JPH02234095A - Pressure testing method for steam relief pipe system of nuclear reactor pressure vessel - Google Patents

Abstract

PURPOSE:To perform the pressure test in a lump by closing up a steam emission hole of a quencher arm, and thereafter, filling a steam relief pipe system with water, freezing a base part of the quencher arm by a refrigerant and forming an ice plug. CONSTITUTION:By winding an adhesive tape 35 to the outside surface of a part in which a steam emission hole 9 of a quencher arm 21 of a quencher 11 is opened, the hole 9 is closed up airtightly. Subsequently, a steam relief pipe system 15 is filled with water. Next, dry ice is brought into contact with the outside peripheral part of a base part 36 of the arm 21 and frozen, and in the arm 21, an ice plug 37 for standing test pressure is formed. The base part 36 is positioned in the outside from a weld zone 31 of a quencher body 20 and the arm 21. Thereafter, the pressure test is executed by applying hydraulic pressure to the pipe system 15. That is, the test is executed in a lump to the weld zone 31, a weld zone 32 of the body 20 and a fitting pipe 22, a tie-in weld zone 33 of a steam relief pipe 8 and the body 20, and all weld zones formed on the pipe 8. In the end, the plug 37 is heated and melted, the tape 35 is removed, and water in the pipe system 15 is discharged, by which the test is ended.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pressure test method for a steam relief pipe system in which a pressure test is performed on all welded parts of a steam relief pipe system in a nuclear reactor pressure vessel at once. [Prior art] In general, a type of nuclear reactor containment vessel as shown in FIGS. 2 and 3 is known.
This reactor containment vessel 1 has four main steam lines installed in order to transfer steam generated in a reactor pressure vessel 2 installed inside the reactor vessel 1 to a power generation turbine 7 installed outside the containment vessel 1. Pipe 6 is connected. Each main steam pipe 6 is interposed with a plurality of safety valves 10 having different set pressures, which release excess steam when the steam pressure generated in the pressure vessel 2 exceeds a predetermined pressure. A steam relief pipe 8 is connected to each of the safety valves 10, and a quencher 11 having a large number of steam release holes 9 is immersed in the pool water 12 of the pressure suppression chamber 4 at the extending end of the steam relief pipe 8. They are arranged in piles. Therefore, the excess steam released from the safety valve 10 flows through the steam relief pipe 8 and is discharged from the quencher 11 to the boule water 12 in the pressure suppression chamber 4, where it is cooled and condensed. At the time of inspection or periodic inspection, a pressure test is performed on the welded portion of the steam relief pipe system 15 consisting of the steam relief pipe 8 and the quencher 11. Conventionally, the steam relief pipe is assembled at the construction site of the reactor pressure vessel. In the system 15, since the steam release hole 9 was opened in the quencher 11, a pressure test could not be performed after the quencher 11 was welded and connected.

