JPS6375694A - Nuclear reactor container - Google Patents

Abstract

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

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a reactor containment vessel that encloses a nuclear reactor in a nuclear power plant, and particularly relates to a suppression chamber/pool water cooling system that has conventionally been dynamically configured. The present invention relates to a nuclear reactor containment vessel that provides inherent safety through a static cooling system and improves economic efficiency through the rationalization of facilities and equipment.

[Prior art] Conventional nuclear reactor residual heat removal safety systems are designed to prevent fuel cladding from melting due to heat generated by core decay heat and water-metal reactions in the event of a loss of coolant accident. Suppression chamber pool water is injected into the reactors along with the cavity pressure injection system, Shirari J depressurization system, low pressure core spray system, etc., and the reactor containment vessel dry well is also injected in conjunction with the above low pressure water injection mode. In order to cool the non-condensable gas in the suppression chamber and condense steam, and to remove the energy released into the reactor containment vessel, the suppression chamber pool water is pumped into the dry well and suppression chamber by the containment vessel spray mode operation. This causes the water temperature in the suppression chamber pool to rise due to the heat transfer caused by the steam blowing down from the main steam relief safety valve etc. to the suppression chamber. In order to prevent this, a suppression chamber pool water cooling mode system is constructed by absorbing and pressurizing the suppression chamber pool water with a residual heat removal system pump, cooling it through a residual heat exchanger, and returning it to the suppression chamber pool. An outline of this conventional system 11 is shown in FIG. 3, which has an equipment configuration that ensures safety.

- As stated in ``Conventional suppression chamber pool water cooling systems are designed to prevent pool water temperature from rising.

As mentioned above, the equipment is configured with a so-called dynamic equipment system, in which pool water is drawn out from the suppression chamber area by a pump through piping, and heat is removed from the pool water by a heat exchanger. Measures have been taken, and structural and functional designs are in place to maintain the functionality of the equipment even against external loads such as earthquakes.

” Suppression with a dynamic mechanical equipment configuration that resembles two legs.
For chamber pool water cooling systems, use rotating equipment such as pumps and large heat exchangers as much as possible.

Furthermore, if a static heat removal system can be considered as a system with a similar cooling function as an alternative to dynamically functioning equipment such as large piping loops, it will be possible to create a large [1] system by reducing the functional demands on dynamic structures. It is thought that this will improve the economic efficiency of the plant due to the rationalization of the equipment itself, as well as improve the safety and reliability of the plant itself. For example, there is a reactor containment vessel cooling system based on the pipe-to-pipe method shown in Japanese Patent Application Laid-Open No. 55-125483.

In this system, a large number of cylindrical heat pipes filled with low boiling point liquid are attached to the outer surface of the steel plate of the reactor containment vessel dry well. This is a heat removal system that allows heat to escape outside the containment vessel.

It is technically possible to apply the heat pipes of this concept to the cooling system of containment vessel suppression chamber pool water, and it is possible to construct the above-mentioned static safety cooling system. Because the heat pipe is installed as a large-scale structure, it not only has a significant impact on the bio-blocking wall outside the containment vessel and the equipment layout installed in the external space, but also has a large impact on the equipment layout as an important safety equipment. Endurance,! ! Due to design requirements and other factors, the structure has many problems in terms of equipment, such as a complicated structure, and it has no economic advantages, making it impractical.

Also similar storage capacity! (Another conventional example related to the cooling system is a method shown in Utility Model Application Publication No. 59-116891, in which the space between the concrete wall of the containment vessel and the liner is filled with liquid to cover the containment vessel with liquid. , in this method, the gap between the concrete wall and the liner is 2
Since the gap direct radiation is too small to statically cool the suppression chamber pool water with the liquid in this part, no circulation flow of external cooling liquid occurs, and the static cooling efficiency is low. It has become unrealistic to expect that the effects will not improve.

[Problems to be Solved by the Invention] In the above conventional example, in order to cool the suppression chamber water in the event of an accident, pool water is drawn out from the suppression chamber area by a pump through piping, and heat is removed from the pool water by a heat exchanger. The equipment is configured with a dynamic system, and there is a need to maintain the structure and function of dynamic equipment that is easily removed, and the cooling efficiency of the static cooling system is extremely poor, and we are not looking forward to its effectiveness. It had the disadvantage of being impractical, such as not being able to do anything.

