JP4254961B2 - Overflow check valve operation inspection method - Google Patents

Description

The present invention relates to an overflow prevention valve provided in an instrumentation pipe downstream of a penetration attached to a nuclear reactor containment vessel, and more specifically, an operation for confirming whether or not the overflow prevention valve operates normally. about the work dynamic test how the over-flow prevention valve to perform the inspection.

  The instrumentation piping on the downstream side of the penetration attached to the reactor containment vessel (in other words, outside the reactor containment vessel) is provided with a main valve and an overflow prevention valve as isolation valves, and a pressure gauge on the downstream side And instruments such as a differential pressure gauge are connected. The overflow prevention valve includes, for example, a valve body disposed in a valve chamber of a casing, a spring that applies an elastic biasing force in a direction in which the valve body is separated from the valve seat, and a valve body in a direction in which the valve body is in proximity to the valve seat. A magnetic body for applying a magnetic urging force, and the valve body is moved by a balance of the elastic urging force of the spring, the magnetic urging force of the magnetic body, and the pressure of the flowing water. And when the pressure of the flowing water (in other words, the differential pressure across the overflow prevention valve for flowing water) becomes equal to or higher than a predetermined set pressure (for example, about several tens of kPa), the overflow prevention valve The instrumentation piping is cut off by sitting on the seat. As a result, for example, when a leakage accident occurs in an instrumentation pipe and an instrument, water from the piping in the reactor pressure vessel and the reactor containment vessel is prevented from flowing out to the outside.

  In addition, the amount of leakage during operation described above is strictly defined in the overflow prevention valve, and in particular, since the gap between the valve chamber wall of the casing and the valve body is very narrow, foreign matter or the like is caught in the gap. May cause malfunction. Therefore, an operation inspection is periodically performed to confirm whether or not the overflow prevention valve operates normally. The operation check of the overflow prevention valve is performed in a reactor that can obtain a sufficient head pressure upstream of the overflow prevention valve, for example, so that the differential pressure that is the operation condition of the overflow prevention valve can be sufficiently secured. This was done during the pressure test of the pressure vessel. In general, the pressure resistance test of the reactor pressure vessel is performed just before the end of the regular equipment inspection, and the timing of performing the operation check of the overflow prevention valve is also constrained just before the end of the regular equipment inspection. Therefore, when a malfunction of the overflow prevention valve is found, there is a possibility that the equipment inspection period must be extended in order to perform an overhaul check of the overflow prevention valve.

  Therefore, in order to cope with this, the original valve for testing provided in the instrumentation piping on the downstream side of the penetration is connected to this original valve for testing via a connection hose, etc., and the overflow prevention valve is opened by supplying water into the instrumentation piping. In addition, a configuration including a test device (water supply / drainage device) that drains water from the instrumentation pipe and closes the overflow prevention valve has been proposed (for example, see Patent Document 1). This test apparatus includes a cylinder connected to the connection hose via a switching valve, a piston that reciprocates in the cylinder, a piston rod connected to the back of the piston, a motor, and rotational power of the motor. A clutch mechanism and rack and pinion that convert to linear motion and transmit it to the piston rod, a spring that gives an elastic biasing force to return the piston, a pipe that injects water into the cylinder, and this pipe It has a water injection valve.

  When the operation check of the overflow prevention valve is performed using the test device, first, the test device is connected to the test valve of the instrumentation pipe via the connection hose, the switching valve of the test device is closed, and the piston Water is poured into the cylinder in a state where is moved backward (retracted). Then, after the cylinder is full of water, for example, the switching valve is opened, the clutch mechanism is connected, and the piston is moved forward (forward) to inject water into the instrumentation pipe. The water in the vicinity of the overflow prevention valve is replaced with clean water. Thereafter, when the clutch mechanism is released, the piston in the cylinder rapidly moves back due to the elastic biasing force of the spring, and the water in the instrumentation pipe is sucked into the cylinder. Whether or not the overflow prevention valve operates in the shut-off state when this suction action creates a differential pressure before and after the overflow prevention valve, and the differential pressure is equal to or higher than the predetermined set pressure that is the operating condition of the overflow prevention valve. Whether or not it is confirmed by an open / close indicator or the like is inspected.

