Coast-down apparatus for reactor coolant pump of small modular nuclear reactor and operating method thereof

Abstract

A coast-down apparatus for a reactor coolant pump (RCP) of a small modular nuclear reactor of the present invention comprises: a solenoid valve; a rotor including an impulse blade and installed on a rotary shaft; and an energy storage unit for rotation-driving the impulse blade, wherein: the rotary shaft of a nuclear reactor coolant pump (RCP) is provided with a rotation detection unit for detecting whether to rotate; the rotor installed on the rotary shaft is provided with a motor, an impeller, and the impulse blade for receiving energy from the energy storage unit to rotate; when power of the nuclear reactor coolant pump (RCP) is lost, the solenoid valve performs a fail-open operation; a power supply unit supplies, when power is not supplied to the reactor coolant pump (RCP), power to each of the motor and the solenoid valve through a power supply line, and when the solenoid valve is opened, receives energy for rotating the impulse blade of the reactor coolant pump (RCP) from the energy storage unit through an energy supply pipe and a nozzle.

Description

Small modular reactor reactor coolant pump inertia slowdown device and operating method

[0001] The present invention relates to enabling coast-down operation of a reactor coolant pump (RCP) even when power is lost by configuring a solenoid valve replacing a flywheel of a small modular nuclear reactor reactor coolant pump and an impulse blade provided on a rotor of the reactor coolant pump.

[0002] Korean Patent Publication No. 10-2020-0018994 describes a reactor coolant system that is formed to allow the flow of reactor coolant to continue by relaxing the inertia slowdown requirement to secure the stability of the nuclear power plant in the early stages of a nuclear power plant accident.

[0003] The reactor coolant system includes a reactor vessel configured to receive a core and a first fluid that transports heat energy generated in the core, a steam generator having a first passage through which the first fluid heated in the core flows and a second passage through which the second fluid, which changes from liquid to vapor through heat exchange with the first fluid, flows, a reactor coolant pump configured to circulate the first fluid, and an inertial structure disposed on the passage through which the first fluid circulates, wherein the inertial structure is configured to be installed spaced apart from the reactor coolant pump.

[0004] A reactor coolant pump capable of more efficiently utilizing the circulation flow of reactor coolant and an integrated reactor equipped with the same are described in Korean Patent Publication No. 10-1802840.

[0005] The reactor coolant pump includes an electric motor mounted on the side of the outer wall of the reactor vessel, an impeller housed inside the reactor vessel and receiving power from the electric motor to circulate the reactor coolant inside the reactor vessel, and a bypass flow reduction unit arranged in a gap between the internal structure of the reactor vessel and a pump flow path structure surrounding the impeller so that both sides can contact the internal structure and the pump flow path structure, respectively, and the reactor coolant discharged from the discharge portion of the pump flow path structure flows back into the impeller through the gap to reduce the bypass flow of the reactor coolant that bypasses.

[0006] The bypass flow reduction unit is configured to seal the gap by using elasticity while being compressed by the internal structure and the pump passage structure when assembling the reactor coolant pump, or to seal the gap by having both sides come into close contact with the internal structure and the pump passage structure as the length expands when the temperature of the reactor coolant rises, or to seal the gap by using elasticity while being compressed by the internal structure and the pump passage structure when assembling the reactor coolant pump, and to maintain the seal by absorbing the amount of length expansion by elasticity while expanding in length and being compressed at the same time when the temperature of the reactor coolant rises.

[0007] [Prior Art Literature]

[0008] [Patent Document]

[0009] (Patent Document 1) Korean Patent Publication No. 10-2020-0018994

[0010] (Patent Document 2) Korean Patent Publication No. 10-1802840

[0011] Since the Fukushima nuclear accident, the design concept of a passive safety system driven by natural forces such as gravity and density differences has been actively introduced even in the event of a long-term power loss or extreme disaster.

[0012] Unlike conventional commercial nuclear power plants, small modular reactors (SMRs) have their main components integrated into the reactor vessel, so each major component is subject to significant constraints in size and placement.

[0013] Accordingly, the present invention aims to enable inertial operation of a reactor coolant pump (RCP) even when power is lost by configuring a solenoid valve replacing a flywheel of a small modular nuclear reactor reactor coolant pump and an impulse blade provided on a rotor of the reactor coolant pump.

[0014] The inertial crawl device of a small modular nuclear reactor coolant pump (RCP) of the present invention includes a rotor installed on a rotating shaft, including a solenoid valve and an impulsive blade, and an energy storage unit that rotates the impulse blade.

