JP3028842B2 - Reactor containment vessel - Google Patents

Description

The present invention relates to the arrangement and use of a suppression pool in a containment vessel.

[Conventional technology]

Conventionally described in JP-A-63-191096 (see Fig. 3)
For example, when the main steam pipe is broken and the water in the reactor pressure vessel 2 is blown down to the dry well 3, the pressure suppression pool 5 is used as a water source for the flooding of the reactor core 1 and the reactor pressure vessel 2 Water is injected and this water further breaks 17
Is discharged into the dry well 3, and the blowdown water and the overflow water raise the water level in the dry well 3 to the opening of the dry well 3 of the vent pipe 11, and then the hot water flows through the vent pipe. It will flow back into the suppression pool 5.

When the water temperature of the suppression pool 5 rises, a temperature difference occurs with the outer peripheral pool 15 of the containment vessel, and the heat of the suppression boule 5 is transmitted to the outer peripheral pool 15 of the containment vessel via the steel containment vessel 14. Then, steam is generated due to the rise in the water temperature of the outer peripheral pool 15 of the containment vessel, and the steam is released to cool the containment vessel 14. Accordingly, the cooling capacity of the containment vessel having the outer peripheral boule 15 depends largely on how large the heat transfer area between the suppression pool 5 and the outer peripheral boule 15 is. However, in the conventional naturally cooled type containment vessel having the containment vessel outer peripheral pool 15, the heat transfer area between the pressure suppression pool 5 and the containment outer peripheral pool 15 in contact therewith has a normal water depth within a certain range. Once determined, the water level change during the accident is small, so even if the heat transfer area is increased, it cannot be changed.

Here, the amount of water in the pressure suppression pool 5 needs to be such that it does not exceed a certain temperature limit based on the water temperature experiment of the pressure suppression boule 5 during the blowdown period at the time of the accident.
On the other hand, the water depth of the pressure suppression pool 5 is also fixed to a certain limit during the blowdown period at the time of the accident by the water depth of the vent pipe based on a steam condensation experiment. As described above, the amount of water in the pressure suppression pool is determined, and the water depth is also limited. Therefore, the conventional containment vessel requires the pressure suppression pool 5 having a certain size (area). Was a big deciding factor.

On the other hand, JP-A-2-129590 discloses the following contents.

In other words, a new pool is installed in the containment vessel at a level higher than the core in the reactor pressure vessel, and in the event of an accident, the increased pressure in the drywell is supplied to the gas phase in the pool to increase the pressure in the pool. Inject the pool water into the reactor pressure vessel without an external power source to cool the core, transfer the pool water after cooling from the lower suppression chamber to the upper pool with the pressure in the suppression chamber, It is disclosed to repeat the use of water injection into a reactor pressure vessel.

However, during the blowdown period during the accident, steam condensation is performed only in the pool water in the lower pressure suppression chamber, so a pressure suppression pool of a certain size (area) is required as in the conventional example described above. However, this is a large determining factor in determining the size of the storage container, and has no effect of contributing to downsizing.

[Problems to be solved by the invention]

As described above, in the related art, since the water volume and the water depth of the pressure suppression pool 5 are determined by other factors, the pressure suppression pool 5 having a certain size is absolutely necessary, and there is a limit to the miniaturization of the containment vessel. Was. Further, in the prior art, the water is injected into the core with the water from the pressure suppression pool 5 as a water source, the dry well 3 is flooded to the vent pipe opening 12, and then returned to the pressure suppression chamber again. Since the water level of the suppression pool 5 does not rise and the heat transfer area does not increase,
Improvements are required to obtain good natural cooling.

An object of the present invention is to reduce the size of a containment vessel.

Another object of the present invention is to provide a containment vessel having a structure capable of increasing a water level of the pressure suppression pool 5 and increasing a heat transfer area with the containment outer peripheral pool 15 to increase long-term containment cooling capacity after an accident. To provide.

[Means for solving the problem]

In order to obtain a core injection system capable of achieving the above-mentioned miniaturization of the containment vessel, a pressure suppression chamber 7 having a pressure suppression pool 5 is arranged vertically, and the dry well 3 and each of the pressure suppression pools 4, Install vent pipes 8 and 11 communicating with 5,
In order to cool the reactor core 1, a water injection line 17 from the lower part of the upper pressure suppression pool 4 to the reactor pressure vessel 2 is installed.

