阅读说明：本技术 一种池式反应堆余热排出系统及方法 (Waste heat discharge system and method for pool type reactor ) 是由 王晨 盛天佑 马如冰 马卫民 元一单 杨小明 张天琦 李贺 朱一鸣 刘冉 于 2021-06-17 设计创作，主要内容包括：本发明涉及一种池式反应堆余热排出系统及方法,该系统包括设置在反应堆容器内的独立余热排出换热器,所述独立余热排出换热器通过换热回路管线与设置在反应堆容器外部高位水箱内的堆外冷凝器连接,构成非能动余热排出系统的闭合循环回路,反应堆容器通过绝热围板分割为热池和冷池,其中,所述独立余热排出换热器设置在隔间内,隔间上部的隔间围板高于正常运行工况下热池的冷却剂液位高度,在所述隔间下部设有自动压紧/开启装置,可实现与冷池的隔离以及事故工况下隔间与冷池和热池的连通。该系统采用密度差、压强差等固有特性,在严重事故工况下导出堆芯余热,提高系统运行可靠性。(The invention relates to a waste heat discharge system and a method for a pool type reactor, the system comprises an independent waste heat discharge heat exchanger arranged in a reactor container, the independent waste heat discharge heat exchanger is connected with an external condenser arranged in a high-level water tank outside the reactor container through a heat exchange loop pipeline to form a closed circulation loop of a passive waste heat discharge system, the reactor container is divided into a hot pool and a cold pool through a heat insulation surrounding plate, wherein the independent waste heat discharge heat exchanger is arranged in a compartment, the compartment surrounding plate at the upper part of the compartment is higher than the coolant liquid level of the hot pool under the normal operation condition, and an automatic pressing/opening device is arranged at the lower part of the compartment, so that the separation from the cold pool and the communication between the compartment and the cold pool and the hot pool under the accident condition can be realized. The system adopts inherent characteristics such as density difference, pressure difference and the like, derives the waste heat of the reactor core under the working condition of serious accidents, and improves the operation reliability of the system.)

1. A pool type reactor residual heat discharge system comprises an independent residual heat discharge heat exchanger (4) arranged in a reactor container (9), the independent waste heat discharge heat exchanger (4) is connected with an external condenser (11) arranged in a high-level water tank (12) outside the reactor container through a heat exchange loop pipeline (13) to form a closed circulation loop of a passive waste heat discharge system, the reactor container (9) is divided into a hot pool (2) and a cold pool (3) through a heat insulation coaming (7), it is characterized in that the independent waste heat discharge heat exchanger (4) is arranged in the compartment (5), the compartment coaming (6) at the upper part of the compartment is higher than the coolant liquid level of the hot pool (2) under the normal operation condition, an automatic pressing/opening device (8) is arranged at the lower part of the compartment (5) and can realize the isolation and the communication with the cold pool (3).

2. The pool reactor residual heat removal system of claim 1, wherein the pool reactor uses a lead/lead bismuth coolant.

3. The tank reactor residual heat removal system according to claim 1 or 2, wherein the automatic hold-down/open device (8) is a one-way open device, and the opening direction is opened from the side of the independent residual heat removal heat exchanger compartment to the side of the cold tank.

4. The tank reactor residual heat removal system according to claim 3, wherein the automatic hold-down/open device (8) is provided with a limiting device, and cannot be closed again after being opened.

5. The residual heat removal system of a pool reactor according to claim 4, wherein the automatic compressing/opening means (8) performs automatic compressing by means of pressure applied thereto by the coolant on the cold pool side before opening, and performs automatic opening when the compartment side pressure increases to the opening pressure.

6. The residual heat removal system of a pool reactor as claimed in claim 5, characterized in that the automatic pressing/opening device (8) can be provided with a counterweight or a precompression spring for adjusting its opening pressure.

7. The waste heat removal system of the pool-type reactor according to claim 1, wherein the heat exchange loop pipeline (13) is provided with an upstream isolation valve (14) and a downstream isolation valve (10), and the upstream isolation valve (14) and the downstream isolation valve (10) can be automatically opened; the standby stage heat exchange loop line (13) is in a water full state.

8. A method for discharging the residual heat of the pool reactor by using the system of any one of claims 1-7, wherein under the normal operation condition, the independent residual heat discharging heat exchanger of the passive residual heat discharging system is in an isolated standby state in the compartment and is not in contact with the coolant of the pool reactor; under the accident condition, the coolant of the pool type reactor enters a compartment where the independent waste heat discharging heat exchanger is located after being heated and expanded, the pressure in the compartment rises along with the increase of the coolant in the compartment, an automatic locking/opening device of the compartment is opened, and the compartment is communicated with a cold pool and a hot pool of the coolant to form a natural circulation loop; the heat exchange medium of the passive residual heat removal system enters the out-of-reactor condenser for cooling after exchanging heat with the coolant of the pool type reactor through the independent residual heat removal heat exchanger, and the cooled heat exchange medium enters the independent residual heat removal heat exchanger again to form another natural circulation process, so that the reactor core residual heat is led out to the external water tank.

