JPS6367679B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a leak testing device that can detect leakage of only desired valves when the main steam isolation valves of a plurality of main steam pipes installed in the reactor pressure vessel of a boiling water reactor are closed. and its method.

Due to the importance of the main steam isolation valve's function of preventing the release of radioactive materials into the environment, leakage tests are conducted using the main steam drain line immediately after the plant is shut down during periodic inspections and immediately before the plant is started. This main steam isolation valve leakage test is conducted simultaneously on four valves, either inside the reactor containment vessel or outside the reactor containment vessel. A leak test for the inner main steam isolation valve in the reactor containment vessel is performed by closing all the inner and outer main steam isolation valves, and using the inner main steam drain piping connected to the inner main steam isolation valve to test the inner main steam isolation valve. Air is pressurized to the main steam pipe on the reactor pressure vessel side from the steam isolation valve to the test pressure, and leakage is detected using a pressure measuring device installed in the main steam pipe on the turbine side from the inner main steam isolation valve. In addition, for leakage tests of the outer main steam isolation valve located outside the reactor containment vessel, all main steam isolation valves on both the inside and outside sides are closed, and the inner main steam drain line is used to connect the inner main steam isolation valve to the reactor pressure vessel side. After pressurizing the main steam pipe with air and filling it with water (until the inner main steam isolation valve is completely submerged), connect the intervalve main steam pipe between the inner and outer main steam isolation valves to the outer main steam isolation valve. Air is pressurized to the test pressure from the connected outer main steam drain pipe, and leakage is detected using a pressure measurement device using the pressure drop method.

By the way, in the main steam isolation valve leakage test conducted immediately after the plant is stopped and immediately before the plant is started during periodic inspections that target all main steam isolation valves, either four inside or outside (total number on each side)
Testing time can be shortened by performing multiple main steam isolation valve tests at the same time. Tests are being conducted together with the main steam isolation valve. If other main steam isolation valves that do not need to be tested are also tested in this way, the time required for air pressurization or air pressurization and water filling becomes longer, which is a major cause of delays in the leak test process. becomes.

An object of the present invention is to provide a main steam isolation valve leak testing device for a nuclear reactor and a method therefor, which can detect leakage from only any one of a plurality of main steam isolation valves.

An embodiment of the present invention will be described below with reference to the drawings. The figure is a piping system diagram of the main steam isolation valve leak test equipment.

Main steam pipes 2, 3, exiting from the reactor pressure vessel 1
Inner main steam isolation valves 6, 7, 8, 9 and outer main steam isolation valves 10, 11, 12, 13 are attached to the inside and outside of the reactor containment vessel wall 29 in the middle of the reactor containment vessel walls 29, respectively. From the inner main steam isolation valves 6 to 9, inner main steam drain pipes 14, 15, 16, 1, respectively.
7 is provided, and outer main steam drain pipes 25, 26, 27, and 28 are provided from the outer main steam isolation valve, respectively. Stop valves 18, 19, 20, and 21 are provided on the inner main steam drain pipes 14 to 17, respectively, and these are integrated into an integrated main steam drain pipe 22. The outer main steam drain pipes 25 to 28 are provided with pressure measuring devices 30, 31, 32, and 33, respectively, such as pressure gauges. Drain isolation valves 2 are installed inside and outside where the integrated main steam drain pipe 22 penetrates the reactor containment vessel wall 29.
3 and 24 are provided.

Using this device, the first inner main steam isolation valve 6
When performing a leak test on main steam pipe 2
The main steam isolation valves 6, 1 on both the inside and outside sides are installed in
Stop valves 19 to 21 of the inner main steam drain piping provided in the inner main steam isolation valves 7 to 9 of 0 and other systems
Close the reactor pressure vessel 1, remove the vessel lid 1a,
A lid 34 is placed over the opening of the main steam pipe 2 and closed. Thereafter, the main steam pipe 2 on the reactor pressure vessel 1 side is pressurized with air to the test pressure from the first inner main steam isolation valve 6 using the integrated main steam drain pipe 22 and the inner main steam drain pipe 14, and the drain isolation valve is 23,
Close and hold 24.

If there is a leak from the first main steam isolation valve 6, it can be detected by a pressure measuring device 30 provided on the first outer main steam drain pipe. In this case, the pressure measuring device 30 may be a U-shaped tube instead of a pressure gauge.