[Action]

If an accident occurs in which the reactor coolant (water) in the reactor pressure vessel 2 is released into the dry well 3 due to a breakage of a pipe or the like, the high-temperature water released into the dry well 3 is dried. Although accumulated in the lower part of the well 3, the vapor is condensed in the respective suppression pools 4, 5 through the upper and lower vent pipes 8, 11, so that there is no excessive pressure increase in the containment vessel. Reactor pressure vessel 2
When the water level in the reactor falls, the blowdown from the break port 18 decreases, and the pressure in the reactor pressure vessel 2 also drops, or after the pressure inside the reactor pressure vessel 2 has been sufficiently lowered by a relief safety valve (not shown). When the water supply line 17 from the upper suppression pool 4 to the reactor pressure vessel 2 is opened, the water in the upper suppression pool 4 flows into the reactor pressure vessel 2 and the core is cooled.

The injected water flows out of the break 18 into the dry well 3, and the water level in the dry well 3 rises. Drywell 3
After the internal water level reaches the dry well side opening 12 of the vent pipe 11 of the lower pressure suppression pool 5, water flows from the dry well 3 into the lower pressure suppression pool 5, and the water level of the lower pressure suppression pool 5 rises. I do.

In this way, the required amount of water in the suppression pool
By dividing the pressure suppression pools 4 and 5, the water depth can be set in the same manner as in the prior art.
5 (area or outer diameter), that is, the diameter of the containment vessel can be reduced.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS.

1 and 2 show a naturally cooled vertical containment chamber type containment vessel, a reactor pressure vessel 2 having a reactor core 1 inside.
Is located in the dry well 3, and a lower pressure suppression chamber 7 having a lower pressure suppression pool 5 is provided outside the dry well 3. The dry well 3 and the lower pressure suppression pool 5 communicate with each other through a vent pipe 11.

The upper pressure suppression chamber 6 is located above the lower pressure suppression chamber 7, and has the upper pressure suppression pool 4. The dry well 3 and the upper pressure suppression pool 4 communicate with each other through a vent pipe 8.

A water injection line 17 having a valve 16 is connected to the reactor pressure vessel 2 from the upper pressure suppression pool 4.

The outer walls of the lower pressure suppression pool 5 and the lower pressure suppression chamber 7 are steel containment vessels 14, and outside the containment vessel outer peripheral pool 15 is disposed. This containment vessel outer pool
The water depth of 15 is set high enough to sufficiently increase the water depth of the lower pressure suppression pool 5 after an accident in order to increase the efficiency of heat transfer from the lower pressure suppression pool 5.

If the piping connected to the reactor pressure vessel 2 is broken (see FIG. 1), the coolant (water and steam) in the reactor pressure vessel 2 is discharged into the dry well 3 from the break 18. You. Among the discharged high-temperature coolant, water accumulates in the lower part of the dry well 3, and the released vapor increases the pressure in the dry well 3, so that the water surfaces in the vent pipes 8, 11 are pushed down, and the dry well The atmosphere (air and steam) in 3 passes through the water in the upper and lower suppression pools 4 and 5, and each suppression chamber
Move to 6,7. During this time, the vapor in the atmosphere is condensed by the water in the suppression pools 4 and 5 to form water, so that only the air in the dry well 3 moves to the suppression chambers 6 and 7, and only the air transfer is suppressed. It contributes to the pressure rise in the chambers 6 and 7 and the dry well 3.

When the pressure in the dry well 3 rises or the water level in the reactor pressure vessel 2 drops, the reactor is automatically stopped and the reactor pressure vessel 2 is isolated.

When the water level in the reactor pressure vessel 2 becomes equal to or lower than the break 18, steam is released from the break 18, and the internal pressure of the reactor pressure vessel 2 also decreases. If the pressure in the reactor pressure vessel 2 does not drop sufficiently, the pressure is reduced by operating a safety valve (not shown) or the like. When the pressure in the reactor pressure vessel 2 drops sufficiently,
The valve 16 of the water supply line 17 from the upper pressure suppression pool 4 to the reactor pressure vessel 2 is opened, and the reactor core 1 is submerged and cooled.

