JP2011012973A - Method and device for hydrogen disposal in reactor containment vessel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydrogen disposal device of a reactor containment vessel capable of improving disposal capacity of hydrogen even if released gas includes radioactive iodine.SOLUTION: Gas containing hydrogen, oxygen, radioactive iodine, and vapor released into the reactor containment vessel 3 in a loss-of-coolant accident is introduced into a condenser 12 and the condenser 12 condenses the vapor. Hydrogen contained in gas that is exhausted from the condenser 12 and is supplied to a high-temperature hydrogen oxidizing device 13 is oxidized by reacting with oxygen to become vapor by action of oxidized copper 14 within the hydrogen oxidizing device 13. A control unit 28 decreases a rotational speed of a blower 11 (or stops the blower 11) when a measurement value of a dose inputted from a radiation measuring device 27 exceeds a set value. Therefore, cuprous iodide generated by reaction between radioactive iodine and the oxidized copper 14 becomes metallic copper. By supplying oxygen into the hydrogen oxidizing device 13, the metallic copper is reproduced into the oxidized copper 14.

Description

  The present invention relates to a reactor containment vessel hydrogen treatment method and a hydrogen treatment apparatus thereof, and more particularly to a reactor containment vessel hydrogen treatment method and a hydrogen treatment apparatus suitable for application to a boiling water nuclear power plant.

  In a boiling water nuclear plant and a pressurized water nuclear plant, a nuclear reactor is installed in a reactor containment vessel. The reactor containment vessel has a function of preventing the radioactive material from being released to the outside environment even if the radioactive material leaks from the reactor.

  For example, in a reactor containment vessel used in a boiling water nuclear power plant, a dry well in which a nuclear reactor is disposed and a wet well isolated from the dry well are formed. A pressure suppression pool in which cooling water is stored is provided in the wet well. The other end of the vent pipe whose one end communicates with the dry well is immersed in the cooling water in the pressure suppression pool.

  For example, when a loss-of-coolant accident occurs in which the main steam pipe connected to the reactor is broken in the reactor containment vessel, the reactor is scrammed and the operation is stopped. The high-temperature water vapor discharged from the broken opening of the main steam pipe into the dry well is discharged into the cooling water in the pressure suppression pool through the vent pipe and condensed. Such a condensation of water vapor suppresses the pressure increase in the reactor containment vessel.

  In the safety design of nuclear reactors, when a loss-of-coolant accident, which is considered as a design basis event, occurs, first the zirconium alloy that constitutes the cladding of the fuel rod due to the temperature rise of the fuel rod in the reactor pressure vessel The zirconium contained in the reactor and the cooling water in the reactor vessel react to generate hydrogen gas, and the water vapor containing the radioactive material released from the fractured portion to the dry well is discharged to the pressure suppression pool as described above, and It is assumed that hydrogen gas and oxygen gas are generated by radiolysis of the cooling water in the reactor pressure vessel.

  As described above, the countermeasure against the water vapor released to the dry well at the time of the coolant loss accident is to provide a pressure suppression pool for condensing the water vapor. During operation of the boiling water nuclear power plant, nitrogen gas, which is an inert gas, is filled in the reactor containment vessel. Hydrogen and oxygen generated at the time of the coolant loss accident are released to the dry well. A part of each of hydrogen and oxygen is released into the pressure suppression pool through the vent pipe and is accumulated in the space above the liquid level of the pool water in the wet well. In boiling water nuclear power plants, there is a risk of explosion when the hydrogen and oxygen concentrations in at least one of the dry well and wet well exceed the set concentrations. A processing device is provided in the reactor containment vessel. The combustible gas processing apparatus boosts the gas in the dry well (or wet well) with a blower and supplies it to the heating recombiner. The heated recombiner heats the supplied gas to recombine hydrogen and oxygen contained in the gas into water. The combustible gas processing apparatus cools the gas having reduced concentrations of hydrogen and oxygen due to the recombination by a cooler and returns the gas to the reactor containment vessel.

