WO2018108068A1

WO2018108068A1 - Ultimate heat sink system utilized in nuclear power plant

Info

Publication number: WO2018108068A1
Application number: PCT/CN2017/115603
Authority: WO
Inventors: 杨廷; 廖金远; 李世光; 魏颖娣; 李增芬
Original assignee: 中广核工程有限公司; 中国广核集团有限公司
Priority date: 2016-12-12
Filing date: 2017-12-12
Publication date: 2018-06-21
Also published as: CN106448774B; CN106448774A

Abstract

An ultimate heat sink system utilized in a nuclear power plant comprises at least one non-safe series used by a non-safe user (200), and at least one safe series (A, B) used by a safe user (100, 110, 120). The non-safe series and the safe series (A, B) comprise water cooling systems and water supply systems. Each of the water supply systems comprises a cooling pump set (500, 510) and a heat exchange set (400, 410). The water supply system in each series comprises a set of a cooling pool (700, 710) and a cooling tower (600, 610). The cooling pool (700, 710) is located at the upstream of the cooling pump set (500, 510), and the cooling pump set (500, 510) is connected to a water outlet of the heat exchange set (400, 410) and the cooling pool (700, 710), respectively. A water supply pool (800) communicating with an external water area is provided at the upstream of the cooling pool (700, 710). The cooling pool (700, 710) of each series communicates with a respective water supply pool (800). The ultimate heat sink system provides a highly reliable water source to a power plant, employs the atmosphere as the ultimate heat sink to maximally reduce the impact of an external hydrological and meteorological condition change, thereby achieving goals of a strong capability of resisting an external extreme condition, a simple system configuration, and low operation and maintenance costs.

Description

Nuclear power plant final heat sink system

Technical field

The invention belongs to the field of nuclear power technology, and more particularly to a nuclear power plant final heat sink system.

Background technique

So far, international nuclear power plant units have lost their off-site power due to external meteorological and hydrological conditions such as earthquakes and tsunamis. At this time, if the emergency power supply (diesel generator) fails, the functions of the reactor cooling system will be completely lost and triggered. Accident, a nuclear accident occurred. Such events have led to thinking about the design of the final heat sink system. In addition to the whole plant power outage accident, a tsunami caused by a strong earthquake may pile a large amount of debris to the sea, causing the water intake of the plant water system to be blocked, resulting in the loss of the final heat trap.

During the design process of the nuclear power plant, it is found that if the temperature of the nuclear power plant is extremely low in the winter, there is a long freezing period; the number of upstream users is large, and the operating conditions vary widely, resulting in a large range of heat load and flow, and the final heat sink system Difficult to control; although the final heat sink system can operate normally through system level improvements, the increased number of equipment and control, operational requirements complicates the final heat sink system.

Referring to FIG. 1, the existing final heat sink system includes a first safety series and a second safety series for the upstream safety level user 10, a public non-safe series for the non-safety level user 20, a safety series and a non-safe series. The safety series includes a equipment cooling water system (CCWS) and a plant water system (SWS). The plant water system includes a cooling pump group 50, a filter group 60, and a radiator group 40. The cooling pump group 50 is directly connected to the sea 70 through a water pipe, and is cooled. The water is discharged to the sea 70 through the filter group 60 and the radiator group 40. The equipment cooling water system includes the CCWS circulation pump group 30 and the pipeline, and the hot water after the user passes through the heat exchanger group 40 to cool down in the pipeline and continues to the user. Cooling, in this system, the plant water system and the circulating water system share the drainage the design of.

This final heat sink system, when one of the independent safety series fails, another independent safety series can dissipate heat to the environment, although taking into account the accidents within the second-generation (including second-generation) nuclear power plant technical design basis. Conditional design requirements, but there is still the possibility of an external sequence of events beyond the technical design basis for the second generation (including the second generation plus) nuclear power plants. The final heat sink system will be completely ineffective under the accident of the total power failure and the loss of the final heat sink. In the case of large-scale red tides or large influx of typhoon, the water intake structure is blocked, even if it is configured. The filter set, which may still be blocked quickly, also causes the final heat sink system to fail completely.

