CN-121977200-A - Nuclear power station two-loop MSR drainage system corrosion prevention system and method

CN121977200ACN 121977200 ACN121977200 ACN 121977200ACN-121977200-A

Abstract

The invention belongs to the technical field of water chemistry working conditions of nuclear power stations, and relates to a corrosion prevention system and method for a two-loop MSR hydrophobic system of a nuclear power station. The steam-water separation reheater is provided with a heat exchange tube, an inlet of the heat exchange tube is connected with a high-pressure cylinder steam extraction pipeline, an outlet of the heat exchange tube is connected with an MSR reheater drain tank, the shell side of the steam-water separation reheater is connected with a high-pressure cylinder steam extraction pipeline and an MSR separator drain tank, a hydrogen peroxide solution tank is connected with the high-pressure cylinder steam extraction pipeline through a first dosing pump, the outlet of the MSR reheater drain tank is provided with a second dioxygen meter and a first iron meter, the hydrogen peroxide solution tank is connected with the high-pressure cylinder steam extraction pipeline through a second dosing pump, the 3-methoxypropylamine solution tank is connected with the high-pressure cylinder steam extraction pipeline through a third dosing pump, and the outlet of the MSR separator drain tank is provided with a third hydrogen peroxide meter, a conductivity meter and a second iron meter.

Inventors

HU ZHENHUA
WANG YUANYUAN
LI JUNWAN
YANG YUMIN
FU GANG
LI JIANBO
Ji dingxi

Assignees

西安热工研究院有限公司

Dates

Publication Date: 20260505
Application Date: 20260128

Claims (10)

