CN114730641A - Melt retention system in a reactor vessel - Google Patents
Melt retention system in a reactor vessel Download PDFInfo
- Publication number
- CN114730641A CN114730641A CN202080047834.1A CN202080047834A CN114730641A CN 114730641 A CN114730641 A CN 114730641A CN 202080047834 A CN202080047834 A CN 202080047834A CN 114730641 A CN114730641 A CN 114730641A
- Authority
- CN
- China
- Prior art keywords
- reactor
- reactor vessel
- storage tank
- tank
- coolant
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C15/00—Cooling arrangements within the pressure vessel containing the core; Selection of specific coolants
- G21C15/18—Emergency cooling arrangements; Removing shut-down heat
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- General Engineering & Computer Science (AREA)
- High Energy & Nuclear Physics (AREA)
- Structure Of Emergency Protection For Nuclear Reactors (AREA)
Abstract
The present invention relates to the field of nuclear power, aiming at improving the safety of nuclear power plants by providing the possibility of retaining the melt in the nuclear reactor body in different accident severity levels, in passive and active modes. The invention relates to a melt retention system in a reactor vessel, comprising a reactor positioned in a shaft, a coolant circulating pump outside the reactor vessel and a storage tank, characterized in that the storage tank is positioned in the shaft below the bottom of the reactor vessel, above the bottom of the reactor vessel, in addition to a pit tank, which can collect coolant in the event of a loss of coolant accident, the storage tank being connected to the upper part of the pit tank by a channel for supplying coolant. The melt retention system in the reactor vessel can be used in various types of nuclear power plants and allows to increase their safety by ensuring the retention of the melt in the reactor vessel in various types of accidents.
Description
Technical Field
The present invention relates to the field of nuclear power and to a device for ensuring the safety of a nuclear power plant in the event of a serious accident. The invention is intended for use in various types of nuclear power plants.
Background
The most important problem of nuclear power is to ensure the safety of the nuclear power plant when a severe accident occurs when the reactor core is melted. The purpose of modern safety systems in nuclear power plants is to prevent the reactor vessel from being melted by so-called corium, i.e. the mixture of nuclear fuel with concrete, metal parts and other accident consequences. In the event of a loss of coolant accident for cooling a nuclear facility, many safety systems are used for cooling the nuclear facility, which use pumps and tanks with prepared boric acid solution to supply it to the reactor vessel, and special pit tanks to collect coolant flowing from damaged pipes, also for feeding the reactor vessel. In case of a severe accident with loss of power source, melt positioning devices are widely used in modern practice, i.e. separate devices located below the bottom of the reactor and filled with specially prepared materials. However, these devices are very expensive to produce and build, and power plants equipped with melt positioning devices do not experience serious accidents and therefore these devices have not been validated, and therefore systems intended to retain reactor core melt in the event of a serious accident, delay this time even if the reactor vessel melts, partially cool the core, thereby providing more opportunity for the melt positioning device to retain the core, and in the event that the melt remains reliably in the reactor vessel, i.e., forgo an expensive melt positioning device. Furthermore, the use of such melt retention systems in reactor vessels in those projects of a nuclear power plant under construction where no melt locating device is provided may significantly increase the safety of such a nuclear power plant.
As described above, various technical solutions have been adopted in the art.
A nuclear reactor is known (RF patent No. 2496163, published 11/27/2011) comprising a tank in which the reactor core is located, a primary circuit for cooling the reactor, a tank well in which the tank is located, an annular coil surrounding the lower part of the tank in the tank well, separate from the volume of the containment vessel, ensuring that excessive steam pressure occurs.
These are devices made with the possibility of creating a forced convection of liquid in the annular channel and devices for activating devices made with the possibility of creating a forced convection using steam collected as specified.
