JP2015072151A - On-site test system and on-site test method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an on-site test system and an on-site test method capable of conducting a test on filtered vent for a reactor containment vessel on site.SOLUTION: An on-site test system for testing a filter vent 3 for a reactor containment vessel includes: a simulation-steam supply pipe 41 for supplying a simulated steam; and a radioactive-substance generator 34 generating a radioactive substance. The system further includes: a test steam generator 35 mixing the simulation steam supplied from the simulation-steam supply pipe 41 with the radioactive substance so as to generate a test steam containing the radioactive substance; and a test-steam supply pipe 47 for supplying the test steam to the filtered vent 3.

Description

  Embodiments described herein relate generally to a field test system and a field test method.

  FIG. 4 is a schematic diagram showing a configuration of a filter vent system of a conventional nuclear power plant.

  This filter vent system includes a dry well 1 and a suppression chamber 2 constituting a reactor containment vessel, a filter vent device 3 for the reactor containment vessel, a rupture disk 4, a stack 5, and a radioactive substance concentration measuring device 6 And.

  The filter vent system further includes a first pipe 11 that connects the dry well 1 and the suppression chamber 2 and the filter vent apparatus 3, and a second pipe 12 that connects the filter vent apparatus 3 and the stack 5 via the rupture disk 4. And. The radioactive substance concentration measuring device 6 is connected to the second pipe 12 and measures the concentration of the radioactive substance contained in the steam flowing through the second pipe 12.

  This filter vent system further connects the first and second isolation valves 21 and 22 provided in the first pipe 11 connecting the dry well 1 and the filter vent device 3, the suppression chamber 2 and the filter vent device 3. Third and fourth isolation valves 23 and 24 provided in the first pipe 11, first and second pressure gauges 25 and 26 connected to the second pipe 12, and a first attached to the filter vent device 3. The second water level gauges 27 and 28 are provided.

  The filter vent device 3 is a device for preventing an overpressure damage of a reactor containment vessel (hereinafter referred to as “containment vessel”) in a severe accident of the reactor. The filter vent device 3 is installed for the purpose of reducing the content of cesium and iodine contained in this gas to a minimum level when the atmosphere gas in the containment vessel is released to decompress the inside of the containment vessel. .

  FIG. 5 is a schematic view showing an operation in a severe accident of a filter vent system of a conventional nuclear power plant. The portions indicated by bold lines in the first and second pipes 11 and 12 in FIG. 5 indicate that steam flows through these portions.

  If the internal pressure of the containment vessel rises during a severe nuclear accident, there is a risk of overpressure damage to the containment vessel. In this case, in order to reduce the internal pressure of the containment vessel, the first and second isolation valves 21 and 22 or the third and fourth isolation valves 23 and 24 that isolate the containment vessel and the filter vent device 3 are opened. The atmospheric gas in the containment vessel is supplied to the filter vent device 3 through the first pipe 11. The filter vent device 3 reduces the content of cesium and iodine contained in this gas to a minimum level and discharges this gas to the second pipe 12. When the pressure of the gas discharged to the second pipe 12 reaches a specified pressure, the rupture disk 4 is ruptured and this gas is released from the stack 5 to the atmosphere.

JP-A-9-61577

  In recent years, the movement of installation of the filter vent device 3 has been accelerating in various countries around the world. At present, the performance test by the type test in the factory using the pilot device smaller than the actual filter vent device 3 is mainstream, and the performance test in the field is not carried out.

  However, it is expected that a test request and a surveillance request at the time of construction of the filter vent device 3 will come out in the future. In this case, there is a possibility that on-site performance tests may be required regardless of whether the filter vent device 3 is an existing one or a new one, and whether the reactor is a BWR (boiling water reactor) or a PWR (pressurized water reactor). .

  In order to carry out the performance test of the filter vent device 3 locally, equipment for generating steam having the same pressure, temperature and flow rate as venting in severe accidents, and aerosol by heating cesium and iodine Equipment for supplying as is required. Therefore, it is necessary to install complex and large-scale facilities locally, which is very difficult. However, in order to ensure the safety of a nuclear power plant in the event of a severe accident, it can be expected that field tests will be required in the future by domestic and foreign regulations, and it is necessary to satisfy those regulations.

  Therefore, the present invention provides an on-site test system and an on-site test method capable of performing on-site testing of a filter vent device for a reactor containment vessel.

