JP2008064649A - Device and method for controlling system water temperature in hydraulic pressure system for driving control rod - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain the system water temperature in a hydraulic pressure system for driving control rods from fluctuating regardless of the fluctuation in the temperature of a supply water source by carrying out a stable operation in a controller for the system water temperature of the hydraulic pressure system for driving the control rods in a nuclear power plant. <P>SOLUTION: The controller includes a system water temperature detector 15 for detecting the temperature of system water, a flow rate regulating valve placed on a flow channel whose supply source is a condensate storage tank 2 and a means for regulating the opening of the valve located on the flow channel whose supply source is the condensate storage tank 2 by sensing the temperature change in the system water on the basis of the output of the system water temperature detector 15. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a system water temperature control device and a control method for a control rod drive hydraulic system in a boiling water reactor.

  The control rod drive hydraulic system, which is one of the systems that constitute the control rod drive system in boiling water nuclear power plants, is the drive water used to insert and withdraw the control rod that controls the reactor output with water pressure during normal plant operation. In addition to filling water for rapid insertion of control rods (scram) in emergency, cooling water for system equipment protection, Primary Loop Recirculation Pump (hereinafter referred to as “PLR pump”) and reactor purification system This is an important system for supplying seal water to a shaft seal mechanism (mechanical seal) of a pump (Reactor Water Clean-Up Pump: hereinafter referred to as “CUW pump”).

  FIG. 8 shows a system for supplying drive water pressure among control rod drive systems of a nuclear power plant composed of a general boiling water reactor. A conventional example of the system water temperature control of the control rod drive hydraulic system will be described with reference to FIG.

  The example shown in FIG. 8 includes two water sources, a condensate system that is a supply water source 1 during normal operation, and a condensate storage tank 2 that is a supply water source when the reactor is shut down. Supply water source valves 3 and 4 are respectively installed on the tank 2 side.

  The supply water is pressurized by the control rod drive water pump 6 via the suction filter 5, and is supplied via the drive water filter 7 to the supply water line 8 to the shaft seal mechanism of the control rod drive system, CUW pump, and PLR pump. Distributed. In addition, a minimum flow line 9 is installed to protect the pump equipment, and the heater outlet water temperature detection for measuring the water temperature of the control rod driving water heater 10 and the outlet of the control rod driving water heater on the flow path. A vessel 11 is installed.

  Further, a minimum flow bypass line 12 for returning the system water to the condensate storage tank 2 is installed, and a motor-operated valve 13 that is normally fully closed is installed on the flow path. The motor-operated valve 13 is operated by the interlock 14 of the control rod driving water heater 10 that is opened when the temperature of the system water temperature detector 11 exceeds a certain set temperature, and the system water circulating through the minimum flow line 9 is supplied. By discharging to the condensate storage tank 2, overheating of the system is prevented.

  In the conventional control rod drive hydraulic system configured as described above, the supply water source 1 of the control rod drive hydraulic system during normal plant operation is condensate using the condenser as the water source, and the condensate temperature is the condensate. Fluctuates depending on the condenser vacuum level because of the saturation temperature of the condenser vacuum. Therefore, if the condenser pressure balance is lost, the condenser vacuum saturation temperature, i.e., the condensate temperature, will fluctuate, causing disturbance to the system water temperature of the control rod drive hydraulic system located downstream of the condensate system. Become.

  During plant operation, the condenser vacuum is usually kept constant, but the condensate is reconstituted by a reverse flow operation (condenser backwashing) operation for cooling the condenser cooling pipes that is carried out regularly. It is known that a change in vessel vacuum appears prominently and an event occurs in which the condensate temperature changes. At this time, when the temperature fluctuation of the condensate is in a decreasing direction, the control rod driving water heater 10 is installed, so that the temperature decrease can be mitigated.

  On the other hand, when the temperature rises, the function of actively cooling the system water is not installed in the system configuration, so that it is difficult to suppress the temperature increase. Furthermore, the shaft seal mechanism of the PLR pump using the control rod drive hydraulic system as the supply water source will be greatly affected.

  The shaft sealing mechanism of the PLR pump installed for the purpose of preventing leakage of high-temperature, high-pressure and radioactive reactor water is a mechanical seal, and is made up of three different parts (stationary ring, seat ring and rotating ring). It is configured. In addition, purge water is supplied using a control rod drive hydraulic system as a water source in order to prevent foreign matter from entering the contact surface and radioactive contamination.

  For this reason, when the water temperature of the control rod drive hydraulic system that is the supply water source rises, the seal surface changes due to the difference in the coefficient of thermal expansion of the member, and the sealing function is lowered, so the soundness of the mechanical seal is maintained. become unable. Furthermore, when the seal function is significantly reduced, the operation of the PLR pump cannot be continued, and the system water temperature of the control rod drive hydraulic system rises, leading to a plant shutdown. For this reason, in terms of plant stable operation and plant operation rate, the system water temperature control in the current control rod drive hydraulic system has a problem in that the system water temperature cannot be stably maintained due to the system configuration.

Conventionally, a technique for reducing the deformation of the sliding surface by reducing the temperature fluctuation range from the reference temperature of the shaft seal chamber as much as possible has been disclosed (see Patent Document 1, etc.).
Japanese Patent Publication No. 5-24359

  Since the conventional control rod drive water pressure system has a system configuration in which it is difficult to keep the system at an appropriate water temperature against the temperature fluctuation of the supply water source, the function of the PLR pump shaft seal mechanism deteriorates especially when the system water temperature rises. It was easy to induce and hindered the operation of the PLR pump and the nuclear power plant.

  The present invention has been made in view of such conventional circumstances, and is intended for stable operation of a nuclear power plant, and control for suppressing fluctuations in the system water temperature of the control rod drive hydraulic system regardless of temperature fluctuations of the supply water source. It aims at providing the system | strain water temperature control apparatus and control method of a rod drive hydraulic system.

  The present invention provides a control rod drive hydraulic system characterized in that the control rod drive hydraulic system of a boiling water reactor is equipped with a system water temperature fluctuation mitigation means for mitigating fluctuations in both directions of temperature rise and fall of the system water. A system water temperature control device is provided.

  Further, the present invention relates to a system water temperature control device of a control rod drive hydraulic system, wherein the system water temperature fluctuation mitigation means is provided on a flow path whose source is a system water temperature detector for detecting the temperature of the system water and a condensate storage tank. The flow adjustment valve installed in the system and the function of adjusting the opening of the valve installed on the flow path using the condensate storage tank as a supply source by detecting the temperature change of the system water based on the output of the system water temperature detector And a system water temperature control device for a control rod drive hydraulic system.

  The present invention also includes a step of calculating a deviation from a set temperature based on an output of a system water temperature detector that detects a temperature of the system water in a boiling water reactor, and a supply water source based on the deviation calculated in this step A step of commanding the opening requirements of the valves installed on the respective flow paths of the condensate system and the condensate storage tank, and on the supply water flow path from the condensate system based on the detector output of the system water temperature from this process Providing a control water temperature control method for a control rod drive hydraulic system, comprising: a step of closing an installed valve and an opening operation of a valve installed on a supply water flow path from a condensate storage tank To do.

  ADVANTAGE OF THE INVENTION According to this invention, stable operation of a nuclear power plant can be aimed at, and the fluctuation | variation of the temperature rise and fall of the system | strain water temperature of a control rod drive hydraulic system can be suppressed irrespective of the temperature fluctuation of a supply water source.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a control rod drive water pressure system water temperature control device and a control method according to the present invention will be described below with reference to the drawings.

[First Embodiment]
FIG. 1 is a configuration diagram showing a system water temperature control device of a control rod drive hydraulic system according to a first embodiment of the present invention, and FIG. 2 is a configuration diagram showing the control device.

  In the present embodiment, a system water temperature control device for a control rod drive hydraulic system including a system water temperature fluctuation mitigating means for mitigating fluctuations in both directions of temperature rise and fall of the system water temperature will be described. In particular, the temperature of the system water based on the output of the system water temperature detector for detecting the temperature of the system water, the flow rate adjusting valve installed on the flow path from the condensate storage tank 2, and the output of the system water temperature detector A system water temperature control device of a control rod drive hydraulic system having means for detecting a change and adjusting a valve opening degree installed on a flow path using the condensate storage tank 2 as a supply source will be described.

  Further, in the present embodiment, there is a function that can arbitrarily set the temperature of the system water, and further, a calculation unit that calculates a deviation from the set temperature based on the output of the system water temperature detector, and the calculation unit calculates A control device comprising a calculation unit for calculating the opening degree requirement of the valve installed on the flow path using the condensate storage tank 2 as a supply source based on the deviation to be supplied. A system water temperature control method of a control rod drive hydraulic system in which the valve installed on the flow path is opened and closed until the temperature deviation becomes zero based on the output of the control device will be described.

  As shown in FIG. 1, the present embodiment includes two systems of water sources, a condensate system that is a supply water source 1 during normal operation and a condensate storage tank 2 that is a supply water source when the reactor is shut down. Water supply source valves 3 and 4 are installed on the side of the condensate storage tank 2 and the side of the condensate storage tank 2, respectively.

  The supply water is pressurized by the control rod drive water pump 6 via the suction filter 5, and is supplied via the drive water filter 7 to the supply water line 8 to the shaft seal mechanism of the control rod drive system, CUW pump, and PLR pump. Distributed. In addition, a minimum flow line 9 is installed to protect the pump equipment, and the heater outlet water temperature detection for measuring the water temperature of the control rod driving water heater 10 and the outlet of the control rod driving water heater on the flow path. A vessel 11 is installed.

  Further, a minimum flow bypass line 12 for returning the system water to the condensate storage tank 2 is installed, and a motor-operated valve 13 that is normally fully closed is installed on the flow path. This motor-operated valve 13 is operated by an interlock 14 of the control rod drive water heater 10 that opens when the temperature of the heater outlet water temperature detector 11 exceeds a certain set temperature, and the system water circulating through the minimum flow line 9 is operated. Is discharged to the condensate storage tank 2 to prevent overheating of the system.

  In such a configuration, the condensate storage tank side supply water source valve 4a that enables flow rate adjustment to the system of the control rod drive hydraulic system, and the system water temperature detector 15 that measures the system water temperature of the control rod drive hydraulic system. And the control part 16a is installed, and the control part 16a has a function which can set arbitrarily the water temperature setting value 17 of the system | strain of a control rod drive hydraulic system.

  Further, as shown in FIG. 2, the control unit 16 a determines the system water temperature based on the detector output 18 of the system water temperature detector 15 that measures the system water of the control rod drive hydraulic system and the system water temperature set value 17. Equipped with a calculation function for calculating a deviation between the detector output 18 and the system water temperature set value 17 and a calculation function for converting an operation amount corresponding to the deviation into a valve opening degree, the condensate storage tank side supply water source valve 4a On the other hand, an opening degree command is output as the controller output 19a.

  In the present embodiment configured as described above, the supply water using the condensate storage tank 2 as a water source usually has a lower water temperature than the supply water source 1 during normal operation. This alleviates the rise in system water temperature and acts as a cooling function for the control rod drive hydraulic system. That is, according to the present embodiment, stable operation of the nuclear power plant can be achieved, and fluctuations in both the temperature rise and fall of the system water temperature of the control rod drive hydraulic system can be suppressed regardless of the temperature fluctuation of the supply water source. .

  Further, according to the present embodiment, since the function of cooling the system water of the control rod drive hydraulic system is equipped, the system water temperature of the control rod drive hydraulic system is improved in robustness against the temperature disturbance of the supply water source. The supply water line 8 to the PLR pump shaft seal mechanism is supplied with system water having a stable water temperature from the control rod drive hydraulic system.

[Second Embodiment]
FIG. 3 is a block diagram showing a system water temperature control device of a control rod drive hydraulic system according to a second embodiment of the present invention, and FIG. 4 is a block diagram showing a control unit.

  In this embodiment, in the control rod drive hydraulic system of the control rod drive mechanism, the valve installed on the flow path of the system water supplied from the condensate system and the flow path of the system water supplied from the condensate storage tank 2 A control rod drive hydraulic system comprising means for operating a valve installed on the water supply, a condensate system valve installed on the flow path from the supply water source, and a condensate storage tank 2 valve The water temperature control device will be described.

  Moreover, based on the deviation which the operation part which has the function which can set the temperature of system water arbitrarily, calculates a deviation with setting temperature based on the output of system water temperature detector 15, and this operation part calculates It comprises a control unit 16b composed of a calculation unit for commanding an opening degree request of a valve installed on the flow path of each of the condensate system and the condensate storage tank 2 serving as a supply water source. A control rod drive hydraulic system that closes the valve installed on the supply water flow path from the condensate system and opens the valve installed on the supply water flow path from the condensate storage tank 2 based on the detector output 18. The system water temperature control method will be described.

  As shown in FIG. 3, in this embodiment, a condensate-side supply water source valve 3 and a condensate storage tank-side supply water source valve 4 b that can be arbitrarily opened and closed respectively are connected to the control rod drive hydraulic system. The system water temperature detector 15 for measuring the system water temperature of the control rod drive hydraulic system and the control unit 16b are installed, and the control unit 16b can arbitrarily set the water temperature set value 17 of the system of the control rod drive hydraulic system. It has a function.

  As shown in FIG. 4, the control unit 16 b detects the system water temperature based on the output 18 of the system water temperature detector 15 that measures the system water of the control rod drive hydraulic system and the system water temperature set value 17. A deviation between the output 18 of the vessel 15 and the system water temperature set value 17 is calculated and equipped with a calculation unit for determining whether the deviation is outside the allowable range, and based on the calculation result as a control unit output 19b, A control logic circuit that outputs an open / close command to the condensate-side supply water source valve 3 and the condensate storage tank-side supply water source valve 4b is mounted.

  Furthermore, at the time of the condenser backwashing operation in which it is known in advance that the temperature change of the condensate serving as the supply water appears prominently, the control unit 16b instructs the condensate backwashing operation 20 performed by the operator. The control unit output 19b is not dependent on the change in the system water temperature, and control logic for outputting an open / close command to the condensate side supply water source valve 3 and the condensate storage tank side supply water source valve 4b is also installed. It is the composition to do.

  In the present embodiment configured as described above, since the supply water source is switched to the condensate storage tank 2 that is hardly affected by the water temperature fluctuation at least when the temperature fluctuation of the supply water source 1 during normal operation is detected, It acts as a temperature disturbance suppression function of the supply water source 1 during normal operation in the control rod drive hydraulic system.

  Also according to this embodiment, stable operation of the nuclear power plant can be achieved, and fluctuations in both the rise and fall of the system water temperature of the control rod drive hydraulic system can be suppressed regardless of the temperature fluctuation of the supply water source.

  In particular, according to the present embodiment, it is possible to suppress the adverse effect caused by fluctuations in the supply water temperature of the control rod drive hydraulic system from being propagated to the entire system, and to stabilize the system water temperature of the control rod drive hydraulic system. It becomes possible to continue supplying the system water having a stable water temperature to the supply water line 8 to the shaft seal mechanism from the control rod drive hydraulic system.

[Third Embodiment]
FIG. 5 is a block diagram showing a system water temperature control device of a control rod drive hydraulic system according to a third embodiment of the present invention, and FIG. 6 is a block diagram showing a control unit.

  In the present embodiment, the system water temperature detector that detects the temperature of the system water, the facility having the function of cooling the system water, and the fluctuation amount of the system water temperature that is detected based on the output of the system water temperature detector A system water temperature control device of a control rod drive hydraulic system having means for operating a facility having a system water cooling function will be described.

  In addition, it has a function that can arbitrarily set the temperature of the system water, and further calculates a deviation from the set temperature based on the output of the temperature detector of the system water, and based on the deviation output by the calculation unit. And a control unit for operating a facility having a cooling function for system water, and this control unit describes a system water temperature control method for a control rod drive hydraulic system that outputs an operation command according to the output of the arithmetic unit to the cooling facility. To do. Furthermore, a control part demonstrates the system water temperature control method of the control rod drive hydraulic system characterized by operating the installation which has the function to cool system water based on the instruction | indication of a condenser backwash operation.

  As shown in FIG. 5, in this embodiment, the control rod drive hydraulic system is provided with a cooling device 21 that is not normally passed on the supply flow path of the system water, and the system water to the cooling device 21. A flow rate adjusting valve 22 having a function of adjusting the inflow amount is provided, and the flow rate adjusting valve 22 is appropriately controlled by an opening degree command that is a control unit output 19c of the control unit 16c.

  Moreover, as shown in FIG. 6, the control part 16c based on the output 18 of the system water temperature detector 15 has a function that can arbitrarily set the system water temperature set value 17, and the system water temperature set value 17 and the detector A calculation function is provided that calculates a deviation based on the output 18, calculates an operation amount corresponding to the deviation, and outputs an opening degree command to the flow rate adjustment valve 22.

  Furthermore, at the time of the condenser backwashing operation in which it is known in advance that the temperature change of the condensate serving as the supply water appears prominently, the controller 16c performs the condenser backwashing operation command 20 executed by the operator. Therefore, a control logic for forcibly outputting an opening command to the flow rate adjusting valve 22 is mounted as the control unit output 19c.

  In the present embodiment configured as described above, it functions as a cooling function of the system water in the control rod drive hydraulic system. That is, according to the present embodiment, stable operation of the nuclear power plant can be achieved, and fluctuations in both the temperature rise and fall of the system water temperature of the control rod drive hydraulic system can be suppressed regardless of the temperature fluctuation of the supply water source. .

  In particular, according to this embodiment, since the function of cooling the system water of the control rod drive hydraulic system will be equipped, the system water temperature of the control rod drive hydraulic system has a great effect of suppressing the temperature disturbance of the supply water source, Stable water temperature water can be supplied to the PLR pump shaft seal mechanism.

[Fourth Embodiment]
FIG. 7 is a block diagram showing a system water temperature control device of a control rod drive hydraulic system according to a fourth embodiment of the present invention.

  In the present embodiment, a system water temperature control device for a control rod drive hydraulic system including equipment for accumulating system water on a flow path of a system supplied from a supply water source for the control rod drive hydraulic system to a seal cavity of the PLR pump will be described.

  As shown in FIG. 7, in this embodiment, a system water storage tank 23 is installed on the system flow path of the control rod drive hydraulic system, and at least a supply water line to the PLR seal cavity that is easily affected by the system water temperature is provided. It arrange | positions so that it may supply from the storage tank 23.

  In the present embodiment configured as described above, the storage tank 23 acts as a buffer device against the system temperature fluctuation of the control rod drive hydraulic system with respect to the water supplied to the shaft seal mechanism of the PLR pump. That is, according to this embodiment as well, stable operation of the nuclear power plant can be achieved, and fluctuations in both the rise and fall of the system water temperature of the control rod drive hydraulic system can be suppressed regardless of the temperature fluctuation of the supply water source.

  In particular, according to the present embodiment, it is possible to alleviate and absorb the temperature fluctuation of the system water without configuring equipment for cooling the system water of the control rod drive hydraulic system, or configuring a complicated control device or control logic. Therefore, it is possible to supply system water having a stable water temperature to the supply water line 8 to the PLR pump shaft seal mechanism.

The block diagram which shows the system | strain water temperature control apparatus of the control-rod drive hydraulic system by 1st Embodiment of this invention. The block diagram which shows the control part in 1st Embodiment of this invention. The block diagram which shows the system | strain water temperature control apparatus of the control-rod drive hydraulic system in 2nd Embodiment of this invention. The block diagram which shows the control part in 2nd Embodiment of this invention. The block diagram which shows the system | strain water temperature control apparatus of the control-rod drive hydraulic system in 3rd Embodiment of this invention. The block diagram which shows the control part in 3rd Embodiment of this invention. The block diagram which shows the system | strain water temperature control apparatus of the control-rod drive hydraulic system in 4th Embodiment of this invention. The system diagram which shows the conventional control rod drive hydraulic system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Supply water source at the time of normal operation 2 Condensate storage tank 3 Condensate side supply water source valve 4, 4a, 4b Condensate storage tank side supply water source valve 5 Suction filter 6 Control rod drive water pump 7 Drive water filter 8 PLR pump Supply water line 9 to shaft seal mechanism Minimum flow line 10 Control rod drive water heater 11 Heater outlet water temperature detector 12 Minimum flow bypass line 13 Motor operated valve 14 Interlock of control rod drive water heater 15 System water temperature detector 16a, 16b, 16c Control unit 17 System water temperature set value 18 Detector output 19a, 19b, 19c Control unit output 20 Condenser backwash operation command 21 Cooling device 22 Flow control valve 23 Stockpile tank

Claims (6)

A system water temperature control device for a control rod drive hydraulic system, characterized in that the control rod drive hydraulic system for a boiling water reactor is equipped with a system water temperature fluctuation mitigation means for reducing fluctuations in both directions of temperature rise and fall of the system water . 2. The system water temperature control device for a control rod drive hydraulic system according to claim 1, wherein the system water temperature fluctuation mitigating means is provided on a flow path whose source is a system water temperature detector for detecting the temperature of the system water and a condensate storage tank. The installed flow control valve and the function to detect the temperature change of the system water based on the output of the system water temperature detector and adjust the opening of the valve installed on the flow path using the condensate storage tank as the supply source A system water temperature control device for a control rod drive hydraulic system. 2. A control water temperature control system for a control rod drive hydraulic system according to claim 1, wherein a valve installed on a flow path of system water supplied from a condensate system and a flow path of system water supplied from a condensate storage tank. Control rod drive water pressure characterized by comprising a valve having a function of operating a valve installed, a condensate system valve and a condensate storage tank valve installed on a flow path from a supply water source System water temperature control device. The system water temperature control apparatus of the control rod drive hydraulic system according to claim 1, wherein the system water temperature fluctuation mitigating means includes a system water temperature detector for detecting the temperature of the system water, a facility having a function of cooling the system water, and a system System water temperature control of a control rod drive hydraulic system characterized by comprising means for operating a facility having a system water cooling function in accordance with a fluctuation amount of the system water temperature detected based on the output of the water temperature detector apparatus. 2. The control rod drive hydraulic system water temperature control apparatus according to claim 1, further comprising a facility for accumulating system water on a flow path of a system supplied from a supply water source of the control rod drive hydraulic system to a seal cavity of the PLR pump. The system water temperature control device of the control rod drive water pressure system characterized. A step of calculating a deviation from the set temperature based on the output of the system water temperature detector for detecting the temperature of the system water in the boiling water reactor, and a condensate system as a supply water source based on the deviation calculated in this step, and The process of commanding the opening requirement of the valve installed on each flow path of the condensate storage tank, and the valve installed on the supply water flow path from the condensate system based on the detector output of the system water temperature from this process The system water temperature control method of the control rod drive hydraulic system characterized by comprising the step of opening the valve installed on the supply water flow path from the condensate storage tank and closing the valve.

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