Such a reactor makes it possible to increase the safety of its operation in autonomous mode, without the need for an external energy supply. However, it has a disadvantage that it is not safe enough to use in an autonomous mode in case of a serious accident, since a complicated device is used to convert thermal energy into mechanical energy and further transmit the mechanical energy.
The reactor vessel is also provided with a melt retention system for the heat conducting wall of the reactor shaft (Chinese patent No. 104036833, published 9/10/2014) in case of accident, which comprises a nuclear reactor arranged in the shaft, a coolant tank arranged above the reactor shaft, a water level maintaining tank connected with the outside of the heat conducting wall of the reactor shaft through a pressure pipeline, and an annular water gallery connected with the water level maintaining tank through a closed pipeline.
Such a system makes it possible to increase the safety of the nuclear power plant by cooling the melt in the reactor vessel, however, it does not provide for operation in a passive mode, since it requires opening of valves to start the system.
Closest to the claimed invention is a heat removal system for nuclear reactor vessels (RF patent No. 2649417, published 2018 on 4/3), comprising at least one pump connected to a source of cooling water, a thermoelectric converter designed to forcibly pump the cooling water outside the enclosure, for directly converting thermal energy into electrical energy mounted on the external surface of the reactor vessel, and at least one electric motor driving the pump by the thermoelectric converter.
Such a system makes it possible to increase the efficiency of the heat exchange due to the forced circulation of the coolant, while ensuring the requirement of passivity of the system operating mode (i.e. absence of external sources and control actions). However, it has a disadvantage that it is not safe enough to use in an autonomous mode in case of a serious accident due to the complicated conversion of thermal energy into electric energy and the need to use an electric motor to drive the pump.
Disclosure of Invention
The technical problem underlying the present invention is to develop a melt retention system in a reactor vessel that allows the possibility of retaining melt in the reactor vessel in different accident severity in passive and active mode. Safety of nuclear power plants is increased by providing the possibility of retaining melt in nuclear reactor bodies of varying accident severity in both passive and active modes.
The technical scheme for solving the technical problems is as follows:
in known internal melt retention systems comprising a reactor located in a shaft, a coolant circulation pump outside the reactor vessel and a storage tank located in the shaft below the reactor vessel bottom, there being a further pit tank above the reactor vessel bottom, the coolant can be collected in the event of a loss of coolant accident, and the storage tank is connected to the upper part of the pit tank by a channel supplying the coolant.
Preferably, the reactor shaft should be equipped with baffles to equalize the heat flow.
Preferably, finned deflectors are made.
Preferably, a filter is provided for the reservoir.
Preferably, the storage tank and the pipes are connected to an external coolant source.
Preferably, the storage tank is connected to a pipe with a steam condensation system located above the reactor vessel and the reactor shaft is connected to a steam condensation system with a steam removal channel.
Preferably, a dedicated storage tank is introduced in the conduit connecting the steam condensation system and the storage tank.
Drawings
The invention is explained by the following figures:
FIG. 1 shows a general view of the contents of a nuclear power plant having a system for retaining a suspension in a reactor loop;
FIG. 2 shows a diagram of a melt retention system in a reactor vessel in a preferred version;
FIG. 3 shows a view of a lower portion of a nuclear power plant containment vessel with a melt retention system in the reactor vessel.
The melt retention system in the reactor vessel comprises a reactor 1 located inside the shaft, one or several coolant circulation pumps (not shown) outside the reactor vessel, at the level of its middle part, a pit pot 2 with emergency cooling system in the reactor area, and at the bottom of the reactor 1 a storage tank 3 connected to the upper part of the pit pot 2 via a coolant inlet channel via a filter 6. The water storage tank 3 is also connected to an external water source, schematically shown in fig. 2, by a pipe 5. One of these sources is a condensing heat exchanger 9, in the conduit 4 connecting them to the tank 3 a special tank 8 is installed. A baffle 5 is installed in the reactor shaft around the reactor vessel with a small gap. A steam removal channel 10 is connected with the common space of the containment vessel at the upper part of the reactor above the guide plate.