The purpose of the present invention is to provide a static and efficient heat removal system for use as a reactor containment vessel suppression chamber pool water cooling system in place of dynamic equipment such as rotating equipment such as pumps, large heat exchangers, and even large piping loops. An object of the present invention is to provide a reactor containment vessel having a heat removal system capable of long-term cooling after an accident.

[Means for Solving the Problems] -1- The purpose is to increase the water depth of the suppression pool in the wet well in the space formed between the reactor containment vessel wet well part and the biological wall surrounding the wet well part. The ratio of L to the cylindrical clearance distance between the reactor containment vessel and the biological barrier wall: d is set to a value that facilitates the generation of natural circulation flow to improve the static cooling efficiency of the suppression pool water. An outer pool area is provided around the container, and equipment is installed to inject non-contaminated water through an injection line from an injection tank that injects outer pool water for cooling the main outer pool in the event of an accident. This is achieved by providing a vent line between the outside atmosphere of the furnace equipment and the purpose of dissipating heat from the peripheral pool for the heat sink.

[Function] Hereinafter, the function of the present invention for solving the problems in the conventional example will be specifically explained using FIG.

FIG. 4(A) schematically shows the outer peripheral pool of the reactor containment vessel of the present invention. Of the double cylinders shown in this figure, the inner cylinder is an atomic container and the outer cylinder is a biological barrier wall, and the gap distance between the cylinder parts: d is the structure of the present invention surrounded by the containment vessel and the biological barrier wall. 7 The water level of the outer peripheral pool of the present invention, which is the outer peripheral pool, has a water level equivalent to that of the suppression chamber pool water in order to improve the heat transfer efficiency through the wall surface of the reactor containment vessel. In order to do this, it is efficient to generate as much circulation flow as possible in the outer pool, and if the cylindrical part clearance distance: d is small, it is generally difficult for the above natural circulation flow to occur;
The cooling system of the present invention will not be established.

On the other hand, Fig. 4(B) shows the tendency of natural circulation flow in the gap of a double cylinder with a heat source in the inner cylinder, which was determined experimentally in general terms, by the gap distance of the cylinder part: d and the suppression pool. Depth: Ratio to L: Expressed as a function of d/L. Here, Ra: Rayleigh number is an index that measures the ease with which a circulation flow is generated, and the lower the value, the more natural circulation flow is generated and the higher the heat removal efficiency becomes. As shown here, the value of d/L is 0.1
It has been found that when the relay number is less than 5, the natural circulation flow is difficult to occur.In order to achieve the static cooling system of the present invention, the ratio of the suppression pool water depth: 1 and the outer loop clearance distance: d is required. The value of d/L is 15 / 1
It is considered effective to set it to 00 or more. Therefore, the above-mentioned gap distance in the reactor containment vessel peripheral pool of the present invention is characterized by being set to the above-mentioned value, and it becomes possible to provide an effective shape for the static cooling system.

[Embodiments] Hereinafter, embodiments of the present invention based on the above principle of operation will be explained with reference to the drawings.

FIG. 1 shows a reactor containment vessel with a peripheral pool constituting a static cooling system according to the present invention.

In this figure, a reactor pressure vessel 6 is enclosed, and a vent wall 4 is shown.
The reactor containment vessel is doubled into a dry well and a wet well part, and has a suppression chamber pool water 3 in the wet well part] and a suppression pool in the outer space part 5 of the containment vessel surrounded by the biological barrier wall 2. A containment vessel outer circumferential pool 7 having a ratio d/L of 15/100 or more between the water depth L and the gap distance: d between the containment vessel 1 and the living body shielding wall 2 is provided. Isolation valve 14 from pool water tank 11
The outer peripheral pool water injection pipe 12 is connected via. Further, an outer peripheral pool vent line 13 is connected to the containment vessel outer space 5 via an isolation valve 15, and is opened to the atmosphere outside the reactor building. Also, in Figure 2,
2 shows a plan view of the suppression chamber pool water level of FIG. 1; FIG.

Next, the storage static cooling system 1 according to the present invention having the above configuration
The operating principle of No. 1 will be explained below.

In the unlikely event that the reactor-subsystem piping in the reactor containment vessel 1 ruptures, a mixture of steam and water will be released from the pipe break in the containment vessel. The water is introduced into the suppression chamber pool water 3 through a connecting portion provided in the water and is condensed therein. On the other hand, the isolation valve 14 is opened by the accident signal, and uncontaminated water is injected from the outer pool water injection tank 11 into the containment vessel outer pool 7 by falling under its own weight. The temperature of the suppression chamber pool water 3 continues to rise due to the condensation action described in -, but as the temperature difference with the outer pool 7 increases, a natural circulation flow occurs in the outer pool 7, and the suppression chamber pool water 3 will be cooled.