  According to one embodiment, a field test system for a filter vent device for a nuclear reactor containment vessel includes a simulated steam supply pipe for supplying simulated steam and a radioactive material generator for generating a radioactive material. Further, the system mixes the simulated steam supplied from the simulated steam supply pipe with the radioactive substance, generates a test steam containing the radioactive substance, and the test steam. A test steam supply pipe for supplying to the filter vent device.

  According to the present invention, a test of a filter vent device for a nuclear reactor containment vessel can be performed on site.

It is the schematic which shows the structure of the field test system of 1st Embodiment. It is the schematic which shows the example of the protection method of the rupture disk of 1st Embodiment. It is the schematic which shows another example of the protection method of the rupture disk of 1st Embodiment. It is the schematic which shows the structure of the filter vent system of the conventional nuclear power plant. It is the schematic which shows the operation | movement at the time of the severe accident of the filter vent system of the conventional nuclear power plant.

  Embodiments of the present invention will be described below with reference to the drawings.

  In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted. Also, illustration of elements not directly related to the description of the embodiment of the present invention is omitted.

(First embodiment)
FIG. 1 is a schematic diagram showing the configuration of the field test system of the first embodiment.

  FIG. 1 shows, as constituent elements of a filter vent system of a nuclear power plant, a dry well 1 and a suppression chamber 2 constituting a reactor containment vessel, a filter vent device 3 for the reactor containment vessel, a rupture disk 4, and a stack. 5 and radioactive substance concentration measuring device 6 and the like.

  1 further shows a house boiler 31, an evaporator 32, a reactor main steam pipe 33 installed in this nuclear power plant, a radioactive material generator 34 constituting a field test system for the filter vent device 3, and a test steam adjustment tank. 35 and a control device 36 are shown. The test steam adjustment tank 35 is an example of the test steam generation device of the present disclosure.

  The field test system further includes a simulated steam supply pipe 41, a first heating steam supply pipe 42, a first heating steam drain pipe 43, a second heating steam supply pipe 44, and a second heating steam supply pipe 42. A heating steam drain pipe 45, a radioactive substance supply pipe 46, and a test steam supply pipe 47 are provided.

  The field test system further includes a house boiler valve 51, an evaporator valve 52, a reactor main steam pipe valve 53, a simulated steam supply valve 54, a heating steam supply valve 55, and a heating steam flow rate control valve 61. A heating steam drain flow control valve 62, a simulated steam flow control valve 63, a radioactive material flow control valve 64, a test steam flow control valve 65, a test steam supply valve 66, and motors 71 to 75. I have.

  The house boiler 31, the evaporator 32, and the reactor main steam pipe 33 are simulation steam sources used in the test. The house boiler 31 is a device that generates steam by heating water. The evaporator 32 is a device that generates seal steam for the steam turbine. The reactor main steam pipe 33 is a pipe for circulating the steam generated from the reactor.

  The simulated steam from these simulated steam supply sources is supplied into the test steam adjustment tank 35 via the simulated steam supply pipe 41. The use of such simulated steam has the advantage that it is not necessary to install an apparatus for generating simulated steam by effectively using steam in the nuclear power plant. Furthermore, as will be described later, since the simulated steam from these simulated steam supply sources is at a high temperature, the simulated steam can be used as a heat source, and there is an advantage that it is not necessary to install a heating device in the field test system. . Note that the on-site test system of this embodiment may acquire simulated steam from other locations in the nuclear power plant.

  The house boiler valve 51, the evaporator valve 52, and the reactor main steam pipe valve 53 are provided in the simulated steam supply pipe 41 before joining. When using steam from the house boiler 31 as simulated steam, the house boiler valve 51 is opened. Further, when using steam from the evaporator 32 and the reactor main steam pipe 33 as simulated steam, the evaporator valve 52 and the reactor main steam pipe valve 53 are opened, respectively. In this embodiment, the steam from the evaporator 32 or the reactor main steam pipe 33 is mainly used, and when this steam is insufficient, the steam from the house boiler 31 is used to compensate for the shortage of steam.

  The simulated steam supply valve 54 is provided in the simulated steam supply pipe 41 after joining. By opening at least one of the house boiler valve 51, the evaporator valve 52, the reactor main steam pipe valve 53, and the simulated steam supply valve 54, simulated steam is supplied to the test steam adjustment tank 35.

