JPH0535835B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an air conditioning system in a reactor containment vessel of a boiling water nuclear power generation facility, and in particular to an air conditioning system for cooling gas in a reactor containment vessel during normal operation of a nuclear reactor. The present invention relates to a gas cooling device in a containment vessel suitable for use in a storage vessel.

[Background of the invention]

FIG. 3 shows a typical example of a conventional technology related to a gas cooling system in a reactor containment vessel. In the figure,
1 is a containment vessel, 2 is a reactor pressure vessel, 3 is a heat insulator, 4 is a gamma ray shield, and 5 is a pedestal. 6 is a gas cooler installed in the upper part of the containment vessel 1, 8 is its cooling coil, and 7 is a fan for sending out the cooled gas from the gas cooler 6, which is placed on the grating 23. 10 is a header attached to the upper part, 11 is an air outlet, 12 is a blower duct extending above the header, and 13 is a gas inlet from the closed space at the top of the containment vessel. The pedestal 5 is provided with an opening 15. A gas cooler 24 including a cooling coil 25 and a fan 18 are placed at approximately the same height as this opening 15 . The cold gas coming out of the fan 18 is sent to the air outlets 20 and 21 by a blower duct 19, and is further guided to the header 10 by a blower duct 26 directed upward.

The conventional technology with such a configuration has the following drawbacks.

(1) Since all of the heat released from the reactor pressure vessel, which accounts for a large proportion of the equipment's calorific value, is released into the gas inside the containment vessel and mixed with it, the amount of air that must be processed by the gas cooler inside the containment vessel becomes enormous. , cooling equipment becomes larger.

(2) In order to house the larger gas cooler inside the containment vessel, it became necessary to install it separately into two levels, upper and lower. As a result, in order to direct the gas cooled by the cooler to the upper area of the containment vessel where the hot gas gathers, a long vertical air duct must be used, which occupies a significant portion of the space inside the containment vessel. .

Prior art related to this is JP-A-51-
No. 35888, No. 53-76291, No. 53-131395, No. 57
The drawbacks of these known examples, such as No.-136191, are as follows.

Japanese Patent Publication No. 51-35888 (1) Requires stand-up air supply duct.

(2) Transporting high-temperature gas from top to bottom in the body space, which is sensitive to gamma rays, goes against the laws of nature, and although it is possible in principle, it is impossible in practice.

JP-A-53-76291 and JP-A-53-131395 (1) Requires a vertical intake duct.

(2) Heat radiation from the pressure vessel cannot be suppressed.

JP-A No. 57-136191 (1) Transferring high temperature gas from top to bottom within the body space due to comma rays goes against the laws of nature, and although it is possible in principle, it is not possible in practice. It is impossible.

(2) Since the cooling gas is low in temperature, it stagnates at the bottom, so if the cooler is installed on the floor, a uniform cooling effect cannot be expected in the startup duct.

On the other hand, as a problem unique to the reactor containment vessel,
There is a problem with corrosion of stainless steel (SUS) piping.
Previously, it was believed that corrosion occurred due to the formation of dew, but recent research has confirmed that corrosion can proceed even in the absence of condensation under conditions of relatively low temperature and constant humidity. It is certainly desirable to lower the gas temperature as much as possible in the space around the pressure vessel where electrical equipment is present. However, for example, for SUS in the space inside the pedestal 5, the system where cold gas is blown from the air outlet 20 and returns from the opening 15 is not necessarily a good environment.

[Purpose of the invention]

The purpose of the present invention is to prevent heat radiation from the reactor pressure vessel from being released into the general area where electrical components are located within the containment vessel, but to return it to the gas cooler in the containment vessel, and to transfer gas from the lower area of the containment vessel to the upper area. To provide a gas cooling device in a containment vessel which effectively cools gas in a containment vessel without a guiding air duct and does not supply extremely low-temperature gas to unnecessary parts.

[Summary of the invention]

In the present invention, the containment vessel gas cooler is installed in the upper area of the containment vessel, and the space between the reactor pressure vessel heat insulating material and the gamma shield body is used as a gas return air path from the lower area to the upper area. The heat radiation from the reactor pressure vessel is guided straight to the gas cooler. The gas cooled by the gas cooler has a low temperature and a high specific gravity, so it descends under its own weight, so there is no need for a ventilation duct to the lower area.

As a result, the drawbacks of the prior art are overcome as follows.

(1) Since the gas that has absorbed the heat radiated from the reactor pressure vessel is returned directly to the gas cooler without being released into the area where electrical components are located, the gas return temperature can be increased from the conventional 57°C to approximately 80°C. It is possible to reduce the processing air volume of the cooler to about half that of the conventional technology.

(2) A gas cooler is installed in the upper part of the containment vessel, and the cooled gas with high specific gravity is allowed to fall naturally.
A long ventilation duct between the upper area and the lower area becomes unnecessary.

