KR102295087B1 - system for reducing the release of radioactive material to the atmosphere under severe accident - Google Patents

Abstract

A system for reducing the emission of radioactive materials to the atmosphere in the event of a serious accident is provided. A system for reducing atmospheric emission of radioactive materials in the event of a serious accident according to an embodiment of the present invention is disposed inside a containment building and produces steam using the heat of a coolant heated in a nuclear reactor, and a turbine and a main steam line as a medium connected steam generator; and a decontamination water tank connected via the main steam line and the connecting line, and containing decontamination water for reducing the emission of radioactive materials to the atmosphere by decontamination of the steam transferred from the steam generator when a serious accident occurs. A water tank is disposed inside the containment building.

Description

System for reducing the release of radioactive material to the atmosphere under severe accident

The present invention relates to a system for reducing the emission of radioactive materials to the atmosphere in the event of a serious accident, which can mitigate the release of radioactive materials to the atmosphere by bypassing the containment building in the event of a serious accident of a nuclear power plant.

After the Fukushima nuclear accident, countries around the world are strengthening regulations to secure the ability to respond to severe accidents not only for the improved LWRs but also for nuclear power plants that are already in operation.

The most important measure to prevent the release of radioactive materials in the event of a serious accident is to secure the integrity of the containment building. To this end, various follow-up measures such as mobile diesel power generation, waterproof sluice installation, and filter exhaust system installation have been carried out for nuclear power plants in operation or under construction after the Fukushima accident. Through this, the safety of nuclear power plants was greatly improved.

However, in the event of a serious accident such as a Steam Generator Tube Rupture (SGTR) or a low-pressure boundary coolant loss accident (ISLOCA), radioactive material bypasses the containment building and is directly discharged into the atmosphere even if the containment integrity is secured. Therefore, it remains an important issue in terms of reactor safety.

US 10-1905724 B1

The present invention has been devised in view of the above points, and provides a system for reducing the emission of radioactive materials to the atmosphere in the event of a serious accident that can alleviate the accident in which radioactive material is released into the atmosphere by bypassing the containment building in the event of a serious accident. There is a purpose.

In order to achieve the above object, the present invention provides a steam generator disposed inside a containment building and producing steam using the heat of a coolant heated in a nuclear reactor and connected to a turbine via a main steam line; and a decontamination water tank connected via the main steam line and the connection line, and containing decontamination water for reducing the emission of radioactive materials to the atmosphere by decontamination of the steam transferred from the steam generator when a serious accident occurs. The water tank provides a system for reducing the emission of radioactive materials to the atmosphere in the event of a serious accident disposed inside the containment building.

According to the present invention, in the event of a serious accident, a decontamination tank for removing radioactive materials from the steam introduced from the steam generator is disposed inside the containment building, so that even if the decontamination tank is partially damaged due to an instantaneous pressure increase and leakage of radioactive material occurs Emissions to the outside can be fundamentally blocked by the containment building. Through this, the present invention can improve the safety of a nuclear power plant by being able to fundamentally prevent an accident in which radioactive materials are released by bypassing the containment building when a serious accident occurs.

In addition, according to the present invention, the performance and safety of the decontamination tank can be improved by preventing an instantaneous increase in the pressure inside the decontamination tank due to the inflow of high-temperature and high-pressure steam into the decontamination tank.

Furthermore, the present invention reduces the pressure of the steam supplied to the decontamination water tank through the decompression power generation means and simultaneously produces emergency power, so that even when a serious accident occurs, driving power can be supplied to electric devices using electricity, so even if a serious accident occurs, the It is possible to check the status of the nuclear power plant and improve the stability of the nuclear power plant.

1 is a schematic diagram showing a system for reducing the emission of radioactive materials to the atmosphere when a serious accident occurs according to an embodiment of the present invention.
Figure 2 is a schematic diagram showing a system for reducing the emission of radioactive materials to the atmosphere when a serious accident occurs according to another embodiment of the present invention.
3 is a view showing the detailed configuration of the decontamination tank that can be applied to the system for reducing the emission of radioactive materials to the atmosphere when a serious accident occurs according to the present invention.

