JPH06317696A - Exhaust pipe reaction force reducing device - Google Patents

Abstract

PURPOSE:To prevent the generation of seat leak to a main steam relief safety valve by measuring and analyzing reaction caused by the heat transfer of an exhaust pipe, and moving the exhaust pipe in the direction of reducing this reaction and also repeating this movement. CONSTITUTION:When heat transfer is generated to an exhaust pipe 4, reaction by the pipe 4 is generated to a connection part between a main steam relief safety valve 1 and the pipe 4. This reaction value data is measured by a reaction measuring device 5 and sent to a diagnostic device 7. In the device 7, the optimum exhaust pipe moving quantity to minimize the reaction value is analyzed respectively on two horizontal directions X, Z and a vertical direction Y, and the optimum moving quantity data is transmitted to reaction reducing devices 9-11, supporting the pipe 4, through a transmission device 8. On the basis of this optimum moving quantity, the devices 9-11 are expanded/ contracted to exert moving action on the pipe 4 through the transmission device 8. The pipe 4 thereby moves, and the exhaust pipe reaction at the connection part between the valve 1 and the pipe 4 approaches the minimum value. This results in reducing the possibility of generating the seat leak of the valve 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a support mechanism for an exhaust pipe connected to a main steam relief valve, which is an important device in a nuclear power plant, and particularly to reduce the reaction force generated in the exhaust pipe to reduce the main steam. The present invention relates to an exhaust pipe reaction force reduction device that eliminates seat leak in a relief safety valve.

[0002]

2. Description of the Related Art A main steam relief valve is one of the important equipment of a nuclear power plant. As shown in the system configuration diagram of FIG. 5, the main steam relief safety valve 1 is installed in the reactor containment vessel (not shown) so as to be connected to the main steam pipe 2, and there is a pressure in the reactor pressure vessel 3. When it exceeds the reference value, it has an opening operation, releases steam in the reactor pressure vessel 3, and has a function of suppressing a pressure increase in the reactor pressure vessel 3.

When the main steam relief safety valve 1 is opened, the steam that has passed through the main steam relief safety valve 1 passes through an exhaust pipe 4 connected to the main steam relief safety valve 1 and enters a pressure suppression chamber called a suppression pool (not shown). Inflow.
The suppression pool is filled with a large amount of water, and the steam flowing out from the exhaust pipe 4 is cooled and condensed here.

On the other hand, in normal times, the main steam relief safety valve 1 is fully closed in order to efficiently send the steam generated in the nuclear reactor to the turbine generator (not shown).
Regarding the main steam relief safety valve 1, in order to prevent the steam in the main steam pipe 2 from leaking into the seat at the time of closing, it is currently called rubbing to enhance the tightness of the valve body of the main steam relief safety valve 1 and the seat portion. I'm working.

However, even if the valve body and the seat portion are carefully rubbed with each other, foreign matter is caught in the seat portion and occurs in the pipe connected to the main steam relief safety valve 1 when the nuclear power plant is started. A seat leak may occur in the main steam relief safety valve 1 due to the reaction force generated by the heat transfer.

Conventionally, there is a snubber as a device that absorbs a reaction force due to heat transfer of piping or the like. This snubber temporarily absorbs the instantaneous load generated by the earthquake to protect the equipment, but with regard to the gradual heat transfer that occurs as the piping system transitions from low temperature to high temperature,
This is a supporting device having a function of giving a degree of freedom to a pipe without restraining it and preventing stress from being generated in the pipe.

[0007]

However, even if the snubber is installed in the exhaust pipe 4, it does not restrain the heat transfer of the exhaust pipe 4, so that the main steam installed in the main steam pipe 2 is not restricted. It was almost impossible to reduce the reaction force generated at the connection between the relief safety valve 1 and the exhaust pipe 4 connected to it.

For this reason, there has been a demand for a measure for preventing a seat leak occurring in the main steam relief safety valve 1 due to the reaction force generated by the heat transfer of the exhaust pipe 4. The object of the present invention is to hold the exhaust pipe movably, measure the reaction force of the connection part between the main steam relief safety valve and the exhaust pipe, and in the direction in which the reaction force of this connection part is minimized. An object of the present invention is to provide an exhaust pipe reaction force reducing device that moves an exhaust pipe.

[0009]

According to the present invention, a reaction force measuring device installed near a connection portion between a main steam relief safety valve and an exhaust pipe and reaction force value data obtained by the reaction force measuring device are analyzed. And a reaction force reducing device for moving the exhaust pipe in a direction in which the reaction force is reduced based on the analysis data thereof.