[0015] The rotating shaft of the reactor coolant pump (RCP) of the present invention is equipped with a rotation detection unit that detects whether it is rotating, and the rotor installed on the rotating shaft is equipped with an impulse blade, a motor, and an impeller that rotate by receiving energy from an energy storage unit.

[0016] The solenoid valve of the present invention operates in a fail open manner when power to the reactor coolant pump (RCP) is lost.

[0017] The power supply unit of the present invention supplies power to the motor and solenoid valve through a power supply line when power is not supplied to the reactor coolant pump (RCP).

[0018] When the solenoid valve of the present invention is opened, it is configured to receive energy for rotating the impulse blade of the reactor coolant pump (RCP) through the energy supply pipe and nozzle from the energy storage unit.

[0019] The rotation detection unit of the present invention is configured to detect whether power is being supplied smoothly to the solenoid valve through the rotation detection unit while power is not being supplied to the reactor coolant pump (RCP), and transmit the detection result to the solenoid valve through the detection line.

[0020] When power is supplied smoothly to the solenoid valve of the present invention, the operator can open the solenoid valve manually by operating it in the main control room (MCR) or on site.

[0021] When the solenoid valve of the present invention is opened, it is configured to receive pneumatic, hydraulic, and water pressure energy supply for rotating the impulse blade of the reactor coolant pump (RCP) through the energy supply pipe and nozzle from the energy storage unit.

[0022] The inertial crawl operation of the reactor coolant pump of the small modular reactor of the present invention is such that the reactor coolant pump (RCP) of the small modular reactor receives power from a power supply unit (not shown) and operates normally.

[0023] The normal operation of the RCP is determined based on whether the rotation shaft detected by the rotation detection unit, which is an auxiliary measuring means for power loss of the reactor coolant pump (RCP) of the present invention, is rotating.

[0024] When the rotation detection unit of the present invention determines that the rotation shaft is not rotating, it determines whether power is supplied to the solenoid valve.

[0025] If it is determined that power is not supplied to the solenoid valve of the present invention, the solenoid valve automatically opens (opens) and fails open in the event of a power loss accident.

[0026] It is determined that power is supplied to the solenoid valve of the present invention, and the operator manually operates the solenoid valve in the main control room (MCR) or on-site to open it.

[0027] When the solenoid valve of the present invention is opened, it receives energy supply such as pneumatic, hydraulic, or water pressure from the energy storage unit through the energy supply pipe and nozzle to rotate the impulse blade of the reactor coolant pump (RCP).

[0028] The reactor coolant pump (RCP) begins coast-down operation by receiving energy from the energy storage unit of the present invention.

[0029] The present invention contributes to improving the safety of nuclear power plants by extending the inertia-slow operation time of a reactor coolant pump by replacing a flywheel that occupies a large weight and volume in a passive reactor coolant pump without an external power source when the power supply to the RCP is lost, by using a solenoid valve that operates when the power to the RCP is lost, and by using an impulse blade provided on the rotor of the RCP.

[0030] Figure 1 illustrates a configuration in which a motor and a flywheel are mounted on a reactor coolant pump.

[0031] Figure 2 illustrates the configuration of a small modular reactor having a reactor coolant pump.

[0032] Figure 3 is a schematic diagram of a small modular nuclear reactor coolant pump inertial crawl device according to the present invention.

[0033] Figure 4 is an operation flow chart of a small modular reactor coolant pump according to the present invention.

[0034] The reactor coolant pump (RCP) of a nuclear reactor provides sufficient forced circulation flow to the reactor coolant system to properly remove heat generated from the reactor core during normal operation.

[0035] The flywheel installed in the reactor coolant pump motor is a circular rigid mass and a rotating mechanical device used to store rotational energy.

[0036] Figure 1 illustrates a configuration in which a motor and a flywheel are mounted on a reactor coolant pump.

[0037] The flywheel's role is to provide sufficient coast-down flow to properly cool the core in the event of a loss of power to the reactor coolant pump (RCP).

[0038] Figure 2 illustrates the configuration of a small modular reactor having a reactor coolant pump.

[0039] Small modular reactors (SMRs) are characterized by integrating major equipment into the reactor vessel, unlike conventional commercial nuclear power plants.

[0040] Due to the integration of such small modular reactors, each major component is subject to significant constraints in size and layout.