Detailed Description
The principles and features of the present invention will be described with reference to the drawings, which are provided by way of example only and are not intended to limit the scope of the present invention.
The specification and accompanying drawings are illustrative of the invention and should not be considered as limiting its scope. In the description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, in certain instances, well-known or conventionally used details are not described in order to avoid obscuring the description. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.
During power operation of the nuclear power plant, the coolant (water containing some boric acid content) is contained in special storage tanks, such as the ECCS accumulator and the secondary accumulator of the emergency cooling system of the reactor area, the correction shaft, and the pit tank 2, and the water level in the pit tank is lower than the intake level of the coolant intake passage 7 and therefore does not enter the storage tank 3. Water ingress is unacceptable at the highest operating temperature of the reactor vessel.
In the event of a loss of coolant without causing an unforeseen failure of the emergency cooling system of the reactor area, liquid is taken from the pit pot 2 by standard means of the system and fed into the reactor 1 so that it does not reach the level of the inlet opening of the coolant inlet channel 7, although coolant enters through a slit in the coolant line, but does not enter the storage tank 3. At the same time, the circulation pump of the pipe 4 for supplying water from the external water source does not work. The water level in the tank 3 cannot reach the reactor vessel 1, which reduces the number of loading cycles of the reactor vessel 1, protecting it from excessive loads.
In a serious accident characterized by loss of energy from the emergency cooling system pump of the reactor area, the water of the pit stops flowing into the reactor 1, so that the water level in the pit 2 exceeds the level of the inlet opening of the coolant inlet channel 7 from a certain point, as a result of which it enters the sump 3 and gradually reaches the level of the reactor vessel 1, cooling it by the deflector 5, which helps to prevent the reactor vessel 1 from melting by retaining the melt of the core and the internal devices inside the reactor vessel.
In addition to the above-described method of cooling the reactor 1, it is also possible to put the system into operation at the command of the operator based on the analysis of the actual state of the core based on the passive principle. This is possible if the respective pump remains operational.
In this case, the water supply to the reactor shaft bay is provided from the maximum number of different sources available (depending on the accident scenario), for example from the main circulation loop, from the hydraulic capacity of the reactor zone emergency cooling system and the hydraulic capacity of the second stage, from the trim shaft, from a source outside the containment.
In both cases, the steam-water mixture produced is discharged through the steam removal channel 10 in the reactor shaft plant into the steam generator box and further into the space under the containment dome where the steam condenses due to the operation of the passive heat removal system, and then the water flows by gravity into the reactor shaft 1. This ensures an infinite evacuation of heat from the containment enclosure to the atmospheric air.
In a preferred embodiment, the conduit 4 connecting the passive heat removal system from the protective casing and the tank 3 has a dedicated tank 8, which tank 8 is designed to collect the condensate from the passive heat removal system heat exchanger of the protective casing and to feed it further to the tank 3. This will reduce contamination of the coolant entering the tank 3 and help to solve the problem of boron build-up by supplying condensed water with a low content of impurities. This enables us to solve an important problem of limiting the deposition of boric acid contained in water on the cooling channels of the reactor vessel 1 and on the surface of the reactor vessel 1, cooling the reactor vessel 1 due to the reduced heat flow caused by the deposition of boric acid.
The components of the molten material containment system in the reactor vessel and associated systems may be equipped with instrumentation to monitor and manage incidents that are severe beyond the design base.
It can also be used in systems where the melt is retained in the reactor vessel to enhance the heat exchange between the reactor and the cooling water as fins of the deflector plates 5.
The use of a melt retention system in power plant and reactor type reactor vessels does not result in performance degradation (increased installed capacity utilization, availability, time and cost of maintenance and repair, and heat loss to the equipment).