  As a static combustible gas processing apparatus that does not require external power, a combustible gas processing apparatus using a recombiner having a hydrogen oxidation catalyst has been proposed. Examples of such a combustible gas processing apparatus are described in Japanese Patent Application Laid-Open Nos. 2-98689 and 2006-322768. The combustible gas processing apparatus described in Japanese Patent Application Laid-Open No. 2-98689 has a hydrogen oxidizer (recombiner) having a steam condenser and a catalyst disposed outside the reactor containment vessel. The water vapor released to the dry well at the time of the loss of coolant accident is led to the vapor condenser to be condensed, and the gas containing hydrogen and oxygen exhausted from the vapor condenser is supplied to the hydrogen oxidizer. Hydrogen and oxygen are recombined into water by the action of the catalyst in the hydrogen oxidizer. The remaining gas exhausted from the hydrogen oxidizer is returned to the dry well.

  The combustible gas treatment apparatus described in JP-A-2006-322768 also has a dry well cooler (vapor condenser) and an ammonia synthesis catalyst layer (recombiner). The dry well cooler is disposed in the dry well, and the ammonia synthesis catalyst layer is disposed outside the reactor containment vessel. The water vapor released to the dry well during the loss of coolant accident is condensed by the dry well cooler, and the hydrogen and oxygen contained in the gas exhausted from the dry well cooler are recombined by the ammonia synthesis catalyst layer. The remaining gas exhausted from the ammonia synthesis catalyst layer is guided into the wet well.

  An example in which copper oxide is used as a catalyst in a recombiner provided in a combustible gas processing apparatus for recombining hydrogen and oxygen in a nuclear reactor containment vessel is disclosed in JP-A-10-288694 and JP-A-2000-9873. It is disclosed in the gazette. Even if the oxygen contained in the gas introduced into the recombiner has a low concentration, the copper oxide can treat the hydrogen contained in the gas using the oxygen contained in the copper oxide ((1 below) ) See formula). When the oxygen contained in copper oxide is reduced to become copper and the oxidation treatment capability of hydrogen is lost, oxygen is supplied into the recombiner, and copper is regenerated into copper oxide by the reaction of formula (2). Can do.

Hydrogen treatment: CuO + H ₂ → Cu + H ₂ O (1)
Regeneration treatment: 2Cu + O ₂ → 2CuO (2)

Japanese Patent Laid-Open No. 2-98689 JP 2006-322768 A Japanese Patent Laid-Open No. 10-288694 JP 2000-9873 A

  The gas released into the dry well at the time of the coolant loss accident may contain radioactive cesium and radioactive iodine in addition to hydrogen and water vapor. In particular, radioactive iodine easily reacts with copper oxide in the recombiner (see the following formula (3)), and changes to a form of copper iodide that does not have hydrogen treatment capability.

2CuO + I ₂ → 2CuI + O ₂ (3)
When a gas containing radioactive iodine flows into a recombiner using copper oxide as a catalyst, the hydrogen treatment capacity of the recombiner using copper oxide gradually decreases.

  An object of the present invention is to provide a hydrogen treatment method for a nuclear reactor containment vessel and a hydrogen treatment apparatus for the same, which can improve the hydrogen treatment capacity even when the released gas contains radioactive iodine.

  A feature of the present invention that achieves the above-described object is that the water vapor contained in the gas supplied from the reactor containment vessel is condensed and the gas condensed with the water vapor is supplied to the hydrogen oxidizer filled with copper oxide. Then, the hydrogen contained in the gas is oxidized by the action of copper oxide, and when the measured dose of the hydrogen oxidizer exceeds the first dose set value, the amount of the gas supplied to the hydrogen oxidizer is decreased. There is.

  When the measured dose of the hydrogen oxidizer exceeds the first dose setting value, the amount of gas supplied to the hydrogen oxidizer is reduced, so that the hydrogen oxidation decreased due to copper iodide in the hydrogen oxidizer. The hydrogen processing capacity of the apparatus can be improved.

  ADVANTAGE OF THE INVENTION According to this invention, even when radioactive iodine is contained in the gas discharge | released in the nuclear reactor containment vessel, the processing capacity of the hydrogen contained in the gas can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram of the hydrogen treatment apparatus of the nuclear reactor containment vessel of Example 1 which is one preferable Example of this invention. It is explanatory drawing which shows the state which is supplying oxygen in the hydrogen oxidation apparatus shown in FIG. It is a block diagram of the hydrogen treatment apparatus of the reactor containment vessel of Example 2 which is another Example of this invention.