  The first heating steam supply pipe 42 is branched from the simulated steam supply pipe 41, and supplies the simulated steam into the test steam adjustment tank 35 as heating steam for the test steam adjustment tank 35. The test steam adjustment tank 35 includes a first space that generates the test steam and a second space that surrounds the first space and through which the heating steam passes. The heating steam from the first heating steam supply pipe 42 is introduced into the second space, used for heating the test steam adjustment tank 35, and then discharged to the first heating steam drain pipe 43. Is done.

  The first heating steam drain pipe 43 discharges the heating steam discharged from the test steam adjustment tank 35 and the drain of the heating steam to the stack 5 disposed downstream of the filter vent device 3. As a result, the heating steam is released to the atmosphere.

  The heating steam flow rate control valve 61 and the heating steam drain flow rate control valve 62 are provided in the first heating steam supply pipe 42 and the first heating steam drain pipe 43, respectively. The heating steam flow rate adjustment valve 61 is used to adjust the flow rate of the heating steam supplied to the test steam adjustment tank 35. The heating steam drain flow rate adjustment valve 62 is used to adjust the flow rate of the heating steam or drain discharged from the test steam adjustment tank 35.

  The second heating steam supply pipe 44 is branched from the simulated steam supply pipe 41 and supplies the simulated steam into the radioactive material generator 34 as steam for heating the radioactive substance. The radioactive substance generator 34 includes a first space that processes the radioactive substance, and a second space that is adjacent to the first space and through which heating steam passes. The heating steam from the second heating steam supply pipe 44 is introduced into the second space, used for heating the radioactive substance, and then discharged to the second heating steam drain pipe 45.

  The second heating steam drain pipe 45 discharges the heating steam discharged from the radioactive substance generator 34 and the drain of this heating steam to the first heating steam drain pipe 43. As a result, the heating steam is released to the atmosphere through the stack 5.

  The heating steam supply valve 55 is provided in the second heating steam supply pipe 44. By opening the heating steam supply valve 55, the heating steam is supplied to the radioactive substance generator 34.

  The simulated steam flow control valve 63 is provided in the simulated steam supply pipe 41 downstream of the branch point of the first and second heating steam supply pipes 42 and 44. The simulated steam flow rate adjustment valve 63 is used to adjust the flow rate of the simulated steam supplied to the test steam adjustment tank 35.

  The radioactive substance generator 34 is an apparatus that generates a radioactive substance. Examples of this radioactive substance include cesium 133 and iodine 127. The radioactive substance generator 34 heats the radioactive substance to the melting point or higher by using the heat of the heating steam, and changes the radioactive substance from a solid to a liquid. Specifically, the radioactive substance generator 34 heats the radioactive substance to make it aerosol, and discharges this aerosol to the radioactive substance supply pipe 46.

  The radioactive substance supply pipe 46 merges with the simulated steam supply pipe 41 and supplies the radioactive substance discharged from the radioactive substance generator 34 into the simulated steam supply pipe 41. The radioactive substance is supplied into the test steam adjustment tank 35 through the simulated steam supply pipe 41 together with the simulated steam.

  The radioactive substance flow control valve 64 is provided in the radioactive substance supply pipe 46. The radioactive substance flow rate adjustment valve 64 is used to adjust the flow rate of the radioactive substance supplied to the test steam adjustment tank 35.

  The test steam adjustment tank 35 is a tank that mixes the simulated steam supplied from the simulated steam supply pipe 41 with a radioactive substance to generate a test steam containing the radioactive substance. The test steam adjustment tank 35 includes a mixing tank for mixing the simulated steam and the radioactive substance in the first space, and a stirring tank for stirring the mixture using a stirrer. Yes. The test steam adjustment tank 35 discharges the generated test steam to the test steam supply pipe 47.

  The test steam supply pipe 47 merges with the first pipe 11, and supplies the test steam discharged from the test steam supply pipe 47 to the filter vent device 3 through the first pipe 11. In this way, the performance test of the filter vent device 3 is performed.

  The test steam flow control valve 65 and the test steam supply valve 66 are provided in the test steam supply pipe 47. The test steam flow rate adjustment valve 65 is used to adjust the flow rate of the test steam supplied to the filter vent device 3. By opening the test steam flow rate adjusting valve 65 and the test steam supply valve 66, the test steam is supplied to the first pipe 11.

