Dual isolation valve system for fuel transfer tube in pressurized light water reactor nuclear power plant

Abstract

The dual isolation valve system for a fuel transfer tube in a pressurized light water reactor nuclear power plant, according to the present invention, is characterized in that: in order to withdraw nuclear fuel from a fuel building and reload nuclear fuel into a reactor within a reactor building through a fuel transfer tube, a motor-operated gate isolation valve and a manual isolation valve are installed at the front side of the fuel transfer tube, relative to the fuel building side, in order to fill and drain a reactor refueling water storage tank; the manual isolation valve on the fuel building side is maintained in an open state; a plurality of disc-fastening holes are formed along the outer circumference of the disc of the motor-operated gate isolation valve; a disc protrusion is inserted into the inside of the fuel transfer tube; a disc step circumference is larger than the outer diameter of the fuel transfer tube so as to seal the fuel transfer tube; and the disc of the motor-operated gate isolation valve moves downward due to the driving of a motor (M), causing the motor-operated gate isolation valve to block the fuel transfer tube and maintain the tube in a closed state, the disc being an isolation valve disc that functions as a blind flange.

Description

Pressurized Water Reactor Fuel Transfer Pipe Double Isolation Valve System

[0001] The present invention relates to a nuclear power plant fuel transfer pipe isolation valve system using an electric motor-driven dual isolation valve to eliminate the inconvenience of operating a manual isolation valve of a fuel transfer pipe and to shorten process time during nuclear fuel reloading in a pressurized light water reactor.

[0002] Korean Registered Patent Publication No. 10-1594879 (February 17, 2016) discloses a device for double automatic closing of a discharge pipe based on a high-temperature signal of effluent water from a nuclear power plant, which detects a high-temperature signal generated in the effluent water piping and automatically closes a discharge water isolation valve to rapidly block the leakage of radioactive material.

[0003] The double automatic closing device for the discharge pipe based on the high temperature signal of the nuclear power plant discharge water is a double automatic closing device for the discharge pipe based on the high temperature signal of the nuclear power plant discharge water composed of a closed circuit consisting of a reactor, a steam generator, a reactor coolant pump, and related piping.

[0004] It is equipped with an effluent pipe through which effluent flows, two effluent isolation valves each installed in the effluent pipe, and two effluent temperature sensors installed on the effluent pipe that detect the temperature of the effluent flowing through the effluent pipe and generate a corresponding high temperature signal.

[0005] It is configured with two effluent temperature signal wires in which high temperature signals generated from two effluent temperature sensors are sent to the two effluent isolation valves.

[0006] It is characterized by the fact that when the effluent piping outside the containment building is ruptured and the effluent temperature exceeds a set value, the effluent temperature sensor sends a high temperature signal to the effluent isolation valve through the effluent temperature signal wiring to promptly and automatically shut off the effluent.

[0007] A water leak prevention valve control system for a consumer, in which a controller receives water flow information from a flow sensor and controls the motorized valve to automatically close when the water usage pattern meets certain conditions to block leakage and prevent unnecessary water usage, is described in Korean Registered Patent Publication No. 10-2684553 (July 15, 2024).

[0008] The water leak prevention valve control system for a water user is equipped with an inlet pipe through which water flows, a bypass union connected to the inlet pipe to receive water, and an electric valve that receives water from the bypass union and opens or closes the flow to the water meter.

[0009] The configuration includes a flow sensor that collects water flow information passing through a bypass union, a supply pipe that supplies water passing through a water meter to a consumer, and a controller that determines the opening and closing of an electric valve by comparing the water flow information received from the flow sensor with a stored usage pattern.

[0010] [Prior Art Literature]

[0011] [Patent Literature]

[0012] (Patent Document 1) Korean Registered Patent Publication KR 10-1594879 B1

[0013] (Patent Document 2) Korean Registered Patent Publication KR 10-2684553 B1

[0014] When performing planned preventive maintenance on a commercial nuclear power plant, it is necessary to fill and drain the reactor cavity within the reactor building to reload nuclear fuel; at this time, after removing the blind flange of the fuel transfer pipe, a flow path can be formed by operating a manual isolation valve.

[0015] However, manual isolation valves increase the fatigue of field operators due to the difficulty of having to rotate the handle hundreds of times to open and close them, and significantly affect the delay of the planned preventive maintenance process.

[0016] The purpose of this invention is to replace the isolation valve of the fuel transfer pipe with an electric motor-driven isolation valve to reduce operator fatigue through the automatic opening and closing of the valve, and to minimize inefficiencies that may occur during the filling and draining process of the reloading tank.

[0017] The pressurized water reactor fuel transfer pipe dual isolation valve system of the present invention installs a motor-driven gate isolation valve and a manual isolation valve on the front side of the fuel transfer pipe from the fuel building side to fill and drain the reactor reloading pool for withdrawing nuclear fuel from the fuel building and reloading the nuclear fuel into the reactor inside the reactor building through the fuel transfer pipe, and the manual isolation valve on the fuel building side is maintained in an open state.