Hereinafter, with reference to the accompanying drawings, the embodiments of the present invention will be described in detail so that those of ordinary skill in the art to which the present invention pertains can easily implement them. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. In order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and the same reference numerals will be added to the same or similar components throughout the specification.

The systems 100 and 200 for reducing atmospheric emission of radioactive materials in the event of a serious accident according to an embodiment of the present invention include a steam generator 110 and a decontamination water tank 120 as shown in FIGS. 1 and 2 .

The steam generator 110 may be disposed inside the containment building 101, and may be supplied to a turbine (not shown) side after generating steam for nuclear power generation. That is, the steam generator 110 may be connected to the turbine via the main steam line 151 to supply the steam to the turbine side.

At this time, at least one valve may be provided on the main steam line 151 to perform various functions such as allowing, blocking, and releasing steam.

As an example, the at least one valve is a main steam safety valve (MSSV) 161 for preventing excessive pressure of the main steam line 151, and steam when the main steam line 151 is damaged. It may include a main steam isolation valve (MSIV) 163 for isolating the steam generator 110 in order to prevent excessive cooling of the reactor coolant system due to discharge.

In addition, the at least one valve is an atmospheric release valve 162 for cooling the coolant system of the nuclear reactor by directly discharging excess steam to the atmosphere when the steam generator 110 is isolated, the turbine is stopped, or the function of the condenser is lost. (atmospheric dump valve: ADV) may be further included. However, the type and number of the valve is not limited thereto and may be appropriately changed according to design conditions.

In this way, the steam generated from the steam generator 110 may be supplied to the turbine after being collected in one main steam cavity pipe in the turbine building through at least one valve.

Here, the main steam safety valve 161 may be automatically opened when the steam pressure reaches a set value, and the atmospheric release valve 162 may be manually operated in a main control room or a remote stop panel.

In addition, in the containment building 101 , the reactor 140 heats a coolant and supplies the heated coolant to the steam generator 110 , and steam is generated using the heat of the coolant supplied from the reactor 140 . A steam generator 110 and the like may be disposed, and a nuclear fuel reloading tank 105 for supplying nuclear fuel to the side of the nuclear reactor 140 may be configured. Since the internal configuration of the containment building 101 is known, a detailed description thereof will be omitted.

The decontamination water tank 120 may decontaminate the steam transferred from the steam generator 110 when a serious accident such as breakage of the tube 112 of the steam generator 110 occurs. Through this, the amount of radioactive material directly emitted to the atmosphere can be reduced by removing the radioactive material from the steam generated from the steam generator 110 when a serious accident occurs through decontamination.

To this end, the decontamination water tank 120 may be filled with decontamination water 121 for decontamination of the steam, and may be connected to the main steam line 151 and the connection line 152 via the connecting line 152 .

For example, the connection line 152 may have one end connected to the decontamination water tank 120 and the other end connected to a valve 165 for reducing atmospheric emission installed on the main steam line 151 , and reducing the atmospheric emission. For the valve 165 may be provided as a three-way valve.

Accordingly, during normal operation, the high-pressure steam generated by the steam generator 110 is supplied to the turbine side along the main steam line 151, thereby generating power, and in the case of a design-based accident, the steam generator 110 generated High-pressure steam may be discharged to the atmosphere through the atmospheric release valve 162 , and when a serious accident occurs, high-pressure steam generated by the steam generator 110 is transferred to the decontamination water tank 120 through the connection line 152 . ) can be transferred to

For this reason, when a serious accident occurs, the radioactive material contained in the high-temperature steam is decontaminated through the decontamination water 121 in the decontamination water tank 120, thereby reducing the emission of the radioactive material contained in the high-temperature steam to the atmosphere.

Here, the serious accident may be a bypass accident of the containment building 101, such as a rupture of the steam generator tube 112 (steam generator tube rupture: SGTR) or a low-pressure boundary coolant loss accident (ISLOCA).