The melt retention system in the reactor vessel does not interfere with the operation of the cavity concrete inner ventilation ducts and the cooling air channels between the thermal insulation of the jacket and the dry-guard metal structure in normal operation, in violation of normal operation, in emergency situations (design accident and out-of-design accident not melting the core).
As indicated above, the design of the elements of the melt retention system in the reactor vessel eliminates the ingress of water on the reactor vessel under all conditions except severe accidents to reduce the number of vessel loading cycles.
The lower part of the guide plate 5 also has the function of heat preservation of the reactor vessel. To provide access to the bottom of the reactor 1, the lower part of the baffle 5 (with insulation) can be made with a downward fall.
A filter 6 for purifying the coolant from contamination is located in the lower part of the reactor shaft around the tank 3.
Filters of the emergency cooling system of the reactor section may also be used to ensure the purity of the water of the melt retention system supplied into the reactor vessel.
As shown in fig. 2, the pipe 4 for supplying water from an external source preferably includes:
emergency cooling system of the reactor zone of the pipe 2 fed with water from the pit-tank.
The water supply channel is located above the nominal water level of the pit 2. At the same time, water is supplied to the reactor shaft only after a loss of coolant accident occurs.
Inside the reactor the manhole equipment water supply pipe.
-a water supply pipe from an external source.
The melt retention system in the reactor vessel can be used in various types of nuclear power plants and allows to increase their safety by ensuring the retention of the melt in the reactor vessel in various types of accidents.
Claims (7)
1. A melt retention system in a reactor vessel, characterized by:
comprising a reactor located within a shaft;
the circulating pump coolant is positioned outside the reactor vessel and the storage tank;
the storage tank is located in a cavity below the bottom of the reactor vessel, there is an additional pit tank above the bottom of the reactor vessel for collecting cooling liquid in the event of a loss of coolant accident, and the storage tank is connected to the upper part of the pit tank through a coolant supply channel.
2. The system of claim 1, wherein: the reactor shaft additionally contains a baffle for equalizing the heat flow.
3. The system of claim 2, wherein: the deflector is made of fins.
4. The system of claim 1, wherein: the storage tank is provided with a filter.
5. The system of claim 1, wherein: the tank is connected to an external coolant source by a conduit.
6. The system of claim 1, wherein: the storage tank is connected by a conduit to a vapor condensation system located above the reactor vessel, and the reactor shaft is connected by a vapor removal channel to a vapor condensation system.
7. The system of claim 6, wherein: a dedicated storage tank is introduced in the conduit connecting the steam condensation system and the storage tank.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| RU2019145006 | 2019-12-30 | ||
| RU2019145006A RU2726226C1 (en) | 2019-12-30 | 2019-12-30 | Melt retention system in reactor housing |
| PCT/RU2020/000208 WO2021137718A1 (en) | 2019-12-30 | 2020-04-30 | System for retaining melt in reactor vessel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114730641A true CN114730641A (en) | 2022-07-08 |
Family
ID=71510157
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202080047834.1A Pending CN114730641A (en) | 2019-12-30 | 2020-04-30 | Melt retention system in a reactor vessel |
Country Status (3)
| Country | Link |
|---|---|
| CN (1) | CN114730641A (en) |
| RU (1) | RU2726226C1 (en) |
| WO (1) | WO2021137718A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112191287B (en) * | 2020-09-30 | 2021-11-02 | 中国核动力研究设计院 | Full-automatic release mechanism for high-temperature melt and control method thereof |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2169953C2 (en) * | 1999-08-12 | 2001-06-27 | Российский научный центр "Курчатовский институт" | Nuclear-reactor core melt trap |