Technical Field

The invention belongs to the nuclear reactor design technology, and particularly relates to a pool type reactor waste heat discharge system and method.

Background

In 2011, 3, 11 days, Fudao in Japan suffered from the nuclear accident of Fudao which raised the world surprise. After an earthquake occurs, the Fudao nuclear power station realizes emergency shutdown, but serious full-field power failure accidents are caused because the tsunami submerges the emergency diesel generator, the emergency cooling system cannot be put into operation, and the waste heat of the reactor core cannot be discharged. This in turn causes the core to melt and the fuel clad to react with the water vapor, and the large amount of hydrogen produced causes an explosion, resulting in radioactive leaks. After the fukushima accident, the world puts higher requirements on the waste heat discharge of the reactor. "passive" has been widely used and studied because of its characteristics of not relying on an external power source but only on natural circulation. At present, passive systems are adopted in the design of the third-generation reactor, and the reliability of system operation is improved by utilizing inherent characteristics such as density difference, gravity and the like. The passive residual heat removal system is an important component of a safety system, and is adopted by three generations of reactors such as Hualong I, AP1000 and the like at present.

In the aspect of the fourth generation reactor, the lead-cooled fast reactor is listed as one of six fourth generation nuclear energy systems with the most development prospect by the international fourth generation heap forum (GIF) due to excellent neutronics performance, thermal hydraulic performance and safety performance. The lead-cooled fast reactor adopts lead or lead-bismuth alloy as a coolant, and adopts an integrated modular design. At present, the lead-cooled fast reactor is mainly miniaturized, and can meet various energy requirements. At present, the countries which are internationally developing the research of the lead-cooled fast reactor comprise Russia, America, European Union, China and the like. In the event of a full outage accident, as in the case of the fukushima accident, the lead-cooled fast reactor can provide a longer operating margin for accident handling because of the high boiling point and thermal inertia of the coolant. However, without effective residual heat removal measures, reactor safety is compromised. Therefore, a residual exhaust system for leading out the waste heat of the reactor core under the accident condition needs to be designed, and the inherent characteristics of density difference, pressure difference and the like are adopted, so that the operation reliability of the system is improved, and the risk of melting the reactor core is reduced.

The system design of the independent waste heat discharging heat exchanger applied to the lead-cooled fast reactor at present is that the independent heat exchanger is immersed in a main loop coolant during operation, and heat is led out by means of water, lead, bismuth and other heat exchange working media in a heat exchange loop. Such as ELSY, ELFR, etc. of the European Union. However, in the current design, the independent waste heat removal heat exchanger is immersed in the lead/lead bismuth coolant under normal operation conditions and is not isolated from the main loop. Due to the high temperature of the lead/lead bismuth coolant, the heat exchanger is always in a heated state, which has a great influence on the life of the heat exchanger and related pipelines. And because of the heating of the coolant, the temperature and the pressure of the heat exchange working medium in the heat exchanger are higher under the normal operation working condition, and great influence is caused on the performance and the heat exchange efficiency of the heat exchange loop.

Therefore, there is a need to provide a reasonably feasible waste heat removal system and method suitable for a pool reactor to solve the above problems.

Disclosure of Invention

The invention aims to provide a waste heat discharging system and method for a pool reactor, which can lead out decay heat of a reactor core, improve the operation reliability of the system and reduce the risk of melting the reactor core.

The technical scheme of the invention is as follows: the utility model provides a pond formula reactor waste heat discharge system, is including setting up the independent waste heat discharge heat exchanger in the reactor container, independent waste heat discharge heat exchanger passes through the heat transfer return circuit pipeline and is connected with the outer condenser of heap that sets up in the outside high-order water tank of reactor container, constitutes passive waste heat discharge system's closed cycle loop, and the reactor container is cut apart into hot pond and cold pond through adiabatic bounding wall, wherein, independent waste heat discharge heat exchanger sets up in the compartment, and the compartment bounding wall on compartment upper portion is higher than the coolant liquid level height of hot pond under the normal operating condition the compartment lower part is equipped with automatic closing/opening device, can realize with the isolation and the intercommunication of cold pond.