(3) Cooling gas that has been warmed to some extent by the heat from electrical components and pressure vessels during natural falling falls near the lower pedestal, so there is no corrosion at low temperatures on the surfaces of SUS piping, etc. .

[Embodiments of the invention]

Hereinafter, two embodiments of the present invention will be described, and the same members as those of the conventional example shown in FIG. 3 described above are given the same numbers.

First, in the embodiment shown in FIG. 1, compared to the conventional example shown in FIG. 3, the gas cooler and the like installed near the lower pedestal 5 are removed. Further, ducts 16 and 17 were provided near the bottom of the pressure vessel in place of the gas outlet. Furthermore, in the upper space, a hermetically sealed partition 30 is installed to separate the part where the gas cooler 6 etc. are provided from the pressure vessel side, and conversely, the long rising duct has been removed. As a result, the area where the top of the containment vessel, the upper part of the containment vessel where the gas cooler is located, and the gamma resistant body space are sealed and separated from each other, and communicate only at the inlet and outlet.

The gas cooler 6 installed in the upper part of the inside of the reactor containment vessel 1 in this embodiment is connected to the heat insulating material 3 of the reactor pressure vessel 2.
The gas flowing between the gamma ray shielding body 4 and the return gas from the top area of the containment vessel is transferred to the suction port 13.
and 14 and led to cooling coils 8 and 9 to cool it to about 35°C. The cooled gas is sent to the header 10 by the buang 7, and is then sent to the air outlet 11 and the air duct 1.
2 to the upper area and top head of the containment vessel, which are separated from each other.

The gas supplied from the air outlet 11 to the upper area of the containment vessel falls while absorbing heat, and flows from the openings 15 and 17 into the lower space of the pressure vessel 2 and into the gamma shielding body 4.
Each is guided to an inner space. The gas led from the opening 15 to the lower space of the pressure vessel 2 further passes through the opening 16 and merges into the gamma resistant body space.

The gas that has entered the internal space of the gamma shield body 4 rises while absorbing the heat radiated from the reactor pressure vessel 2, and reaches a temperature of about 80° C. at the inlet of the gas cooler 6.

Since the cooler inlet gas temperature can be raised from the conventional 57°C to 80°C, the air flow rate processed by the cooler can be reduced to about half that of the conventional technology, as shown below.

Assuming that the amount of heat generated inside the containment vessel is constant, the relationship between the air volume processed by the gas cooler inside the containment vessel and the gas outlet/inlet temperature is expressed by the following equation.

q = Q ₁ γC (T ₁₁ - T ₁₂ ) = Q ₂ γC (T ₂₁ - T ₂₂ ) ...(1) Where, q = Calorific value inside the containment vessel (kcal/h) Q ₁ = Conventional gas Cooler processing air volume (m ³ /h) Q ₂ = Gas cooler processing air volume of the present invention (m ³ /h) γ = Gas specific weight (Kg/m ³ ) C = Gas specific weight (kcal/Kg°C) T ₁₁ = Cooler gas inlet temperature of the prior art (°C) T ₂₁ = Cooler gas inlet temperature of the present invention (°C) T ₁₂ = Cooler gas inlet temperature of the prior art (°C) T ₂₂ = Chiller gas of the present invention Inlet temperature (°C) From equation (1), the processing air volume ratio is as follows.

Q/Q=(T ₁₁ −T ₁₂ )/(T ₂₁ −T ₂₂ ) Here, T ₁₁ = 57°C, T ₁₂ = 35°C, T ₂₁ = 80°C,
If T ₂₂ = 35℃, then Q/Q = (57-35)/(80-35)≒0.5 The amount of heat released from the reactor pressure vessel is proportional to the difference between the internal fluid temperature and the gas temperature outside the insulation material. Therefore, the amount of heat dissipated by the present invention is approximately equal to that of the conventional technology as shown below.
Can be made 10% smaller.

(q ₂ / q ₁ ) = (T ₁ − T _a2 ) / (T ₁ − T _a1 ) where, q ₁ = pressure vessel heat release amount in conventional technology
(kcal/h) q ₂ = Heat radiation amount of the pressure vessel in the present invention (kcal/h) T ₁ = Average temperature inside the pressure vessel (°C) T _a1 = Temperature outside the pressure vessel insulation material of the conventional technology (°C) T _a2 = Book Temperature outside the pressure vessel insulation material of the invention (℃) Assuming that T ₁ = 275℃, T _a1 = 57℃, and T _a2 = 80℃, (q ₂ /q ₁ ) = (275-80) / (275-57 )≒0.9 Therefore, the above treatment air volume ratio will be further improved.

According to this embodiment, there are the following effects.

(1) The gas outlet/inlet temperature of the gas cooler can be increased from 35°C/57°C in the conventional technology to 35°C/80°C, and the processing air volume can be reduced to approximately half that of the conventional technology.

(2) The gas temperature outside the reactor pressure vessel insulation material can be raised higher than before, reducing the amount of heat released and saving energy.

