JPH0413559B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a leak detection device for a nuclear reactor recirculation pump.

[Technical Background of the Invention] For example, in a boiling water nuclear reactor, a reactor recirculation pump is provided to recirculate cooling water within the reactor pressure vessel.

The pressure-resistant part of this reactor recirculation pump is composed of, for example, a pump casing, a casing cover, and a motor stand, and the casing cover is three-piece fastened by the pump casing and the motor stand and pressed by stud bolts. Conventionally, the contact portion between the pump casing and the casing cover is sealed from the outside by a sealing mechanism such as a gasket.

In the reactor recirculation pump configured as described above, cooling water may leak from the pressure-resistant part due to deterioration of the gasket, etc., so leaks are detected visually during inspections and the like. After a certain period of use, the gasket is replaced regardless of its sealing effect to prevent leakage from the pressure-resistant part.

[Problems with the Background Art] However, when taking measures to prevent leaks from pressure-resistant parts using such a method, it is necessary to replace the gasket even if the gasket is healthy, which causes a great deal of work for the operator. It is labor-intensive and there is a risk that workers may be exposed to radiation.

Additionally, since it is generally impossible to visually detect leaks during plant operation, there is a problem in that leaks from pressure-resistant parts cannot be detected quickly.

[Object of the Invention] The present invention has been made in response to the above-mentioned conventional circumstances, and is a nuclear reactor recirculation pump that can detect leaks from a reactor recirculation pump quickly and remotely even during plant operation. It is an object of the present invention to provide a leakage detection device for a circulation pump.

[Summary of the Invention] That is, the present invention includes a set of sealing mechanisms disposed at intervals between opposing surfaces of a pump casing and a casing cover, and a sealing mechanism between the pair of sealing mechanisms that is located between the pump casing or the casing cover. A pocket formed on the opposing surface of the casing cover, a leak detection pipe opening into the pocket, a pressure gauge for measuring pressure within the leak detection pipe, and a pressure gauge disposed downstream of the pressure gauge in the leak detection pipe. A leak detection device for a nuclear reactor recirculation pump, comprising: a gate valve; and a leak detection operation panel that inputs a signal from the pressure gauge, displays a pressure value, and opens and closes the gate valve. It is.

[Embodiment of the Invention] The details of the present invention will be described below with reference to an embodiment shown in the drawings.

FIG. 1 shows an embodiment of a nuclear reactor recirculation pump to which an embodiment of the present invention is applied, and in the figure, reference numeral 1 indicates a pump casing equipped with a hot fluid inlet 2 and an outlet 3. There is. A pump chamber 4 is formed within this pump casing 1, and an impeller 5 is housed within this pump chamber 4.
A rotating shaft 6 is attached to the back side of the impeller 5,
The rotating shaft 6 passes through a casing cover 7 that covers the upper surface of the pump casing 1, is led out, and is connected to an electric motor or the like (not shown). impeller 5
A journal 8 is disposed between the rotary shaft 6 and the casing cover 7, and an underwater bearing 9 is further disposed surrounding the journal 8.

Furthermore, a mechanical seal 10 is provided between the casing cover 7 and the rotating shaft 6, and the casing cover 7 is fastened to the motor stand 11 and the pump casing 1 in three pieces, and is fixed to the pump casing 1 with stud bolts 12. ing. A leak detection device 13 for a reactor recirculation pump according to an embodiment of the present invention is disposed between the pump casing 1 and the casing cover 7.

FIG. 2 shows details of part A in FIG. 1. In the figure, reference numeral 1 indicates a pump casing, and the lower end of a casing cover 7 is placed in contact with the upper surface of the pump casing 1. There is. A recess 14 is formed at the upper edge of the inner circumference of the pump casing 1, and a sealing mechanism 15 made of, for example, a gasket is disposed in the recess 14. A groove 16 is formed on the outer periphery of the lower surface of the casing cover 7, and a sealing mechanism 17 made of, for example, an O-ring is disposed in the groove 16. A pocket 18 having a rectangular cross section is formed between the sealing mechanism 15 and the sealing mechanism 16 on the lower surface of the casing cover 7.
This pocket 18 has a communication hole 19 that opens on the side surface of the casing cover 7 . Communication hole 19
A leak detection pipe 21 is connected to the side opening of the leak detection pipe 2 by an elbow 20.
1 includes a pressure gauge 22 and a gate valve 23 in order from the upstream.
is installed.