[0018] The disc of the electric motor-driven gate isolation valve of the present invention has a plurality of disc fastening holes formed on the outer circumference of the disc, the disc protrusion is inserted into the inner diameter of the nuclear fuel transfer pipe, and the disc step circumference is formed larger than the outer diameter of the nuclear fuel transfer pipe to seal the nuclear fuel transfer pipe.

[0019] The present invention is characterized in that the disc of the motor-driven gate isolation valve moves downward by driving a motor (M), thereby blocking the nuclear fuel transfer pipe and maintaining the motor-driven gate isolation valve in a closed state, and the disc is an isolation valve disc that acts as a blind flange.

[0020] In the present invention, the disc of the electric motor-driven gate isolation valve has a plurality of disc fastening holes formed on the outer circumference of the disc, the disc protrusion is inserted into the inner diameter of the nuclear fuel transfer pipe, and the disc step circumference is formed larger than the outer diameter of the transfer pipe to seal the nuclear fuel transfer pipe.

[0021] In the present invention, when it is necessary to maintain the valve closed of the electric motor drive gate isolation valve, airtightness is maintained by fastening and connecting with a stud bolt and a nut through a disc fastening hole formed on the outer circumference of the disc acting as a blind flange.

[0022] In the present invention, the disc acting as a blind flange has a configuration different from other conventional flanges, with the center closed, so it is configured to block the flow of fluid in the nuclear fuel transfer pipe.

[0023] In the present invention, a leak verification space for checking leakage is provided at the bottom of the disc of the electric motor-driven gate valve.

[0024] The present invention is characterized by detecting water accumulation in the lower portion when leakage occurs in the disc of the electric motor drive gate isolation valve and generating an alarm in the main control room.

[0025] In the present invention, if it is impossible to block leakage of the electric motor drive gate valve, the manual isolation valve is closed to prevent additional leakage.

[0026] The double isolation valve system for the fuel transfer pipe of the pressurized water reactor of the present invention has the effect of increasing the efficiency of the nuclear fuel reloading process and reducing operator fatigue through an electric motor-driven double isolation valve, while enhancing safety through a leak detection function.

[0027] FIG. 1 is a schematic diagram of a double isolation valve system for a pressurized light water reactor fuel transfer pipe according to the present invention.

[0028] Figure 2 illustrates the configuration of a disk of a motor-driven gate isolation valve according to the present invention.

[0029] The present invention adds an electric motor-driven isolation valve to the existing manual isolation valve of the fuel transfer pipe to reduce operator fatigue through the automatic opening and closing of the valve and minimize inefficiencies that may occur during the filling and draining process of the reloading tank.

[0030] Hereinafter, the double isolation valve system for a pressurized water reactor fuel transfer pipe according to the present invention will be described in more detail with reference to the attached drawings.

[0031] FIG. 1 is a schematic diagram of a double isolation valve system for a pressurized light water reactor fuel transfer pipe according to the present invention.

[0032] Figure 2 illustrates the configuration of a disk of a motor-driven gate isolation valve according to the present invention.

[0033] In order to withdraw nuclear fuel from the nuclear fuel building (100) in a pressurized water reactor and reload the nuclear fuel into the reactor inside the reactor building (200) through the nuclear fuel transfer pipe (300), a isolation valve is required for filling and draining the reactor reloading tank.

[0034] An electric motor-driven gate isolation valve (400) and a manual isolation valve (600) are installed on the front side of the nuclear fuel transfer pipe (300) from the fuel building (100) side and are used for filling and draining the reloading tank.

[0035] The manual isolation valve (600) on the nuclear fuel building (100) side is kept in an open state, and the motor-driven gate isolation valve (400) is kept in a closed state.

[0036] The disc (500) of the motor-driven gate isolation valve (400) moves downward by driving the motor (M), so that the motor-driven gate isolation valve (400) blocks the nuclear fuel transfer pipe (300) and keeps it in a closed state.

[0037] The disc (500) of the motor-driven gate isolation valve (400) is a disc of the valve that acts as a blind flange.

[0038] The disc (500) of the electric motor drive gate isolation valve (400) has a plurality of disc fastening holes (520) formed in the outer diameter circumference (510) of the disc, the disc protrusion (530) is inserted into the inner diameter of the nuclear fuel transfer pipe (300), and the disc step circumference (540) is formed larger than the outer diameter (310) of the nuclear fuel transfer pipe (300) to seal the nuclear fuel transfer pipe (300).

[0039] When it is necessary to maintain the valve closed of the motor drive gate isolation valve (400), airtightness is maintained by fastening it with a stud bolt and nut through the disc fastening hole (520) formed in the outer circumference (510) of the disc (500) which acts as a blind flange.

[0040] Fluid may leak if the pressure of the fluid flowing through the piping is too high, if fittings, flanges, or valves are not properly tightened, or if the airtightness is low.

[0041] Blind flanges are used for pressure testing of piping lines, when a piping line needs to be temporarily blocked, or when changing or repairing pipelines.

[0042] The disc (500) acting as a blind flange has a different configuration from other ordinary flanges and is closed in the middle, so it serves to block the flow of fluid in the nuclear fuel transfer pipe (300).

