JPS63193092A - Cooling device for liquid-metal cooling type reactor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Objective of the Invention) (Industrial Field of Application) The present invention relates to a cooling device for a liquid metal cooled nuclear reactor that uses liquid metal as a coolant, and particularly relates to a cooling device for a nuclear reactor that uses liquid metal as a coolant. Regarding improvements.

(Prior art) In fast breeder reactors that use liquid metals such as sodium as coolants, the reactor cold W material, or secondary coolant, has a high level of radioactivity, so the secondary cooling system requires steam generation. isolated from the system.

On the other hand, heat exchange equipment between liquid metal and water is essential to generate the steam that drives the turbine generator.

The primary coolant, such as sodium, easily combines violently with air and water, and the heat of the chemical reaction is large.

Therefore, in order to prevent the effects of the water-liquid metal reaction from spreading to the core in the event that the steam side piping of the steam generator is damaged, a secondary cooling system is installed between the primary cooling system and the steam generation system. is set up.

It is currently used in a cooling system in a conventional liquid metal cooled nuclear reactor, with reference to FIG.

At the center of the reactor vessel 1 is a reactor core 2 loaded with fuel assemblies.
is arranged, and a cold U1 material 3 such as a liquid metal such as sodium for cooling the core 2 is loaded. The coolant 3 is
It is circulated by a primary main circulation bomb 4 installed inside the reactor vessel 1. A primary cooling shrine 3 that cools this core, -
A primary cooling system is constituted by the primary circulation bomb 4 and an intermediate heat exchanger [i5] that exchanges heat between the secondary coolant and the secondary cooled TRR material.

On the other hand, the secondary cooling uj system includes an intermediate heat exchanger 5, a steam generator 6 that generates steam to be supplied to a turbine generator (not shown), and a vertical right-hand coolant for circulating the secondary coolant. It is composed of a surface mechanical secondary main circulation pump 7 and first to third piping 8a, 8b, and 8C that connect these devices.

In the conventional secondary cooling system, the steam generator 6 and the secondary main circulation pump 7 are arranged in separate lu1M with the reactor building 9 as the boundary.

(Problems to be Solved by the Invention) According to the conventional arrangement of the secondary cooling system, the secondary main circulation pump 7 and the steam generator 6 are installed separately, and their equipment and piping are installed in the reactor auxiliary building. occupies a large proportion of the space of
There was an uneconomical need to increase the size of the building and ancillary equipment such as drain tanks.

In addition, since the connection parts of the pipes 8a, 8b, and 8c that connect the steam generator 6 and the secondary main circulation pump 7, etc. all have one fixed anchor point, the pipes connecting the various pipes are protected against thermal expansion. Absorb. Therefore, it is necessary to form a piping loop or meander in the middle of the piping, which results in a long piping length, a large space occupied by the piping, and an increase in the size of the incidental equipment. Furthermore, the free liquid level rises and falls according to the output of the plant, requiring a relatively large space to absorb the thermal expansion of the secondary cooling system.

For example, in the case of a 1 million KW class nuclear power plant, the thermal expansion of the secondary cooling system is approximately 25 M1, and the free liquid level in the steam generator is approximately 2 m or more above and below, so there is space for this. There was a need.

The present invention has been made for the purpose of eliminating the above-mentioned drawbacks, and in order to simplify the structure and arrangement of a steam generator, it is possible to develop a liquid metal cooled nuclear reactor that can maintain a constant free liquid level in the steam generator at all times. It provides a cooling device.

(Structure of the Invention) (Means for Solving the Problems) The present invention is characterized in that an intermediate heat exchanger disposed inside a nuclear reactor vessel and a steam generator disposed outside the reactor vessel are connected by piping. In a cooling system for a liquid metal cooled nuclear reactor, a liquid metal inlet pipe is provided in the upper part of the main body shell of the steam generator, and a liquid metal riser pipe having an opening in the lower part of the main body shell is installed in the main body shell in the axial direction. A liquid platform bottom outlet pipe is connected to the upper end of the liquid metal riser pipe, an electromagnetic pump is arranged in a space above the liquid metal surface around the upper part of the liquid metal riser pipe, and a steam generator body An overflow nozzle is provided in the upper part of the shell, and the overflow nozzle is connected to an overflow tank through an overflow pipe, and the overflow tank is connected to a pumping pipe that connects the reactor vessel and the steam generator. This is a cooling device for a liquid metal cooled nuclear reactor, characterized in that an electromagnetic pump for transferring liquid metal from the overflow tank is installed in the middle.