[0041] Therefore, the present invention enables the inertial slowdown operation of the reactor coolant pump (RCP) even when power is lost by configuring a solenoid valve replacing the flywheel of the reactor coolant pump (RCP) of a small modular reactor and an impulsive blade provided on the rotor of the reactor coolant pump.

[0042] Hereinafter, with reference to the attached drawings, the inertial crawl device and operating method of the small modular nuclear reactor coolant pump according to the present invention will be described in more detail.

[0043] Figure 3 is a schematic diagram of a small modular nuclear reactor coolant pump inertial crawl device according to the present invention.

[0044] An inertial crawl device replacing a flywheel of a small modular reactor coolant pump includes a solenoid valve (100) that operates to fail open in the event of a power loss accident of the reactor coolant pump, an impulsive blade (200) provided on a rotor (600) of the reactor coolant pump, and an energy storage unit (300) that rotates and drives the impulsive blade provided on the rotor.

[0045] The solenoid valve (100) is designed to operate in a fail-open configuration when power to the reactor coolant pump (RCP) is lost.

[0046] A rotation detection unit (410) is provided to detect whether the rotation shaft (400) is rotating as an auxiliary measurement means for power loss of the reactor coolant pump (RCP).

[0047] That is, although power is not supplied to the reactor coolant pump (RCP), it can be detected through the rotation detection unit (410) whether power is being supplied smoothly to the solenoid valve (100).

[0048] The detection result of the rotation detection unit (410) is transmitted to the solenoid valve (100) through the detection line (420).

[0049] In this case, the solenoid valve (100) can be opened by an operator manually operating the solenoid valve (100) in the main control room (MCR) or on site.

[0050] A rotor (600) installed on a rotating shaft (400) is provided with an impulse blade (200), a motor (500), and an impeller (700) that rotate by receiving energy from an energy storage unit (300).

[0051] When power is not supplied to the reactor coolant pump (RCP), the power supply unit (800) supplies power to the motor (500) and the solenoid valve (100) through the power supply lines (810, 820).

[0052] The motor (500) provided in the rotor (600) can drive the rotor (600) by supplying power to the motor (500) when power is not supplied to the reactor coolant pump (RCP).

[0053] When the solenoid valve (100) is opened, energy is supplied from the energy storage unit (300) through the energy supply pipe and nozzle (310) to rotate the impulse blade (200) of the reactor coolant pump (RCP), such as pneumatic, hydraulic, or water pressure.

[0054] The capacity of air storage tanks, water tanks, etc., which are energy storage and supply devices such as compressed air or pressurized water sources, is equipped with the capacity to supply air and water sources so that the reactor coolant pump (RCP) can coast in the event of a power loss to the RCP.

[0055] It is configured to be usable with air receiver tanks or portable gas storage tanks, such as compressed air systems, hydrogen systems, nitrogen systems, and carbon dioxide systems, which are already reflected in the auxiliary systems of nuclear power plants.

[0056] When applying a water tank to supply water, it should be positioned so that it can be pressurized at a higher location than the reactor coolant pump (RCP) location.

[0057] Figure 4 is an operation flow chart of a small modular reactor coolant pump according to the present invention.

[0058] At stage S10, the reactor coolant pump (RCP) of the small modular reactor is powered by an unillustrated power supply and operates normally.

[0059] Step S20 determines whether the reactor coolant pump (RCP) is operating normally based on whether the rotation shaft is rotating as detected by the rotation detection unit, which is an auxiliary measure for power loss of the RCP.

[0060] Step S30 determines whether to supply power to the solenoid valve if the rotation sensor determines that the rotation shaft is not rotating.

[0061] Step S40 determines that there is no power supply to the solenoid valve, which automatically opens the solenoid valve and fails open in the event of a power loss.

[0062] S50 stage determines that the solenoid valve is energized and the operator manually opens the solenoid valve in the main control room (MCR) or on-site.

[0063] In the S60 stage, when the solenoid valve is opened, the energy supply, such as pneumatic, hydraulic, or water pressure, is received from the energy storage unit through the energy supply pipe and nozzle to rotate the impulse blade of the reactor coolant pump (RCP).

[0064] In stage S70, the reactor coolant pump (RCP) begins coast-down operation, receiving energy from the energy storage unit.

[0065] The present invention can provide a means for enabling a passive reactor coolant pump (RCP) to operate at an inertial crawl without an external power source even when power supply is lost.

