JPH0216462B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pressure test method for a feed water heater system, and more particularly to a pressure test method for a pressure system comprising a turbine feed water heater of a nuclear power plant and piping around the feed water heater.

FIG. 1 illustrates the system configuration of a conventional nuclear power plant extraction system. This system supplies the necessary amount of heated steam generated by the turbine 1 to the feed water heater 4, and also safely transfers the moisture-separated condensate in the stage of the turbine 1 to the condenser 2.
It is installed for processing inside. In this way, the piping 3 around the feed water heater is provided with (air-operated) flow control valves 6, 9, 10 and a check valve 5 for regulating the heating steam. In the illustrated example, a gate valve for separating fluid is not installed because there is no space for installing it. In such a system, if the feed water heater 4 and drain piping are modified, the pressure test conducted after the modification is to cut a part of the piping 3, weld a flange to it, and close the piping with a closing plate. It was necessary to close the cut.

By the way, as shown in FIG. 3, the steam coming out of the turbine 1 enters the valve from the left inlet of the above-mentioned (air-operated) two-seat type flow control valve, and passes through the valve ports 15 and 16. Exit the valve from the right outlet. The flow of passing steam is regulated by the vertical movement of the valve body 17, but with this type of control valve, it is extremely difficult to completely shut off the steam even when the control valve is fully closed. In addition, as shown in FIG. 5, the check valve 5 described above is designed to press the valve seat with the valve body 17 and close the valve port, but it is difficult to exhibit sufficient pressure resistance. It is. For this reason, a portion of the piping was cut as described above. In addition, in FIGS. 3 and 5, 11 is the bonnet, 12 is the valve body,
13 is a blind head, and 14 is a tightening bolt.

These conventional methods have the drawbacks of extremely low work efficiency, long construction periods, and high costs.

SUMMARY OF THE INVENTION An object of the present invention is to provide a simple pressure test method that allows rapid pressure test work and requires a small amount of expense.

That is, the present invention closes off the valve ports of each of the flow rate control valve and check valve that are pre-installed in the piping around the feed water heater using a jig that closes the valve port during on-site work, and then closes off the valve port with a jig that closes the valve port after the closure. It is characterized by forming a pressure-resistant boundary with a flow control valve and a check valve whose valve ports are closed, and measuring pressure fluctuations within a pressure-resistant area surrounded by these pressure-resistant boundaries. The valve port becomes blocked.

The present invention will be explained below based on the illustrated embodiments. An embodiment of the present invention is shown in FIGS. 2, 4, and 6. Note that parts that are the same as those in the conventional system are given the same reference numerals, and therefore their explanations will be omitted. In this embodiment, the valve ports of the flow control valves 6, 9, 10 and the check valve 5, which are installed in advance in the piping 3 around the feed water heater, are closed off using a jig 20 for closing the valve ports by on-site work. , the flow control valve 6 whose valve port is closed with these jigs 20 after closing,
9, 10 and the check valve 5 formed a pressure-resistant boundary, and pressure fluctuations within a pressure-resistant area surrounded by these pressure-resistant boundaries were measured. By doing this, the valve port is blocked by the jig 20, and there is no need to cut a part of the piping 3 as in the conventional method, allowing for quick pressure test work and at the same time reducing the necessary expenses. It is possible to obtain a simple pressure test method for a feed water heater system.

That is, as shown in FIG. 2, the piping 3 around the feed water heater 4 is provided with (air-operated) flow control valves 6, 9, 10 and a check valve 5. These individual valve ports are closed using jigs during on-site work. The jig is for valve type, pipe diameter,
Various types are used depending on the pipe internal pressure. Using these jigs, the piping 3 is divided at the positions of the flow control valves 6, 9, 10 and the check valve 5 to form pressure-resistant areas. A pressurizing device is connected to a part of this pressure-resistant area.
In the example shown in FIG. 2, a pressurizing pump 7 is used as the pressurizing device, and an operation is performed to pressurize the pressure-resistant area to a predetermined level via the main valve 23. The pressure in the pressurized pressure-resistant area is measured by a pressure gauge 8.

In this case, the flow control valves 6, 9, and 10 are modified as follows using a jig 20 as shown in FIG. explain. First, the bonnet 11 and the blind head 13 fixed with the tightening bolts 14 are removed from the valve body 12, and then the valve body 17 is removed. Next, a part of the jig 20 is inserted into the valve ports 15 and 16, and the peripheral O-rings 18 and 19 are inserted into the valve port 1.
5 and 16 are completely occluded. Jig 20 is bolt 1
4 to the valve body 12. Similarly, bolts 14 are used to secure blind head 13 to valve body 12. Thus, valve port 1
5 and 16, a reliable pressure-resistant boundary is formed.

The check valve is modified as shown in FIG. The jig 20 in this example has a function of taking a reaction force with a part of the valve body 12 and pushing the valve body 17 leftward. The valve body 17 is connected to the jig 20 via the cap 21.
By turning the rotary lever 22, the cap 21
is pushed out to the left, and the valve body 17 is fixed in pressure contact with the valve seat. In this way, the valve body 17 closes the valve port, and the valve body 17 is held by the jig 20 to exhibit sufficient pressure resistance.

