CN-122010348-A - Nuclear power plant primary circuit boric acid water silicon removal method and system

CN122010348ACN 122010348 ACN122010348 ACN 122010348ACN-122010348-A

Abstract

The invention discloses a method and a system for removing silicon from primary circuit boric acid water of a nuclear power plant, wherein the method comprises the following steps of S1, selecting a filter element of a filter of the primary circuit boric acid water of the nuclear power plant; S2, changing water of boric acid water of a primary circuit of a nuclear power plant, S3, desilicating boric acid water of a REA system boric acid tank, namely, loading mixed bed resin and desilication resin in a PTR system desalting bed and/or a TEP system desalting bed, conveying the boric acid water of the REA system boric acid tank to a nanofiltration membrane through the PTR system to perform desilication, preparing new boric acid water in the REA system boric acid tank to replace the boric acid water to be desilicated, wherein the desilication system comprises a TEP system desalting bed, the REA system boric acid tank, a PTR system loading well or a transfer well, a PTR system desalting bed and a nanofiltration membrane desilication device, and loading desilication resin in the TEP system desalting bed and the PTR system desalting bed. The silicon removal method and the silicon removal system can effectively reduce the silicon concentration of the boric acid water in the primary circuit.

Inventors

YE WEI
MIN CHUN
LV TENG
DENG TAO
HUANG YAN
SHEN ZHICHENG
ZHENG DECHAO
ZHOU ZHIMENG
XU FALUN
WANG JIANTAO
ZHAO HONGJIE
GAO YUZONG
LIU XIAOJUN
HONG JIANHUA

Assignees

广西防城港核电有限公司

Dates

Publication Date: 20260512
Application Date: 20260317

Claims (10)

1. The method for removing the silicon from the boric acid water in the primary circuit of the nuclear power plant is characterized by comprising the following steps of: S1, selecting a filter element of a filter of a primary circuit boric acid water of a nuclear power plant; S2, changing water of boric acid water in a primary circuit of the nuclear power plant, enabling boric acid water to be removed to enter a boric acid tank of an REA system through a TEP system, and supplying boric acid water from boric acid of the REA system and deoxidized desalted water of the TEP system; S3, adopting at least one of the following modes to remove silicon from boric acid water in the REA system boric acid tank: The REA system boric acid tank is connected with the PTR system, and mixed bed resin and desilication resin are filled in the PTR system desalting bed and/or the TEP system desalting bed; boric acid water in the REA system boric acid tank is conveyed to a nanofiltration membrane through a PTR system to remove silicon; and preparing new boric acid water in the REA system boric acid tank to replace the boric acid water to be removed.
2. The method for removing silicon from boric acid water in a first loop of a nuclear power plant according to claim 1, wherein in the step S1, natural boric acid is adopted in the first loop of the nuclear power plant, a glass fiber filter core is adopted in the filter, or enriched boric acid is adopted in the first loop of the nuclear power plant, a silicon-free filter core is adopted in the filter, and a filter material of the silicon-free filter core comprises polyester composite fibers.
3. The method for removing silicon from primary circuit boric acid water in a nuclear power plant according to claim 1, wherein in the step S1, the filter comprises an RCV system bleed filter, an RCV system resin trap filter, an RCV system shaft seal injection filter, an RCV system shaft seal reflux filter, and a TEP system filter.
4. The method for removing silicon from primary circuit boric acid water in a nuclear power plant according to claim 1, wherein in the step S2, the volume of the makeup boric acid water is calculated using formula (1), and the formula (1) is represented as follows: (1) Wherein, the Is the total volume of the boric acid water in the primary circuit, In order to replenish the volume of boric acid water, In order to replenish the silicon concentration of the boric acid water, To change the silicon concentration of boric acid water in the previous circuit, The silicon concentration of boric acid water in the subsequent circuit was changed.
5. The method for removing silicon from primary circuit boric acid water of a nuclear power plant according to claim 1, wherein in the step S3, the silicon removing resin is a strong base anion resin, the silicon removing resin contains iron oxide and/or triethylamine, and/or the mixed bed resin is GR-3-9 NG mixed bed resin, and/or the filling volume ratio of the silicon removing resin to the mixed bed resin is 1 (1-3).
6. The method for removing silicon from primary circuit boric acid water of a nuclear power plant according to claim 1, further comprising the steps of: S4, a reference model of the influence of the filter material of the boric acid water in the loop on the silicon concentration of the boric acid water is established, and the silicon concentration change of the boric acid water in the actual running process of the loop is compared with the reference model.
7. A nuclear power plant primary circuit boric acid water desilication system, which is characterized in that the method for desilication of the nuclear power plant primary circuit boric acid water according to any one of claims 1 to 6 is adopted, the desilication system comprises a TEP system desilication bed (13), a REA system boric acid tank (21), a PTR system loading well or a transfer well (31), a PTR system desilication bed (33) and a nanofiltration membrane desilication device (4), and the TEP system desilication bed (13) and the PTR system desilication bed (33) are filled with desilication resin; TEP system desalination bed (13) REA system boric acid tank (21) with PTR system loading well or transfer well (31) connect gradually, PTR system loading well or transfer well (31) are connected respectively PTR system desalination bed (33), nanofiltration membrane removes silicon device (4) and TEP system desalination bed (13) to carry out the desilication to the boric acid water of return circuit boric acid with the waiting of REA system boric acid tank (21) removes silicon boric acid water.
8. The nuclear power plant primary circuit boric acid water desilication system of claim 7, further comprising a primary reactor circuit (71), wherein the primary reactor circuit (71) is connected with a TEP system boric acid water tank (11), and the TEP system boric acid water tank (11) is connected with the TEP system desalination bed (13) so as to desilicate primary circuit boric acid water, and the boric acid water after desilication enters the REA system boric acid tank (21); And/or, the REA system boric acid tank (21) is connected with the RPE system transfer tank (5), the RPE system transfer tank (5) is connected with a TEP system, and then the TEP system desalting bed (13) is used for desilication; and/or, the filter of the primary circuit boric acid water adopts a silicon-free filter element.
9. The nuclear power plant primary circuit boric acid water desilication system of claim 7, wherein the REA system boric acid tank (21) is connected with the PTR system loading well or transferring well (31) through an REA system pipeline and a PTR system pipeline, boric acid water of the REA system boric acid tank (21) and desalted water of a TEP system are mixed and then enter the PTR system loading well or transferring well (31), desilication is carried out through the PTR system desalting bed (33) and the nanofiltration membrane desilication device (4), and then the boric acid water returns to the PTR system loading well or transferring well (31) through the PTR system pipeline.
10. The system for removing silicon from boric acid water in a primary circuit of a nuclear power plant according to claim 7, wherein boric acid water in a loading well or a transferring well (31) of the PTR system enters a TEP system through a pipeline of the PTR system and is removed silicon by a desalting bed (13) of the TEP system, and/or, The REA system boric acid tank (21) is connected with the waste treatment system (6) to replace the boric acid water to be removed.