At this time, as shown in FIG. 3 , in the systems 100 and 200 for reducing the emission of radioactive materials to the atmosphere when a serious accident occurs according to an embodiment of the present invention, the connection line 152 is connected to the lower side of the decontamination water tank 120 . may be connected, and at least one nozzle 122 may be provided at an end of the connection line 152 .

Here, the nozzle 122 may be disposed at a lower end inside the decontamination water tank 120 . Through this, the nozzle 122 can always maintain a state submerged in the decontamination water 121 filled in the decontamination water tank 120 .

In addition, the decontamination water tank 120 may include an outlet, and the outlet may be provided at an upper side of the decontamination water tank 120 . Accordingly, after being transferred to the decontamination water tank 120 , the vapor not dissolved in the decontamination water 121 may be discharged to the outside through the outlet.

In this case, the vapor not dissolved in the decontamination water 121 may contain radioactive materials. Accordingly, if the vapor not dissolved in the decontamination water 121 is directly discharged to the outside through the outlet of the decontamination water tank 120 , the radioactive material contained in the vapor not dissolved in the decontamination water 121 is released to the outside. can be

In order to prevent this, in the system 100,200 for reducing the emission of radioactive materials to the atmosphere when a serious accident occurs according to an embodiment of the present invention, the decontamination water tank 120 is filtered and exhausted through the bypass line 153. can be connected with Through this, the vapor that has passed through the decontamination water tank 120 may not be directly discharged to the atmosphere through the outlet, but may be discharged to the outside after passing through the filter and exhaust device 130 .

Here, the bypass line 153 may be connected to the nuclear fuel reloading tank 105 and the discharge line 154 provided in the containment building 101, and a valve 164 is provided on the bypass line 153 side. may be provided.

As a non-limiting example, the valve 164 may be a three-way valve. Accordingly, the steam discharged from the decontamination water tank 120 may move toward the nuclear fuel reload tank 105 inside the filter and exhaust device 130 or the containment building 101 through the adjustment of the three-way valve.

Through this, the steam discharged from the decontamination water tank 120 may be decontaminated with radioactive materials further through the filter and exhaust device 130 or the nuclear fuel reload tank 105 .

In the present invention, the decontamination water tank 120 may be disposed inside the containment building 101 as shown in FIGS. 1 and 2 .

In this case, since the decontamination water tank 120 for removing the radioactive material of the steam introduced from the steam generator 110 is disposed inside the containment building 101 when a serious accident occurs, the decontamination water tank 120 instantaneously increases the pressure. Even if the radioactive material leaks from the decontamination tank 120 due to partial damage, the radioactive material leaked from the decontamination tank 120 may be discharged into the containment building 101 .

Through this, the radioactive material leaked from the decontamination water tank 120 can be moored inside the containment building 101, so that the release to the outside atmosphere can be fundamentally blocked. For this reason, the systems 100 and 200 for reducing atmospheric emission of radioactive materials in the event of a serious accident according to an embodiment of the present invention bypass the containment building 101 in the event of a serious accident and fundamentally prevent an accident in which radioactive materials are emitted to the outside. By doing so, the safety of nuclear power plants can be further improved.

In this case, the systems 100 and 200 for reducing the emission of radioactive materials to the atmosphere when a serious accident occurs according to an embodiment of the present invention may further include a cooling means 124 . Such a cooling means 124 may be disposed to surround the outside of the decontamination water tank 120 as shown in FIG. Accordingly, the cooling means 124 may cool the decontamination water tank 120 .

That is, the cooling means 124 can sufficiently condense the vapor introduced into the decontamination water tank 120 by reducing the pressure and temperature in the decontamination water tank 120 through cooling. Through this, it is possible to prevent the risk of damage to the decontamination tank by the dynamic load.

Here, the cooling means 124 may be installed outside the decontamination water tank 120, and may be in the form of a water tank. In addition, the cooling means 124 may include at least one cooling fin to improve external cooling performance, and fire water may be filled therein.

On the other hand, the system 200 for reducing the emission of radioactive materials to the atmosphere when a serious accident occurs according to an embodiment of the present invention may further include reduced pressure power generation means 170 and 180 as shown in FIG. 2 .