  Since copper oxide has a function of oxidizing hydrogen even when oxygen is low, it is preferable to apply it as a catalyst to a hydrogen treatment apparatus of a nuclear reactor containment vessel that performs treatment of combustible gas. The inventors of the present invention, when radioactive iodine is contained in the water vapor released from the reactor to the dry well at the time of the loss of coolant accident, the hydrogen of the hydrogen oxidation apparatus using the copper oxide having such advantages as a catalyst We examined measures that could improve the processing capacity. The result of this examination will be described below.

  Iodine has the property of being extremely easy to react with copper oxide, and is accumulated in the copper oxide filling portion in the hydrogen oxidation apparatus. For this reason, the radioactive iodine amount chemically combined with copper oxide can be obtained by measuring the radioactivity accumulated in the copper oxide. Based on the value of the amount of radioactive iodine obtained, the degree of decrease in the hydrogen treatment capacity of copper oxide can be evaluated.

  Most of the radioactive iodine generated in the reactor is I-131 and I-133. The half-life of I-131 is 8.06 days and that of I-133 is 20.8 hours, which is relatively short. Further, after any radioactive iodine is destroyed, it becomes Xe which is a gas component.

  Copper oxide becomes copper iodide by reacting with radioactive iodine. The inventors have confirmed by experiments that the hydrogen treatment performance can be regenerated after the radioactive iodine in the copper iodide is destroyed using this copper iodide. The experimental results will be described below. After the radioactive iodine in copper iodide is destroyed, the copper iodide returns to copper alone. By reacting the copper simple substance with oxygen and performing a regeneration treatment, the copper simple substance is regenerated into copper oxide. When a hydrogen-containing gas was brought into contact with the regenerated copper oxide, the hydrogen contained in the gas was combined with oxygen in the copper oxide to become water, and the hydrogen concentration of the gas was lowered. Based on the above experimental results, the inventors can obtain copper oxide with regenerated hydrogen treatment capacity by performing regeneration treatment using oxygen after the radioactive iodine in copper iodide has been destroyed. It was confirmed.

  Furthermore, the inventors have paid attention to the fact that radioactive iodine in copper iodide is destroyed when left for a certain period of time even if the hydrogen treatment performance of copper oxide once decreases due to radioactive iodine. Based on this phenomenon and the knowledge obtained from the above experimental results, the amount of radioactivity accumulated in the copper oxide was measured, and the hydrogen treatment by the copper oxide was adjusted based on the measurement result. The inventors have found that the hydrogen treatment capability can be improved even when the gas contains radioactive iodine.

  Specifically, when the copper oxide dose is higher than the set value, a part of the copper oxide reacts with radioactive iodine, and the hydrogen treatment capacity of copper oxide is reduced. Control and reduce the amount of gas supplied. Thereafter, the dose of radioactive iodine in the copper oxide decreases based on the half-life of radioactive iodine. When the radioactivity of copper oxide falls below the set value, the amount of gas supplied to the hydrogen oxidizer filled with copper oxide is increased. Also, instead of continuing to supply gas by reducing the gas supply amount to the hydrogen oxidizer, if the copper oxide dose becomes higher than the set value, the gas supply to the hydrogen oxidizer is stopped. It is also effective to stop the hydrogen treatment and restart the hydrogen treatment with copper oxide when the dose of the hydrogen oxidizer drops below the set value.

  When the dose of the hydrogen oxidizer becomes higher than the set value, the condensation performance of the condenser may be improved, and the amount of water vapor contained in the gas supplied to the hydrogen oxidizer may be reduced. By improving the condensing performance of the condensing device, the amount of water vapor condensed increases, and the amount of radioactive iodine recovered in the condensed water produced by condensing the water-containing radioactive iodine by the water vapor increases. For this reason, the amount of radioactive iodine supplied to the hydrogen oxidizer filled with copper oxide is reduced.

  A hydrogen treatment apparatus for a reactor containment vessel according to embodiment 1, which is a preferred embodiment of the present invention, will be described with reference to FIG.

