阅读说明：本技术 一种用于解决核电站设备冷却水系统冬季低温问题的回路 (A return circuit for solving nuclear power station equipment cooling water system low temperature problem in winter ) 是由 廖亮 洪金英 王洪 杨纪晨 于 2020-03-19 设计创作，主要内容包括：本发明属于核电站技术改造技术领域,具体涉及一种用于解决核电站设备冷却水系统冬季低温问题的回路,包括贝类捕集器分出两路与热交换器A和热交换器B连接,在热交换器A与贝类捕集器之间设置有热交换器上游隔离阀A,在热交换器B与贝类捕集器之间设置有热交换器上游隔离阀B；经过两个热交换器之后,汇合通往重要厂用水接收池,在汇合点与热交换器A之间设置有热交换器下游隔离阀A,在汇合点与热交换器B之间设置有热交换器下游隔离阀B。本发明解决了核电站设备冷却水系统冬季温度过低的问题。(The invention belongs to the technical field of nuclear power station technical improvement, and particularly relates to a loop for solving the low temperature problem of a cooling water system of nuclear power station equipment in winter, which comprises a shellfish catcher, a heat exchanger upstream isolation valve A, a heat exchanger downstream isolation valve B, a shell catcher and a shell catcher, wherein the shell catcher is divided into two paths to be connected with the heat exchanger A and the heat exchanger B; after passing through the two heat exchangers, the water is converged and led to an important plant water receiving pool, a heat exchanger downstream isolation valve A is arranged between the converging point and the heat exchanger A, and a heat exchanger downstream isolation valve B is arranged between the converging point and the heat exchanger B. The invention solves the problem of over-low temperature of the cooling water system of the nuclear power station equipment in winter.)

1. A loop for solving the problem of low temperature of a cooling water system of nuclear power plant equipment in winter comprises a heat exchanger upstream isolation valve A11, a heat exchanger upstream isolation valve B14, a heat exchanger A12, a heat exchanger B15, a heat exchanger downstream isolation valve A13 and a heat exchanger downstream isolation valve B16;

the method is characterized in that: the shellfish catcher is divided into two paths to be connected with a heat exchanger A12 and a heat exchanger B15, a heat exchanger upstream isolating valve A11 is arranged between the heat exchanger A12 and the shellfish catcher, and a heat exchanger upstream isolating valve B14 is arranged between the heat exchanger B15 and the shellfish catcher; after passing through the two heat exchangers, the streams are merged to a critical plant water receiving tank, a heat exchanger downstream isolation valve a13 is provided between the point of merger and heat exchanger a12, and a heat exchanger downstream isolation valve B16 is provided between the point of merger and heat exchanger B15.

2. The loop for solving the problem of low temperature in winter of a cooling water system of nuclear power plant equipment as claimed in claim 1, wherein: two bypasses are arranged on a pipeline before the shellfish catcher is divided into two paths, wherein the first bypass passes through a manual isolation valve A1, then passes through an electric control valve A2, finally passes through a manual isolation valve B3 and finally is connected between an upstream isolation valve A11 of the heat exchanger and a heat exchanger A12.

3. The loop for solving the problem of low temperature in winter of a cooling water system of nuclear power plant equipment as claimed in claim 2, wherein: two bypasses are arranged on a pipeline before the shellfish catcher is divided into two paths, the second bypass firstly passes through a manual isolation valve C4, then passes through an electric control valve B5 and finally passes through a manual isolation valve D6, and finally is connected between an upstream isolation valve B14 of the heat exchanger and a heat exchanger B15.

4. The loop for solving the problem of low temperature in winter of a cooling water system of nuclear power plant equipment as claimed in claim 1, wherein: and a third bypass is arranged before the shellfish catcher is divided into two bypasses, the third bypass firstly passes through a manual isolation valve E7, then passes through an electric control valve C8, then passes through a flow meter 9, and finally passes through a manual isolation valve F10, and finally is connected between an important plant water receiving pool and a junction point after passing through two heat exchangers.

5. The loop for solving the problem of low temperature in winter of the cooling water system of the nuclear power plant equipment as claimed in claim 4, wherein: the diameter of the third bypass pipe is 350 mm.

6. The loop for solving the problem of low temperature in winter of a cooling water system of nuclear power plant equipment as claimed in claim 1, wherein: the pipe diameter of the downstream pipe of the shellfish catcher is 700 mm.

7. A circuit for solving the problem of low temperature in the winter season in a cooling water system of nuclear power plant equipment as claimed in claim 2 or 3, wherein: the tube diameter of the branch is 250 mm.

Technical Field

The invention belongs to the technical field of nuclear power station technical improvement, and particularly relates to a loop for solving the problem of low temperature of a cooling water system of nuclear power station equipment in winter.