The reduced pressure power generation means 170 and 180 can produce emergency power while lowering the pressure of the steam transferred from the steam generator 110 to the decontamination water tank 120 side when a serious accident occurs.

To this end, the reduced pressure power generation means 170 and 180 may be disposed on a connection line 152 connecting the main steam line 151 and the decontamination water tank 120 as shown in FIG. 2 .

Through this, the high-pressure steam generated from the steam generator 110 passes through the reduced pressure power generation means 170 and 180 through the main steam line 151 and the connection line 152 and then moves to the decontamination water tank 120 side. have.

For example, the reduced pressure power generation means 170 and 180 includes a turbine 170 including a plurality of blades rotating through high-pressure steam transferred from the steam generator 110 , and emergency power through the rotation of the turbine 170 . It may include a generator 180 to produce.

For this reason, the high-pressure steam transferred from the steam generator 110 may be decompressed in the process of passing through the turbine 170 , and the high-pressure steam transferred from the steam generator 110 is decontaminated in a depressurized state. It may be transferred to the water tank 120 side.

Accordingly, by blocking the supply of the instantaneous high pressure steam from the steam generator 110 to the decontamination water tank 120 side, the decontamination water tank 120 can be significantly reduced in risk of damage due to the high-pressure steam. .

That is, the high-pressure steam supplied from the steam generator 110 to the reduced-pressure power generation means 170 and 180 is decompressed in the process of passing the reduced-pressure power generation means 170 and 180 so that the momentum can be reduced, and the momentum of the steam is reduced. is supplied to the decontamination water tank 120 side, so that damage to the decontamination water tank 120 due to high-pressure steam can be prevented in advance.

Through this, the system 200 for reducing the emission of radioactive materials to the atmosphere when a serious accident occurs according to an embodiment of the present invention can increase the stability of the decontamination water tank 120 .

In addition, in the system 200 for reducing atmospheric emission of radioactive materials in the event of a serious accident according to an embodiment of the present invention, since the decontamination water tank 120 is disposed inside the containment building 101, decontamination by high-pressure steam Even if a part of the water tank 120 is damaged, the radioactive material leaking from the decontamination water tank 120 can be blocked from being released to the outside by the containment building 101, so that a bypass accident in which the radioactive material is released can be fundamentally blocked. have.

In addition, the system 200 for reducing the emission of radioactive materials to the atmosphere in the event of a serious accident according to an embodiment of the present invention uses the high-pressure steam transferred from the steam generator 110 to emergency in the reduced pressure power generation means 170 and 180 . can generate electricity.

Accordingly, the system 200 for reducing atmospheric emission of radioactive materials when a serious accident occurs according to an embodiment of the present invention is emergency power produced by the reduced pressure power generation means 170 and 180 even if the power supplied from the outside is cut off when a serious accident occurs. can be used to monitor the state inside the containment building 101 .

To this end, the system 200 for reducing atmospheric emission of radioactive materials in the event of a serious accident according to an embodiment of the present invention is installed in the containment building 101 to detect the internal state of the containment building 101. At least one sensor 190 may be included, and the at least one sensor 190 may use the emergency power generated through the reduced pressure power generation means 170 and 180 as driving power.

Here, the at least one sensor 190 may be all known various sensors such as a temperature sensor, a water level sensor, and a pressure sensor for detecting a state inside the containment building.

Accordingly, in the system 200 for reducing atmospheric emission of radioactive materials in the event of a serious accident according to an embodiment of the present invention, even if the supply of power is interrupted due to a serious accident occurring inside the containment building 101, the reduced pressure power generation means Various electric devices installed in the containment building 101 may be driven using the emergency power generated through 170 and 180 . For this reason, the system 200 for reducing atmospheric emission of radioactive materials in the event of a serious accident according to an embodiment of the present invention can quickly determine the initial state of the occurrence of a serious accident and quickly perform an appropriate response.

As shown in FIG. 2 , the reduced pressure power generation means 170 and 180 may be installed inside the containment building 101 , like the decontamination water tank 120 .

