JPH077090B2 - Condensate leakage prevention device in condensate storage facility - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a condensate storage facility for storing condensate condensed from steam by a condenser after finishing work on a turbine in a nuclear power plant. The present invention relates to a leak prevention device for condensed water, which prevents the condensed water from leaking outside when it leaks from a tank or a pipe.

[Technical background of the invention and its problems]

Since the condensate used in the nuclear power plant is radioactive, all measures are taken to prevent its leakage.
However, even if such measures are taken, it is necessary to take measures for further leakage.
If it should leak, the leaked water will leak to the outside, and the radioactive contamination will spread.

For this reason, conventionally, the condensate storage facility has been provided with a condensate leakage prevention device as shown in FIG. First,
Such a conventional condensate leakage prevention device will be described.

In FIG. 2, a bottom wall 3 is stretched at the bottom of a hole 2 formed by excavating the ground 1, and a semi-underground condensate storage whose upper part faces the ground 1 on this bottom wall 3. A tank 4 is installed. The condensate storage tank 4 has a closed structure and communicates with a condenser (not shown) through a pipe (not shown). On the bottom wall 3, a shield wall 6 surrounding the outer periphery of the condensate storage tank 4 is provided upright integrally with the bottom wall 3 via an annular space 5.

A semi-underground type turbine building 7 is installed at a position separated from the shielding wall 6 like the shielding wall 6, and a bottom wall 8 of the turbine building 7 is located below the bottom wall 3. . Piping (not shown) related to the condensate storage tank 4
Is an opening 9 formed from the condensate storage tank 4 to the lower end of the shielding wall 6 and the outer wall of the turbine building 7.
Turbine building 7 through opening 11 formed at the lower end of 10
It is introduced inside and extends between the shielding wall 6 and the outer wall 10 in the middle of a pipe duct 12 connected to the shielding wall 6 and the outer wall 10, respectively. This piping duct
The vertical portion 14 connects the horizontal portion 13 on the side of the shield wall 6 and the horizontal portion 15 on the side of the outer wall 10 lower than the horizontal portion 13 with the vertical portion 14.

The bottom wall 3, the shielding wall 6, and the bottom wall 8 of the turbine building 7
The outer wall 10 and the piping duct 12 are formed by waterproofing concrete. A roof member 16 covering the upper end of the annular space 5 is stretched between the upper ends of the condensate storage tank 4 and the shielding wall 6 to prevent rainwater from entering the annular space 5. There is.

According to the above-described configuration, even if the condensate leaks due to cracks or breaks in pipes, valves, or cracks in the welds of the condensate storage tank 4 due to an earthquake, etc. Since it flows into the turbine building 7 from 12, the leaked water does not leak outside the radiation controlled area.

However, in such a condensate leakage prevention device in the conventional condensate storage facility, a very small amount of leakage water from pipes, valves, etc. in the annular space 5 inside the shielding wall 6 is
Although it does not flow out of the radiation control area outside the shielding wall 6,
Opening 9 of the shielding wall 6 and opening of the outer wall 10 of the turbine building 7
Pollution of radioactive liquid by water leaking through 11 piping duct
There is a risk that it will be expanded from 12 to the inside of the turbine building 7.

On the other hand, if a large amount of leaked water is generated inside the shielding wall 6, it is necessary to transfer and process the leaked water in order to prevent the leaked water from flowing into the turbine building 7. A large amount of labor is required for temporary construction.

Further, since the inside of the turbine building 7 is controlled to have a negative pressure due to the mechanism of the nuclear power plant, the opening 11 must be provided with a mechanism for airtight treatment, which complicates the structure.

[Object of the Invention]

The present invention has been made in consideration of such a point, and prevents the expansion of radioactive contamination in the turbine building at the time of minute leakage from pipes, valves, etc., and prevents the condensate storage tank and the shielding wall, respectively. An object of the present invention is to provide a condensate leakage prevention device in a condensate storage facility that can store and treat leakage water in an annular space or a piping duct between them.

[Outline of Invention]

The present invention provides a drainage pipe that opens into a shielding wall and reaches the turbine building through a piping duct, and a sluice valve is installed in the drainage pipe, and a turbine building wall that divides the piping duct and the turbine building. A communication opening is formed, and the communication opening is covered with a pressure rupture plate that is ruptured by a predetermined water pressure.

Example of Invention

The present invention will be described below with reference to embodiments shown in the drawings. The same components as those of the conventional one described above are designated by the same reference numerals in the drawings, and the description thereof will be omitted.

FIG. 1 shows an embodiment of the present invention, in which the tip end faces a groove (not shown) formed in the bottom wall 3 at the lower end of the annular space 5 and extends in the pipe duct 12 to extend the turbine. A drainage pipe 17 connected to a radioactive liquid waste treatment device (not shown) in the building 7 is provided, and a sluice valve 18 facing the inside of the pipe duct 12 is interposed in the drainage pipe 17. The shield wall 6 that divides the annular space 5 and the pipe duct 12 is completely sealed except for the drain pipe 17 and the passage of the related pipe of the not-shown condensate storage tank 4.