  The boiling water nuclear power plant 1 has a reactor 2 installed in a reactor containment vessel 3. A main steam pipe 4 connected to a turbine (not shown) is connected to the nuclear reactor 2. The main steam pipe 4 penetrates the reactor containment vessel 3, and isolation valves 5 and 6 are installed in the main steam pipe 4 inside and outside the reactor containment vessel 3. The reactor containment vessel 3 is airtight and has a function of preventing the radioactive material from leaking to the external environment even if the radioactive material leaks from the reactor 2.

  The hydrogen treatment device 10 includes a blower 11, a condensing device 12, a hydrogen oxidation device 13, a radiation measurement device 27, and an oxygen supply device 16. The blower 11 and the condensing device 12 are installed in a pipe 17 connected to the reactor containment vessel 3, and the pipe 17 is connected to a switching valve 23. The pipe 18 connected to the switching valve 23 is connected to the inlet of the hydrogen oxidizer 13. A copper oxide 14 as a catalyst is filled in the hydrogen oxidizer 13. A heater 15 surrounds the hydrogen oxidizer 13 and is provided in the hydrogen oxidizer 13. A pipe 19 connected to the outlet of the hydrogen oxidizer 13 is connected to a switching valve 24. The pipe 20 connected to the switching valve 24 is connected to the reactor containment vessel 3. The pipes 17, 18, 19, and 20 constitute a circulation pipe of the hydrogen treatment apparatus 10 that circulates the gas in the reactor containment vessel 3.

  The oxygen supply device 16 is connected to a pipe 21 that connects the switching valve 23 and the switching valve 24, and an oxygen performance meter 26 is installed in the pipe 21.

  A hydrogen concentration meter 25 is provided in the pipe 19, and a radiation measurement device 27 is installed around the hydrogen oxidation device 13. A hydrogen concentration meter 25 and a radiation measuring device 27 are connected to the control device 28.

  During normal operation of the boiling water nuclear power plant, water vapor generated in the nuclear reactor 2 is supplied to the turbine through the main steam pipe 4. At this time, the isolation valves 5 and 6 are open. The turbine is driven by steam and rotates a connected generator (not shown). Power is generated by this generator. The reactor containment vessel 3 has a nitrogen gas atmosphere.

  For example, it is assumed that the main steam pipe 4 is broken in the reactor containment vessel 3 and a coolant loss accident occurs. The high-temperature and high-pressure cooling water in the nuclear reactor 2 is discharged as high-temperature water vapor into the reactor containment vessel 3 from the broken opening of the main steam pipe 4. This water vapor is discharged into a pool water of a pressure suppression pool (not shown) formed in a wet well (not shown) in the reactor containment vessel 3 and condensed. The increase in pressure in the reactor containment vessel 3 is suppressed by the condensation of the water vapor.

  When a coolant loss accident occurs, the blower 11 is driven and the copper oxide 14 in the hydrogen oxidizer 13 is heated by the heater 15. The heating device 15 controls the heating amount so that the temperature of the copper oxide 14 becomes 250 ° C.

  The water vapor released into the reactor containment vessel 3 at the time of the loss of coolant accident contains hydrogen and oxygen generated by radiolysis of the cooling water in the reactor 2. A gas containing hydrogen, oxygen, and water vapor in the reactor containment vessel 3 flows into the pipe 17 by the drive of the blower 11 and is guided into the condenser 12. The water vapor is condensed by the condenser 12 and removed from the gas. The water generated by the condensation of water vapor is discharged to the pressure suppression pool in the reactor containment vessel 3 through the pipe 22.

  The control device 28 that has input the occurrence signal of the loss of coolant accident controls the switching valves 23 and 24, connects the pipe 17 to the pipe 18 by the switching valve 23, and connects the pipe 19 to the pipe 20 by the switching valve 24. At this time, communication of the pipe 21 to the pipes 17 and 18 is blocked by the switching valve 23. The connection of the pipe 21 to the pipes 19 and 20 is blocked by the switching valve 24.

  The gas containing hydrogen and oxygen discharged from the condenser 12 is supplied into the hydrogen oxidizer 13 through the pipe 18. Hydrogen contained in the gas supplied to the hydrogen oxidizer 13 reacts with oxygen contained in the gas by the action of the copper oxide 14 serving as a catalyst and is oxidized to become water. When the hydrogen concentration contained in the gas supplied to the hydrogen oxidizer 13 is higher than the oxygen concentration contained in the gas, the hydrogen reacts with the oxygen contained in the copper oxide 14 and is oxidized to become water. The copper oxide 14 is adjusted to 250 ° C., which is a temperature suitable for the reaction between hydrogen and copper oxide, by the heating device 15. Since the inside of the hydrogen oxidizer 13 is in a high temperature state of 250 ° C., the water generated by the hydrogen oxidation reaction in the hydrogen oxidizer 13 is in a steam state.