1. The corrosion prevention system of the nuclear power station secondary loop MSR drainage system is characterized by comprising a steam-water separation reheater (24), wherein a heat exchange tube is arranged on the steam-water separation reheater (24), an inlet of the heat exchange tube is connected with a high-pressure cylinder steam extraction pipeline, an outlet of the heat exchange tube is connected with an MSR reheater drainage tank (25), and a shell side of the steam-water separation reheater (24) is connected with a high-pressure cylinder steam extraction pipeline and an MSR separator drainage tank (26); Still include hydrogen peroxide solution case (1) and 3-methoxypropylamine solution case (15), hydrogen peroxide solution case (1) are connected through first charge pump (3) high-pressure cylinder steam extraction pipeline, the export of MSR re-heater drain tank (25) is equipped with second dioxygen water gauge (8) and first indisputable table (9), hydrogen peroxide solution case (1) are connected through second charge pump (10) high-pressure cylinder steam extraction pipeline, 3-methoxypropylamine solution case (15) are connected through third charge pump (16) high-pressure cylinder steam extraction pipeline, the export of MSR separator drain tank (26) is equipped with third hydrogen peroxide table (21), electric conductivity table (22) and second indisputable table (23).
2. The nuclear power station two-loop MSR drainage system corrosion prevention system according to claim 1, wherein a first valve (4) and a first flowmeter (5) are sequentially arranged between the first dosing pump (3) and the high-pressure cylinder steam extraction pipeline.
3. The nuclear power station two-loop MSR hydrophobic system corrosion protection system according to claim 2, characterized in that a first check valve (6) is arranged between the first flowmeter (5) and the high-pressure cylinder steam extraction pipeline.
4. The nuclear power station two-loop MSR drainage system corrosion prevention system according to claim 1, wherein a second valve (11), a second flowmeter (12) and a second check valve (13) are sequentially arranged between the second dosing pump (10) and the high-pressure cylinder steam exhaust pipeline.
5. The nuclear power station two-loop MSR drainage system corrosion prevention system according to claim 1, wherein a third valve (17), a third flowmeter (18) and a third check valve (19) are sequentially arranged between the third dosing pump (16) and the high-pressure cylinder steam exhaust pipeline.
6. The corrosion prevention system of a nuclear power station two-loop MSR drainage system according to claim 1, wherein a first hydrogen peroxide table (2) is arranged on the hydrogen peroxide solution tank (1).
7. The nuclear power plant two-circuit MSR hydrophobic system corrosion protection system according to claim 1, wherein a shell side of the steam-water separator reheater (24) is provided with a shell side inlet, a first shell side outlet and a second shell side outlet which are mutually communicated, the shell side inlet is connected with the high pressure cylinder steam exhaust pipeline, the first shell side outlet is connected with the MSR separator hydrophobic tank (26), and the second shell side outlet is used for being connected with a low pressure cylinder (27).
8. A nuclear power plant two-circuit MSR hydrophobic system corrosion protection method based on the nuclear power plant two-circuit MSR hydrophobic system corrosion protection system of any one of claims 1 to 7, comprising the steps of: for MSR reheater drainage system: Starting the first dosing pump (3), injecting hydrogen peroxide in the hydrogen peroxide solution tank (1) into the high-pressure cylinder steam extraction pipeline, monitoring the hydrogen peroxide concentration at the outlet of the MSR reheater drain tank (25) in real time through the second dioxygen meter (8), and monitoring the iron content at the outlet of the MSR reheater drain tank (25) through the first iron meter (9); According to the hydrogen peroxide concentration and the iron content of the outlet of the MSR reheater drain tank (25), the operation frequency of the first dosing pump (3) is adjusted to enable the hydrogen peroxide concentration of the outlet of the MSR reheater drain tank (25) to be located in a first threshold range and the iron content of the outlet of the MSR reheater drain tank (25) to be located in a second threshold range; for MSR separator hydrophobic system: starting the second dosing pump (10) and the third dosing pump (16), injecting hydrogen peroxide in the hydrogen peroxide solution tank (1) and 3-methoxypropylamine solution in the 3-methoxypropylamine solution tank (15) into the high-pressure cylinder steam exhaust pipeline, monitoring the concentration of hydrogen peroxide at the outlet of the MSR separator drain tank (26) in real time through the third hydrogen peroxide table (21), monitoring the conductivity at the outlet of the MSR separator drain tank (26) through the conductivity table (22), and monitoring the iron content at the outlet of the MSR separator drain tank (26) through the second iron table (23); adjusting the operating frequency of the second dosing pump (10) according to the hydrogen peroxide concentration and the iron content at the outlet of the MSR separator drain tank (26), so that the hydrogen peroxide concentration at the outlet of the MSR separator drain tank (26) is in a first threshold range, and the iron content at the outlet of the MSR separator drain tank (26) is in a second threshold range; and adjusting the operating frequency of the third dosing pump (16) according to the conductivity of the outlet of the MSR separator drain tank (26) so that the concentration of hydrogen peroxide at the outlet of the MSR separator drain tank (26) is within a third threshold range.
9. The corrosion prevention method for the nuclear power station two-loop MSR hydrophobic system is characterized in that the first threshold range is 0.2-0.3 mg/L, the second threshold range is 0-3 mug/L, and the third threshold range is 2.7-3.0 mug/cm.
10. The corrosion prevention method for the nuclear power station two-loop MSR hydrophobic system according to claim 8 is characterized by further comprising the step of detecting the concentration of hydrogen peroxide in the hydrogen peroxide solution tank (1) in real time through a first hydrogen peroxide table (2); according to the concentration of hydrogen peroxide in the hydrogen peroxide solution tank (1) and the concentration and iron content of hydrogen peroxide at the outlet of the MSR reheater drain tank (25), the operation frequency of the first dosing pump (3) is adjusted; Adjusting the operating frequency of the second dosing pump (10) according to the concentration of hydrogen peroxide in the hydrogen peroxide solution tank (1) and the concentration and iron content of hydrogen peroxide at the outlet of the MSR separator drain tank (26); And adjusting the operating frequency of the third dosing pump (16) according to the concentration of hydrogen peroxide in the hydrogen peroxide solution tank (1) and the conductivity of the outlet of the MSR separator drain tank (26).