Next, when performing a leakage test on the first outer main steam isolation valve 10, if the air is pressurized as in the test of the first inner main steam isolation valve 6, the inner main steam isolation valve 6 is completely Fill with water until it is completely submerged. Thereafter, the first inter-valve main steam pipe 2a between the inner and outer main steam isolation valves 6, 10 is pressurized with air to the test pressure using the first outer main steam drain pipe 25, and the pressure drop method is used. The first pressure measuring device 30 detects the presence or absence of leakage. In this case, the pressure measuring device 30
A pressure gauge is suitable; a U-shaped tube is not suitable.

Next, the effect will be explained.

In this embodiment, the stop valves 18 to 21 are used to select only the reactor pressure vessel 1 side of a predetermined inner main steam isolation valve, for example 6, to pressurize air or to pressurize air and fill with water. The time required for air pressurization or air pressurization and water filling can be shortened, and leakage tests can be conducted in a short time. When performing a leak test on two, three, or all main steam isolation valves at the same time, the appropriate stop valves 18 to 2
Of course, it is sufficient to select 1 as appropriate and open it.

It should be noted that the present invention is not limited to the embodiments described above and shown in the drawings, but can of course be implemented with various modifications without changing the gist thereof.

As explained above, according to the present invention, the stop valves of the inner main steam drain piping provided in each of the plurality of inner main steam isolation valves are appropriately selected, and By pressurizing only the main steam isolation valves with air or pressurizing them with air and filling them with water, it is possible to conduct a leakage test on only the predetermined main steam isolation valves in a short period of time.

[Brief explanation of drawings]

The accompanying drawing is a piping system diagram of an apparatus for carrying out an embodiment of the main steam isolation valve leakage testing method for a nuclear reactor according to the present invention. 1...Reactor pressure vessel, 2-5...Main steam pipe, 2a
~5a... Inter-valve main steam pipe, 6-9... Inner main steam isolation valve, 10-13... Outer main steam isolation valve, 14-17
...Inner main steam drain piping, 18-21...stop valve,
22... Integrated main steam drain piping, 25-28... Outer main steam drain piping, 29... Reactor containment vessel wall, 3
0-33...Pressure measuring device, 34-37...Lid.

Claims (1)

[Claims] 1. A plurality of main steam pipes are connected to the reactor pressure vessel of a boiling water reactor, penetrate the reactor containment vessel wall, and provide main steam isolation valves inside and outside of the penetration part. In a test device for detecting leakage when the main steam isolation valve of a device that supplies steam to a turbine is closed, each inner main steam isolation valve is provided with an inner main steam drain exhaust pipe, which is connected to a stop valve. each outer main steam isolation valve is provided with an outer main steam drain pipe having a pressure measuring device, and the reactor pressure vessel of the main steam pipe communicating with the inner main steam isolation valve is connected to the integrated main steam drain piping through the A main steam isolation valve leakage testing device for a nuclear reactor, characterized in that an inner opening is provided with a lid that is covered during a leakage test. 2 A plurality of main steam pipes are connected to the reactor pressure vessel of a boiling water reactor, and these pipes penetrate the reactor containment vessel wall, and main steam isolation valves are installed inside and outside the penetration part to supply steam to the turbine. In the test method for detecting leakage when the main steam isolation valve of a device is closed, each inner main steam isolation valve is provided with an inner main steam drain drain pipe, which is connected to the integrated main steam through a stop valve. Each outer main steam isolation valve is connected to a drain pipe, and each outer main steam isolation valve is provided with an outer main steam drain pipe having a pressure measuring device, and the opening in the reactor pressure vessel of the main steam pipe communicating with a predetermined inner main steam isolation valve is cover, select the stop valve, pressurize air or pressurize air and fill with water from a predetermined main steam drain pipe to the predetermined inner main steam isolation valve, and use the pressure measuring device to A method for testing a main steam isolation valve for a nuclear reactor, characterized by detecting leakage in a steam isolation valve or an outer main steam isolation valve communicating therewith. 3. When performing a leakage test on the inner main steam isolation valve,
The inner main steam isolation valve and the outer main steam isolation valve connected thereto are closed, and the main steam pipe on the reactor pressure vessel side is pressurized with air from the inner main steam isolation valve to detect leakage. A main steam isolation valve leak test method for a nuclear reactor as described in Scope 2. 4 When performing a leakage test on the outer main steam isolation valve,
The outer main steam isolation valve and the inner main steam isolation valve connected to it are closed, and after the main steam pipe on the reactor pressure vessel side is pressurized with air and filled with water from the inner main steam isolation valve, the outer main steam drain pipe is connected between the valves. 3. A method for testing leakage of a main steam isolation valve in a nuclear reactor according to claim 2, wherein leakage is detected by pressurizing the main steam pipe of a nuclear reactor.