Further, the system for discharging the residual heat of the pool reactor is characterized in that the pool reactor adopts a lead/lead bismuth coolant.

Further, the system for discharging the residual heat of the pool reactor is characterized in that the automatic compressing/opening device is a one-way opening device, and the opening direction of the automatic compressing/opening device is opened from the compartment side of the independent residual heat discharging heat exchanger to the cold pool side.

Furthermore, the automatic pressing/opening device is provided with a limiting device, and the automatic pressing/opening device cannot be closed again after being opened.

Furthermore, before the automatic pressing/opening device is opened, the automatic pressing is realized by the pressure exerted on the device by the lead/lead bismuth coolant on the cold pool side, and when the pressure on the compartment side is increased to the opening pressure, the device can be automatically opened.

Further, the automatic pressing/opening device may be provided with a weight or a pre-compressed spring for adjusting its opening pressure.

Further, according to the tank reactor waste heat discharge system, the heat exchange loop pipeline is respectively provided with an upstream isolation valve and a downstream isolation valve, and the upstream isolation valve and the downstream isolation valve can be automatically opened; the standby stage heat exchange loop pipeline is in a full water state.

Under the normal operation condition, an independent waste heat discharge heat exchanger of the passive waste heat discharge system is in an isolated standby state in a compartment and is not in contact with a coolant of the pool reactor; under the accident condition, the coolant of the pool type reactor enters a compartment where the independent waste heat discharging heat exchanger is located after being heated and expanded, the pressure in the compartment rises along with the increase of the coolant in the compartment, an automatic locking/opening device of the compartment is opened, and the compartment is communicated with a cold pool and a hot pool of the coolant to form a natural circulation loop; the heat exchange medium of the passive residual heat removal system enters the out-of-reactor condenser for cooling after exchanging heat with the coolant of the pool type reactor through the independent residual heat removal heat exchanger, and the cooled heat exchange medium enters the independent residual heat removal heat exchanger again to form another natural circulation process, so that the reactor core residual heat is led out to the external water tank.

The invention has the following beneficial effects: by utilizing the waste heat discharging system and method for the pool reactor, the waste heat of the reactor core can be led out by relying on inherent characteristics such as density difference, pressure difference and the like without human intervention, the risk of melting the reactor core is reduced, and the reliability of system operation is improved.

According to the invention, the heat exchanger and the hot pool are isolated under the normal working condition through the compartment enclosing plate of the waste heat discharge heat exchanger compartment, and the coolant automatically flows into the waste heat discharge heat exchanger compartment by utilizing the thermal expansion characteristic of the coolant; the heat exchanger and the cold pool are isolated under normal working conditions by the automatic pressing/opening device and depending on the pressure of the coolant in the cold pool; under the accident condition, the opening of the automatic pressing/opening device is realized by utilizing auxiliary pressure adjusting means such as a balance weight, a pre-compression spring and the like in cooperation with the gradually-increased coolant pressure in the compartment, and the establishment of a natural circulation loop is completed; the surplus row system utilizes the density difference caused by the heat exchange medium in the processes of being heated and condensed in the independent surplus row heat exchanger and the condenser to realize natural circulation. The whole system can lead out the waste heat of the reactor core under the working condition of serious accidents, and the safety of the reactor core is ensured.

Drawings

FIG. 1 is a schematic diagram illustrating the composition of an exemplary waste heat removal system for a pool reactor of the present invention;

fig. 2-1 and 2-2 are schematic structural views of an automatic pressing/opening device according to an embodiment of the present invention.

In the figure, 1. the core; 2. a hot tank; 3. a cold pool; 4. the independent waste heat is discharged out of the heat exchanger; 5. the waste heat is discharged out of the heat exchanger compartment; 6. a compartment coaming; 7. heat insulation coaming plates; 8. an automatic pressing/opening device; 9. a reactor vessel; 10. a downstream isolation valve; 11. an out-of-pile condenser; 12. a water tank; 13. a heat exchange loop line; 14. an upstream isolation valve; 15. pre-compressing the spring; 16. a limiting device; 17. a piston; 18. and the valve clack.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