(Function) In the cooling system for a liquid metal cooled nuclear reactor of the present invention, the liquid metal heated by the intermediate heat exchanger passes through the liquid metal inlet pipe, is supplied to the steam generator, and is supplied with water while descending through the steam generator. It exchanges heat with and generates steam. The liquid metal whose temperature has been lowered by heat exchange is sucked up from the lower end opening of the liquid metal riser pipe by the action of the electromagnetic pump, and is further returned to the intermediate heat exchanger. An electromagnetic pump disposed in a space above the liquid metal level around the upper part of the liquid metal riser creates a moving magnetic field that moves the liquid metal in the direction of the liquid metal outlet pipe.

The temperature of the liquid metal in the secondary system rises as the output of the plant increases, and the volumetric expansion flows into the overflow tank from the overflow nozzle of the steam generator, increasing the inventory in the secondary cooling system. Absorb swelling.

Further, according to the above configuration, since the electromagnetic pump is built into the steam generator as a substitute for the conventionally installed secondary main circulation pump, the equipment arrangement is simplified and the total length of the piping is also shortened.

(Example> Next, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a system diagram showing an embodiment of a cooling system for a nuclear reactor using liquid metal cooling 7J according to the present invention. In the figure, reference numeral 10 indicates a reactor vessel of a liquid metal cooled nuclear reactor, and a reactor core 11 is disposed in this reactor vessel 10C. core 11
is cooled by the primary coolant 13 of the reactor-primary cooling system 12. The reactor secondary cooling system 12 includes a primary main circulation pump 14 and an intermediate heat exchanger 15 disposed inside the reactor vessel 10, and the primary cooling system 12 provides primary cooling within the reactor vessel 10 by the primary circulation pump 14. The material 13 can be circulated.

The primary coolant 13 of the reactor secondary cooling system 12 is heat exchanged with the secondary coolant 18 of the reactor secondary cooling system 17 in the intermediate heat exchanger 15 . This secondary cooling system 17 is arranged between the reactor-secondary cooling system 12 and the steam generation system 19. The reactor secondary cooling system 17 connects the intermediate heat exchanger 15, a steam generator 20 disposed outside the reactor vessel 10, and the intermediate heat exchanger 15 and the steam generator 20. Furnace lJ! It is composed of hot leg piping 22 and cold leg piping 23 which are disposed through a roof wall 21.

At the upper part of the main body shell 25 of the steam generator 20, liquid total notification artificial pipes 26 and 27 are provided. On the other hand, the above main body 1N25
Inside the main body 1 is a liquid metal riser pipe 28 having an opening at the bottom.
125 , and a liquid metal outlet pipe 26 is connected to the upper end of the liquid metal riser pipe 28 . Further, an electromagnetic pump 29 is disposed above the liquid metal riser pipe 28 .

In addition, an overflow nozzle 3 is installed at the top of the steam generator 20.
0, and this overflow nozzle 30 is connected to an overflow tank 31 by an overflow pipe 32.

Furthermore, overflow tank 31 and hot leg piping 22
are connected by a pumping pipe 33, and the pumping pipe 33
An electromagnetic pump 34 for pumping is provided in the middle.

By the way, the steam generator 20 has a vertical cross-sectional structure shown in FIG. A heat exchanger tube shroud 36 is disposed outside of the heat exchanger shroud 28, and a large number of heat exchanger tubes 38 are further disposed in an annular space (heat exchange chamber 37) outside the shroud.

By the way, a free liquid surface FL of the liquid metal is formed inside the upper part of the main body JI20, and the space 39 above the free liquid surface FL absorbs the volume change due to thermal expansion of the liquid metal, so that the above-mentioned overflow occurs. A nozzle is provided and has the function of maintaining the liquid level in the secondary cooling system.

On the other hand, the inlet portion of the water supply is constituted by the water inlet pipe 41 into which the water supplied from the water supply pump 40 in FIG. Ru. Further, the steam outlet portion is composed of an outlet steam chamber 45, an outlet steam distribution pipe 46, an outlet steam header 47, and an outlet steam pipe 48.

FIG. 3 is a plan view of the steam generator 20 in FIG. 2. The liquid metal inlet pipe 27 is branched into two lines and provided on the upper part of the main body layer, while the liquid metal outlet pipe 26 is led out from the center of the top of the main body.