After welding the quencher 11 to the extending end of the steam relief pipe 15, it may be possible to attach a pressure-resistant cap to the quencher 11 to cover the steam release hole 9. However, as shown in FIG. There is a short gap between the quenchers 11 installed next to each other! ! DI, I was unable to attach the above pressure cap to this quencher 11. Therefore, the pressure test of the quencher 11 was conducted as shown in FIG. First, the quencher arm 21 is attached to the cylindrical pressure-resistant cap 2.
4 to completely cover the steam release hole 9 of this arm 21, and weld this cap 24 to the base of the arm 21.
A mounting pipe 22 welded to the quencher body 20
A cap 25 with a test jig is attached to the upper opening 23, and hydraulic pressure or the like is applied inside the quencher 11, and the welded part 31 between the quencher body 20 and the arm 21, and the quencher body 20 and the mounting pipe 22 are removed. A pressure test was being carried out on the welded part 32. After this test, the cap 25 with the test jig is
Then, the pressure cap 24 is removed, and the pressure test of the quencher 11 is completed. Further, the pressure test of the welded portion of the steam relief pipe 8 is carried out on-site after the steam relief pipe 8 is attached to the safety valve 10 of the main steam pipe 6 as shown in FIG. As shown in the figure, this test is carried out by attaching a test cap 25 to the lower opening 34 of the steam relief pipe 8, sealing the steam relief pipe 8, and applying hydraulic pressure or the like. After this liquor pressure test, the test cap 25 is removed. Then, the upper opening 23 of the quencher 11 is welded to the lower opening 34 of this steam relief pipe 8, and the relief pipe 8 and the quencher 11 are connected.
was formed. That is, the pressure test of the quencher 11 was carried out at its assembly factory, and the pressure test of the steam relief pipe 8 connected to the safety valve 10 was carried out on site. [Problems to be Solved by the Invention] However, when inspecting the joint between the steam relief pipe 8 and the quencher 11, it is not possible to perform a pressure test as described above.
There was a problem in that non-destructive inspections such as X-rays, magnetic deep scratches, and color checks had to be performed on behalf of the company. In addition, since non-destructive testing was performed on behalf of the company, arranging testing equipment and workers was complicated. Furthermore, for the pressure test of the quencher 11, a pressure cap 24 is required to seal the steam exhaust hole 9 of the quencher arm 21, and it takes a lot of man-hours to weld the pressure cap 24 to the quencher 11 and remove it. There was a problem. The present invention was made to solve these problems, and its purpose is to connect a steam relief pipe and a quencher to form a steam relief pipe system, and then, at the construction site of a nuclear reactor, The object of the present invention is to provide a pressure resistance test method for a steam relief pipe system of a reactor pressure vessel, which allows the pressure resistance test of this steam relief pipe system to be performed all at once. [Means for Solving the Problems] In order to achieve the above object, the present invention provides a steam pipe that supplies steam from the reactor pressure vessel to the turbine with a steam relief valve that connects the steam pipe to the pool water in the suppression chamber via a safety valve. In the pressure test method for a steam relief pipe system, a quencher is integrally welded to the lower end of the steam relief pipe using adhesive tape, etc., and the steam release hole of the quencher is hermetically closed. After filling the relief pipe system with water and freezing the base of each arm of the quencher with refrigerant to form an ice plug, perform a pressure test on all welded parts of the steam relief pipe system. [Function] By forming an ice plug at the base of the quencher arm that is welded to the steam relief pipe, the portion of the quencher arm where the steam release hole is formed is separated from the steam relief piping system, and a pressure test is performed. The pressure-resistant fluid will not leak from the steam release hole. Therefore, a pressure test can be performed even if the joint between the steam relief pipe and the quencher is welded. In this way, the pressure resistance test of the steam relief pipe system can be carried out all at once at the reactor construction site, reducing the pressure resistance test of the quencher that uses a pressure cap at the assembly plant, and reducing the welded part between the steam relief pipe and the quencher. , it is possible to perform a regular pressure test without having to use a non-destructive test instead. In addition, it is possible to make effective use of equipment and workers for pressure tests. [Example] A preferred embodiment of the present invention will be described based on the drawings. The steam relief pipe 8 to which the liquor pressure test method according to this example is applied is constructed as shown in FIG. 1. This steam relief pipe 8 is shown in FIG. 2 and is connected to four main steam pipes 6 arranged to send steam from