  The test steam supply pipe 47 joins the first pipe 11 at a point between the first isolation valve 21 and the second isolation valve 22 and a point between the third isolation valve 23 and the fourth isolation valve 24. doing. Therefore, the test steam is supplied to the filter vent device 3 through the first pipe 11 by opening the second isolation valve 22 or the fourth isolation valve 24.

  The control device 36 is a device that controls the operation of the field test system. The control device 36 is, for example, an electric valve, and is a heating steam flow rate adjustment valve 61, a heating steam drain flow rate adjustment valve 62, a simulated steam flow rate adjustment valve 63, a radioactive material flow rate adjustment valve 64, and a test steam flow rate adjustment valve 65. Is controlled through electric motors 71-75. Thereby, the control apparatus 36 can generate | occur | produce the vapor | steam which has the pressure, temperature, flow volume, and radioactive substance density | concentration equivalent to the time of the vent at the time of a severe accident as a test steam with the time passage at the time of a severe accident. It becomes. That is, the control device 36 can adjust the test steam condition to the steam condition at the time of venting in a severe accident.

  Thereafter, in this embodiment, the radioactive substance concentration measuring device 6, the first and second pressure gauges 25 and 26, the first and second water level gauges 27 and 28, etc. are used for the equipment design requirements for the filter vent system. Data collection is performed. Examples of device design requirements include the ability of the filter vent device 3 to remove radioactivity, the necessary water level maintenance time after the start of venting, and the presence or absence of blockage due to aerosol inflow.

1) Effects of the First Embodiment As described above, according to the present embodiment, the on-site test of the filter vent device 3 for the containment vessel is performed by configuring the on-site test system as described above. It becomes possible. In other words, according to the present embodiment, it is possible to carry out an on-site test using the actual filter vent device 3 instead of a factory test using a pilot device.

  Moreover, in this embodiment, the high temperature steam supplied from the nuclear power plant in which the nuclear containment vessel and its filter vent device 3 are installed is used as the simulated steam. Therefore, according to the present embodiment, it is not necessary to install a device for generating simulated steam or a device for heating test steam or radioactive material in the field test system, making the field test plant easy and inexpensive. Can be realized.

  Moreover, the field test system of this embodiment is provided with the control apparatus 36 which controls the valve opening degree of the control valve in a system. Therefore, according to the present embodiment, it is possible to adjust the test steam conditions to the steam conditions at the time of venting in a severe accident and to perform an appropriate test.

  In the present embodiment, the injection point of the test vapor into the filter vent system may be provided in the inert gas pipe. In this case, the diameter of the pipe is set to a diameter that allows both the inert gas and the test steam to flow.

2) Protection method of the rupture disk 4 In a severe accident of the reactor, the rupture disk 4 is ruptured and the gas from the filter vent device 3 is released to the atmosphere. However, if the rupture disk 4 bursts during the field test, the cost of preparing a new rupture disk 4 is not preferable.

  Therefore, in this embodiment, it is desirable to prevent the rupture disk 4 from bursting by the following method.

  FIG. 2 is a schematic diagram illustrating an example of a method for protecting the rupture disk 4 of the first embodiment.

  FIG. 2A shows spools 12 a and 12 b constituting the second pipe 12. These spools 12 a and 12 b are arranged at positions adjacent to the rupture disk 4.

  In the present embodiment, the rupture disk 4 is replaced with a normal pipe (spool) 12c before the start of the test (specifically, before the test steam is injected into the filter vent device 3) (see FIG. 2B). . This makes it possible to simulate a rupture state without actually rupturing the rupture disk 4. The pipe 12c is replaced with the rupture disk 4 again after the end of the test.

  FIG. 3 is a schematic diagram showing another example of the method for protecting the rupture disk 4 of the first embodiment.

  The second pipe 12 in this example is connected to a bypass pipe 48 for bypassing the rupture disk 4. The second pipe 12 includes a first valve 67 immediately before the rupture disk 4, and the bypass pipe 48 includes a second valve 68.

  In this example, before starting the test, the first valve 67 is closed and the second valve 68 is opened. Thereby, by letting gas escape to the bypass piping 48, it becomes possible to simulate the rupture state without actually rupturing the rupture disk 4. After the end of the test, the first valve 67 is opened and the second valve 68 is closed.