In this case, one end of the connection line 152 connecting the main steam line 151 and the decontamination water tank 120 is connected to the decontamination water tank 120 and the other end is installed on the main steam line 151 to reduce atmospheric emission. It may be disposed to be positioned inside the containment building 101 while being connected to the valve 165 for use, and the reduced pressure power generation means 170 and 180 may be installed in the connection line 152 .

Through this, it is possible to easily wire a cable (not shown) for providing the power generated from the reduced pressure power generation means 170 and 180 to the at least one sensor 190 .

Although one embodiment of the present invention has been described above, the spirit of the present invention is not limited to the embodiments presented herein, and those skilled in the art who understand the spirit of the present invention can add components within the scope of the same spirit. , changes, deletions, additions, etc. will be able to easily suggest other embodiments, but this will also fall within the scope of the present invention.

100,200: A system for reducing the emission of radioactive materials to the atmosphere in the event of a serious accident
101: containment building 105: nuclear fuel reloading tank
110: steam generator 112: customs
120: decontamination water tank 121: decontamination water
122: nozzle 124: cooling means
130: filtering exhaust device 140: nuclear reactor
151: main steam line 152: connection line
153: bypass line 154: discharge line
161: main steam safety valve 162: atmospheric release valve
163: main steam isolation valve 164: valve
165: valve for reducing atmospheric emission 170: turbine
180: generator 190: sensor

Claims (10)

a steam generator disposed inside the containment building and producing steam using the heat of the coolant heated in the reactor and connected to the turbine via the main steam line;
a decontamination water tank connected via the main steam line and the connecting line, and including decontamination water for reducing the emission of radioactive materials to the atmosphere by decontamination of the steam transferred from the steam generator when a serious accident occurs; and
a filtering exhaust device connected to the outlet of the decontamination water tank through a bypass line; including,
The decontamination tank is a system for reducing the emission of radioactive materials to the atmosphere when a serious accident occurs that is disposed inside the containment building. a steam generator disposed inside the containment building and producing steam using the heat of the coolant heated in the reactor and connected to the turbine via the main steam line; and
a decontamination water tank connected via the main steam line and the connecting line, and including decontamination water for reducing the emission of radioactive materials to the atmosphere by decontamination of the steam transferred from the steam generator when a serious accident occurs; and
a cooling means disposed to surround the outside of the decontamination water tank to cool the decontamination water tank; including,
The decontamination tank is a system for reducing the emission of radioactive materials to the atmosphere when a serious accident occurs that is disposed inside the containment building. 3. The method of claim 1 or 2,
The system for reducing the emission of radioactive materials to the atmosphere when a serious accident occurs, when a serious accident occurs, a reduced pressure power generation means for lowering the pressure of the steam transferred from the steam generator to the decontamination water tank and at the same time generating emergency power; A system for reducing atmospheric emissions of radioactive materials. 4. The method of claim 3,
The reduced pressure power generation means includes a turbine including a plurality of blades rotating through the steam transferred from the steam generator, and a generator for generating electric power through the rotation of the turbine. system. 4. The method of claim 3,
The reduced pressure power generation means is a system for reducing the emission of radioactive materials to the atmosphere when a serious accident occurs, which is disposed on the connection line so as to be located inside the containment building. 4. The method of claim 3,
The system for reducing the emission of radioactive materials to the atmosphere when the serious accident occurs,
A system for reducing atmospheric emission of radioactive materials in the event of a serious accident, wherein at least one sensor for checking the internal state of the containment building is disposed inside the containment building when a serious accident occurs. 7. The method of claim 6,
The at least one sensor is a system for reducing the emission of radioactive materials to the atmosphere when a serious accident occurs, which is driven through the emergency power generated through the reduced pressure power generation means. 3. The method of claim 1 or 2,
The serious accident is a system for reducing the emission of radioactive materials to the atmosphere in the event of a serious accident, which is a tube rupture accident of a steam generator or an accident of loss of coolant at the low pressure boundary. 3. The method of claim 1 or 2,
The system for reducing the emission of radioactive materials to the atmosphere in the event of a serious accident including at least one nozzle provided at the end of the connection line in the decontamination tank. delete

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