The water flowing into the reactor pressure vessel 2 rises in temperature due to the decay heat from the reactor core 1 and becomes hot water and continues to flow out from the break 18 into the dry well 2, so that the water level in the dry well 2 rises , Rise to the vent tube opening 12. Since the hot water continues to flow out from the break port 18, the hot water flows from the dry well 2 into the lower suppression pool 5 through the vent pipe 11, and the water level and the water temperature of the lower suppression pool 5 rise. The water level of the lower pressure suppression pool is 5
When the level rises to around level 12, the upper suppression pool 4
Is emptied and the outflow from the break 18 stops, so that the water level in the pressure suppression pool 5 described below also stops rising. The pressure in the lower pressure suppression chamber 7 also rises due to the rise in the water level of the lower pressure suppression boule 5, but when the check valve 19 has a higher pressure in the lower pressure suppression chamber 7 than in the dry well 3. Work,
Since the air is returned from the lower pressure suppression chamber 7 to the dry well 3 to maintain the pressure balance, the water level in the lower pressure suppression pool 5 is not prevented from rising.

As the water temperature in the lower pressure suppression pool 5 rises, heat is transferred to the containment outer peripheral pool 15 through the steel containment vessel 14,
The water vapor evaporated due to the rise in the water temperature of the containment outer peripheral pool 15 is released to the outside, and the steel containment container 14 is cooled without rising above a certain temperature.

In the long term, water in the reactor pressure vessel 2 is reduced by evaporation, but a line connecting the lower pressure suppression pool 5 and the reactor pressure vessel 2 or the lower part of the dry well 3 to the reactor pressure vessel 2 (described) The water level in the reactor pressure vessel 2 is maintained by, for example, providing a pressure level.

According to the embodiment as described above, the following effects are exhibited.

In other words, since water can flow from the upper pressure suppression pool to the reactor pressure vessel using the head, cooling of the core flooding can be performed without a driving source such as a pump.

Further, since the water level of the lower pressure suppression pool after the accident rises greatly, the heat transfer area with the outer peripheral pool of the containment vessel can be increased, so that the performance as a naturally cooled containment vessel is greatly improved, and safety is enhanced.

Furthermore, by arranging the suppression pools vertically, the water depth of the suppression pool can be doubled vertically, so that the outer diameter of the suppression pool can be reduced. Increase.

〔The invention's effect〕

ADVANTAGE OF THE INVENTION According to this invention, since the suppression pool which condenses the vapor | steam at the time of an accident is arrange | positioned up and down and the outer diameter of a suppression pool can be made small, miniaturization of a reactor containment vessel can be achieved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a situation immediately after an accident of a naturally cooled vertical pressure suppression chamber type containment vessel according to an embodiment of the present invention.
FIG. 3 is a longitudinal sectional view of the containment vessel of the upper and lower pressure suppression chamber showing the state after the situation of FIG. 1 has passed, and FIG. 3 is a longitudinal sectional view of the containment equipment of the prior art. 1 ... core, 2 ... reactor pressure vessel, 3 ... dry well, 4 ... upper suppression pool, 5 ... lower suppression pool, 6 ... upper suppression chamber, 7 ... lower suppression chamber ,
8 ... vent pipe, 9 ... vent pipe opening, 10 ... vent pipe outlet, 11 ... vent pipe, 12 ... vent pipe opening, 13 ...
... vent pipe outlet, 14 ... steel containment vessel, 15 ... containment vessel outer pool, 16 ... valve, 17 ... injection line, 18 ... break port, 19 ... check valve.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-129590 (JP, A) JP-A-64-75992 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G21C 9/00 G21C 15/18

Claims (1)

(57) [Claims] 1. A reactor containment vessel having a drywell having a reactor pressure vessel and a suppression chamber, wherein the suppression chamber is divided into an upper suppression chamber and a lower suppression chamber, and each of the upper and lower parts is provided. The pressure suppression chamber has a vent pipe communicating the dry well with the pool water area in each of the upper and lower pressure suppression chambers, and the pool water area in the upper pressure suppression chamber and the reactor pressure vessel are connected by piping. A containment vessel for a nuclear reactor.