Background

The equipment cooling water system (RRI) is an important nuclear auxiliary system of a nuclear power plant, and the main function of the equipment cooling water system is to transfer heat from important safety-related structures, systems and equipment to a final heat sink, namely seawater, and form a barrier between a nuclear island heat exchanger and the seawater to prevent the uncontrollable release of radioactive fluid into the seawater.the maximum value of the outlet temperature of the equipment cooling water heat exchanger is limited in the design and construction specifications of a nuclear island system of a2 × 600MW PWR nuclear power plant (GB/T15761) and RCCP-P French 900MW PWR nuclear power plant system design and construction guidelines, and generally the inlet temperature of each cooler of the equipment cooling water system is limited to 35 ℃ while no clear requirements are given to the minimum value of the outlet temperature.

The temperature of the cooling water of the equipment is too low, and the following problems mainly exist:

1) excessive cooling of the main pump oil cooler may result in increased main pump bearing oil viscosity;

2) the downstream temperature of the non-regenerative heat exchanger of the chemical volume system is too low, so that the desalting efficiency of a downstream desalting bed is influenced, the boron concentration is further influenced, and the control rod acts;

3) the long-term stable operation of the DEG system is not facilitated;

4) is not favorable for the long-term stable operation of the DE L system.

Disclosure of Invention

The invention aims to solve the problems that the temperature of a cooling water system of equipment of a nuclear power station is too low in winter by providing a loop for solving the problem of low temperature of the cooling water system of the equipment of the nuclear power station in winter.

The technical scheme of the invention is as follows:

a loop for solving the low temperature problem of a cooling water system of nuclear power plant equipment in winter comprises a heat exchanger upstream isolation valve A, a heat exchanger upstream isolation valve B, a heat exchanger A, a heat exchanger B, a heat exchanger downstream isolation valve A and a heat exchanger downstream isolation valve B;

the shellfish catcher is divided into two paths to be connected with a heat exchanger A and a heat exchanger B, a heat exchanger upstream isolation valve A is arranged between the heat exchanger A and the shellfish catcher, and a heat exchanger upstream isolation valve B is arranged between the heat exchanger B and the shellfish catcher; after passing through the two heat exchangers, the water is converged and led to an important plant water receiving pool, a heat exchanger downstream isolation valve A is arranged between the converging point and the heat exchanger A, and a heat exchanger downstream isolation valve B is arranged between the converging point and the heat exchanger B.

A loop for solving the problem of low temperature of a cooling water system of nuclear power station equipment in winter is characterized in that two bypasses are arranged on a pipeline before a shellfish catcher is divided into two paths, the first bypass firstly passes through a manual isolation valve A, then passes through an electric control valve A, finally passes through a manual isolation valve B and finally is connected between an upstream isolation valve A of a heat exchanger and the heat exchanger A.

A loop for solving the problem of low temperature of a cooling water system of nuclear power station equipment in winter is characterized in that two bypasses are arranged on a pipeline before a shellfish catcher is divided into two paths, the second bypass firstly passes through a manual isolation valve C, then passes through an electric regulating valve B, finally passes through a manual isolation valve D and finally is connected between an upstream isolation valve B of a heat exchanger and the heat exchanger B.

A loop for solving the problem of low temperature of a cooling water system of nuclear power plant equipment in winter is characterized in that a third bypass is arranged before a shellfish catcher is divided into two bypasses, the third bypass firstly passes through a manual isolation valve E, then passes through an electric control valve C, then passes through a flow meter, finally passes through a manual isolation valve F, and finally is connected between an important plant water receiving pool and a junction point after passing through two heat exchangers.

A loop for solving the low temperature problem of a cooling water system of nuclear power plant equipment in winter is characterized in that the diameter of a third bypass pipe is 350 mm.

A pipe diameter of a downstream pipe of a shellfish catcher is 700 mm.

A loop for solving the low temperature problem of a cooling water system of nuclear power station equipment in winter has a shunt pipe diameter of 250 mm.

The invention has the beneficial effects that:

before the application of the invention, the nuclear power unit has the condition that the temperature of the equipment cooling water plate exchange outlet is lower under the condition that the temperature of seawater in winter is lower, and the temperature reaches 11 ℃ once at the lowest.

After a bypass pipeline is added to an important service water System (SEC), the inner seawater flow is adjusted and changed in the following way, so that the purpose of controlling the temperature of equipment cooling water can be achieved:

1) bypass seawater double-plate exchange: the system is operated by a single pump, a seawater main bypass pipe is opened, so that seawater flows through a bypass pipeline and two tables for exchanging at the same time, and the flow rate of the seawater flowing through each table for exchanging is one third of the total flow rate in the mode;

2) exchanging a bypass seawater single plate: the system is operated by a single pump, a seawater main bypass pipe is opened, a seawater side isolation valve of a certain platen exchanger is closed, so that seawater only flows through the platen exchanger and the seawater main bypass pipe, and the seawater design flow rate of the flow plate exchanger is half of that of the seawater in the mode;

3) the bypass seawater single plate exchange + the seawater flow in the plate exchange is reduced: on the basis of the operation mode of the bypass seawater single plate exchange, the seawater auxiliary bypass pipe exchanged on the operation plate is opened, the isolating valve exchanged on the plate is closed, and the seawater auxiliary bypass pipe is provided with the regulating valve, so that the flow of the seawater flowing through the plate for exchange can be regulated.

The temperature of the exchange outlet of the cooling water plate of the equipment is ensured to be higher than 15 ℃, and the flow rate of the seawater needing to flow through each plate for exchange is 379m³H is used as the reference value. As shown in the following table:

TABLE 1 calculation of plate-shift seawater side stream

According to the arrangement condition of the field devices of the nuclear power plant, the problem that the temperature of equipment cooling water is too low in winter can be effectively solved by adding the bypass pipeline, the water supply temperature of an equipment cooling water system can be increased, and the popularization value is good.

Drawings

FIG. 1 is a schematic structural view of the present invention;

in the figure: 1 manual isolation valve a; 2, electrically adjusting a valve A; 3, manually isolating the valve B; 4, manually isolating the valve C; 5, an electric control valve B; 6, manually isolating the valve D; 7 a manual isolation valve E; 8, electrically adjusting a valve C; 9 a flow meter; 10 a manual isolation valve F; 11 heat exchanger upstream isolation valve a; 12 heat exchanger A; 13 heat exchanger downstream isolation valve a; 14 heat exchanger upstream isolation valve B; 15 heat exchanger B; 16 heat exchanger downstream isolation valve B.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

As shown in FIG. 1, the loop for solving the problem of low temperature of a cooling water system of nuclear power plant equipment in winter comprises a heat exchanger upstream isolation valve A11, a heat exchanger upstream isolation valve B14, a heat exchanger A12, a heat exchanger B15, a heat exchanger downstream isolation valve A13 and a heat exchanger downstream isolation valve B16; the shellfish catcher is divided into two paths to be connected with a heat exchanger A12 and a heat exchanger B15, a heat exchanger upstream isolating valve A11 is arranged between the heat exchanger A12 and the shellfish catcher, and a heat exchanger upstream isolating valve B14 is arranged between the heat exchanger B15 and the shellfish catcher; after passing through the two heat exchangers, the streams are merged to a critical plant water receiving tank, a heat exchanger downstream isolation valve a13 is provided between the point of merger and heat exchanger a12, and a heat exchanger downstream isolation valve B16 is provided between the point of merger and heat exchanger B15.

Two bypasses are arranged on a pipeline before the shellfish catcher is divided into two paths, wherein the first bypass passes through a manual isolation valve A1, then passes through an electric control valve A2, finally passes through a manual isolation valve B3 and finally is connected between an upstream isolation valve A11 of the heat exchanger and a heat exchanger A12;

the second passes first through manual isolation valve C4, then through electrically actuated regulator valve B5, and finally through manual isolation valve D6, and finally is connected between heat exchanger upstream isolation valve B14 and heat exchanger B15.

And a third bypass is arranged before the shellfish catcher is divided into two bypasses, the third bypass firstly passes through a manual isolation valve E7, then passes through an electric control valve C8, then passes through a flow meter 9, and finally passes through a manual isolation valve F10, and finally is connected between an important plant water receiving pool and a junction point after passing through two heat exchangers.

A seawater main bypass pipe with the pipe diameter of 350mm is led out from a hole on a seawater main pipe with the pipe diameter of 700mm at the downstream of the shellfish catcher of the important factory water system. A manual isolating valve E7 and a manual isolating valve F10 are additionally arranged on the seawater main bypass pipe and used for isolating the newly-added main bypass pipeline, an electric regulating valve C8 is additionally arranged and used for regulating the flow of the seawater main bypass pipeline, and a flowmeter 9 is additionally arranged and used for detecting the flow on the seawater main bypass pipeline.

The sea water auxiliary bypass pipe with the pipe diameter of 250mm is additionally arranged on two sides of the heat exchanger upstream isolating valve A11 and the heat exchanger upstream isolating valve B14, a branch (the pipe diameter of 250mm) is led out from a shellfish catcher outlet main pipe (the pipe diameter of 600mm), the branch is divided into two parts which are respectively connected to a pipeline (the pipe diameter of 400mm) between an inlet of the heat exchanger A (12) and an inlet of the heat exchanger B15 and the heat exchanger upstream isolating valve A11 and the heat exchanger upstream isolating valve B14, the newly-added pipeline (the pipe diameter of 250mm) is about 8.2m, and 4 newly-added manual isolating valves are arranged: and the manual isolating valve A1, the manual isolating valve B3, the manual isolating valve C4 and the manual isolating valve D6 are used for isolating the newly-added seawater auxiliary bypass pipe. Two electric control valves are newly added on the seawater auxiliary bypass pipeline: and the electric control valve A2 and the electric control valve B5 are used for adjusting the seawater flow of the seawater auxiliary bypass pipeline.