Description

Nuclear power station two-loop MSR drainage system corrosion prevention system and method Technical Field The invention belongs to the technical field of water chemistry working conditions of nuclear power stations, and relates to a corrosion prevention system and method for a two-loop MSR hydrophobic system of a nuclear power station. Background The steam-water separation reheater (MSR) is key equipment of a high-temperature gas-cooled reactor and a sodium-cooled fast reactor nuclear power station, and has the main functions of separating steam from water discharged from a high-pressure cylinder of a steam turbine, removing about 98% of water, and reheating the separated steam to improve the superheat degree of the steam and then entering a low-pressure cylinder. The internal operation temperature of the MSR is usually in the range of 180-280 ℃, the medium is a vapor-liquid two-phase flow, and the condition is just in the sensitive range of Flow Acceleration Corrosion (FAC) of carbon steel materials. Therefore, carbon steel components and connecting pipes inside MSRs are commonly exposed to FAC risks. The MSR drainage system mainly comprises an MSR reheater drainage system and an MSR separator drainage system. The MSR reheater drain originates from condensate formed by heat released latent heat from condensation of heating steam (e.g., main steam) outside the tube bundle, which drain is collected in the MSR reheater drain tank and is typically recycled to the high pressure heater steam side. However, once the MSR develops FAC, this results in a significant increase in the iron content of the MSR reheater's hydrophobicity. This portion of the high iron MSR reheater drain return feedwater system will increase the total iron content of the main feedwater, thereby exacerbating the risk of clogging the steam generator heat transfer tube throttling assembly. The MSR separator mainly comprises moisture separated by MSR and condensate formed by condensing steam in the shell, and the drain is collected in a drain tank of the MSR separator and is generally recycled to the steam side of the low-pressure heater or the condenser. If the iron content of the part of the water is increased due to FAC, the iron load of the condensate is directly increased, and the operation load of the condensate fine treatment system is further increased. Currently, ammonia is generally adopted in a secondary loop of a nuclear power station to adjust the pH value of a water vapor system so as to inhibit corrosion. However, ammonia has a characteristic of high vapor-liquid partition coefficient, i.e., ammonia is preferentially distributed to the vapor phase when the vapor-liquid two phases coexist. Inside the MSR, ammonia enters the low pressure cylinder with the vapor phase, resulting in a relatively low ammonia concentration in the liquid phase. Therefore, the MSR separator has a low pH of the liquid phase of the hydrophobic system and a poor buffering capacity. In this weakly alkaline or even near neutral environment, the presence of trace impurity ions is extremely likely to cause localized corrosion exacerbation, and it is difficult to effectively suppress the occurrence of FAC. In summary, the prior art has obvious disadvantages that, on one hand, the MSR separator hydrophobic system has low pH, insufficient buffering capacity and weak self corrosion resistance due to the distribution characteristic of ammonia, and on the other hand, both the MSR reheater and the separator hydrophobic system face serious FAC challenges, high iron content generated by corrosion is hydrophobic, and the high iron content generated by corrosion flows back to the water supply system and the condensate system respectively, and the generated corrosion products bring a series of operation risks to downstream key equipment. Disclosure of Invention The invention aims to provide an anti-corrosion system and method for a secondary loop MSR (multi-stage reactor) hydrophobic system of a nuclear power station, which are used for solving the technical problems of corrosion product migration caused by flow accelerated corrosion of the secondary loop MSR system of the nuclear power station, low pH value of the hydrophobic system of a separator caused by ammonia distribution characteristics and poor buffering capacity. In order to achieve the above purpose, the invention is realized by adopting the following technical scheme: In a first aspect, the invention provides an anti-corrosion system of a nuclear power station two-loop MSR drainage system, which comprises a steam-water separation reheater, wherein a heat exchange tube is arranged on the steam-water separation reheater, an inlet of the heat exchange tube is connected with a high-pressure cylinder steam extraction pipeline, an outlet of the heat exchange tube is connected with an MSR reheater drainage tank, and a shell side of the steam-water separation reheater is connected with a high-pressure cylinder steam ex