(3) The duct that guides the gas inside the containment vessel from the lower area to the upper area, which was required in the conventional technology, is no longer necessary, and the gas cooling equipment can be made more compact. Also, since there is no cooling equipment at the bottom, that space can be used for other purposes.

Next, the embodiment shown in FIG. 2 will be described. The configuration and installation location around gas cooler 6 in the containment vessel is
This is similar to the embodiment shown in the figure.

This example is used when cooling gas descends from a gas cooler installed in the upper area of the containment vessel, and the arrangement of equipment and piping may be biased to one side, which may obstruct an even flow of air. It is designed to ensure an even flow of air.

The gas in the lower area is evenly sucked in from suction ducts 22 arranged evenly within the area, is pressurized by the fan 18, and is sent into the blower duct 19. The air is then supplied from the blow-off ports 20 and 21 to the lower space of the reactor pressure vessel 2 and the inner space of the gamma ray shielding body 4, respectively. The gas supplied to the lower space of the reactor pressure vessel passes through the opening 16,
Gamma rays are guided into the inner body space. The subsequent gas flow is the same as in Example 1 shown in FIG.

According to this embodiment, in addition to the effects of the embodiment shown in FIG. 1, there is an effect that the inside of the containment vessel can be evenly cooled even if the arrangement of equipment and piping inside the containment vessel is biased to one side.

In the above two embodiments, the gas from the top of the containment vessel was shown to be recovered through the suction port 13, but as in the conventional example, the gas may be discharged once into the gamma-resistant body space and then recovered through the suction port 14. You can also do it.

〔Effect of the invention〕

According to the present invention, the heat released from the reactor pressure vessel is recovered to the gas cooler without being released into the containment vessel, and the space between the reactor pressure vessel heat insulating material and the gamma ray shielding body is Since it can be used as an internal gas circulation airway, the amount of air processed by the gas cooler inside the containment vessel is reduced, and the gas cooler at the bottom of the reactor pressure vessel and the long dedicated gas blowing from there to the upper space, which were required with conventional technology, are reduced. No need for ducts.

In addition, since the space inside the pedestal does not reach a low temperature that causes corrosion of SUS, it has the effect of preventing corrosion.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing one embodiment of the reactor containment gas cooling system according to the present invention, FIG. 2 is a system diagram showing another embodiment, and FIG. 3 is a system diagram showing a conventional example. . 1...Reactor containment vessel, 2...Reactor pressure vessel, 3...Heat insulation material, 4...Gamma ray shielding body,
5... Pedestal, 6... Gas cooler, 7... Fan, 8, 9... Cooling coil, 10... Header,
11...Air outlet, 12...Blower duct, 13,1
4... Suction port, 15, 16, 17... Opening, 18
...Fan, 19...Blower duct, 20,21...
...Air outlet, 22...Suction duct, 23...Grating, 24...Gas cooler, 25...Cooling coil, 26...Blower duct, 30...Airtight partition.

Claims (1)

[Scope of Claims] 1. A gas for absorbing and removing heat generated by the reactor pressure vessel, etc. within the reactor containment vessel, which is held on a pedestal by surrounding the reactor pressure vessel wrapped with a heat insulating material with a gamma shield. In the containment vessel gas cooling system, which includes a cooler, a gas cooler is installed in the reactor containment vessel near the top of the gamma shield to cool the gas in the containment vessel and allow it to fall naturally, thereby preventing high temperature gas from rising. A partition is installed above the body of the Gamma Shyahei to seal the space inside the Gamma Shyahei's body that is sealed from the space where the gas cooler is installed. A suction port is provided to penetrate the partition, an opening is formed at the bottom of the pedestal to communicate the space inside the reactor containment vessel and the space inside the pedestal, and an opening is formed at the bottom of the pedestal to communicate the space inside the gamma resistant body and the space inside the pedestal. A containment vessel characterized in that a reactor pressure vessel is formed on a member that is held on a pedestal, and an opening that communicates the internal space of the reactor containment vessel and the space inside the gamma shield body is formed in the lower part of the gamma shield body. Internal gas cooling system. 2. A containment vessel that includes a gas cooler for absorbing and removing heat generated by the reactor pressure vessel, etc. inside the reactor containment vessel, which is held on a pedestal by surrounding the reactor pressure vessel wrapped in heat insulating material with a gamma shield and holding it on a pedestal. In the internal gas cooling system, a gas cooler is installed inside the reactor containment vessel near the top of the gamma shield body to cool the gas inside the containment vessel and allow it to fall naturally. A partition is installed above the gamma shield body that seals the body space from the space where the gas cooler is installed, and an opening that communicates the gamma shield body space and the space inside the pedestal is installed in the reactor pressure vessel above the pedestal. Formed on the holding member, suction ducts are arranged evenly in the lower area outside the pedestal, and a fan is provided to increase the pressure of the gas sucked in from the suction duct, and the pressurized gas is gamma-distributed to the lower end of the body space and the pedestal. A gas cooling device in a containment vessel, characterized by having an air outlet for blowing air into an internal space.