KR100348973B1 - Satety valve tester for pressurizer in atomic reactor - Google Patents

Abstract

The present invention relates to a safety valve test apparatus for the set pressure test and adjustment of the pressurizer (PRESSURIZER) to maintain a constant pressure of the reactor coolant system in response to the secondary output fluctuations of the pressurized water reactor type nuclear power plant.

Conventionally, the use of carbon steel accumulators makes it difficult to remove iron oxide corrosive particles, which results in leakage rate increase due to deviations from allowable or repeated tests during the leakage test, and inconvenient handling due to the heavy chain. Difficult to clean, it was difficult to remove very small particles (particles) that can cause leakage.

The safety valve test apparatus body 1 of the present invention has a flange shape, and a gasket contact surface 6 and a pressure storage chamber 7 are formed at an inner central portion, and the corner of the socket 12 is coupled to the pressure storage chamber 7. The part 2 is curved, and the socket 12 is coupled to the pressurized / van detachable union 5, and the hydraulic wrench reaction plate contact portion 4 formed on the outer circumferential surface of the body 1 operates a high pressure hydraulic wrench. It is characterized in that it is processed into a structure that has a wrench torsion by force and accurate tightening pressure.

Description

Pressure valve safety valve tester {Satety valve tester for pressurizer in atomic reactor}

The present invention relates to a pressurized water reactor type nuclear power plant, and more particularly, a set pressure test of a pressurizer, which is one of pressure regulating equipments of a pressurizer that maintains a constant pressure in a reactor coolant system in response to a secondary output change. And an inspection device for checking a safety valve for adjustment and seat leakage test.

In pressurized water reactor type nuclear power plants, the performance test of the safety valve of the pressurizer system (set pressure test and adjustment of the pressurizer and seat leakage test) is performed to keep the pressure in the reactor coolant system constant.

In the past, a pressurized and vented device was added to a carbon steel accumulator manufactured by each power plant to perform set pressure test and adjustment, seat leakage test (performance test after maintenance), and operation test of the pressurizer safety valve periodically every five years. Since the sealing capacity of the seat is not confirmed after the operation test, it is separated from the system and the sheet leakage test (selected by power plant after the operation test (ASME / ANSI OMc-1990)) is performed.

As described above, performance tests on safety valves are performed in two situations. In the past, the following problems are encountered and performance tests are difficult.

That is, it is difficult to remove the iron oxide corrosion particles by using the carbon steel accumulator, which caused the leakage rate to increase due to the deviation from the tolerance during the leakage test or by repeated tests.

In addition, the test bench (TEST BENCH) is composed of a heavy weight (160KG), which was inconvenient to handle, pressurized / vent pipes are made of small holes, which is difficult to clean the inside, which can cause leakage Difficulties in removing small particles.

In addition, high torque of 3000 ft-lbs was required for the bolts fixed to the workbench for the test, but the workbench produced by itself was greatly lacking in rigidity.

Processing method after sealing gasket and surface roughness are not manufactured (restricted) according to ANSI Standard Flange standard of 6 ″ × 2500lbs. have.

Accordingly, in the present invention, in order to solve the problems of the conventional safety valve test apparatus as described above, it is possible to prevent the occurrence of oxidized corrosion, and also to remove the fine dust in the pressurized / vent pipe to the accumulator. The purpose is to make it.

In addition, the present invention is to solve the problem of stiffness and gasket sealing force in accordance with the ANSI standard code, and to prevent the foreign matter remaining in the accumulator and to facilitate the cleaning of foreign matter. It is.

In order to achieve the above object, in the present invention, the O-ring sealing device is accommodated so as to facilitate internal cleaning, and the union is detachable, and the sealing part of the body can be improved in quality and reliability based on the code. It is formed in a structure that is characterized in that it consists of a hydraulic wrench reaction plate contact portion for proper tightening pressure and easy handling, an accumulator chamber sufficient to maintain internal foreign matter remaining and pressurized pressure.

Hereinafter, with reference to the accompanying drawings, the configuration and operation effects of the present invention will be described in more detail as follows.

1 is an exemplary view of a state in which the safety valve is assembled to the test apparatus of the present invention,

Figure 2 is a cross-sectional view showing the internal structure of the test apparatus according to the present invention,

3 is an exemplary view of a removable pressurized / vant union assembly according to the present invention;

4 is another embodiment of the present invention,

※ Explanation of code for main part of drawing

1: body 2: inner corner of accumulator chamber

3: sealing cover 4: hydraulic wrench reaction plate contact

5: Removable pressure / vant union 6: Gasket contact surface

7: accumulator chamber 8: support leg

9: pressure gauge 12: socket

1 is an exemplary view of a state in which the safety valve is assembled to the inspection device of the present invention, Figure 2 is a cross-sectional view showing the internal structure of the inspection device according to the present invention.

On the upper surface of the body (1) of the inspection device according to the invention in the form of a flange to which the sealing cover (3) is fastened by eight bolts to provide a sealing force (gasket contact surface) for the seating and the system pressure of the safety valve to be tested. Consists of.

The body (1) is made of stainless steel in order to reduce the test failure and test error caused by sufficient stiffness and corrosion products during the test.

The upper surface of the body 1, that is, the contact surface 6 which is in contact with the gasket, is lathed to maintain the surface roughness (3.2 μm) of 6 ″ × 2500 lbs SA182, F316 according to the ASA B16.5 code, and is the same as the field equipment. By applying it properly, the gasket can be inspected for leaks in advance.