Description

Nuclear power plant primary circuit boric acid water silicon removal method and system Technical Field The invention relates to the technical field of water chemistry control of nuclear power plants, in particular to a method and a system for removing silicon from primary circuit boric acid water of a nuclear power plant. Background During power operation of a nuclear power plant, silicon in boric acid water in a primary circuit of the nuclear power plant does not corrode materials, but in the presence of other impurities (such as calcium, magnesium and aluminum), silicon can be converted into low-solubility compounds (aluminosilicate, silicate, zeolite-based on magnesium, calcium and aluminum and the like), and the low-solubility compounds can be concentrated on fuel rods to form precipitates, so that the fuel rods are locally overheated, and the risks of corrosion and breakage caused by scale deposition of fuel cladding are increased. Silicon in a primary loop of a nuclear power plant can enter other nuclear auxiliary systems, for example, silicon in boric acid water after primary loop water replacement of the nuclear power plant is recycled into a boric acid tank of a boron and water supply system (REA) of the reactor through a coolant storage and treatment system (TEP), boric acid water replacement is carried out between a unit start-stop period and a safety injection system, the boric acid water replacement is carried out, the unit start-stop period and the boric acid water replacement enters a containment built-in material replacement water tank (IRWST) and the like, and the problem of high silicon content of boric acid in the primary loop and the nuclear auxiliary system of the nuclear power plant is commonly found in domestic and foreign pressurized water nuclear power plants. The enriched boric acid is used in the primary loop of the nuclear power plant, compared with the natural boric acid, the enriched boric acid is beneficial to controlling nuclear reaction to reach a higher level, the pH value of boric acid water in the primary loop of the nuclear power plant is improved, corrosion protection of system equipment is facilitated, and the reliability of safe operation of the nuclear power unit is improved. However, the pH of the primary circuit boric acid water in the nuclear power plant increases, which results in the release of silicon easily from the glass filter element of the conventionally used primary circuit coolant filter, so that the use of the boric acid-enriched nuclear power unit requires a high-efficiency silicon content control method. Disclosure of Invention The invention aims to solve the technical problem of providing a method and a system for removing silicon from primary circuit boric acid water of a nuclear power plant. The invention solves the technical problems by adopting the technical scheme that the method for removing the silicon from the boric acid water in a primary loop of a nuclear power plant comprises the following steps: S1, selecting a filter element of a filter of a primary circuit boric acid water of a nuclear power plant; S2, changing water of boric acid water in a primary circuit of the nuclear power plant, enabling boric acid water to be removed to enter a boric acid tank of an REA system through a TEP system, and supplying boric acid water from boric acid of the REA system and deoxidized desalted water of the TEP system; s3, adopting at least one of the following modes to remove silicon from boric acid water in a boric acid tank of the REA system: the REA system boric acid tank is connected with the PTR system, and mixed bed resin and desilication resin are filled in the PTR system desalting bed and/or the TEP system desalting bed; Boric acid water in a boric acid tank of the REA system is conveyed to a nanofiltration membrane through a PTR system to remove silicon; And preparing new boric acid water in a boric acid tank of the REA system to replace the boric acid water to be removed. Preferably, in the step S1, the primary loop of the nuclear power plant adopts natural boric acid, the filter adopts a glass fiber filter element, or the primary loop of the nuclear power plant adopts enriched boric acid, the filter adopts a silicon-free filter element, and the filter material of the silicon-free filter element comprises polyester composite fibers. Preferably, in step S1, the filter comprises an RCV system bleed filter, an RCV system resin trap filter, an RCV system shaft seal injection filter, an RCV system shaft seal reflux filter, and a TEP system filter. Preferably, in the step S2, the volume of the makeup boric acid water is calculated using the formula (1), the formula (1) being represented as follows: (1) Wherein, the Is the total volume of the boric acid water in the primary circuit,In order to replenish the volume of boric acid water,In order to replenish the silicon concentration of the boric acid water,To change the silicon concentration of boric a