| RU2187852C1 (en) * | 2001-05-11 | 2002-08-20 | Российский научный центр "Курчатовский институт" | Nuclear reactor molten core catcher |
| RU35463U1 (en) * | 2003-08-18 | 2004-01-10 | Хабенский Владимир Бенцианович | The device for localization and cooling of the corium of an emergency nuclear water-type reactor |
| FR2922678A1 (en) | 2007-10-22 | 2009-04-24 | Commissariat Energie Atomique | NUCLEAR REACTOR WITH IMPROVED COOLING IN ACCIDENT CONDITIONS |
| CN104036833B (en) | 2014-05-23 | 2017-05-10 | 中国核电工程有限公司 | In-pile melt retention system with thermal-conductive pile pit outer wall after nuclear power station accident |
| RU2649417C1 (en) * | 2017-01-24 | 2018-04-03 | Общество с ограниченной ответственностью "Научно-технический центр инноваций" | System and method of removing heat from nuclear reactor case |
| CN108550406B (en) * | 2018-03-16 | 2020-05-05 | 中国核电工程有限公司 | Reactor core melt trapping device |
| RU2700925C1 (en) * | 2018-09-25 | 2019-09-24 | Акционерное Общество "Атомэнергопроект" | Nuclear reactor core melt localization device |
| RU2696012C1 (en) * | 2018-11-08 | 2019-07-30 | Федеральное государственное унитарное предприятие "Научно-исследовательский технологический институт имени А.П. Александрова" | Device for localization of corium of nuclear reactor of pressurized water type |
| RU2696612C1 (en) * | 2018-12-26 | 2019-08-05 | Акционерное Общество "Атомэнергопроект" | Melt localization device |
-
2019
- 2019-12-30 RU RU2019145006A patent/RU2726226C1/en active
-
2020
- 2020-04-30 CN CN202080047834.1A patent/CN114730641A/en active Pending
- 2020-04-30 WO PCT/RU2020/000208 patent/WO2021137718A1/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| RU2726226C1 (en) | 2020-07-10 |
| WO2021137718A1 (en) | 2021-07-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP0389231B1 (en) | Containment heat removal system | |
| EP1583105B1 (en) | Pressure suppression and decontamination apparatus and method for reactor container | |
| US6810099B2 (en) | Boiling water reactor nuclear power plant and its construction method | |
| US10290379B2 (en) | Passive containment cooling and filtered venting system, and nuclear power plant | |
| US7522693B2 (en) | Passive safety-grade decay-heat removal method and decay-heat removal system for LMR with pool direct heat cooling process | |
| RU2496163C2 (en) | Nuclear reactor with improved cooling in emergency situation | |
| US5265136A (en) | Sodium cooled fast reactor | |
| US20040196948A1 (en) | Integral pwr with diverse emergency cooling and method of operating same | |
| EP0476563B1 (en) | Nuclear reactor installation with passive cooling | |
| EP0460805A1 (en) | Isolation condenser passive cooling of a nuclear reactor containment | |
| EP0397509B1 (en) | Indirect passive cooling system for liquid metal cooled nuclear reactors | |
| JPH0216496A (en) | Isolation condenser with stop cooling system heat exchanger | |
| US4382908A (en) | After-heat removal system for a gas-cooled nuclear reactor | |
| JPH06242279A (en) | Reactor containment equipment | |
| CN109643587B (en) | Nuclear reactor provided with a raised heat exchanger | |
| CN114730641A (en) | Melt retention system in a reactor vessel | |
| EP3492811B1 (en) | Nuclear power plants | |
| JP2014157029A (en) | Nuclear reactor system and nuclear reactor molten material retaining device | |
| JP4031259B2 (en) | Reactor containment cooling equipment | |
| US20230215589A1 (en) | Self-cleaning liquid purification system | |
| US5289511A (en) | Liquid-metal cooled nuclear reactor | |
| EA046615B1 (en) | MELT RETENTION SYSTEM IN THE REACTOR CASE | |
| WO2015089662A1 (en) | Nuclear reactor safety system | |
| CN112420226B (en) | Passive residual heat removal system based on annular air cooler | |
| JPS59131801A (en) | Secondary heat transmission circuit for liquid metal nuclearreactor |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |