JPS6168530A - Leakage detection mechanism for door valve - Google Patents

Abstract

PURPOSE:To enable the detection of leaked gas from a valve body and a valve seat of a door valve disregarding dropping of a liquid sodium, by arranging a plurality of detection holes for communication between a packing groove of a valve seat and the surface thereof and a detection hole for communication between two rows of packing grooves and an external detection piping. CONSTITUTION:A door valve 1 which is provided on the top of a closed container housing a internal component elements of a nuclear reactor holding a liquid sodium while an inert gas for a cover is sealed into the top thereof is made up of a valve box 2, a valve body 4 and a lower flange 3 as valve seat. The valve body 4 comprising a main valve unit 4a and a seal plate 3 runs through the valve box 2 with a drive screw 6. A space is forced in the packing grooves 3b and 3c of the valve seat 3 with an O ring packing 7 and a plurality of detection holes 3g and 3h are provided for communication between spaces 3e and 3f and the surface o the valve seat while a detection hole 3i connected to a detection piping 8 communicating with the spaces 3e and 3f. Thus, sound detection holes 3g and 3h remains even when the liquid sodium drops with the opening of the door valve 1 thereby enabling the detection of leaked gas at the contact surface between the valve body and the valve seat.

Description

[Detailed description of the invention] [Technical field to which the invention pertains]

In the present invention, the reactor components are provided in the upper part of a closed container that accommodates the reactor components of a nuclear reactor, which contains liquid sodium and in which an inert gas for a cover is sealed in the upper part, so that the reactor components can be vertically moved in and out. The present invention relates to a door valve leakage detection mechanism that detects gas leaking from the valve seat of the door valve from the outside using detection piping.

[Prior art and its problems]

For example, in a fast breeder reactor that uses liquid sodium as a coolant, a door valve is installed when entering and exiting the reactor components from a closed container filled with liquid sodium and sealed with an inert gas such as argon at the top. Opening and closing aisles or containers. The prior art will be described below with reference to the drawings. FIG. 4 is a sectional view of the main structural parts of the door valve. In FIG. 4, reference numeral 1 denotes a door valve, and a valve box 2 of the door valve 1 is provided with a lower flange 3 as a valve seat, and a valve hole 3a as a passage is provided in the center of the lower flange 3. The valve body 4 is connected to a drive device 5 provided outside the valve body 2 via a drive screw 6, and is able to travel inside the valve body 2 by rollers 4c provided on the valve body 4. ing. In the valve body 4, a valve body 4a and a seal plate 4b are connected via a taper cam (not shown). A sodium receiver 4d is provided at the upper part of the valve body 4a to receive sodium droplets from the sodium-wetted components in the furnace. As shown in FIG. 5, which is an enlarged view of the circle P in FIG. 4, the lower flange 3 is provided with two rows of groove-shaped packing grooves 3b and 3c surrounding the valve hole 3a. An O-ring packing 7 is inserted into the packing groove. A detection hole 3d, which opens in the surface of the lower flange 3 between the packing grooves 3b and 30 and communicates with the outside, is provided at one location and is connected to an external detection pipe 8. In FIG. 4, the valve body 4 is moved in the valve closing direction by the roller 4c by driving of the drive device 5, and the seal plate 4 is moved by the roller 4c.
When b hits the protrusion 2a of the valve body 2, the seal plate 4b stops at a position covering the valve hole 3a. When the valve body 4 is further moved, only the valve body 4a is slightly moved by a taper cam (not shown), and the valve body 4a comes into contact with a fixed portion (not shown). Then, the seal plate 4b presses against the O-ring packing 7 of the lower flange 3 by the taper cam, and the seal plate 4b and the 01J ring packing 7 are brought into close contact with each other to ensure a seal. However, when a leak occurs between the seal plate 4b and the OIJ packing 7 due to deterioration of the sealing performance of the door valve during the operation of the nuclear reactor, this leaked gas is transferred to the detection hole 3d.
flows to the outside through Therefore, detection pipe 8 (5th
The amount of leaked gas can be measured stationarily by providing a detector in the detector (see figure), or by supplying gas from the detection pipe, pressurizing it to a predetermined pressure, leaving it to stand, and measuring the rate of pressure drop. However, when the in-furnace components housed in the liquid sodium in the closed container open the door valve I and move in and out in the vertical direction through the valve hole 3a, sodium adheres to the in-furnace components 9 as shown in FIG. As a result, the sodium droplets 10 form and drip onto the valve seat surface of the lower flange 3, solidifying and blocking the detection hole 3d. Therefore, detection hole 3
Due to blockage of d, leak detection becomes impossible. When the valve is closed, sodium droplets from the furnace components 9 are stored in a sodium receiver 4d provided in the valve body 4a to prevent excessive sodium from being dispersed into the valve box. Also, seal play when the valve is closed)
Since the dripped sodium on the lower flange 3 serving as the valve seat is attached in a solid state to the surface of 4b covering the valve seat, when the valve is opened, the hole 3d is blocked by the attached sodium by movement of the valve body. also occurs. In any case, since the above structure has only one hole for detecting leakage, there is a fear that dripping sodium may cause the reactor to become stale during long-term operation, making it impossible to detect leakage gas.

[Purpose of the invention]

In view of the above-mentioned points, the present invention provides a leakage detection mechanism for a door valve that can detect leakage gas from a valve body and a valve seat without blocking a detection hole even if liquid sodium drips. With the goal.

[Key points of the invention]

According to the present invention, among the spaces formed at the bottom of the two rows of packing grooves of the valve seat, the O-ring packings communicate with the two rows of annular spaces on the opposing sides, and A plurality of first detection holes that open between two O-ring packings on the surface, and a second detection hole that communicates with the two rows of annular spaces and that penetrate the valve seat and open to the outside are provided. This is achieved by connecting detection piping to the second detection hole to detect the inert gas.

[Embodiments of the invention]

Embodiments of the present invention will be described below based on the drawings. FIG. 1 shows a door pulp leak detection mechanism according to an embodiment of the present invention, and is a partial sectional view when the door valve is closed. In addition, Fig. 2 and Fig. 3. In FIGS. 4 and 5, the same parts as in FIG. 1 are given the same reference numerals. In FIG. 1, the valve body 4 of the door valve consists of a valve body 4a and a seal plate 4b, which have the same structure and function as those of the prior art, and the valve body 4 is in the closed position. That is, the seal plate 4b contacts the protrusion 2a of the valve box 2, and the valve body 4a presses the seal plate 4b downward by a taper cam (not shown). Therefore, the seal plate 4b has O
The ring seal 7 is pressed against the O-ring seal 7 to form a seal. The O-ring packing 7 installed in the packing grooves 3b and 3c forms a space defined by the bottom and sides of the groove and the surface of the 01J padding. The two Q IJ ring packings in this annular space communicate with the annular spaces 3e and 3f on opposite sides, respectively, and the first detection opens into the valve seat between the two O-ring packings 7, respectively. A plurality of holes 3g and 3h are provided. 2 and 3 are views of the lower flange as a valve seat according to an embodiment of the invention. These first detection holes 3g, 3h
As shown in the partial plan view of the lower flange 3 shown in FIG. 2, a plurality of grooves are provided for each row of packing grooves over the entire circumference. FIG. 3 is a sectional view taken along the line A-A in FIG. 2, and shows that the first detection hole 3g+3h described above communicates with the annular spaces 3e and 3f of the groove-shaped packing groove and opens into the valve seat. This is an enlarged view of the cane. Returning to FIG. 1, the lower flange 3 is connected to the annular spaces 3e and 3f of the packing groove, and the second detection hole which penetrates the lower flange 3 and opens to the outside is used as a valve seat. One penetrating portion is connected to the detection pipe 8. With the above structure, the plurality of first detection holes 3g and 3h provided between the two rows of O-ring packings form an annular space 3e of two rows of packing grooves surrounding the valve hole 3a. 3f and the second detection hole 31, it communicates with the detection pipe 8. Therefore, the first detection 7L3g detects the presence of some sodium droplets dripping from the reactor internal components leaking into the liquid sodium when the door valve is opened, and some sodium adhering to the seal plate when the valve is opened and closed.31. Even if the first detection holes 3g and 3h are closed, other healthy first detection holes 3g and 3h will still exist because there are a large number of these holes. Spaces 3e, 3 communicating with these healthy first detection holes
Since f is to be provided inside the lower flange, these spaces 3e and 3f will not be blocked by the dripping sodium. Therefore, the first detection hole ag, 3h
Even if some of the spaces 3e and 3 are blocked by sodium,
f forms a ring-shaped passage. Therefore, spaces 3e and 3f are created by the remaining healthy first detection holes 3g and 3h.
The leakage gas from the contact surface between the valve body and the valve seat can be detected by the detection pipe 8 through the second detection hole 31, and the amount of leakage gas can be measured.