  Although several embodiments have been described above, these embodiments are presented as examples only and are not intended to limit the scope of the invention. The novel systems and methods described herein can be implemented in a variety of other forms. Various omissions, substitutions, and changes can be made to the system and method embodiments described in the present specification without departing from the scope of the invention. The appended claims and their equivalents are intended to include such forms and modifications as fall within the scope and spirit of the invention.

1: dry well, 2: suppression chamber, 3: filter vent device,
4: Rupture disk, 5: Stack, 6: Radioactive substance concentration measuring device,
11: 1st piping, 12: 2nd piping, 12a, 12b, 12c: Spool,
21: 1st isolation valve, 22: 2nd isolation valve, 23: 3rd isolation valve, 24: 4th isolation valve,
25: 1st pressure gauge, 26: 2nd pressure gauge, 27: 1st water level gauge, 28: 2nd water level gauge,
31: House boiler, 32: Evaporator, 33: Reactor main steam pipe,
34: Radioactive substance generator, 35: Steam adjustment tank for test, 36: Control device,
41: Simulated steam supply pipe, 42: First heating steam supply pipe,
43: first heating steam drain pipe, 44: second heating steam supply pipe,
45: Second heating steam drain pipe, 46: Radioactive substance supply pipe,
47: Steam supply pipe for test, 48: Bypass pipe,
51: House boiler valve, 52: Evaporator valve, 53: Reactor main steam pipe valve,
54: Simulated steam supply valve, 55: Steam supply valve for heating,
61: Steam flow rate regulating valve for heating, 62: Steam drain flow rate regulating valve for heating,
63: Simulated steam flow rate control valve, 64: Radioactive material flow rate control valve,
65: Steam flow control valve for test, 66: Steam supply valve for test,
67: 1st valve, 68: 2nd valve, 71, 72, 73, 74, 75: Electric motor

Claims (12)

A field test system for a filter vent device for a containment vessel,
Simulated steam supply piping for supplying simulated steam;
A radioactive substance generator for generating radioactive substances;
A test steam generator that mixes the simulated steam supplied from the simulated steam supply pipe with the radioactive substance, and generates a test steam containing the radioactive substance;
A test steam supply pipe for supplying the test steam to the filter vent device;
Field testing system with.   The on-site test system according to claim 1, further comprising a simulated steam flow rate adjusting valve provided in the simulated steam supply pipe for adjusting the flow rate of the simulated steam.   The field test system according to claim 1, further comprising a test steam flow rate adjusting valve provided in the test steam supply pipe for adjusting a flow rate of the test steam. further,
A radioactive substance supply pipe for supplying the radioactive substance from the radioactive substance generator to the simulated steam supply pipe;
A radioactive substance flow control valve provided in the radioactive substance supply pipe for adjusting the flow rate of the radioactive substance;
The field test system according to any one of claims 1 to 3, further comprising:   5. The field test system according to claim 1, wherein the simulated steam supply pipe supplies, as the simulated steam, steam supplied from a nuclear power plant in which the reactor containment vessel is installed.   And a first heating steam supply pipe for branching from the simulated steam supply pipe and supplying the simulated steam to the test steam generation apparatus as steam for heating the test steam generation apparatus. Item 6. The field test system according to any one of items 1 to 5. And a second heating steam supply pipe for branching from the simulated steam supply pipe and supplying the simulated steam to the radioactive substance generator as steam for heating the radioactive substance,
The field test system according to any one of claims 1 to 6, wherein the radioactive substance generation device changes the radioactive substance from a solid to a liquid using heat of the heating steam.   The field test system according to claim 7, wherein the radioactive substance generation device aerosolizes the radioactive substance.   The heating steam drain pipe for discharging the heating steam and the drain of the heating steam to a stack disposed downstream of the filter vent device, further comprising: a heating steam drain pipe. Field test system as described in section.   And a control device that controls at least one of a simulated steam flow control valve provided in the simulated steam supply pipe and a test steam control valve provided in the test steam supply pipe. Item 10. The field test system according to any one of items 1 to 9. A field test method for a filter vent device for a containment vessel,
Supply simulated steam through simulated steam supply piping,
Generate radioactive material,
Mixing the simulated steam supplied from the simulated steam supply pipe with the radioactive substance, and generating a test steam containing the radioactive substance;
Supplying the test steam to the filter vent device via a test steam supply pipe;
Field test methods including   The field test method according to claim 11, comprising replacing a rupture disk disposed downstream of the filter vent device with a pipe before injecting the test steam into the filter vent device.

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