In the extremely cold or extremely hot area, because the SWS system and the CWS system share the drainage design, and the CWS system flow far exceeds the SWS system, the operating cycle and the SWS system are significantly different, so the non-safety CWS system is instead The final heat sink system has a direct impact; and because of the large number of users, the start-stop law is not uniform, resulting in a large number of working conditions, a large range of heat load and flow, it is difficult to implement a simple control scheme, resulting in the design of the final heat sink system envelope Large, complex operation plan, improve the operating costs of nuclear power plants, and have a negative impact on the safety of nuclear power plants.

In view of this, it is indeed necessary to provide a nuclear power plant final heat sink system that is highly reliable and sufficiently simplified.

Summary of the invention

It is an object of the invention to provide a nuclear power plant final heat sink system that is highly reliable and sufficiently simplified.

In order to achieve the above object, the present invention provides a nuclear power plant final heat sink system comprising at least one non-safe series for non-safety users, and at least one safety series for safety level users, said non-safe series and The safety series includes a device cooling water system including a cooling pump set and a heat exchanger group, wherein the plant water system of each series is configured with a cooling pool and a cooling tower group in a group, the cooling The pool is located upstream of the cooling pump group, and the cooling tower group is respectively connected with the heat exchanger group water outlet and the cooling pool; the cooling pool is provided with a water pool connected to the external water area, each of which The series of cooling pools are connected to the sink.

As an improvement to the final heat sink system of the nuclear power plant of the present invention, the plant water system further includes a sedimentation tank connected to the make-up pool and the external waters, respectively.

As an improvement of the final heat sink system of the nuclear power plant of the present invention, a filtering device is disposed between the sedimentation tank and the external water area.

As an improvement of the final heat sink system of the nuclear power plant of the present invention, the sedimentation tank is connected to the make-up pool through at least one water supply channel.

As an improvement of the final heat sink system of the nuclear power plant of the present invention, the cooling water pool is connected to the water supply tank, and the pipeline connecting the water supply channel and the water supply tank is provided with a gate.

As an improvement to the final heat sink system of the nuclear power plant of the present invention, the safety series further includes an emergency drainage channel connected to the water outlet of the heat exchanger group and directly leading to the external waters.

As an improvement to the final heat sink system of the nuclear power plant of the present invention, the final heat sink system includes a non-safe series for cooling non-safety users and two safety series for cooling safety level users.

As an improvement to the final heat sink system of the nuclear power plant of the present invention, the final heat sink system includes two non-safe series for cooling non-safety users and four safety series for cooling safety level users for heat Large load unit.

As an improvement of the final heat sink system of the nuclear power plant of the present invention, the safety level user is divided into an accident relief group, a normal shutdown group and a spent fuel cooling group, and the safety series can be an accident relief group alone. Cooling is provided by the normal shutdown group and the spent fuel cooling group.

As an improvement of the final heat sink system of the nuclear power plant of the present invention, when the unit is in normal operating conditions, the safety series carries a normal shutdown group and a spent fuel cooling group, and isolates the accident relief group.

As an improvement of the final heat sink system of the nuclear power plant of the present invention, in the event of an accident, the safety series carrying the accident relief group and the spent fuel cooling group isolates the normal shutdown group.

As an improvement of the final heat sink system of the nuclear power plant of the present invention, the cooling pump in the non-safe series Groups, heat exchanger groups, and cooling tower groups all meet non-safety requirements.

As an improvement to the final heat sink system of the nuclear power plant of the present invention, the cooling pump set, the heat exchanger set and the cooling tower set in the safety series all meet the safety level requirements.

As an improvement of the final heat sink system of the nuclear power plant of the present invention, the safety series is equipped with independent factory power sources, emergency power sources and independent power sources.