JP-A-8-247899

However, the above prior art has room for improvement as follows.
That is, in the above test apparatus, the piston rapidly moves back due to the elastic biasing force of the spring when the clutch mechanism is released, and the water in the instrumentation pipe is generated by the water absorption force (in other words, the reduced pressure generated in the cylinder). Is supposed to suck. Then, before and after the overflow prevention valve, a differential pressure corresponding to the upstream pressure and the water absorption force by the test apparatus is generated. Here, although the upstream pressure of the overflow prevention valve varies depending on the upstream water level of the overflow prevention valve, the installation position of the instrumentation piping, etc., the water absorption force by the above test device is fixed by the elastic biasing force of the spring. Has been. Therefore, in the above prior art, for example, when the upstream pressure of the overflow prevention valve is low, the differential pressure across the overflow prevention valve does not reach the predetermined set pressure of the operating condition due to insufficient water absorption by the test device. In such a case, there is no choice but to carry out the above-mentioned operation inspection at a time when the upstream pressure of the overflow prevention valve becomes high, or to overhaul the overflow prevention valve. However, if the water absorption force by the test device is increased so that the above operation inspection can be performed even when the upstream pressure of the overflow prevention valve is low, for example, when the upstream pressure of the overflow prevention valve is high, the pressure is more than necessary Was added to the instrumentation piping, etc., and there was a need to worry about the occurrence of seat leaks such as valves in the instrumentation piping.

An object of the present invention, regardless of the level of the upstream side pressure of the over-flow blocking valve is to provide a work dynamic test how the over-flow blocking valve can be performed operation test of the over-flow blocking valve.

To achieve the above Symbol object, the present invention is, in the operating method of inspecting over flow blocking valve to perform the operation test of the over-flow blocking valve provided on the penetration downstream of instrumentation pipe of which is attached to the containment vessel A drainage device having a tank and a vacuum pump is connected to the downstream side of the overflow prevention valve in the instrumentation pipe, and the open / close valve provided in the first pipe line between the instrumentation pipe and the tank is closed. In a state, the gate valve provided in the second pipe line between the tank and the vacuum pump is opened, and the vacuum pump is driven to adjust the pressure so that the inside of the tank has a desired pressure . By switching the open / close valve to the open state and the gate valve to the closed state, the water in the instrumentation pipe is drained into the tank, and the operation check of the overflow prevention valve is performed.

According to the present invention, the operation check of the overflow prevention valve can be performed regardless of the level of the upstream pressure of the overflow prevention valve.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic view showing an embodiment of an overflow prevention valve operation inspection system according to the present invention together with the entire configuration of instrumentation piping. In the following, the filled valve shown in the figure represents the closed state, and the white valve represents the opened state.

  In FIG. 1, a penetration 3 attached so as to penetrate the reactor containment vessel 1 and the reactor containment shield 2 is connected to the upstream side (left side in FIG. 1) of the penetration 3 from the reactor pressure vessel 4. An instrumentation pipe 5, an instrument 7 such as a pressure gauge and a differential pressure gauge disposed in the instrument rack 6, an instrument 7 in the instrument rack 6 from the downstream side (right side in FIG. 1) of the penetration 3, and An instrumentation pipe 9 connected to the drain header 8 is provided.

  The instrumentation pipe 9 includes a pipe line 10 connected from the penetration 4 to the drain header 8, and a measurement pipe line 11 branched from the pipe line 10 and connected to the instrument 7. The pipe 10 is provided with a main valve 12, an overflow prevention valve 13, a rack inlet valve 14, and blow valves 15 and 16 in that order toward the downstream side, and the measurement pipe 11 is connected to the pipe 10. Is branched between the rack inlet valve 14 and the blow valve 15. A meter inlet valve 17 is provided in the measurement pipe 11, and a meter test valve 18 for meter calibration is branched and connected between the meter inlet valve 17 and the meter 7.