  The hydrogen concentration and oxygen concentration are reduced by the oxidation reaction of hydrogen in the hydrogen oxidizer 13, and the gas containing water vapor generated by the reaction is discharged from the hydrogen oxidizer 13 and stored in the reactor through the pipes 19 and 20. Returned into the container 3. Since the gas in the reactor containment vessel 3 circulates in the circulation pipe of the hydrogen treatment device 10, hydrogen and oxygen are processed in the hydrogen oxidation device 13, so that the hydrogen contained in the gas in the reactor containment vessel 3 And the respective concentration of oxygen decreases.

  When most of the copper oxide 14 in the hydrogen oxidizer 13 is reduced to copper and the hydrogen treatment capability of the copper oxide 14 is reduced, oxygen is supplied from the oxygen supply device 16 into the hydrogen oxidizer 13. The supply of oxygen into the hydrogen oxidizer 13 is performed as follows.

  When radioactive iodine is contained in the gas supplied into the hydrogen oxidizer 13, the copper oxide 14 in the hydrogen oxidizer 13 reacts with the radioactive iodine to become copper iodide. Radiation is emitted from the produced copper iodide. The radiation measuring device 27 measures the radiation emitted from the copper iodide. The dose (dose measurement value) measured by the radiation measurement device 27 is input to the control device 28. The concentration of hydrogen contained in the gas discharged from the hydrogen oxidizer 13 to the pipe 19 is measured by a hydrogen concentration meter 25. The hydrogen concentration measurement value measured by the hydrogen concentration meter 25 is also input to the control device 28. When the hydrogen treatment capability by the copper oxide 14 is reduced due to the copper iodide conversion of the copper oxide 14 and the copperization of the copper oxide 14, the hydrogen concentration of the gas discharged from the hydrogen oxidation apparatus 13 to the pipe 19 increases. The decrease in the hydrogen treatment capacity of the copper oxide 14 can be determined based on the hydrogen concentration measurement value measured by the hydrogen concentration meter 25.

  When the dose measurement value input from the radiation measurement device 27 is lower than the dose setting value and the hydrogen concentration measurement value input from the hydrogen concentration meter 25 is higher than the hydrogen concentration setting value, the control device 28 causes the copper oxide 14 to be copperized. It is determined that the hydrogen treatment capacity of the copper oxide 14 has decreased. At this time, as shown in FIG. 2, the control device 28 switches the switching valve 23 to connect the piping 21 and the piping 18, blocks communication between the piping 17 and the piping 18, and further switches the switching valve 24 to switch the piping. 21 and the piping 19 are connected, and the communication between the piping 19 and the piping 20 is blocked. At the same time, the control device 28 stops the blower 11. The control device 28 starts supplying oxygen from the oxygen supply device 16 to the pipe 21 after the switching of the switching valves 23 and 24 is completed.

  Oxygen supplied from the oxygen supply device 16 into the pipe 21 is supplied into the hydrogen oxidizer 13 through the switching valve 23 and the pipe 18. The reaction of the formula (2) occurs in the hydrogen oxidizer 13 supplied with oxygen, and copper is regenerated into copper oxide. The concentration of oxygen discharged from the hydrogen oxidizer 13 and returned to the pipe 21 through the switching valve 24 is measured by the oxygen concentration meter 26. While monitoring the oxygen concentration measurement value measured by the oxygen concentration meter 26 with the control device 28, the supply of oxygen from the oxygen supply device 16 into the pipe 21 is controlled. When all the copper in the hydrogen oxidizer 13 is regenerated to copper oxide by supplying oxygen, the concentration of oxygen returned from the hydrogen oxidizer 13 to the pipe 21 through the switching valve 24 increases. When the oxygen concentration measurement value measured by the oxygen concentration meter 26 becomes higher than the oxygen concentration setting value, the control device 28 stops the supply of oxygen from the oxygen supply device 16 to the pipe 21 and switches the switching valves 23 and 24. Switch.