In the figure, the reference numeral 24 indicates an external leak detection operation panel disposed, for example, in the central operation room. The valve 23 is opened and closed.

In the reactor recirculation pump leak detection device configured as described above, for example, when cooling water leaks from the seal mechanism 15 due to deterioration of the seal mechanism 15, the cooling water is transferred to the pocket 18, the communication hole 19, and the leak detection device. It passes through the pipe 21 and increases the pressure value of the pressure gauge 21.

In general, the pressure inside the reactor recirculation pump is
For example, since the cooling water is 70Kg/ ^cm2 , the sealing mechanism 1
5, the pressure value of the pressure gauge 22 changes significantly. In addition, the gate valve 23 is normally closed.

If the pressure value of the pressure gauge 22 displayed on the external leak detection operation panel 24 increases in this way, the operator temporarily opens the gate valve 23 by operating the external leak detection operation panel 24 and 2
The pressure inside 1 is lowered to approximately atmospheric pressure, and the gate valve 23 is closed again. By closing this gate valve 23, the pressure inside the leak detection pipe 21 increases again, and the pressure value displayed on the external leak detection operation panel 24 changes. The amount of leakage of cooling water from the seal mechanism 15 can be calculated from .

Therefore, with the reactor recirculation pump leak detection device configured as described above, leaks in the reactor recirculation pump can be detected quickly and reliably from a remote location, thereby increasing the reliability of the reactor recirculation pump. performance can be significantly improved. Further, unnecessary replacement work of the sealing mechanism 15 such as a gasket is not required, so the labor of the worker is reduced, and the accompanying radiation exposure of the worker can be significantly reduced. Further, since the amount of leakage can be calculated from the rate of pressure rise of the pressure gauge 22, it is possible to quickly take appropriate measures depending on the magnitude of the amount of leakage.

[Effects of the Invention] As described above, according to the reactor recirculation pump leak detection device of the present invention, leaks from the reactor recirculation pump can be detected quickly and reliably remotely even during plant operation. , the reliability of the reactor recirculation pump can be significantly improved. Furthermore, the labor and radiation exposure of workers associated with replacing the seal mechanism can be significantly reduced. Furthermore, since the amount of leakage can be calculated from the pressure rise rate of the pressure gauge, it is possible to quickly take appropriate measures depending on the size of the amount of leakage.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view showing a reactor recirculation pump to which a leakage detection device for a reactor recirculation pump according to an embodiment of the present invention is applied, and FIG. 2 is a longitudinal sectional view showing a reactor recirculation pump according to an embodiment of the present invention. FIG. 2 is a longitudinal cross-sectional view showing a leakage detection device for a pump. DESCRIPTION OF SYMBOLS 1... Pump casing, 7... Casing cover, 15, 17... Seal mechanism, 18... Pocket, 21... Leak detection piping, 22... Pressure gauge, 23... Gate valve.

Claims (1)

[Claims] 1. A pair of seal mechanisms arranged at intervals between opposing surfaces of the pump casing and casing cover, and a seal formed between the pair of seal mechanisms on the opposing surfaces of the pump casing or casing cover. a leak detection pipe that opens into the pocket, a pressure gauge that measures the pressure in the leak detection pipe, a gate valve that is disposed downstream of the pressure gauge in the leak detection pipe, and the pressure gauge. 1. A leak detection device for a nuclear reactor recirculation pump, comprising a leak detection operation panel that inputs a signal from a reactor recirculation pump, displays a pressure value, and opens and closes the gate valve.