JPH0521519B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a high pressure gas decompression device for leakage testing of a reactor containment vessel in a nuclear power plant.

(Prior Art) FIG. 2 shows a piping system diagram of a conventional high-pressure gas decompression device for leak testing of a reactor containment vessel. In the figure, piping 2 whose one end is connected to reactor containment vessel 1 has butterfly valves 3A, 3B, 3C, and 3 in the middle.
D, a purge exhaust fan 4, an exhaust filter casing 5 housing a prefilter 6 and a high-performance particle filter 7, a reactor building exhaust fan 8 are connected, and the other end is connected to a main exhaust stack 9.

As is well known, a leakage test of the reactor containment vessel 1 is performed during construction or every periodic inspection. The pressure of the high-pressure gas at this time is 3 to 4 kg/cm ² , but it is necessary to reduce the pressure to a steady state after the leak test is completed.

Therefore, the pressure reduction after the leakage test will be explained.
Close the butterfly valve 3B and close the butterfly valves 3C, 3.
D is fully opened, the butterfly valve 3A, which is very thin compared to the pipe 2, is gradually opened and at the same time the purge exhaust fan 4 is operated to reduce the pressure inside the reactor containment vessel 1.

In this case, since the reactor building exhaust fan 8 is always operating, the exhaust gas that has passed through the purge exhaust fan 4 is passed through the prefilter 6 and the high performance particle filter 7.
After passing through the air, dust and the like are removed, and the air is discharged into the atmosphere from the main exhaust stack 9.

(Problem to be Solved by the Invention) However, the opening degree setting of the butterfly valve 3A requires experience because it must be changed depending on the pressure state inside the reactor containment vessel 1. If 3A is opened, the pressure in the reactor containment vessel 1 will drop rapidly, which may damage the purge exhaust fan 4, prefilter 6, high-performance particle filter 7, etc., which is not preferable.

Therefore, an object of the present invention is to reduce the pressure of high-pressure gas for leak testing of reactor containment vessels, which does not damage equipment even if the butterfly valve is suddenly opened and improves system reliability. The goal is to provide equipment.

[Structure of the Invention] (Means for Solving the Problems) The present invention adjusts the pressure of high-pressure gas for leak testing of a reactor containment vessel, and passes it through a purge fan and a filter connected in series to the main exhaust stack. In this system, a pressure relief device is installed in parallel with a purge fan and a filter that are connected in series in a pressure reduction device for high pressure gas for leak testing of a reactor containment vessel.

(Function) Normally, the pressure of the high-pressure gas for leak testing is adjusted and then the pressure is released from the main exhaust stack via a purge fan and filter connected in series to reduce the pressure, but due to incorrect operation or other reasons, the pressure is not adjusted properly. In this case, the high-pressure gas for leak testing operates the pressure relief device and releases it directly from the main exhaust stack to prevent damage to the purge fan or filter.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. Note that the same parts as in FIG. 2 are denoted by the same reference numerals, and redundant explanation will be omitted.

FIG. 1 shows a piping system diagram of an embodiment of the present invention. In the same figure, a butterfly valve 3E is connected to the pipe 2 in parallel with the butterfly valve 3C, and a rapture disk 10 is connected after the butterfly valve 3E.
This Lapture disk 10 is connected to the main exhaust pipe 9 via a pipe 11. In other words, a new line is added to bypass the conventional purge exhaust fan 4, exhaust filter casing 5, and exhaust fan 8.

Next, the pressure reduction after the leakage test will be explained. Close the butterfly valve 3B and close the butterfly valves 3C, 3D,
3E is fully opened, and the butterfly valve 3A, which is much thinner than pipe 2, is gradually opened in the same way as above, and at the same time,
Operate purge exhaust fan 4. As a result, the exhaust gas enters the exhaust filter casing 5, passes through the pre-filter 6 and the high-performance particle filter 7, removes dust, etc., and then is transferred to the main exhaust stack 9 by the reactor building exhaust fan 8, which is constantly in operation. released into the atmosphere. In addition, in this case, Laputia disk 1
Although exhaust gas pressure is applied to the 0, the pressure is so small that the Lapture disk 10 will not be damaged.

However, if the butterfly valve 3A is suddenly opened for some reason, the pressure of the exhaust gas applied to the Lapcha disk 10 will also increase, and if this pressure exceeds a certain level, the Lapcha disk 10 will be damaged. Acting as a safety valve,
The purge exhaust fan 4, prefilter 6, high performance particle filter 7, and reactor building fan 8 are bypassed, and the high-pressure exhaust gas is guided directly to the main exhaust stack 9. Therefore, equipment such as the purge exhaust fan 4, pre-filter 6, high-performance particle filter 7, and reactor building exhaust fan 8 is protected from damage.

Note that after the Lapture disk 10 is damaged, the butterfly valve 3E is closed and the Lapture disk 10 is replaced with a new Lapture disk 10.

[Effects of the Invention] Since the present invention is configured as described above,
High-pressure gas can be depressurized after a reactor containment vessel leak test is completed without damaging equipment connected to the system even if the operating procedure is incorrect, improving the reliability of the system. .

[Brief explanation of the drawing]

FIG. 1 is a piping system diagram showing an embodiment of the present invention;
FIG. 2 is a piping system diagram showing a conventional pressure reducing device for leak test gas in a reactor containment vessel. 1... Reactor containment vessel, 2, 11... Piping, 3
A, 3B, 3C, 3D, 3E...Butterfly valve,
4... Purge exhaust fan, 5... Exhaust filter casing, 6... Pre-filter, 7... High performance particulate filter, 8... Reactor building exhaust fan, 9
...Main exhaust stack, 10...Teptiya disc.

Claims (1)

[Scope of Claims] 1. Leak test of reactor containment vessel in which high pressure gas for leak test of reactor containment vessel is depressurized by adjusting the pressure and releasing it from the main exhaust stack through a purge fan and filter connected in series. An apparatus for reducing the pressure of high-pressure gas for leak testing of a nuclear reactor containment vessel, characterized in that a pressure relief device is provided in parallel with the purge fan and filter connected in series. 2. A high-pressure gas decompression device for leak testing of a reactor containment vessel as set forth in claim 1, wherein the pressure relief device is a Lapture disc.