  By the switching operation of these switching valves, the piping 17 is communicated with the piping 18 via the switching valve 23, and the piping 19 is communicated with the piping 20 via the switching valve 24. The pipe 21 is separated from the pipes 18 and 19. The control device 28 resumes driving of the blower 11. A gas containing hydrogen, oxygen and water vapor in the reactor containment vessel 3 is supplied to the condensing device 12, and water vapor is removed and a gas containing hydrogen and oxygen is supplied to the hydrogen oxidizing device 13. The hydrogen oxidation process is resumed by the copper oxide 14 in the hydrogen oxidizer 13.

  When the dose measurement value input from the radiation measurement device 27 exceeds the first dose setting value, the control device 28 determines that the hydrogen treatment capability of the copper oxide 14 has decreased due to the copper iodide conversion of the copper oxide 14. When this determination is made, the control device 28 decreases the rotational speed of the blower 11. For this reason, the flow rate of the gas flowing into the pipe 17 from the reactor containment vessel 3 is reduced, and the amount of gas containing hydrogen and oxygen supplied to the hydrogen oxidizer 13 is also reduced. As a result, the amount of radioactive iodine contained in the gas supplied to the hydrogen oxidizer 13 is remarkably reduced, and the rate at which the copper oxide 14 becomes copper iodide is reduced. The amount of hydrogen oxidized by the copper oxide 14 is also reduced.

  When the radioactive iodine contained in the copper iodide produced | generated by the effect | action of the half-life of a radioactive iodine disintegrates, the copper iodide turns into copper. It can be known that the dose of copper iodide in the hydrogen oxidizer 13 has decreased because the measured dose measured by the radiation measuring device 27 has decreased. When the dose measurement value input from the radiation measurement device 27 is equal to or lower than the second dose setting value lower than the first dose setting value, the control device 28 determines that the copper iodide dose in the hydrogen oxidation device 13 has decreased. judge. When this determination is made, the control device 28 stops the blower 11 and operates the switching valves 23 and 24 to cause the piping 21 and the piping 18 to communicate with each other. Thereafter, oxygen from the oxygen supply device 16 is supplied to the hydrogen oxidation device 13 to regenerate copper into the copper oxide 14 as described above. When the oxygen concentration measurement value measured by the oxygen concentration meter 26 becomes higher than the oxygen concentration setting value, the control device 28 stops the supply of oxygen from the oxygen supply device 16 to the pipe 21 and switches the switching valves 23 and 24. Switch to the original state and drive the blower 11. In the hydrogen oxidizer 13, the hydrogen oxidation process by the copper oxide 14 is resumed.

  In the present embodiment, since the radiation measuring device 27 is provided, it is known that the copper oxide 14 is converted to copper iodide due to the inflow of radioactive iodine into the hydrogen oxidizing device 13 and the hydrogen treatment capability of the hydrogen oxidizing device 13 is reduced. be able to. Since the amount of gas supplied to the hydrogen oxidizer 13 is reduced based on the dose measurement value of the radiation measurement device 27 to change the copper iodide in the hydrogen oxidizer 13 to metal copper, and this metal copper is regenerated into the copper oxide 14. The hydrogen treatment capability of the hydrogen oxidation apparatus 13 whose hydrogen treatment capability has been reduced by radioactive iodine can be improved.

  According to the present embodiment, since the water vapor contained in the gas supplied to the hydrogen oxidizer 13 is previously condensed by the condenser 12 and removed, the amount of water vapor supplied to the hydrogen oxidizer 13 is significantly reduced. The reduction in the amount of water vapor supplied to the hydrogen oxidizer 13 improves the efficiency of hydrogen treatment by the copper oxide 14.

  Even when the copper oxide 14 is converted to metallic copper by the oxidation treatment of hydrogen using oxygen contained in the copper oxide 14, oxygen is supplied into the hydrogen oxidizing apparatus 13 to regenerate the metallic copper into the copper oxide 14. can do. For this reason, even when oxygen contained in the copper oxide 14 is utilized for the oxidation treatment of hydrogen, the hydrogen treatment capability of the hydrogen oxidation apparatus 13 can be improved by regeneration.

  The dose measurement value measured by the radiation measurement device 27 and the hydrogen concentration measurement value measured by the hydrogen concentration meter 25 are displayed on a display device of an operation panel (not shown). For this reason, the operator can grasp the state of the copper oxide 14 in the hydrogen oxidizer 13, that is, the hydrogen treatment capacity of the hydrogen oxidizer 13 by viewing this display device.

  In order to reduce the amount of gas supplied to the hydrogen oxidizer 13, instead of reducing the rotational speed of the blower 11, a flow control valve is provided in the pipe 17 on the outlet side of the blower 11, and the opening of the flow control valve is reduced. It may be done by.

  The operator may manually perform each control executed by the control device 28 based on the dose measurement value and the hydrogen concentration measurement value displayed on the display device.

  In the above-described embodiment, when the dose measurement value input from the radiation measurement device 27 exceeds the first dose setting value, the control device 28 decreases the rotational speed of the blower 11, but the control device 28 drives the blower 11. May be stopped. Since the supply of the gas containing radioactive iodine to the hydrogen oxidizer 13 is stopped, no new copper iodide is generated in the hydrogen oxidizer 13, and the iodide already generated while the blower 11 is stopped. All of the copper can be converted to metallic copper. Thereafter, as described above, oxygen is supplied into the hydrogen oxidizer 13 to regenerate the metallic copper into the copper oxide 14. By stopping the blower 11, all the copper iodide in the hydrogen oxidizer 13 can be regenerated into the copper oxide 14 in a shorter time.

  In order to reduce the amount of gas supplied to the hydrogen oxidizer 13, instead of reducing the rotational speed of the blower 11, a flow control valve is provided in the pipe 17 on the outlet side of the blower 11, and the opening of the flow control valve is reduced. It may be done by.

  A hydrogen treatment apparatus for a reactor containment vessel according to embodiment 2, which is another embodiment of the present invention, will be described with reference to FIG. The hydrogen treatment apparatus 10A of the present embodiment reduces the rotational speed of the blower 11 (or stops the blower 11) when the dose measurement value measured by the radiation measurement apparatus 27 exceeds the dose set value. 32 is configured to reduce the speed of the cooling water supplied to the condenser 12 by reducing the speed of 32.

  As in the first embodiment, the control device 28 that has input the occurrence signal of the loss of coolant accident operates the switching valves 23 and 24 to connect the pipe 17 and the pipe 18 and the pipe 19 and the pipe 20, respectively. Drive. For example, a gas containing hydrogen, oxygen, and water vapor, which has been ejected into the reactor containment vessel 3 from a broken portion of the main steam pipe 4 at the time of the coolant loss accident, flows into the pipe 17. Similar to the hydrogen treatment apparatus 10 of the first embodiment, the hydrogen treatment apparatus 10 </ b> A condenses water vapor with the condensing device 12, and oxidizes hydrogen by the action of the copper oxide 14 with the hydrogen oxidation device 13 to generate water vapor.

  The cooling water is supplied into the heat transfer pipe 30 provided in the condenser 12 through the cooling water supply pipe 31 by driving the pump 32. The water vapor supplied into the condensing device 12 by the pipe 17 is cooled and condensed by the cooling water flowing in the heat transfer tube 30. Such a mechanism for condensing water vapor also includes the condensing device 12 in the first embodiment.

  The regeneration process for copper oxide by supplying oxygen to the hydrogen oxidizer 13 is also performed in this embodiment, as in the first embodiment.

  When the dose measurement value measured by the radiation measurement device 27 exceeds the dose setting value, the control device 28 that has input the dose measurement value increases the rotational speed of the pump 32. For this reason, the amount of cooling water supplied into the heat transfer tube 30 increases, and the amount of water vapor condensed supplied to the condensing device 12 increases. For this reason, the quantity of the radioactive iodine contained in water vapor | steam collect | recovered by the condensed water produced | generated by the condensation of water vapor | steam in the condensation apparatus 12 increases. As a result, the amount of radioactive iodine contained in the gas supplied to the hydrogen oxidizer 13 is significantly reduced. In the present embodiment, the control device 28 performs control (or control for stopping the blower 11) to reduce the rotation speed of the blower 11 when the dose measurement value measured by the radiation measurement device 27 exceeds the dose setting value. Absent.

  In the present embodiment, the amount of radioactive iodine supplied to the hydrogen oxidizer 13 can be remarkably reduced because the amount of water vapor condensed is increased by increasing the flow rate of the cooling water supplied to the condenser 12. Since copper iodide of the copper oxide 14 filled in the hydrogen oxidizer 13 is remarkably reduced, the hydrogen treatment capability of the copper oxide 14 can be improved. In the present embodiment, each effect produced in the first embodiment can also be obtained.

  The hydrogen treatment apparatus for the reactor containment vessel according to the first and second embodiments can be applied to the reactor containment vessel of the pressurized water nuclear plant.

  The present invention can be applied to a boiling water nuclear plant and a pressurized water nuclear plant.

  DESCRIPTION OF SYMBOLS 1 ... Boiling water type nuclear power plant, 2 ... Reactor, 3 ... Reactor containment vessel, 4 ... Main steam piping, 10, 10A ... Hydrogen treatment apparatus, 11 ... Blower, 12 ... Condensing apparatus, 13 ... Hydrogen oxidizer, 14 DESCRIPTION OF SYMBOLS ... Copper oxide, 15 ... Heating device, 16 ... Oxygen supply device, 23, 24 ... Switching valve, 25 ... Hydrogen concentration meter, 27 ... Radiation measuring device, 28 ... Control device, 30 ... Heat transfer tube, 31 ... Cooling water supply tube 32 ... Pump.

Claims (7)

  Water vapor contained in the gas supplied from the reactor containment vessel is condensed, and the gas condensed with the water vapor is supplied to a hydrogen oxidizer filled with copper oxide to supply hydrogen contained in the gas. When the gas oxidized by the action of the copper oxide and having a reduced hydrogen concentration is returned from the hydrogen oxidizer into the reactor containment vessel, and the measured dose of the hydrogen oxidizer exceeds a first dose setting value. A method for hydrogen treatment of a containment vessel, wherein the amount of the gas supplied to the hydrogen oxidizer is reduced.   2. The hydrogen treatment method for a reactor containment vessel according to claim 1, wherein when the measured dose of the hydrogen oxidizer exceeds the first dose set value, the supply of the gas to the hydrogen oxidizer is stopped.   3. The atom according to claim 1, wherein oxygen is supplied into the hydrogen oxidizer when the measured dose of the hydrogen oxidizer is equal to or lower than a second dose set value lower than the first dose set value. Hydrogen treatment method for reactor containment vessel.   Water vapor contained in the gas supplied from the reactor containment vessel is condensed by a condensing device, and the gas exhausted from the condensing device is supplied to a hydrogen oxidation device filled with copper oxide and contained in the gas. The oxidized hydrogen is oxidized by the action of the copper oxide, and the gas having a reduced hydrogen concentration is returned from the hydrogen oxidizer into the reactor containment vessel, and the measured dose of the hydrogen oxidizer is a first dose setting value. The reactor containment vessel hydrogen treatment method is characterized by increasing the flow rate of cooling water supplied to the condensing device to increase the amount of condensation of the water vapor.   A condensing device connected to the reactor containment vessel to condense water vapor, a gas discharged from the condensing device, a hydrogen oxidizer filled with copper oxide for oxidizing hydrogen contained in the gas, and A radiation measuring device for measuring the dose of the hydrogen oxidizer, and a flow control device for controlling the amount of the gas supplied to the hydrogen oxidizer when the dose measured by the radiation measuring device exceeds a dose setting value And a control device for adjusting the hydrogen content in the reactor containment vessel.   The hydrogen treatment apparatus for a nuclear reactor containment vessel according to claim 5, wherein the flow control device is a blower for supplying a gas containing the water vapor to the condensing device.   A condensing device connected to the reactor containment vessel to condense water vapor, a gas discharged from the condensing device, a hydrogen oxidizer filled with copper oxide for oxidizing hydrogen contained in the gas, and A radiation measurement device that measures the dose of the hydrogen oxidation device, and a control device that increases the rotational speed of a pump that supplies cooling water to the condensing device when the dose measured by the radiation measurement device exceeds a dose setting value And a hydrogen treatment apparatus for a reactor containment vessel.

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