A separate socket 12 is coupled to the accumulator chamber 7 formed in the inner central portion of the body 1 by welding, and the socket 12 has an assembly portion in which a detachable pressure / vant union 5 is screw-assembled ( 14) is formed.

In order to prevent foreign matters from accumulating in the inner edge portion 2 of the pressure storage chamber 7 to which the socket 12 is coupled, it is processed obliquely by welding to remove and clean foreign substances.

The gasket contact surface 6 of the body 1 is provided with a sealing cover 3 having a structure surrounding it, and the sealing cover 3 is fixed to the body 1 by eight separate bolts.

The sealing cover (3) is formed of a circular cover shape of light aluminum to prevent damage to the sealing surface (gasket contact surface (6)) during external contact, foreign matter into the accumulator chamber (7) of the body (1) during storage This is to block the inflow.

The hydraulic wrench reaction plate contact portion 4 formed on the outer circumferential surface of the body 1 provides a twist prevention and accurate tightening pressure of the wrench when the reaction force caused by the bite of the wrench is applied during the operation of the high pressure hydraulic wrench, and prevents the wrench from being detached. The contact area is machined at right angles so that the hydraulic wrench reaction plate maintains contact with the hydraulic wrench vertically.

And the removable pressure / vant union (5) disassembled and assembled on the socket 12 is composed of a screw type disassembled and assembled with the socket 12 in order to facilitate the cleaning of the inside foreign matter, the union with the socket 12 In (5), two O-rings are sealed to prevent leakage due to high pressure.

CHAMBER (7) is a space sufficient to prevent the pressure drop even in the case of minute leakage to maintain the pressurized state for at least 10 minutes during the leak test (appropriate space by experiment: a diameter of 131.8 mm penetrating the upper and lower surfaces) To have a hole).

In addition, the present invention is configured to include a support leg (8) and a pressure gauge (9) for setting the pressurized pressure and leak detection so that the test device and the test valve safety valve is fixed and maintained.

Fig. 4 shows the configuration of the pressurization circuit in the case where the safety valve inspected by the test apparatus inspects using gas.

The set pressure test and adjustment of the pressurizer and the seat leakage test using the safety valve test apparatus of the present invention configured as described above are as follows.

First, the safety valve to be inspected is fixedly installed on the test apparatus body according to the present invention.

Then securely couple the removable pressure / vant union assembly to the socket 12 of the test apparatus body 1.

After the removable pressurization / vant union assembly is fitted to the test apparatus, the test is carried out by pressurizing the sheet leakage test pressure or the set pressure using a separate booster.

Thus, the present invention is easy to install the valve, satisfies the surface roughness (Seat Leakage Rate) limit in API 527, there is no gasket leakage, it is also easy to remove very small particles (particles) that can be the cause of leakage The use of stainless steel parts ensures that the retest results are inconsistent.

Therefore, in the related art, it is difficult to prepare for the test in many aspects, such as high weight, small holes for pressure / vant permanently installed in the body, and carbon steel, in which component materials can be easily corroded. It can be.

As described above, according to the present invention, the tube connected to the removable pressure / vant union can be separated by accommodating the O-ring sealing device to install the removable pressure / vant union to facilitate the internal cleaning, and the sealing portion of the body. It is possible to improve the quality and reliability of the test by installing and processing according to the code.

In addition, when the reaction force of the hydraulic wrench reaction plate of the body protrudes at a right angle, when the reaction force by the tightening force of the hydraulic wrench is applied, it is easy to prevent the wrench from twisting and provide and tighten the appropriate tightening pressure. It is composed of seals, and the use of stainless steel parts has the effect of retesting the same result without deviation.

Claims (5)

(correction) The body 1 has a flange shape, and a gasket contact surface 6 and a pressure storage chamber 7 are formed at an inner central portion, and the corner portion 2 of the socket 12 coupled to the pressure storage chamber 7 is curved. Removable pressure / vant union (5) is coupled to the socket (12), the wrench of the hydraulic wrench reaction plate contact portion (4) formed on the outer peripheral surface of the body (1) by the reaction force by the tightening force of the hydraulic wrench It is formed at right angles to the body to prevent and have an accurate tightening pressure, and the support leg 8 is fixed to the body 1 to fix and maintain the test device and the safety valve for the test object, and the removable pressure / vant union ( A pressure gauge (9) safety valve tester, characterized in that the pressure gauge (9) is installed in the tube connected to 5) for the pressure setting and leakage detection. (delete) 2. The pressurizer safety valve test apparatus according to claim 1, wherein the surface roughness of the gasket contact surface (6) is maintained at 3.2 mu m. (correction) The pressure storage chamber (7) according to claim 1, wherein the accumulator chamber (7) has a space (diameter of Ø 131.8 mm penetrating the upper and lower surfaces of the body to prevent a drop in the pressing force due to leakage so that the pressurized chamber 7 can be maintained at a pressurized state for at least 10 minutes or more during a leak test. Pressurizer safety valve test apparatus, characterized in that the (hole) having. 2. The pressurizer safety valve testing apparatus according to claim 1, wherein the body (1) is provided with a sealing cover (3) for preventing damage to the gasket contact surface (6) during storage.