Further, as the water temperature of the outer circumferential pool of the containment vessel further increases, evaporation starts from the outer circumferential pool of the containment vessel 7, and heat of evaporation is removed from this pool. This heat removal effect is further increased by being released through the outer circumferential pool vent line 13 provided in the outer space 5 of the containment vessel via the isolation valve 15 and the line connected to the reactor building construction period. The integrity of the containment vessel 1 can be maintained in the event of an accident.

In addition, since water is injected into the outer pool from the separately installed non-contaminated outer pool water injection tank 11 in the event of an accident, the heat radiated from the above heat removal is directly released into the atmosphere outside the building. However, there are no particular radiation safety problems, and it has the advantage that simplified equipment can be used because water is injected by falling under its own weight.

As mentioned above, in the static cooling system for the containment vessel of the present invention, the gap distance between the outer circumferential pool of the containment vessel is set to a shape that facilitates the generation of natural circulation flow, and therefore it is possible to suitably provide static cooling efficiency. However, when the present invention is applied, for example, the suppression pool water depth is approximately 6 m.
In the case of a conventional containment vessel of about
．． It is considered appropriate to set the height to 9m or more in terms of cooling efficiency.
If a gap of this magnitude is installed between the containment vessel 1 and the biological barrier wall 2, it becomes possible to start construction of the containment vessel 1 and the biological barrier wall 2 in parallel, especially during construction work. It is possible to have the effect of shortening the construction period of the reactor building, which has a great advantage.

[Effects of the Invention] According to the present invention, it is possible to provide a reactor containment vessel that constitutes an effective static heat removal system for suppression chamber pool water in the reactor containment vessel, and it is possible to provide a reactor containment vessel that constitutes an effective static heat removal system for suppression chamber pool water in the reactor containment vessel, and to replace conventional pumps,
It becomes possible to eliminate the suppression chamber water cooling equipment, which uses dynamic mechanical equipment such as heat exchangers and large piping loops, and also has the effect of improving the constructability of the entire equipment. .

[Brief explanation of the drawing]

Figure 1 shows a nuclear reactor installation a having a reactor containment vessel according to the present invention.
FIG. 2 is a similar plan view, FIG.
The figures show a conventional reactor containment vessel suppression chamber pool water cooling system; Figure 4 (A) shows a reactor containment vessel according to the present invention; B) The figure shows the cooling efficiency depending on the suppression pool depth and the outer pool gap. 1...Reactor containment vessel, 2...Biological shield wall, 3... ... Suppression chamber pool water, 4 ... Vent wall, 5 ... External containment vessel space, 6 ... Reactor pressure vessel, 7 ...
...Containment vessel peripheral pool, 8...Residual heat removal system piping, 9...Residual heat removal system pump, lO...
...Residual heat removal system heat exchanger, 11...Outer pool water injection tank, 12...Outer pool water injection piping, 13...Outer pool vent line, 14...
...Isolation valve, 15...Whisper 1 L-T7-L--2Sian7-IL)tCd-IU
ll';Gsu;'3';&PjL No. 20 Fig. 3 0 ・戎f! Neijuku V Jinmu Senj F) Bu 10-・-・Remaining Loss Foreign Scale ζmu Daring 7 Exchanges 4 Laughs “8 PM (A)■

Claims (1)

[Claims] 1. In a steel self-supporting reactor containment vessel, in a space formed between the reactor containment vessel wet well (suppression chamber) and the biological shielding wall surrounding the wet well, The value of the ratio d/L based on the water depth of the suppression pool in the wet well: L and the cylindrical gap distance between the reactor containment vessel and the biological shield wall: d is 15/10.
A reactor containment vessel characterized by having a reactor containment vessel outer peripheral pool having a clearance distance of 0 or more and having a heat sink function for suppression pool water. 2. An outer circumferential pool water injection tank and an outer circumferential pool water injection piping having the purpose of injecting outer circumferential pool water for static cooling of the suppression pool water in the event of an accident into the reactor containment vessel outer circumferential pool; It has an outer pool vent line between the gas phase part of the upper space of the pool and the outside atmosphere of the reactor equipment for the purpose of dissipating heat from the outer pool for heat sink, which improves the static cooling efficiency of the outer pool. A nuclear reactor containment vessel according to claim 1.