After the above operations are completed, the pressure pump 7 is used to pressurize the partitioned pressure area, as shown in FIG. The pressure in the pressure-resistant area is increased to 1.5 times the maximum working pressure P, and the main valve 23 is fully closed. next,
A pressure gauge 8 measures the change in pressure in the pressure-resistant area over time. Figure 7 is a model graph explaining the time-lapse measurement method for pressure resistance tests. The pressure test takes approximately 10 minutes. If the measured pressure change decreases as shown in Figure 8, and the degree of decrease (rate of decrease) is within the decrease curve calculated from the allowable leakage of each valve, there is no leakage from the pressure-resistant area. The pressure test is deemed to have passed.

In this way, according to this embodiment, there is no need to cut the piping. By simply modifying a portion of the flow control valve and check valve, the boundary of the pressure-resistant area can be easily formed. Therefore, the pre-steps for the pressure test can be greatly simplified, and an economical pressure test method that can be performed with a small number of workers can be achieved.

The present invention is not limited to what is otherwise described.

For example, instead of the configuration shown in FIG. 4, a configuration as shown in FIG. 10 may be adopted. In this example,
Remove the valve seat rings 27, 28 from the valve ports 15, 16, and attach the closing plates 24, 25 as a jig to them.
are attached and returned to the original position of the valve port.

Moreover, the pressurization of the pressure-resistant area can of course be carried out from a position other than that shown in FIG.
As an example, as shown in FIG.
0 may be provided with a pressure conduit 26 and the pressure-tight area may be pressurized via this pressure conduit 26.

As mentioned above, according to the present invention, the pressure-resistant system to be tested can be partitioned very easily to form a pressure-resistant test area, and the present invention is far superior to conventional methods in terms of speeding up and simplifying the construction work. . Therefore,
The testing period has been significantly shortened, and the cost-restricting effects are also extremely noticeable. The economic effects are noteworthy.

[Brief explanation of drawings]

Fig. 1 is a flowchart showing a piping system of a conventional feed water heater system, Fig. 2 is a flowchart showing an example of a piping system to which the pressure test method according to the present invention is applied, and Fig. 3 is a flowchart showing a piping system of a conventional (air (Operation) A vertical cross-sectional view showing an example of the structure of a two-seat type flow control valve. Fig. 4 is a longitudinal cross-sectional view showing an example of a structure in which a jig is incorporated into the control valve of Fig. FIG. 6 is a vertical cross-sectional view showing an example of a structure of a valve, FIG. 6 is a vertical cross-sectional view showing an example of a structure in which a jig is incorporated into the check valve of FIG. 5, and FIGS. 7 and 8 are a pressure test method according to the present invention. Fig. 9 is a vertical sectional view showing a modification of Fig. 4, and Fig. 10 is another configuration example in which a jig is incorporated into the control valve of Fig. 3. FIG. 1... Turbine, 3... Piping, 4... Feed water heater, 5
... Check valve, 7 ... Pressure pump (pressurization device), 6, 9,
10...Flow control valve, 15, 16...Valve port, 20
... jig, 24, 25... jig (closing plate).

Claims (1)

[Scope of Claims] 1. A pressure-resistant system consisting of a turbine-type feedwater heater of a nuclear power plant and piping around the feedwater heater is isolated from the rest to form a pressure-resistant area, and a pressurizing device is installed from a part of this pressure-resistant area. In the pressure test method for the feed water heater system, which pressurizes the pressure area using a pressure gauge and at the same time installs a pressure gauge in another part of the pressure area to measure the pressure resistance performance in the area, the piping around the feed water heater is The valve ports of the flow control valves and check valves installed in advance are closed off using jigs for closing the valve ports during on-site work, and after the closure, the flow control valves and check valves are closed with these jigs. A pressure test method for water heater systems that forms pressure-resistant boundaries with valves and measures pressure fluctuations within the pressure-resistant area surrounded by these pressure-resistant boundaries. 2. In the pressure resistance test method according to claim 1, the pressure resistance test in the pressure resistance area is performed based on the pressure drop rate in the pressure resistance area and the closed valve ports of the flow control valve and the check valve. A pressure test method for a feed water heater system that compares the allowable pressure leak from the water heater system. 3. In the pressure test method according to claim 1 or 2, the flow rate control valve is a two-seat type flow rate control valve, and the jig for closing the valve port is A pressure test method for a feed water heater system that is newly installed at a valve port in place of the valve body after the valve body is removed. 4. In the pressure test method according to claim 1 or 2, the jig used for the check valve acts to press and fix the valve body of the check valve to the valve seat. Pressure test method for feed water heater system. 5. In the pressure test method according to claim 3, the jig is provided with a pressurizing conduit that communicates with the pressure-resistant area, and the feed water heater system is pressurized in the pressure-resistant area through the pressurizing conduit. Pressure test method.