On the other hand, the outer wall 10 of the turbine building 7 that divides the pipe duct 12 and the turbine building 7 is also completely sealed except for the drain pipe 17 and the passage portion of the related pipe of the condensate storage tank 4, and the outer wall 10 A communication opening 19 is formed at an intermediate position in the vertical direction of a portion facing the pipe duct 12, and the communication opening 19 is covered with a pressure rupture plate 20. The pressure rupture plate 20 normally partitions the piping duct 12 and the turbine building 7 to store leaked water in the piping duct 12, and also makes the negative pressure control in the turbine building 7 good, and When the water level in the leak water in 12 reaches a set level, it is destroyed by this water pressure, and leak water above the lower limit of the communication opening 19 is introduced into the turbine building 7. The pressure rupture plate 20 is preferably configured to be destroyed when the level of leaked water in the pipe duct 12 exceeds the water limit level in terms of strength of the pipe duct 12.

A sump 21 for storing leaked water is provided at the lower end of the pipe duct 12.
The leak water in the sump 21 is
Is transported to the radioactive liquid waste treatment device in the turbine building 7.

Next, the operation of the above-described embodiment will be described. First, when a small amount of condensate leaks in the shielding wall 6 or the pipe duct 12, the drain pipe 17 or the pump 22 respectively guides it to the radioactive liquid waste treatment device in the turbine building 7 for treatment.

In addition, if a large amount of condensate leaks at once due to breakage of the pipe in the shielding wall 6 or the pipe duct 12, it cannot be processed at one time, so that the shielding wall 6 or the pipe duct 12 can be temporarily treated. Drain pipe 17 after storing leaked water inside
Alternatively, it is gradually processed by the pump 22. By the way, when the water level of the leaked water in the pipe duct 12 exceeds the strength of the pipe duct 12, the pressure rupture plate 20 is broken by the water level, and the leaked water in the pipe duct 12 is guided into the turbine building 7. .

As described above, according to the present embodiment, since it is possible to temporarily store in the shielding wall 6 or the pipe duct 12, radioactive leaked water can be treated without diffusing outside or inside the turbine building 7. Therefore, the safety can be further improved.

[Effects of the Invention] As described above, the leakage prevention device of the condensate in the condensate storage facility according to the present invention is provided with a drain pipe that opens into the shielding wall and reaches the turbine building through the pipe duct. A sluice valve is installed in this drain pipe, and a communication opening is formed in the wall of the turbine building that divides the piping duct and turbine building, and this communication opening is covered with a pressure rupture plate that is destroyed by a predetermined water pressure. Despite its unique structure, it is possible to prevent the inflow of a small amount of leaked water from pipes, valves, etc. into the turbine building, prevent the diffusion of radioactivity inside the turbine building, and treat the leaked water. Also in this case, there is an excellent effect that labor can be saved. Further, if there is a leak that cannot be treated, the leak water can be prevented from leaking out of the radiation control area as in the conventional case.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view showing an embodiment of a condensate leakage prevention device in a condensate storage facility according to the present invention, and FIG. 2 is a schematic vertical sectional view showing a conventional condensate leakage prevention device. 4 ... Condensate storage tank, 5 ... Annular space, 6 ... Shielding wall, 7 ... Turbine building, 10 ... Outer wall, 12 ... Piping duct, 17 ... Drain pipe, 18 ... Gate valve, 19 ...... Communication opening, 20
...... Pressure rupture plate, 21 …… sump, 22 …… pump.

Claims (2)

[Claims] Claim: What is claimed is: 1. An outer periphery extends from a condensate storage tank surrounded by a shielding wall, the bottom wall is located below the bottom wall of the condensate storage tank, and the turbine building wall is sealed. In a condensate storage facility in which a pipe reaching the partitioned turbine building is arranged in a pipe duct connected to each of the shielding wall and the turbine building wall, an opening is made in the shielding wall and the inside of the pipe duct is inserted. A drainage pipe that is guided to the inside of the turbine building and connected to the radioactive liquid waste treatment device, a drain valve is installed in this drainage pipe, and a communication opening is formed in the turbine building wall that partitions the turbine building. The communication opening is covered with a pressure rupture plate that is ruptured by a predetermined water pressure, and a pump is arranged to convey the leaked water in the pipe duct to the radioactive waste treatment device. Security apparatus of condensate in the water storage facilities. 2. The pressure rupture plate is configured to be destroyed when the water level of leaked water in the pipe duct exceeds a water level limit in terms of strength of the pipe duct. Condensate leakage prevention device in the condensate storage facility described.