Compared with the prior art, the final heat sink system of the nuclear power plant of the invention has the following beneficial technical effects:

Through user classification, it can flexibly cope with variable heat load and user changes; through independent and reliable water source, it can eliminate the influence of water level change in external waters and reduce the influence of external water temperature with seasonal changes; by setting sedimentation tanks, taking water channels and hydrating water Pool, cancel some equipment to cope with changes in external conditions, reduce the range of design boundary conditions; use the atmosphere as the final heat sink, the external open water as a backup heat sink, minimize the impact of external hydrometeorological conditions, and thus resist The ability to external extreme conditions, simple system configuration, low operating and maintenance costs.

DRAWINGS

The final heat sink system of the nuclear power plant of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments, wherein:

1 is a schematic diagram of a prior art final heat sink system.

2 is a schematic view of a final heat sink system of a nuclear power plant of the present invention.

detailed description

The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The specific embodiments described in the specification are to be construed as illustrative only and not limiting.

Referring to Figure 2, a nuclear power plant final heat sink system includes a non-safe series for cooling non-safety users and two safety series for cooling safety level users.

The safety level users are divided into three categories: accident mitigation group 100, normal shutdown group 110 and spent fuel cooling group 120. Safety series A and safety series B can be separately used for accident mitigation group 100, normal shutdown group 110 and spent fuel cooling group. 120 is cooled, when the unit is in normal operating condition, the safety series carries the normal shutdown group 110 and the spent fuel cooling group 120, and the accident relief group 100 is isolated. In the event of an accident, the safety series loaded accident relief group 100 And the spent fuel cooling group 120 isolates the normal shutdown group 110. The accident mitigation group 100 and the normal shutdown group 110 are users whose heat load and cooling flow can be coupled to each other, and the non-safety level user 200 is independent of the unit safety, so that the central heat exchange device of the final heat sink system is reduced in size, and the user is reduced in size. The classification setting can flexibly cope with the variable heat load and user changes, so the thermal load design of the final heat sink system of the nuclear power plant will be simplified.

Safety Series A and Safety Series B have the same composition, including equipment cooling water system and plant water system. The equipment cooling water system includes circulating pump set 300 and piping to cool the safety level users, and the circulating water pump 300 allows the cooling water to be in the system. The cycle, the cooling water temperature after cooling the user is increased, and the heat release temperature is lowered through the heat exchanger group 400 of the water system of the plant, and then used for cooling the user.

The plant water system includes a cooling pump group 500 and a heat exchanger group 400. Each safety series is arranged in groups with a cooling pool 700 and a cooling water tower group 600. The two cooling pools 700 share a water pool 800, and the water pool 800 is a cooling pool. The main water source of the 700, the cooling pump set 500 takes water directly from the cooling pool 700, and the cooling tower set 600 is connected to the water outlet of the heat exchanger group 400 and is in communication with the cooling pool 700.

The plant water system also includes a settling tank 810 that is in communication with the fill pool 800 and the external waters 900, respectively.

A filtering device is disposed between the sedimentation tank 810 and the external waters 900 to remove large foreign matter in the water, and the sedimentation pool 810 communicates with the water supply tank 800 through the two water supply channels 820 to control the water flow velocity in the sedimentation tank 810 and the water supply channel 820. Thereby, smaller foreign matter in the water can be precipitated.

The cooling pool 700 is replenished by the replenishment tank 800. The replenishing tank 800 stores sufficient water and has sufficient protection between the external waters 900. In any case, the cooling tower 600 can be supplied with cooling water for a long time.

A pipe 830 is installed in the pipe in which the cooling water pool 700 communicates with the water supply tank 800, and the water pipe 820 and the water supply pipe 800 are connected to each other, so that the cooling water pool 700 can take water from the water filling pool 800, and can also close the gate 830 and hydrate water. The pool 800 is isolated and independent; a gate 830 is installed between the fill pool 800 and the water supply channel 820. In the case of abnormal water quality, the water supply channel 820 and the water area outside the water supply channel 820 can be isolated by closing the gate 830, so that the water pool 800 is opposite to the external water area. The 900 became an independent source of water.