the reactor pressure vessel 2 to the power generation turbine 7, similar to the one described as the prior art. It is connected to a plurality of safety valves 10 which are provided to release excess pressure steam. Quencher 11 is assembled at an assembly factory. Quencher arms 21 are welded to both end ports of a quencher body 20 that forms this quencher 11 to form a welded portion 31. This quencher arm 21 is provided with an appropriate number of steam release holes 9 for releasing excess steam. Further, the mounting pipe 22 is welded to the upper opening of the quencher body 20 to form a welded portion 32. This quencher 11 is transported to the reactor construction site without undergoing a pressure test at the assembly plant. At this construction site, a safety valve 10 installed in the main steam pipe 6
A steam relief pipe 8 is connected to the steam relief pipe 8, and the upper opening 23 of the quencher 11 is integrally welded to the lower end portion 34 of this steam relief pipe 8 to form a welded portion 33, thereby forming a steam relief pipe system 15. ．． Adhesive tape 35 or the like is wrapped multiple times around the outer surface of the portion of the quencher arm 21 where the steam release hole 9 is opened, to airtightly close the release hole 9. Then, this steam relief pipe system 15 is filled with water. This water does not leak because the steam release hole 9 is closed. Next, a refrigerant such as dry ice is brought into contact with the outer periphery of the base 36 of the quencher arm 21 of the quencher 11 and frozen to form an ice plug 37 within the quencher arm 21. , located outward from the welded part 31 between the quencher 11 and the quencher arm 21. By freezing this base 36, a strong ice plug 37 that can withstand the pressure of the pressure test is formed in the base 36 of the quencher arm 21. Thereafter, water pressure is applied to this steam relief pipe system 15 to perform a pressure resistance test.
This liquor pressure test was carried out on the welded part 31 between the quencher body 20 and the quencher arm 21, the welded part 32 between the body 20 and the attachment pipe 22, and the steam relief pipe 8 and quencher 20, which had been conventionally performed by non-destructive inspection. All welds formed on the joint weld 33 and the steam release pipe 8 are performed at once. After this pressure test, the ice plug 37 of the quencher arm 21 is heated and melted, the adhesive tape 35 is removed, and the water in the steam release pipe system 15 is discharged to complete the pressure test. This pressure test method for the steam relief pipe system 15 is performed by forming an ice plug 37 at the base of the quencher arm 21 of a plurality of steam relief pipe systems 15 connected to the main steam pipe 6. This can be done by [Effects of the Invention] According to the present invention, the pressure resistance test of the steam relief pipe system is conducted at the construction site of the nuclear reactor by forming an ice plug on the quencher arm. All of the relief pipe system welds can be welded at once. Therefore, there is no need to use a pressure cap for the pressure resistance test of the quencher, and the pressure resistance test of the welded joint between the steam relief pipe and the quencher can be conducted using a regular pressure test instead of using non-destructive testing. Furthermore, equipment and workers for pressure tests can be used effectively.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an example of a steam relief pipe system for carrying out the method of the present invention, FIG. 2 is a cross-sectional view of a reactor containment vessel in which a conventional steam relief pipe system is arranged, and FIG. ■1■ of figure 2
4 is a configuration diagram of a steam relief pipe system for carrying out a conventional pressure test. In the figure, 2 is a reactor pressure vessel, 4 is a pressure suppression chamber, 6 is a main steam pipe, and 7 is a block diagram of a steam relief pipe system for carrying out a conventional pressure test. is a turbine, 8 is a steam relief pipe, 9 is a steam release hole, 10 is a safety valve, 11 is a quencher, 12 is a pool water,
15 is a steam relief pipe system, 31, 32, 33 are welded parts, 36
is the arm base, and 37 is the ice plug. Patent applicant: Patent attorney representing Ishikawajima-Harima Heavy Industries Co., Ltd.
Nobuo Kinutani (1 other person) 3rd 4th

Claims (1)

[Claims] 1. In the pressure test method for a steam relief pipe system in which a steam relief pipe is installed in the steam pipe that supplies steam from the reactor pressure vessel to the turbine so as to reach the pool water in the pressure suppression chamber via a safety valve, the above steam relief After integrally welding a quencher to the lower end of the pipe and sealing the steam release hole of the quencher airtight with adhesive tape, etc., fill the steam release pipe system with water and freeze the base of each arm of the quencher with refrigerant. 1. A pressure resistance test method for a steam relief pipe system of a nuclear reactor pressure vessel, characterized in that after forming an ice plug, a pressure resistance test is performed on all welded parts of the steam relief pipe system.