[0043] A leak check space (550) for checking for leaks is provided at the bottom of the disk (500) of the electric motor drive gate valve (400).

[0044] If a leak occurs in the disk (500) of the motor drive gate isolation valve (400), water accumulates in the lower part, and this is detected to generate an alarm in the main control room.

[0045] If it is not possible to block leakage of the motor drive gate valve (400), the manual isolation valve (600) is closed to prevent further leakage.

[0046] As seen above, the double isolation valve system for the fuel transfer pipe of a pressurized water reactor enables double isolation by additionally installing a motor-driven gate isolation valve in front of the existing manual isolation valve on the fuel building side, thereby further enhancing safety by including a leak detection space in the closed state of the motor-driven gate isolation valve.

[0047] This is a fuel transfer pipe isolation valve system in which, when the motor-driven gate valve is closed, the disc acts as a blind flange to maintain airtightness, and a manual isolation valve can be used as an auxiliary valve when necessary.

[0048] Therefore, the pressurized water reactor fuel transfer pipe double isolation valve system of the present invention has the effect of increasing the efficiency of the nuclear fuel reloading process and reducing operator fatigue through an electric motor-driven double isolation valve, while enhancing safety through a leak detection function.

[0049] Although the present invention has been described in detail through representative embodiments above, those skilled in the art will understand that various modifications can be made to the above-described embodiments within the scope of the present invention.

[0050] Therefore, the scope of the rights of the present invention should not be limited to the described embodiments, but should be determined by the claims set forth below as well as all modifications or variations derived from the claims and equivalent concepts.

[0051] [Explanation of the symbol]

[0052] 100: Nuclear fuel building

[0053] 200: Reactor Building

[0054] 300: Nuclear fuel transfer pipe

[0055] 400: Motor-driven gate isolation valve

[0056] 500: Disk

[0057] 510: Outer circumference of the disc

[0058] 520: Disc mounting hole

[0059] 530: Disc protrusion

[0060] 540: Disc step perimeter

[0061] 550: Leakage verification space

[0062] 600: Manual isolation valve

[0063] M: Motor

Claims

1. A pressurized water reactor fuel transfer pipe double isolation valve system is installed with a motor-driven gate isolation valve (400) and a manual isolation valve (600) on the front side of the fuel transfer pipe (300) from the fuel building (100) side to fill and drain the reactor reloading tank in order to withdraw nuclear fuel from the nuclear fuel building (100) and reload the nuclear fuel into the reactor inside the reactor building (200) through the nuclear fuel transfer pipe (300). The manual isolation valve (600) on the side of the nuclear fuel building (100) is kept in an open state, and The disc (500) of the electric motor drive gate isolation valve (400) has a plurality of disc fastening holes (520) formed on the outer diameter circumference (510) of the disc, and The disc protrusion (530) is inserted into the inner diameter of the nuclear fuel transfer tube (300), and The disc step perimeter (540) is formed larger than the outer diameter (310) of the nuclear fuel transfer tube (300) to seal the nuclear fuel transfer tube (300), and A pressurized light water reactor fuel transfer pipe double isolation valve system characterized in that the disc (500) of the motor-driven gate isolation valve (400) moves downward by driving the motor (M), thereby blocking the nuclear fuel transfer pipe (300) and maintaining it in a closed state, and the disc (500) is a disk of the isolation valve that acts as a blind flange.

2. In Paragraph 1, A pressurized light water reactor fuel transfer pipe double isolation valve system characterized by the fact that the disc (500) of the motor drive gate isolation valve (400) has a plurality of disc fastening holes (520) formed in the outer diameter circumference (510) of the disc, the disc protrusion (530) is inserted into the inner diameter of the nuclear fuel transfer pipe (300), and the disc step circumference (540) is formed larger than the outer diameter (310) of the transfer pipe (300) to seal the nuclear fuel transfer pipe (300).

3. In Paragraph 2, A pressurized water reactor fuel transfer pipe double isolation valve system characterized by maintaining airtightness by fastening a disc with a stud bolt and a nut through a disc fastening hole (520) formed in the outer circumference (510) of a disc (500) that acts as a blind flange when it is necessary to maintain the valve closed of the motor drive gate isolation valve (400).

4. In Paragraph 3, The disc (500) acting as a blind flange has a closed center with a configuration different from other ordinary flanges, so it serves to block the flow of fluid in the nuclear fuel transfer pipe (300), and A pressurized light water reactor fuel transfer pipe double isolation valve system characterized by having a leak detection space (550) for leak detection at the bottom of the disk (500) of the electric motor drive gate valve (400).

5. In any one of paragraphs 1 to 4, A pressurized light water reactor fuel transfer pipe double isolation valve system characterized by detecting water accumulation in the lower part when leakage occurs in the disk (500) of the motor drive gate isolation valve (400) and generating an alarm in the main control room.

6. In Paragraph 5, A pressurized light water reactor fuel transfer pipe double isolation valve system characterized by closing a manual isolation valve (600) to prevent additional leakage when it is not possible to block leakage of the motor drive gate valve (400).

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