The cooling water enters the sedimentation pool 810 from the external waters 900 and then precipitates, enters the water pool 800 through the water supply channel 820 and reaches a certain storage capacity, and the water supply tank 800 supplies cooling water to the cooling water pool 700, and the cooling pump group 500 directly from the cooling water pool 700 After taking water, after cooling the equipment cooling water system through the heat exchanger group 400, the temperature of the water rises into the cooling tower group 600, and is radiated to the atmosphere through the cooling tower group 600, taking the atmosphere as a conventional final heat trap, and the water after the heat is released. Returning to the cooling pool 700.

The cooling tower group 600 is in units of the heat load of the normal operation of the unit, and each unit is provided with an integer number of cooling towers; the central heat exchanger group is in units of the heat load of the normal operation of the unit, and each unit is provided with an integer heat exchanger group 400. This ensures that the cooling capacity can be flexibly adjusted.

Since the cooling water source passes through the sedimentation action of the sedimentation tank 810 and the water supply channel 820, the water supply tank 800 does not need to be provided with filtering equipment such as a filter screen or a water bio-trapper. Since the water replenishing tank 800 is the main water source, the influence of the external water level can be eliminated; The influence of the water quality change of the pool 800 is smaller than that of the external waters 900. Therefore, the range of the degree of equipment clogging of the plant water system will also be greatly reduced, and the margin of the central heat exchanger design can be appropriately reduced. The setting of the sedimentation tank 810, the hydration channel 820 and the replenishment tank 800 eliminates some equipment for responding to changes in external conditions, reduces the range of design boundary conditions, and thus has strong ability to resist external extreme conditions, simple system configuration, operation and The purpose of low maintenance costs.

In addition, in cold regions, the hot water from the outlet of the heat exchanger group 400 can also be returned to the cooling pool 700 without passing through the cooling tower 600, so that the temperature of the water source operating in cold regions is not too low.

The cooling pool 700 directly draws water directly from the replenishing pool 800. The replenishing pool 800 replenishes water from the external waters 900 through the sedimentation tank 810 and the hydration channel 820. The replenishing pool 800 has a certain amount of water storage, and can be independently a safe series in the case of losing water replenishment. Provide at least 3 months of cooling water source to ensure the place where it occurs Unit safety under extreme weather conditions such as earthquakes, tsunamis, red tides and typhoons. The cooling pump set 500, the circulating pump set 300, the heat exchanger set 400, and the cooling tower set 600 in Safety Series A and Safety Series B are all safety grades, meeting the requirements of the safety series, even in the event of serious external events such as large aircraft impacts. In this case, ensure that at least one of the safety series is working properly.

The plant water system also includes an emergency drainage channel 750, one end is connected to the water outlet of the heat exchanger group 400, and the other end is directly connected to the external water area 900. When the cooling tower group 600 of the safety series A fails due to an external event, the safety series B Under the condition of other event failure, the water intake channel and the emergency drainage channel 750 may be opened, and the safety series A that has lost the cooling tower group 600 directly discharges the hot water to the external waters 900 (such as the sea, lake, reservoir, etc.) through the emergency drainage channel 750. The external waters 900 are used as emergency standby final heat sinks.

The safety series A and safety series B of the final heat sink system are equipped with independent factory power supply, emergency power supply and independent power supply. The factory power supply provides the normal operation of the unit, and the emergency power supply provides the power supply when the unit loses the power supply for the factory. The independent power supply is reserved in the case where the above power supply is lost, and is used to defend against the SBO (full plant power failure) accident.

Referring to FIG. 2, the non-safety series for the non-security level user 200 includes a device cooling water system and a factory water system, wherein the equipment cooling water system and the factory water system are the same as the safety series A and the safety series B, Each device in the non-secure series is a non-security level requirement. The non-safe series of equipment cooling water systems include a non-safety level circulation pump 310 and piping to cool the non-safety level user 200.

The non-safe series of plant water systems include non-safety grade cooling pump set 510 and non-safety grade heat exchanger set 410, as well as groups of non-safety grade cooling water tanks 710 and non-safety grade cooling water tower sets 610, non-safety series and safety series A shared water pool 800, a sedimentation tank 810, a water supply channel 820, and an external water area 900 are shared.