【Effect of the invention】

As is clear from the above description, according to the present invention, the O-ring packings face each other in the spaces formed in the seats of the two rows of ring-shaped packing grooves provided on the lower flange as the valve seat. The first opening opens between the two OQ ring packings on the lower flange surface and communicates with the side annular spaces respectively.
A large number of detection holes are provided, and a second detection hole is provided that communicates with the annular space and opens to the outside through the lower flange, and a detection pipe connected to the second detection hole connects the valve body. By detecting leaking gas from the contact surface with the valve seat, all the first detection holes are prevented from being blocked by dripping sodium droplets or sodium adhering to the valve body due to the opening/closing operation of the valve body. Furthermore, since the annular space is not blocked by sodium, leakage gas can be detected and measured. Therefore, it is possible to reliably inspect the door valve during its service life, which has the effect of improving the reliability of the door valve.

[Brief explanation of drawings]

FIG. 1 shows a leakage detection mechanism for a door valve according to an embodiment of the present invention, and is a partial sectional view when the door pulp is closed. FIG. 2 is a partial plan view of the lower flange as a valve seat in FIG. 1.
The drawings are a sectional view taken along the line AA in FIG. 2, FIG. 4 is a sectional view of the main structural parts of a conventional door valve, and FIG. 5 is an enlarged view of the circle P in FIG. 4. 1: Door valve, 3: Lower flange as valve seat, 3a
: Valve hole, 3b, 3c: Packing groove, 3d: Detection hole,
3e, 3f: annular space, 3g, 3h: first
detection hole, 31: second detection hole, 4: valve body, 7: O
IJung Pasokin, 8: Detection piping. Figure 2 / X1ll J 3b 3e 3g 3h 3t 3c Figure 4 Figure 3 Figure 5

Claims (1)

[Claims] 1) The reactor internal components are housed in a sealed container, liquid sodium is filled as a coolant, and an inert gas for a cover is filled in the upper part of the sealed container. A door valve is provided for allowing components to enter and exit the closed container, and the door valve includes a valve seat having a valve hole and a movable valve body, and the valve seat has two rows of annular grooves with a groove-shaped cross section disposed on the surface. a packing groove, two O-ring packings inserted into the packing groove, and a detection hole that passes through the valve seat and communicates with the outside, and when the door valve is closed with the valve body placed on the valve seat. , in the mechanism for detecting leakage of the door valve by detecting inert gas discharged from the detection hole, the space formed at the bottom of the two rows of packing grooves of the valve seat is located on the side facing the O-ring packing. A second detection hole is provided which communicates with each of the two rows of annular spaces and opens to the outside through a plurality of first detection holes opened between two O-ring packings on the surface of the valve seat. A leak detection mechanism for a door valve, characterized in that a detection pipe is connected to the detection hole of No. 2 to detect an inert gas.