[0066] Unlike conventional commercial nuclear power plants, small modular reactors are characterized by integrating major components into the reactor vessel, and therefore each major component is subject to significant constraints in size and placement.

[0067] However, the present invention replaces a flywheel that takes up a large amount of weight and volume, and has a compact configuration with a solenoid valve that operates when the power of the reactor coolant pump is lost, and an impulse blade provided on the rotor of the reactor coolant pump, thereby extending the inertia slowdown operation time of the reactor coolant pump, thereby contributing to the improvement of nuclear power plant safety.

[0068] Although the present invention has been described in detail through representative examples above, those skilled in the art to which the present invention pertains will understand that various modifications can be made to the above-described embodiments without departing from the scope of the present invention.

[0069] Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by all changes or modifications derived from the claims and equivalent concepts as well as the claims described below.

[0070] [Explanation of symbols]

[0071] 100: Solenoid valve

[0072] 200: Impulse Blade

[0073] 300: Energy storage unit

[0074] 310: Energy supply piping and nozzles

[0075] 400: Rotation axis

[0076] 410: Rotation detection unit

[0077] 500: Motor

[0078] 600: Rotor

[0079] 700: Impeller

[0080] 800: Power supply

Claims

1. A small modular reactor reactor coolant pump (RCP) inertial locomotion device includes a solenoid valve (100), a rotor (600) installed on a rotational axis (400) including an impulsive blade (200), and an energy storage unit (300) that rotates the impulsive blade. The rotation shaft (400) of the reactor coolant pump (RCP) is equipped with a rotation detection unit (410) that detects whether it is rotating. An impulse blade (200), a motor (500), and an impeller (700) that rotate by receiving energy from an energy storage unit (300) are installed on a rotor (600) installed on a rotation axis (400). The solenoid valve (100) operates in a fail open state when the power of the reactor coolant pump (RCP) is lost. When power is not supplied to the reactor coolant pump (RCP), the power supply unit (800) supplies power to the motor (500) and the solenoid valve (100) through the power supply lines (810, 820). A small modular reactor coolant pump inertia crawl device characterized in that when the solenoid valve (100) is opened, energy is supplied from the energy storage unit (300) through the energy supply pipe and nozzle (310) to rotate the impulse blade (200) of the reactor coolant pump (RCP).

2. In paragraph 1, A small modular reactor coolant pump inertia crawl device characterized in that the rotation detection unit (410) detects whether power is supplied smoothly to the solenoid valve (100) even though power is not supplied to the reactor coolant pump (RCP), and transmits the detection result to the solenoid valve (100) through the detection line (420).

3. In paragraph 2, A small modular reactor coolant pump inertia crawl device characterized in that the solenoid valve (100) is manually opened by an operator in the main control room (MCR) or on-site when power is supplied smoothly to the solenoid valve (100).

4. In paragraph 3, A small modular nuclear reactor coolant pump inertia crawl device characterized in that when the solenoid valve (100) is opened, it receives energy supply of pneumatic, hydraulic, and water pressure to rotate the impulse blade (200) of the reactor coolant pump (RCP) through the energy supply pipe and nozzle (310) from the energy storage unit (300).

5. A method for operating a small modular reactor coolant pump inertia creep device according to any one of paragraphs 1 to 4, The reactor coolant pump (RCP) of the small modular reactor is in a normal operation stage (S10) by receiving power from an unillustrated power supply unit. A step (S20) for determining whether the RCP is operating normally based on whether the rotation shaft detected by the rotation detection unit, which is an auxiliary measuring means for power loss of the reactor coolant pump (RCP), is rotating. When the rotation detection unit determines that the rotation shaft is not rotating, a step (S30) is performed to determine whether power is supplied to the solenoid valve. If it is determined that power is not supplied to the solenoid valve, a step (S40) is performed to automatically open the solenoid valve in the event of a power loss accident. It is determined that power is supplied to the solenoid valve, and the step (S50) is to manually operate the solenoid valve to open it in the main control room (MCR) or on-site. When the solenoid valve is opened, a step (S60) of receiving energy supply such as pneumatic, hydraulic, or water pressure to rotate the impulse blade of the reactor coolant pump (RCP) through the energy supply pipe and nozzle from the energy storage unit, and A method for coast-down operation of a small modular nuclear reactor reactor coolant pump (RCP), characterized in that it includes a step (S70) of starting coast-down operation of the RCP by receiving energy from an energy storage unit.

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