  A drain receiving port 21 is connected to one side (left side in FIG. 1) of the drain header 8 via a drain valve 19 and a drain pipe 20, and a water filling valve 22 is connected to the other side (right side in FIG. 1) of the drain header 8. And a water filling device (not shown) is connected through the water filling pipe 23.

  The overflow prevention valve 13 is known as this type, and for example, the pressure of the flowing water (in other words, the differential pressure before and after the water flows) exceeds a predetermined set pressure (for example, about several tens of kPa). Then, the pipe line 10 of the instrumentation pipe 9 is cut off. Normally, the main valve 12, the rack inlet valve 14, the instrument inlet valve 17, and the drain valve 19 are in an open state, and the instrument test valve 18, blow valves 15, 16 and the water filling valve 22 are in a closed state (described later). 2).

  Here, as a major feature of the present embodiment, for example, an inspection connection port 24 is provided between the branch portion of the measurement pipe 11 in the pipe 10 of the instrumentation pipe 9 and the blow valve 15 by a T-shaped joint or the like. A drainage device 26 is connected to the inspection connection port 24 via a connection pipe 25 (for example, a connection hose). In general, a closing plug 27 (see FIG. 2 described later) is attached to the inspection connection port 24 of the instrumentation pipe 9 instead of the connection pipe 25.

  The drainage device 26 includes a connection port 28 to which the connection pipe 25 can be connected, a tank 30 connected to the connection port 28 via a pipeline 29, and a device inlet valve (open / close valve) 31 that communicates and blocks the pipeline 29. And a vacuum pump 34 connected to the tank 30 via a pipe line 32 and a pump gate valve 33, a pipe 35 branched from the pipe line 32 and a pressure gauge gate valve 36, and the pressure in the tank 30. Is provided with a pressure gauge 37, a discharge line 38 connected to the lower side of the tank 30, and a discharge valve 39 provided in the drain line 38.

  Then, the pressure in the tank 30 is reduced by driving the vacuum pump 34 with the apparatus inlet valve 31 and the discharge valve 39 closed and the pump gate valve 33 and pressure gauge gate valve 36 opened. It has become. At this time, the inspector drives and stops the vacuum pump 34 while confirming the pressure in the tank 30 with the pressure gauge 37, thereby adjusting the pressure so that the inside of the tank 30 becomes a desired pressure. Further, by closing the pump gate valve 33, the pressure gauge gate valve 36, and the discharge valve 39 and opening the device inlet valve 31, the water in the instrumentation pipe 9 is connected to the inspection connection port 24. The water is drained into the tank 30 through the pipe 25, the connection port 28, the pipe line 29, and the apparatus inlet valve 31. Thereafter, the device inlet valve 31, the pump gate valve 33, and the pressure gauge gate valve 36 are closed, and the discharge valve 39 is opened, so that the water in the tank 30 flows into the discharge pipe 38 and the discharge valve 39. It is discharged to a recovery container or the like (not shown).

  Next, the operation check method for the overflow prevention valve in this embodiment will be described with reference to FIGS. 2 and 3 and FIG.

  First, normally, a closing plug 27 is attached to the inspection connection port 24 of the instrumentation pipe 9, and the main valve 12, the rack inlet valve 14, the instrument inlet valve 17, and the drain valve 19 of the instrumentation pipe 9 are in an open state. The instrument test valve 18, the blow valves 15 and 16, and the water filling valve 22 are closed (see FIG. 2). The inspector removes the closing plug 27 from the inspection connection port 24 of the instrumentation pipe 9 for the purpose of inspecting the operation of the overflow prevention valve 13, and the drainage device is connected to the inspection connection port 24 via the connection pipe 25. 26 is connected (see FIG. 1). At this time, the pump gate valve 33 and the pressure gauge gate valve 36 in the drainage device 26 are opened, and the device inlet valve 31 and the discharge valve 39 are closed. In order to protect the instrument 7, the inspector switches the instrument inlet valve 17 of the instrumentation pipe 9 to the closed state and the instrument test valve 18 to the opened state.