An exemplary waste heat removal system for a pool reactor according to the present invention is shown in fig. 1, in which the pool reactor is a lead/lead bismuth cooled reactor, a core 1 is disposed in a closed reactor vessel 9 at the bottom thereof, and the entire reactor vessel 9 is partitioned into a hot pool 2 and a cold pool 3 by a heat insulation enclosure 7. Under the normal operating condition, the coolant in the cold pool enters the hot pool through the core heating, and then the coolant in the hot pool enters the cold pool after the heat exchange of the steam generator. Inside the container has set up waste heat discharge heat exchanger compartment 5 for independent waste heat discharge heat exchanger 4 simultaneously, and independent waste heat discharge heat exchanger 4 is installed in this compartment, and compartment bounding wall 6 on compartment upper portion highly is higher than hot pond liquid level under the normal operating mode, keeps apart independent waste heat discharge heat exchanger 4 and hot pond 2, and independent waste heat discharge heat exchanger 4 is not in the heating state this moment. An automatic locking/unlocking device 8 is arranged at the lower part of the compartment 5, and the compartment is isolated from the cold pool 3 under the normal operation condition. The external condenser 11 is arranged in the water tank 12, is in a full water state in a standby state, is full of water in the water tank 12, and is arranged at a higher position of the relatively independent waste heat discharging heat exchanger 4. The heat exchange loop pipeline 13 is communicated with the independent waste heat discharging heat exchanger 4, the upstream isolating valve 14, the downstream isolating valve 10 and the out-of-reactor condenser 11 to form a closed circulation loop of the passive waste heat discharging system, the upstream isolating valve 14 and the downstream isolating valve 10 can be automatically opened and cut off, and if the upstream isolating valve 14 and the downstream isolating valve 10 are automatically opened according to a reactor shutdown signal, the heat exchange loop pipeline 13 in the standby stage is in a full water state.

One embodiment of the automatic pressing/opening device 8 is shown in fig. 2-1 and 2-2, and the automatic pressing/opening device 8 is a one-way opening device which is opened from the side of the independent waste heat discharging heat exchanger compartment to the side of the cooling tank and cannot be closed again after being opened. The device is designed with a precompression spring 15, a stop 16, a piston 17, a flap 18. Under normal operating conditions, the flap 18 is automatically compressed by the pressure exerted on it by the bath side lead/lead bismuth coolant (as shown in fig. 2-1), and the pressure inside increases progressively as the coolant enters the heat exchanger compartment 5. The device can realize automatic opening by matching with the force applied by the pre-compressed spring and the pressure of the inner side gradually exceeds the pressure of the cold pool side. After opening, the device is prevented from closing by the upward movement of the piston 17 by virtue of the ejection of the stop means 16 (as shown in figures 2-2). Meanwhile, the opening pressure can be adjusted by designing a balance weight on the device, adjusting the pressure of the pre-compression spring and the like.

Under the normal operating condition, the independent waste heat discharging heat exchanger 4 is in an isolation standby state, the heat exchanger is isolated from the coolant in the hot pool 2 by the aid of the compartment enclosing plate 6 on the upper portion of the compartment, and the heat exchanger is isolated from the coolant in the cold pool 3 by the aid of the automatic pressing/opening device 8 on the lower portion of the compartment. The independent waste heat discharging heat exchanger 4, the heat exchange loop pipeline 13 and the outside-pile condenser 11 are all in a full water state, and the independent waste heat discharging heat exchanger is not in a heated state.

Under the accident condition, because the residual heat of the reactor core 1 cannot be led out, the temperature of the lead/lead bismuth coolant is increased, the volume of the lead/lead bismuth coolant is expanded, the liquid level of the lead/lead bismuth coolant in the hot pool 2 is gradually higher than the compartment coaming 6 and enters the compartment 5 of the residual heat discharge heat exchanger, the side pressure of the compartment of the automatic pressing/opening device 8 is still smaller than the side pressure of the residual cold pool 3, and the device is in a closed state. Along with the rise of the liquid level of the coolant in the compartment, the side pressure of the compartment is gradually increased, meanwhile, the automatic locking/opening device 8 is opened by utilizing pressure adjusting means such as a balance weight, a pre-compression spring and the like, and the device cannot be closed after being opened due to the design of the limiting device, and the compartment is communicated with the cold pool 3 and the hot pool 2 to form a natural circulation loop of the lead/lead bismuth coolant. In the aspect of a heat exchange loop, the upstream isolation valve 14 and the downstream isolation valve 10 are automatically opened after an accident, heat exchange media in the independent waste heat discharging heat exchanger 4 exchange heat with lead/lead bismuth coolant entering the waste heat discharging heat exchanger compartment 5, the heat exchange media enter the out-of-stack condenser 11 for cooling, the cooled heat exchange media reenter the independent waste heat discharging heat exchanger 4 to form a natural circulation process of another heat exchange media, and then reactor core waste heat is led out to the water tank 12 through the passive waste heat discharging system. The whole system adopts inherent characteristics such as density difference, pressure difference and the like, and leads out the waste heat of the reactor core under the working condition of serious accidents, thereby improving the operation reliability of the system, reducing the risk of melting the reactor core and ensuring the safety of the reactor.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.