many years of experience in nuclear power operations at home and abroad, adjusting the pH of the coolant to a weakly alkaline environment is beneficial to reducing the generation and migration of corrosion products and reducing the radioactive level outside the core. Adjusting the pH of the primary loop during reactor operation T (T refers to the temperature of the coolant) between 6.9 and 7.4, which is a good practice in current engineering and is very beneficial for the protection of primary circuit materials, fuel and radiation protection design. [0003] With the enlargement of pressurized water reactors, the increase of core power d...

AI Technical Summary

Problems solved by technology

Based on this simplification, the primary loop weak alkaline water quality adjustment system becomes simple, and the commonly used alkalizing agents are mainly NH 4 OH and LiOH, NH 4 OH as an alkalizing agent will not produce induced radioactivity, and generally will not concentrate in the gaps of the core to cause caustic corrosion of metal materials. The hydrogen produced by pyrolysis can inhibit the decomposition of water. The disadvantage is that its continuous decomposition will cause The accumulation of non-condensable gas nitrogen will affect the safety of operation, so degassing is required, and NH needs to be added continuously 4 OH complicates system operation

After LiOH is used as an alkalizing agent, the cation resin in the purified mixed bed needs to be converted into a lithium type. The lithium type resin has a better purification effect on the coolant than the hydrogen type resin, but if the concentration of lithium hydroxide is too high, it will cause damage to the fuel cladding. Onshore power stations require a higher concentration of lithium due to the addition of boron

Images