[0010]

According to the present invention, the reaction force due to the heat transfer of the exhaust pipe applied to the connecting portion between the main steam relief safety valve and the exhaust pipe is measured by the reaction force measuring device and analyzed by the diagnostic device, The amount of movement that reduces the force and the command for that direction are output to each reaction force reduction device.

Based on this command, each reaction force reducing device moves the exhaust pipe, and this is repeated to finally move the exhaust pipe to a position where the exhaust pipe reaction force is minimized. This allows
No seat leak occurs in the main steam relief safety valve.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. It should be noted that the same components as those in the above-described conventional technique are designated by the same reference numerals and detailed description thereof will be omitted. As shown in the schematic configuration diagram of FIG. 1, a main steam relief valve 1 is installed on a main steam pipe 2, and a reaction force measuring device 5 is installed near a connecting portion of an exhaust pipe 4 connected to the main steam relief valve 1. ing. As shown in the sectional view taken along the line AA of FIG. 1 in FIG. 2, this reaction force measuring device 5 has a reaction force detector 6 composed of, for example, a strain gauge on the outer circumference of the exhaust pipe 4 at four locations in the circumferential direction. It is formed by mounting it on the table.

The reaction force measuring device 5 is connected to a diagnostic device 7 for analyzing the optimum movement amount of the exhaust pipe 4 and the direction in which the reaction force value becomes smaller from the measured reaction force value data.
Further, as a support mechanism of the exhaust pipe 4, two horizontal directions (X, Z)
And in the vertical direction (Y) in three directions, respectively, by a command from the diagnostic device 7 via the transmission device 8 to expand and contract.
For example, a reaction force reduction device 9 (X direction), a reaction force reduction device 10 (Y direction), and a reaction force reduction device 11 (Z direction), which are pneumatic or hydraulic cylinders, are fixedly installed in a building or the like not shown. Has been done.

In the transmission device 8, the reaction force reducing devices 9 to 11 support the exhaust pipe 4 so that it can move three-dimensionally in two horizontal and vertical directions. As shown in the side view, it is necessary to provide at least a two-dimensional degree of freedom for the attachment portion with the exhaust pipe 4 by providing a link mechanism with two rotating pins 14 and 15 having different rotating directions at right angles. is there.

The diagnostic device 7 includes a reaction force measuring device 5
Is connected to a reaction force display device 12 for displaying the reaction force value data from the above, analysis data by the diagnostic device 7, etc., and a database 13 for storing the reaction force value data and the analysis result and outputting them appropriately.

Next, the operation of the above configuration will be described. The operation flow diagram of FIG. 4 shows the flow of the operation of reducing the exhaust pipe reaction force. When heat transfer occurs in the exhaust pipe 4 at the time of starting the nuclear power plant, the main steam relief safety valve 1 and the exhaust pipe 4 are connected. A reaction force due to the exhaust pipe 4 is generated at the connecting portion. This reaction force and the reaction force value data in that direction are measured by the reaction force measuring device 5 and sent to the diagnostic device 7.

In the diagnostic device 7, the optimum exhaust pipe movement amount with which the reaction force value becomes small is analyzed in each of the two horizontal directions (X, Z) and the vertical direction (Y). The data of the optimum movement amount in the three directions is transmitted via the transmission device 8 to the exhaust pipe 4
Is transmitted to each of the reaction force reducing devices 9 to 11 supporting the.

Each of the reaction force reducing devices 9 to 11 expands and contracts based on the optimum movement amount of the exhaust pipe 4 calculated by the diagnostic device 7, and exerts a moving action on the exhaust pipe 4 via the transmission device 8.
As a result, the exhaust pipe 4 moves, but as a result, the connecting portion between the main steam relief safety valve 1 and the exhaust pipe 4 is newly added by the action exerted on the exhaust pipe 4 of each of the reaction force reducing devices 9 to 11. Reaction force is occurring. Therefore, a new action is performed on the exhaust pipe 4 based on the process described above with respect to the exhaust pipe reaction force.

By repeating this process, the exhaust pipe reaction force at the connection between the main steam relief safety valve 1 and the exhaust pipe 4 approaches the minimum value. In addition, the analysis data analyzed by the diagnostic device 7 is displayed on the reaction force display device 12 every moment and provided to the operator. The momentary analysis data and the reaction force value data input from the reaction force measuring device 5 when the reaction force of the exhaust pipe 4 finally becomes the minimum are stored.

As described above, by adopting the present invention, the exhaust pipe, which is considered to be one of the seat leak factors in the main steam relief safety valve 1 generated by the heat transfer of the exhaust pipe 4 at the time of starting the nuclear power plant, Since the exhaust pipe reaction force applied to the connection portion with 4 is reduced, the possibility of a seat leak in the main steam relief safety valve 1 is reduced.