The cooling water enters the sedimentation tank 810 from the external waters 900 through the filtering device, and then precipitates, and then enters the replenishing pool 800 through the water supply channel 820 to reach a certain storage amount, and the replenishing pool 800 supplies cooling water to the non-safety cooling pool 710. The safety grade cooling pump set 510 draws water directly from the non-safety level cooling water tank 710, and after cooling the equipment cooling water system via the non-safety class heat exchanger group 410, the temperature of the water is The heat enters the non-safety cooling tower group 610, dissipates heat to the atmosphere through the non-safety cooling tower group 610, and the atmosphere is the conventional final heat sink, and the heat released water returns to the non-safety cooling water tank 710.

For units with large thermal loads, the final thermal trap system of a nuclear power plant can also include four safety series and two non-safe series to meet demand.

In combination with the above detailed description of the present invention, it can be seen that the present invention has at least the following beneficial technical effects with respect to the prior art:

According to the above principle, the present invention can also be appropriately modified and modified as described above. Therefore, the invention is not limited to the specific embodiments disclosed and described herein, and the modifications and variations of the invention are intended to fall within the scope of the appended claims. In addition, although specific terms are used in the specification, these terms are merely for convenience of description and do not limit the invention.

Claims

A nuclear power plant final heat sink system comprising at least one non-safe series for non-safety users, and at least one safety series for safety level users, including equipment cooling water systems and plants A water system comprising a cooling pump set and a heat exchanger group, wherein each series of plant water systems is configured with a cooling pool and a cooling tower group, the cooling water pool being located upstream of the cooling pump group. The cooling tower group is respectively connected with the heat exchanger group water outlet and the cooling pool; the cooling pool is provided with a water pool connected with the external water area, and each series of cooling pools is respectively connected with the water pool.
The nuclear power plant final heat sink system according to claim 1, wherein said plant water system further comprises a sedimentation tank connected to the water supply tank and the external water area, respectively.
The nuclear power plant final heat sink system according to claim 2, characterized in that a filtering device is arranged between the sedimentation tank and the external water area.
The nuclear power plant final heat sink system according to claim 2, wherein the sedimentation tank is connected to the water supply tank through at least one water supply channel.
The final heat sink system of a nuclear power plant according to claim 1, characterized in that: the pipeline connecting the cooling pool and the water pool, and the pipeline connecting the water supply channel and the water pool are provided with a gate.
The nuclear power plant final heat sink system according to claim 1, wherein the safety series further comprises an emergency drainage channel connected to the heat exchanger group water outlet and directly leading to the external water area.
The nuclear power plant final heat sink system of claim 1 wherein said final heat sink system includes a non-safe series for cooling non-safety users and two safety series for cooling safety level users.
The nuclear power plant final heat sink system of claim 1 wherein said final heat sink system comprises two non-safe series for cooling non-safety users and four safety series for cooling safety level users. For units with large heat loads.
The nuclear power plant final heat sink system according to claim 1, characterized in that: in the safety series, the safety level users are divided into an accident mitigation group, a normal shutdown group and a spent fuel cooling group, and the safety series can be separately used for accident relief. Cooling is provided by the group, the normal shutdown group, and the spent fuel cooling group.
The nuclear power plant final heat sink system according to claim 9, wherein the safety series carries a normal shutdown group and a spent fuel cooling group, and isolates the accident relief group when the unit is in a normal operating condition.
The nuclear power plant final heat sink system according to claim 9, characterized in that: in the event of an accident, the safety series carries an accident relief group and a spent fuel cooling group, and isolates the normal shutdown group.
The nuclear power plant final heat sink system of claim 1 wherein the non-safe series of cooling pump sets, heat exchanger sets, and cooling tower sets meet non-safety level requirements.
The nuclear power plant final heat sink system of claim 1 wherein the cooling pump set, the heat exchanger set, and the cooling tower set in the safety series meet safety level requirements.
The nuclear power plant final heat sink system according to claim 1, wherein the safety series is provided with independent factory power sources, emergency power sources, and independent power sources.