FIG. 4 is a sectional view taken along the line IV--IV in FIG. 3, showing the top of the steam generator 20. An electromagnetic pump 29 is provided on the inner periphery of the enlarged diameter portion at the upper part of the liquid metal riser pipe 28.
This electromagnetic pump 29 is constructed with a two-stage coil system in which an electromagnetic coil 51 is wound inside and outside of a liquid metal scrap flow path 50 formed in an annular shape, and generates a magnetic field using a current from an external power source. , circulating liquid metal.

A liquid metal riser pipe 28 containing an electromagnetic pump 29 is connected to a liquid metal outlet pipe 26 , and the liquid metal outlet pipe 26 is further connected to a cold leg pipe 23 .

Next, the operation of the above embodiment will be explained.

By circulating the primary coolant 13 that cools the heat generated in the reactor core 11 by the primary main circulation pump 14, the heat is transferred to the secondary cooling system via the intermediate heat exchanger 15. On the other hand, the liquid metal in the secondary cooling system is circulated by the electromagnetic pump 29 built into the steam generator 20, and the high-temperature liquid metal condensed in the intermediate heat exchanger 15 passes through the leg piping 22.
It enters the steam generator 20 via the liquid metal inlet pipe 27 .

Then, the high-temperature liquid metal flows down inside the heat exchange chamber 37 in which the heat transfer tubes 38 are installed, giving heat to the feed water to turn it into steam.
It cools down and becomes a low-temperature liquid metal. This low-temperature liquid metal rises in a liquid metal riser pipe 28 that is installed in the lower part of the steam generator 20, and is further given discharge pressure by an electromagnetic pump 29, and then flows through a liquid metal outlet pipe 26. and intermediate heat exchanger 5 via cold leg piping 23
is refluxed to.

Also, when filling the plant with liquid metal, the steam generator 20
is filled up to the free liquid level FL of the overflow nozzle 30. Thereafter, when the output of the plant is increased, the liquid metal thermally expands, and the increased inventory overflows from the overflow nozzle 30 to the overflow tank 31, freeing up the space inside the steam generator 20 of the reactor secondary cooling system. The liquid level FL is always maintained constant.

Conventional liquid metal cooled nuclear reactors are not equipped with an overflow line, so the free liquid level in the steam generator rises and falls according to the output to the steam generator. Therefore, in order to absorb the thermal expansion of the liquid metal (secondary cooled JJI material) in the reactor secondary cooling system, it was necessary to provide a relatively large upper space.

For example, in the case of a 1 million KW class nuclear power plant, the thermal expansion of the liquid metal in the secondary cooling system is about 25 d, and the upper and lower liquid levels in the steam generator are about 2 TrL or more, so it is necessary to create a space for this. It was necessary to hold it.

However, in the liquid metal June 1 reactor shown in FIGS. 1 to 4, the overflow nozzle 46
Since the liquid level within is always maintained constant, there is no vertical movement of the free liquid level of the liquid metal, and the upper space 39 for vertical movement is
is not necessary. In the event that the heat transfer tube 38 of the steam generator 520 is damaged, the function as a buffer tank is used to prevent the excessive pressure wave generated at that time from directly propagating to the intermediate heat exchanger 5. The steam generator can be made more compact by simply providing a gas space having the following characteristics.

By the way, in the steam generator 20 shown in FIG.
On the water/steam side, water fed from a water supply pump (not shown) flows into a water inlet header 42 from a water inlet pipe 41, is distributed in flow through a water inlet distribution pipe 43, and is then divided into a plurality of parts to form a water inlet header 42. This leads to room 44. The water supplied from this water inlet water chamber 44 into the heat exchanger tube 38 is distributed to the heat exchanger tube 38.
As it rises inside, it exchanges heat with the liquid metal, reaches a temperature rise and becomes steam, and then reaches the outlet steam chamber 45. After passing through the outlet steam distribution pipe 46 and merging at the outlet steam header 47, the steam flows out from the outlet steam pipe 48 and is sent to a steam turbine (not shown).

As explained above, according to this embodiment, by integrating the electromagnetic pump into the steam generator, the secondary main circulation pump of the secondary cooling system, which is required in the conventional reactor cooling system, can be used. This makes it possible to significantly shorten the piping length.

In addition, in this embodiment, the free liquid level F at the top of the steam generator 20
By keeping L constant and arranging the electromagnetic pump 29 in the space formed above the free liquid level FL, the electromagnetic coil is less affected by temperature directly from the liquid metal 18. Moreover, the liquid metal flowing inside the electromagnetic pump 29 is
It is in a low temperature state because it has just undergone heat exchange. Therefore, the electromagnetic pump 29 is installed at the bottom of the steam generator 20.
Since the temperature at the installation location is lower than in the case of the conventional method, the reliability of the electromagnetic coil is increased and the life of the electromagnetic pump 29 can be extended.