  The inspector then depressurizes the tank 30 by driving the vacuum pump 34 with the apparatus inlet valve 31 of the drainage apparatus 26 closed. After that, when the inspector confirms that the pressure in the tank 30 becomes a desired pressure with the pressure gauge 37, the inspector stops the vacuum pump 34, and switches the pump gate valve 33 and the pressure gauge gate valve 36 to the closed state. When the inspector switches the pump gate valve 33 and the pressure gauge gate valve 36 of the drainage device 26 to the closed state and further switches the device inlet valve 31 to the open state (see FIG. 3), the instrumentation pipe 9 The water from the drain is drained into the tank 30 through the connection pipe 25 and the apparatus inlet valve 31 and the like, and upstream and downstream pressures (for example, water head pressure) and the reduced pressure in the tank 30 before and after the overflow prevention valve 13. A differential pressure according to the pressure is generated. At that time, the inspector checks whether or not the overflow prevention valve 13 is operated in the shut-off state by checking with an open / close indicator or the like (not shown).

  After the operation inspection of the overflow prevention valve 13 is completed, the inspector switches the apparatus inlet valve 31 of the drainage device 26 and the rack inlet valve 14 of the instrumentation pipe 9 to the closed state, and from the inspection connection port 24 of the instrumentation pipe 9. The connection pipe 25 is removed, and a closing plug 27 is attached to the inspection connection port 24. The inspector first switches the instrument test valve 18 to the closed state and switches the instrument inlet valve 17 and the rack inlet valve 14 to the open state in order to fill the instrumentation pipe 9 with water. Thereafter, the inspector switches the drain valve 19 to the closed state, further switches the water filling valve 22 and the blow valves 15 and 16 to the open state, and fills the instrumentation pipe 9 with the water filling device. After completion of water filling of the instrumentation pipe 9, the inspector switches the water filling valve 22 and the blow valves 15 and 16 to the closed state, and further switches the drain valve 19 to the open state (returns to the state shown in FIG. 2).

  As described above, in the present embodiment, when the device inlet valve 31 of the drainage device 26 is switched to the open state, the differential pressure generated before and after the overflow prevention valve 13 reaches a predetermined set pressure that is an operating condition. The pressure in the tank 30 of the drainage device 26 can be adjusted under reduced pressure according to the upstream pressure of the overflow prevention valve 13. Thereby, for example, when the upstream pressure of the overflow prevention valve 13 is low, the pressure reduction is adjusted so that the pressure in the stagnation tank 30 becomes low. Therefore, the differential pressure that is the operating condition of the overflow prevention valve 13 is reduced. In this case, it is possible to check and check whether or not the overflow prevention valve 13 has been operated. Further, for example, even when the upstream pressure of the overflow prevention valve 13 is high, the differential pressure across the overflow prevention valve 13 can be set to the above-mentioned predetermined set pressure, and an excessive pressure is applied to the instrumentation pipe 9 and the like. In addition, it is possible to reduce the occurrence of seat leak in the valves of the instrumentation pipe 9 (for example, the main valve 12, the rack inlet valve 14, the instrument inlet valve 17, the blow valve 15 and the like). Therefore, in the present embodiment, the operation check of the overflow prevention valve 13 can be performed regardless of the level of the upstream pressure of the overflow prevention valve 13. Therefore, the operation check of the overflow prevention valve 13 can be performed at an arbitrary time.

  By the way, for the purpose of replacing the water in the vicinity of the overflow prevention valve 13 in the instrumentation pipe 9 with clean water before the operation check of the overflow prevention valve 13 is started, for example, water is supplied to the water supply tank and the water supply tank. A case is assumed in which water injection means for supplying water and water supply means for supplying water in the water supply tank to the instrumentation pipe 9 are provided. In such a case, it is necessary to make the capacity of the water supply tank relatively large in order to cope with the capacity of various instrumentation pipes 9, and the entire apparatus equipped with the water supply tank etc. is enlarged and its carrying labor increases. It is easy to think about. In particular, the number of overflow prevention valves 13 installed is an enormous number of about 80 or more on average although it varies depending on the output of each power generation facility. In the drainage device 26 of the present embodiment, the above-described water supply tank or the like is not provided, and the capacity of the tank 30 into which the water from the instrumentation pipe 9 flows is sufficiently large considering the operation response of the overflow prevention valve 13. Therefore, the entire drainage device 26 can be reduced in size, and the carrying labor can be reduced. In practice, since the water in the instrumentation pipe 9 is replaced with clean water after the calibration work of the instrument 7, it is sufficient if the operation check of the above-described overflow prevention valve 13 is performed thereafter. Further, the drainage device 26 of the present embodiment can be configured with off-the-shelf parts such as the tank 30 and the vacuum pump 34, and the cost can be reduced.

  In the above embodiment, the drainage device 26 has been described by taking as an example a configuration in which the inspector checks and confirms the pressure in the tank 30 with the pressure gauge 37, and drives and stops the vacuum pump 34. Not limited. That is, for example, an input means for setting and inputting a desired pressure in the tank 30; a pressure sensor for detecting the pressure in the tank 30; and an input signal from the setting input means and a detection signal from the pressure sensor. It is good also as a structure provided with the controller which controls drive. In such a case, the same effect as described above can be obtained.

  In the above embodiment, the inspection connection port 24 of the instrumentation pipe 9 has been described as an example in which the inspection connection port 24 is provided between the branch portion of the measurement pipe 11 in the pipe 10 and the blow valve 15. Not limited to this. That is, the inspection connection port 24 of the instrumentation pipe 9 is preferably provided close to the overflow prevention valve 13 from the viewpoint of pressure loss, and may be provided, for example, on the upstream side of the rack inlet valve 14 in the conduit 10. In this case, the same effect as described above can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic showing one Embodiment of the overflow prevention valve action inspection system of this invention with the whole structure of instrumentation piping. It is the schematic for demonstrating one Embodiment of the operation | movement inspection method of the overflow prevention valve of this invention, and represents the state by which the drainage device is not connected to instrumentation piping. It is the schematic for demonstrating one Embodiment of the operation | movement inspection method of the overflow prevention valve of this invention, and represents the state by which the water from an instrumentation piping is drained by the drainage apparatus.

Explanation of symbols

1 Reactor containment vessel 3 Penetration 9 Instrumentation piping 13 Overflow prevention valve 24 Connection port for inspection (connecting means)
25 Connection piping (connection means)
26 Drainage device (drainage means)
30 Tank 31 Inlet valve (open / close valve)
34 Vacuum pump 37 Pressure gauge

Claims (1)

In the operation check method of the overflow prevention valve that performs the operation inspection of the overflow prevention valve provided in the instrumentation piping downstream of the penetration attached to the reactor containment vessel,
A drainage device having a tank and a vacuum pump is connected to the downstream side of the overflow prevention valve in the instrumentation piping,
The on-off valve provided in the first pipe line between the instrumentation pipe and the tank is closed, and the gate valve provided in the second pipe line between the tank and the vacuum pump is opened, and the vacuum Drive the pump and adjust the pressure so that the tank has the desired pressure,
Thereafter, by switching the open / close valve to the open state and the gate valve to the closed state, water in the instrumentation pipe is drained into the tank, and the operation check of the overflow prevention valve is performed. How to check the operation of the flow check valve.

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