Incidentally, FIG. 3 described above shows an example in which the transmission device 8 moves in the Y-axis direction, and a link mechanism including rotating pins 14 and 15 is provided between the exhaust pipe 4 and the transmission device 8. It is provided. This means that when the reaction force reducing device 9 in the X-axis direction operates, a moment around the Z-axis is generated in the exhaust pipe mounting portion of the transmission device 8. The pivot pin 14 pivots to cancel this moment.

Similarly, when the reaction force reducing device 11 in the Z-axis direction operates, a moment around the X-axis is generated, but this moment is canceled by the rotation of the rotating pin 15. By disposing this link mechanism at the connecting portion between the transmission device 8 and the reaction force reducing devices 9 to 11, the three-dimensional movement of the exhaust pipe 4 caused by the operation of the exhaust pipe reaction force reducing device is absorbed. It becomes possible to do.

Further, the database 13 stores the time-varying analysis data calculated by the diagnostic device 7 while the present invention is in operation, and the reaction force value data when the exhaust pipe reaction force finally becomes the minimum. Although it is saved, at the time of starting the nuclear power plant, the reaction force value data at the time of the previous start stored in the database 13 is provided to the diagnostic device 7, and the diagnostic device 7 provides the reaction force value at the present time and the value at the time of the previous start. An optimal pipe movement amount is calculated by comparing with the reaction force value, and the exhaust pipe 4 is moved in the direction in which the reaction force value is reduced by the reaction force reduction devices 9 to 11 based on this pipe movement amount.

Thus, by referring to the reaction force value up to the last plant startup, it is possible to estimate the pipe movement amount and direction this time, and to move the exhaust pipe 4 in advance based on the estimated value. As a result, it is possible to suppress the generation of an excessive reaction force in the exhaust pipe 4 during the transitional period of operation of the present invention, and it is possible to reduce the generated reaction force early.

Further, by using elastic materials such as air pressure, hydraulic pressure and springs as the transmission device drive source of the reaction force reducing devices 9 to 11, the exhaust pipe 4 is used at the time of starting the nuclear power plant.
Is used to move the plant, and on the other hand, after the plant is started, it is possible to absorb the shock load generated at the time of the earthquake. Therefore, the gentle load due to the heat transfer of the exhaust pipe 4 is positively reduced, and the shocking vibration at the time of an earthquake is absorbed though it is static.

The following are the embodiments of the present invention. “(1) An exhaust pipe reaction force reducing device according to claim 1, further comprising a reaction force display device for displaying the exhaust pipe reaction force value analyzed by the diagnostic device”.

“(2) The reaction force values analyzed every moment by the diagnostic device during operation of this device and the reaction force value data when it becomes the minimum are saved, and these data are saved at the next plant startup. The exhaust pipe reaction force reducing device according to claim 1, further comprising a database provided to the diagnostic device. [3] The exhaust pipe reaction force reducing device according to claim 1, wherein the reaction force reducing device has an elastic function.

[0028]

As described above, according to the present invention, the exhaust pipe reaction force generated by the movement due to heat at the time of startup of the nuclear power plant is positively and appropriately moved to be reduced, and the seat in the main steam relief safety valve is reduced. Since the possibility of leakage is reduced, the reliability of the sealing function of the main steam relief safety valve is improved, and the burden on operators and maintenance personnel is reduced. Further, since vibration generated in the exhaust pipe during an earthquake is also absorbed, there is an effect that the installation space for the exhaust pipe support and the like can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an exhaust pipe reaction force reducing device according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is an enlarged side view of an essential part for mounting an exhaust pipe and a transmission device according to an embodiment of the present invention.

FIG. 4 is an operation flow chart of an embodiment according to the present invention.

FIG. 5 is a system configuration diagram of a main steam relief safety valve main part.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Main steam relief safety valve, 2 ... Main steam piping, 3 ... Reactor pressure vessel, 4 ... Exhaust pipe, 5 ... Reaction force measuring device, 6 ... Reaction force detector, 7 ... Diagnostic device, 8 ... Transmission device, 9 ... Reaction force reduction device (X direction), 10 ... Reaction force reduction device (Y direction), 11 ... Reaction force reduction device (Z direction), 12 ... Reaction force display device, 13 ... Database, 14, 15 ... Rotating pin .

Claims (1)

[Claims] 1. A reaction force measuring device installed in the vicinity of a connection portion between a main steam relief safety valve and an exhaust pipe, a diagnostic device for analyzing reaction force value data obtained from this reaction force measuring device, and its analysis data. The exhaust pipe reaction force reducing device is characterized in that a reaction force reducing device for moving the exhaust pipe in a direction in which the reaction force is reduced is installed in the exhaust pipe.