Furthermore, according to this embodiment, during maintenance, Ti
Since the magnetic pump 29 can be easily pulled upward from the top of the steam generator 20, maintenance work is easier than when the electromagnetic pump 29 is installed at the bottom of the steam generator 20.

Furthermore, in this embodiment, since the piping length is significantly shortened, it is also possible to reduce the sodium inventory in the secondary cooling system, and therefore the capacity of auxiliary equipment such as a drain tank can be reduced. Furthermore, by reducing the number of conventional secondary main circulation pumps, the number of rooms and space in the reactor building can be reduced, and by shortening the piping length, the space in the reactor auxiliary building occupied by the piping can be reduced. Can be covered.

〔Effect of the invention〕

J'3 in the cooling device for a liquid metal cooled nuclear reactor according to the present invention.
In this case, the overflow nozzle can maintain a constant liquid level in the steam generator, so there is no need to take up space for the liquid level to move up and down. Further, the steam generator can be downsized by absorbing the thermal expansion of the liquid metal from the steam generator using the A-buff flow nozzle.

Furthermore, the capacity of auxiliary equipment such as drain tanks and the space volume of the reactor building and reactor auxiliary buildings have been reduced, which in turn has led to a significant reduction in the construction cost of nuclear power generation plan 1. It shows its effectiveness.

[Brief explanation of the drawing]

Fig. 1 is a system diagram showing an embodiment of the cooling device for a liquid metal cooled nuclear reactor according to the present invention, Fig. 2 is a half-longitudinal sectional view showing the structure of the steam generator in Fig. 1, and Fig. 3 is a plan view of the steam generator in Fig. 2, and Fig. 4 is a plan view of the steam generator in Fig. 3.
FIG. 5, a sectional view taken along line -IV, is a system diagram showing a cold IJI device for a conventional liquid metal cooled nuclear reactor. DESCRIPTION OF SYMBOLS 10... Reactor vessel, 11... Reactor core, 12... Reactor secondary cooling system, 13... Coolant, 171...-main circulation pump, 15... Intermediate heat exchanger , 17... Reactor secondary cooling system, 19... Steam generation system, 20... Steam generator, 21... Reactor building wall, 22... Hora 1
- Leg piping, 23...Cold leg piping, 25...
Main body trunk, 26... Liquid metal outlet piping, 27... Liquid metal inlet piping, 28... Liquid metal riser pipe, 29...
Electromagnetic pump, 30... Overflow nozzle, 31...
・Overflow tank, 32...overflow piping,
33... pumping piping, 34... electromagnetic pump for pumping, 3
5... Main body support skirt, 36... Heat exchanger tube shikoroud, 38... Heat exchanger tube, 3... Space part, 41...
Water inlet piping, 42... Water inlet header, 43... Water inlet distribution pipe, 44... Water inlet ice chamber, 45... Outlet steam chamber, 46... Outlet steam distribution pipe, 47... Output [1 Steam header, 48... Outlet steam piping, 5o... Liquid metal channel, 51... Electromagnetic coil, FL... Free liquid level. Representative Patent Attorney Yudo Noriyuki Chika Hiroshi Mitsumata Figure 2 Figure 3 Notice Figure 4 Near "°--121- is folded"

Claims (1)

[Claims] In a cooling system for a liquid metal-cooled nuclear reactor, which has a pipe connection between an intermediate heat exchanger disposed inside the reactor vessel and a steam generator disposed outside the reactor vessel, the main body shell of the steam generator is A liquid metal inlet pipe is provided in the upper part, a liquid metal riser pipe having an opening in the lower part of the main body shell is provided in the main body shell in the axial direction, a liquid metal outlet pipe is connected to the upper end of the liquid metal riser pipe, and the liquid metal riser pipe is connected to the upper end of the liquid metal riser pipe. An electromagnetic pump is arranged in a space above the liquid metal surface around the upper part of the metal riser pipe, and an overflow nozzle is provided in the upper part of the body of the steam generator body, and the overflow nozzle is communicated with an overflow tank by an overflow pipe, The overflow tank is connected to a pumping pipe that connects the reactor vessel and the steam generator, and an electromagnetic pump is installed in the middle of the pumping pipe to transfer liquid metal from the overflow tank. A cooling device for a liquid metal cooled nuclear reactor characterized by: