Main steam pressure control device and method under emergency shutdown condition of high-temperature gas cooled reactor

Abstract

The invention relates to the technical field of automatic control of high-temperature reactors, and discloses a main steam pressure control device and method under an emergency shutdown condition of a high-temperature gas cooled reactor, which are applied to a steam turbine control system with one machine in two reactors. The device is characterized in that a total valve position reference value output module corresponding to shut-down power calculates a total valve position reference value corresponding to the shut-down power in a voltage control mode; the band rate output module generates a feed-forward value for the pressure controller based on the value. The pressure controller outputs a pressure control value based on a preset pressure set value, a pressure actual value and a feedforward value; the pressure control trigger module switches the valve control mode into the pressure control mode when emergency shutdown occurs in the valve control mode or a pressure control button is input; the valve control instruction generation module generates a valve control instruction according to a pressure control value in a pressure control mode or a preset valve position target value in a valve position mode and after an RB action is triggered by emergency shut-down, the valve control instruction generation module is combined with the RB rate, and it can be guaranteed that the fluctuation of the pressure of the steam mother pipe is within the allowable range in the DEH pressure control or valve control mode.

Description

Technical Field

[0001] The present invention relates to the technical field of automatic control of high temperature reactors, and in particular to a main steam pressure control device and method for a high temperature gas-cooled reactor under emergency shutdown conditions. Background Art

[0002] The pressurized water reactor nuclear power plant units adopt the reactor-following-machine control mode. The steam in front of the steam turbine is saturated steam, and the pressure is in the sliding pressure operation mode. There is no separate steam pressure control, and the steam pressure changes with the load changes of the unit. The high-temperature gas-cooled reactor demonstration project is equipped with two reactors. Each reactor is equipped with an independent water supply system, a start-stop system and a bypass system. The superheated steam of the two reactors is merged into the steam main pipe and directly connected to the turbine. The unit adopts the machine-following-the-reactor operation mode. The reactor controls the reactor power to achieve unit load control, and the steam turbine control system (DEH) or the bypass system controls the steam pressure. The schematic diagram of the steam system is as follows Figure 1 When the first reactor is started, the steam enters the steam turbine through its start-stop system and the isolation valve before the bypass valve for start-up, grid connection and pressure increase, and then the steam is switched to the steam main pipeline for operation. If another reactor needs to be started, the steam is pressurized through its start-stop system and bypass valve, and then cut to its steam main pipeline and then merged into the steam main pipe to enter the steam turbine for operation.

[0003] DEH has three control modes: speed control, pressure control and valve control. Speed ​​control is used for turbine run-up; the turbine generator automatically switches to valve control after being connected to the grid; after the main steam pressure rises to 11MPa, DEH is in pressure control mode, and pressure control uses a proportional integral controller. When a single reactor is in operation or the total load of a dual reactor is less than 20%, the main steam pressure can be maintained stable only by the pressure control feedback effect; when the dual reactor is operating with one unit power, the emergency shutdown of a reactor will cause its steam generator to be cut off from water, the steam in the steam main pipe will be reduced, and the pressure will drop suddenly. At this time, it is difficult to curb the large fluctuations in steam pressure by relying solely on the pressure control feedback effect, which poses a threat to the stable operation of the other reactor.

[0004] In addition, the steam generator of the high-temperature reactor is the first set of equipment, which adopts a vertical, DC spiral tube assembly structure. At the same time, the steam generator acts as a barrier and needs to ensure the integrity of the pressure boundary of the first circuit to prevent the first circuit coolant and radioactive materials from being released into the second circuit. Therefore, the pressure fluctuation of the steam generator needs to be strictly controlled to be less than ±1MPa. Summary of the invention

[0005] In view of this, the present invention provides a main steam pressure control device and method under emergency shutdown conditions of a high temperature gas-cooled reactor, so as to control and reduce the fluctuation of steam pressure under emergency shutdown conditions.

[0006] In a first aspect, the present invention provides a main steam pressure control device for a high temperature gas-cooled reactor under emergency shutdown conditions, which is applied to a steam turbine control system with two reactors and one machine, comprising:

[0007] A total valve position reference value output module corresponding to the shutdown power of the stack, used to calculate the total valve position reference value corresponding to the shutdown power of the stack 1# and the stack 2# in a pressure control mode based on the shutdown signal of the stack 1# and / or the shutdown signal of the stack 2#;

[0008] A rate output module is provided, which is used to obtain a total valve position reference value corresponding to the shutdown power and generate a corresponding feedforward value of a pressure controller;

[0009] A pressure controller, configured to output a pressure control value based on a preset pressure setting value, an actual pressure value, and the feedforward value;

[0010] The pressure control trigger module is used to switch the valve control mode to the pressure control mode when an emergency shutdown occurs in the valve control mode or the pressure control button is put into operation;

[0011] The valve regulating instruction generation module is used to generate a valve regulating instruction based on the pressure control value output by the pressure controller in the pressure control mode, or based on the preset valve position target value in the valve position mode and the RB rate after the emergency shutdown triggers the RB action, so as to make the valve regulating action respond to the main steam pressure fluctuation.

[0012] The main steam pressure control device under the emergency shutdown condition of the high-temperature gas-cooled reactor provided by the embodiment of the present invention can realize the rapid reduction of the turbine regulating command under DEH pressure control or valve control mode when the dual-reactor is operating with one unit power, ensuring that the fluctuation of the steam main pipe pressure is within the allowable range, and ensuring that the other reactor continues to operate normally and stably with load.

[0013] In an optional implementation manner, the total valve position reference value output module corresponding to the shutdown power includes:

[0014] The shutdown power calculation unit of the 1# stack is used to calculate the shutdown power of the 1# stack according to the shutdown signal of the 1# stack, the power operation signal of the 1# stack and the power of the 1# stack;

[0015] A shutdown power calculation unit of the 2# stack, used for calculating the shutdown power of the 2# stack according to the shutdown signal of the 2# stack, the power operation signal of the 2# stack and the power of the 2# stack;

[0016] The total valve position reference value output unit corresponding to the shutdown power is used to add the shutdown power of the 1# stack and the shutdown power of the 2# stack, input the sum into the function of the reactor dual stack power percentage and the total valve position reference value, obtain the total valve position reference value corresponding to the shutdown power, and then invert it.

[0017] The embodiment of the present invention calculates the shutdown power of the 1# and 2# stacks respectively based on the shutdown signal, the power operation signal and the actual power, which can fully consider various influencing factors and ensure the accuracy of the calculation results. The shutdown power of the two stacks is added and then input into a specific function, which can fully reflect the overall shutdown power level of the dual-stack system. By performing an inversion operation on the function result, an inverse relationship can be established between the shutdown power and the total valve position reference value. In this way, when an emergency shutdown condition occurs, the total valve position reference value will be adjusted in a decreasing direction accordingly, thereby achieving more precise control of the system.

[0018] In an optional implementation, the threshold adjustment instruction generation module includes:

[0019] A total valve position reference value output unit is used to obtain a total valve position reference value based on a pressure control value output by a pressure controller in a pressure control mode, or to generate a total valve position reference value based on a preset valve control target value and an RB rate after an emergency shutdown triggers an RB action in a valve control mode;

[0020] The valve control command output unit is used to input the total valve position reference value into a preset valve control flow function and then output the valve control command.

[0021] In the embodiment of the present invention, the total valve position reference value is determined by the pressure control value output by the pressure controller in the pressure control mode, so as to realize the precise control of the system pressure, help to ensure the stable operation of the system under different working conditions, and avoid the damage to the equipment and process caused by excessive pressure fluctuations; in the valve control mode, the total valve position reference value is generated based on the preset valve control target value, so as to accurately achieve the specific valve control target. After the emergency shutdown triggers the RB action, the total valve position reference value is generated according to the RB rate, so that the system can respond quickly and reduce the large fluctuation of the steam pressure.

[0022] In an optional embodiment, the device also includes: a two-level three-out-of-two logic module, which is used to generate an emergency shutdown signal based on the auxiliary contacts of the emergency shutdown interlock feedwater pump stop instruction and the network quantity of the DCS, and generate a 1# stack shutdown signal and / or a 2# stack shutdown signal under the premise that the quick release button is put into operation and the total valve position parameter is greater than a preset percentage.

[0023] The embodiment of the present invention can improve the reliability of the signal through the two-stage three-choose-two logic module to conveniently locate and isolate the fault. When the system is abnormal, by monitoring each channel of the two-stage three-choose-two logic module, it can be quickly determined which channel or which stage has a problem, so as to carry out maintenance and replacement in time without affecting the basic function of the entire shutdown system.

[0024] In an optional implementation, the above device further includes: a total valve position reference value calculation module corresponding to the remaining stack power and an RB action reset logic module, wherein:

[0025] RB action reset logic module is used to trigger the RB action signal to automatically reset when the deviation between the pressure setting value and the actual value is less than the preset value and the main steam pressure reaches a steady state after a preset delay time; or,

[0026] When the total valve position reference value is less than the output value of the total valve position reference value calculation module corresponding to the remaining stack power, the RB action signal is triggered to automatically reset; or,

[0027] When the automatic reset of the RB action signal fails, after the quick release button is manually exited or the operator resets the emergency shutdown interlock instruction of the reactor protection system, the 1# stack shutdown signal or the 2# stack shutdown signal is reset, triggering the RB action reset and the RB action signal is automatically reset.

[0028] The embodiment of the present invention triggers the RB action signal reset through multiple conditions, so that the system can avoid being in an abnormal state for a long time. If the RB action (rapid power reduction action) is not reset for a long time, it will bring human traps to the operator's operation, which may cause the reactor to shut down abnormally. The embodiment of the present invention can restore the normal power regulation function of the system in time under the premise of ensuring safety by setting a reasonable reset mechanism, prevent other safety problems caused by overprotection, and enable the system to resume normal steam production and power generation as soon as possible under the premise of safety, thereby improving the performance and efficiency of the entire system.

[0029] In an optional implementation, the total valve position reference value calculation module corresponding to the remaining stack power includes:

[0030] The remaining stack power calculation unit of the 1# stack is used to calculate the remaining stack power of the 1# stack according to the 1# stack shutdown signal, the 1# stack power operation signal and the 1# stack power;

[0031] The remaining stack power calculation unit of the 2# stack is used to calculate the remaining stack power of the 2# stack according to the 2# stack shutdown signal, the 2# stack power operation signal and the 2# stack power;

[0032] The total valve position reference value output unit corresponding to the remaining stack power is used to add the remaining stack power of stack 1 and the remaining stack power of stack 2 and input the result into the function of the reactor dual stack power percentage and the total valve position reference value to obtain the total valve position reference value corresponding to the remaining stack power.

[0033] The embodiment of the present invention considers the shutdown signal, power operation signal and actual power of the 1# and 2# reactors respectively, and can calculate the remaining reactor power of each reactor more comprehensively and accurately. The remaining reactor power of the two reactors is added and input into a specific function to obtain the total valve position reference value, which fully considers the comprehensive power situation of the entire system. In this way, it can be ensured that the total valve position reference value can reflect the overall demand of the dual-reactor system, thereby achieving more effective control of the system.

[0034] In a second aspect, the present invention provides a method for controlling the main steam pressure of a high temperature gas-cooled reactor under emergency shutdown conditions. The method, based on the device described in the first aspect, comprises:

[0035] When the dual-stack with one unit is operating normally, the turbine control system is in pressure control mode, the 1# stack power is operating and the 2# stack power is operating, the total valve position reference value is greater than the preset percentage value, the quick release button is in operation, and the feedforward value of the pressure controller is 0; when an emergency shutdown condition occurs, the RB action signal is triggered based on the generated 1# stack shutdown signal and / or 2# stack shutdown signal, and the turbine regulating valve is quickly closed to the opening corresponding to the remaining stack power through the feedforward effect, and the pressure is maintained near the preset target pressure by the pressure control proportional integral feedback effect of the pressure controller. When the deviation between the pressure set value and the actual value is less than the preset value, and after the preset delay time, the RB action signal is triggered to automatically reset after the main steam pressure reaches a steady state;

[0036] When the dual-stack with one unit operates normally, when the turbine control system switches the control mode to the valve control mode according to the unit status requirements, the total valve position reference value is equal to the preset valve position target value, and the output value of the pressure control automatically tracks the preset valve position target value. If an emergency shutdown condition occurs, the RB action signal is triggered based on the generated 1# stack shutdown signal and / or 2# stack shutdown signal, the total valve position reference value decreases at the RB rate, and the regulating valve is closed to control the pressure until the total valve position reference value is less than the total valve position reference value corresponding to the remaining stack power. The RB action signal is triggered to automatically reset, the pressure controller is automatically put into operation, and the main steam pressure is adjusted by the proportional integral effect.

[0037] The main steam pressure control method under the emergency shutdown condition of a high-temperature gas-cooled reactor provided in an embodiment of the present invention can realize the rapid reduction of the turbine throttle command under DEH pressure control or valve control mode when a dual-reactor is operating with one unit power, thereby ensuring that the fluctuation of the steam main pipe pressure is within the allowable range and ensuring that the other reactor continues to operate normally and stably with load.

[0038] In an optional embodiment, the process of generating the 1# stack shutdown signal and / or the 2# stack shutdown signal includes: generating the emergency shutdown signal based on the auxiliary contacts of the emergency shutdown interlock feedwater pump stop instruction and the network quantity of the DCS, and generating the 1# stack shutdown signal or the 2# stack shutdown signal under the premise that the quick release button is put into operation and the total valve position reference value is greater than a preset percentage;

[0039] In an optional embodiment, the method also includes: when the automatic reset of the RB action signal fails, manual exit is performed through the quick release button or when the operator resets the emergency shutdown interlock instruction of the reactor protection system, the 1# stack shutdown or 2# stack shutdown is reset, triggering the automatic reset of the RB action signal.

[0040] In an optional embodiment, when a No. 1 stack shutdown signal or a No. 2 stack shutdown signal is generated, the feedforward value of the pressure controller changes from 0 to a preset negative value at a first preset rate; when the operator resets the reactor protection system emergency shutdown interlock instruction or manually exits the quick release button, and the No. 1 stack shutdown signal or the No. 2 stack shutdown signal is reset, the feedforward value of the pressure controller recovers from the preset negative value to an initial value of 0 at a second preset rate, and the second preset rate is much smaller than the first preset rate.

[0041] The embodiment of the present invention can respectively achieve rapid response and smooth recovery during shutdown and signal reset by setting the above feedforward value changes, thereby improving the safety, stability and reliability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0043] Figure 1 is a schematic diagram of a steam system according to an embodiment of the present invention;

[0044] Figure 2 A schematic diagram of the functional modules of a main steam pressure control device under emergency shutdown conditions of a high temperature gas-cooled reactor according to an embodiment of the present invention;

[0045] Figure 3 is a schematic diagram of the components of a specific example of a main steam pressure control device under emergency shutdown conditions of a high temperature gas-cooled reactor according to an embodiment of the present invention;

[0046] Figure 4 is a schematic diagram of the composition of functional modules of a main steam pressure control device under emergency shutdown conditions of another high temperature gas-cooled reactor according to an embodiment of the present invention;

[0047] Figure 5 It is a component schematic diagram of a specific example of a two-stage three-out-of-two logic module, a total valve position reference value calculation module corresponding to the remaining stack power, and an RB action reset logic module in an embodiment of the present invention. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0049] like Figure 1 The schematic diagram of the steam system is shown, which includes the following components: 1# stack steam generator 1, 1# stack start and shutdown system 2, 1# stack bypass valve front isolation valve 3, 1# stack bypass valve 4, 1# stack conventional island side steam isolation valve 5, 1# stack conventional island side steam isolation valve 6, 2# stack steam generator 7, 2# stack start and shutdown system 8, 2# stack bypass valve front isolation valve 9, 2# stack bypass valve 10, 2# stack conventional island side steam isolation valve 11, 2# stack conventional island side steam isolation valve 12, 1# main steam valve 13, 2# main steam valve 14, 1# regulating valve 15, 3# regulating valve 16, 2# regulating valve 17, 4# regulating valve 18, generator 19, and steam turbine 20.

[0050] When the reactor is started, the steam enters the condenser through the bypass valve through the start-stop system, or enters the turbine for start-up; when two reactors are running with one unit, the steam of the two reactors passes through their respective steam main pipes and then merges into the steam main pipe and enters the turbine for operation; when the turbine trips, the steam of one of the reactors enters the condenser through the isolation valve before the bypass valve and the bypass valve.

[0051] In order to reduce the fluctuation of steam pressure under emergency shutdown conditions, the embodiment of the present invention designs a main steam pressure control logic configuration device and method, which can quickly reduce the turbine throttle command under DEH pressure control or valve control when dual reactors are operating with one unit power, ensure that the fluctuation of steam main pipe pressure is within the allowable range, and ensure that the other reactor continues to operate normally and stably with load.

[0052] Figure 2 Schematic diagram of a main steam pressure control device under emergency shutdown conditions of a high temperature gas-cooled reactor according to an embodiment of the present invention, comprising:

[0053] A total valve position reference value output module corresponding to the shutdown power of the stack, used to calculate the total valve position reference value corresponding to the shutdown power of the stack 1# and the stack 2# in a pressure control mode based on the shutdown signal of the stack 1# and / or the shutdown signal of the stack 2#;

[0054] With rate output module, it is used to obtain the total valve position reference value corresponding to the shutdown power and generate the feedforward value of the pressure controller;

[0055] A pressure controller, used for outputting a pressure control value based on a pressure set value, an actual pressure value, and a feedforward value;

[0056] The pressure control trigger module is used to switch the valve control mode to the pressure control mode when an emergency shutdown occurs in the valve control mode or the pressure control button is put into operation;

[0057] The valve regulating instruction generation module is used to generate a valve regulating instruction based on the pressure control value output by the pressure controller in the pressure control mode, or based on the preset valve position target value in the valve position mode and the RB rate after the emergency shutdown triggers the RB action, so as to make the valve regulating action respond to the main steam pressure fluctuation.

[0058] It should be noted that the RB (Run Back, rapid load reduction) action is mainly a series of control actions taken to ensure the safe and stable operation of the turbine and the entire system when a fault condition such as emergency shutdown of one or more modules occurs during the operation of a multi-module high-temperature gas-cooled reactor turbine and reactor.

[0059] The main steam pressure control device under the emergency shutdown condition of the high-temperature gas-cooled reactor provided by the embodiment of the present invention can realize the rapid reduction of the turbine regulating command under DEH pressure control or valve control mode when the dual-reactor is operating with one unit power, avoid excessive fluctuations in the steam pressure before the turbine, ensure that the fluctuation of the steam main pipe pressure is within the allowable range, and ensure that the other reactor continues to operate normally and stably with load.

[0060] The total valve position reference value output module corresponding to the shutdown power in the embodiment of the present invention includes:

[0061] The shutdown power calculation unit of the 1# stack is used to calculate the shutdown power of the 1# stack according to the shutdown signal of the 1# stack, the power operation signal of the 1# stack and the power of the 1# stack;

[0062] A shutdown power calculation unit of the 2# stack, used for calculating the shutdown power of the 2# stack according to the shutdown signal of the 2# stack, the power operation signal of the 2# stack and the power of the 2# stack;

[0063] The reference value output unit is used to add the shutdown power of the No. 1 stack and the shutdown power of the No. 2 stack, and then input it into the function of the reactor dual stack power percentage and the total valve position reference value to obtain the total valve position reference value corresponding to the shutdown power, and after inverting it, input it into the said rate output module.

[0064] The embodiment of the present invention calculates the shutdown power of the 1# and 2# stacks respectively based on the shutdown signal, the power operation signal and the actual power, which can fully consider various influencing factors and ensure the accuracy of the calculation results. The shutdown power of the two stacks is added and then input into a specific function, which can fully reflect the overall shutdown power level of the dual-stack system. By performing an inversion operation on the function result, an inverse relationship can be established between the shutdown power and the total valve position reference value. In this way, when an emergency shutdown condition occurs, the total valve position reference value will be adjusted in a decreasing direction accordingly, thereby achieving more precise control of the system.

[0065] In one embodiment, if Figure 3 As shown, the total valve position reference value output module corresponding to the stopped power calculates the stopped power of the 1# stack according to the 1# stack shutdown signal, the 1# stack power operation signal and the 1# stack power using the selection module 1 and the selection module 2, and calculates the stopped power of the 2# stack according to the 2# stack shutdown signal, the 2# stack power operation signal and the 2# stack power using the selection module 3 and the selection module 4, wherein each selection module outputs In2 ​​when SW=true; and outputs In1 when SW=false. The power calculated by the selection module 2 and the selection module 4 are added together and input into the function f(x) of the reactor dual stack power percentage and the total valve position reference value, f(x) is obtained from the unit power increase process, and the total valve position reference value corresponding to the stopped power is obtained after being inverted, and is input into the belt rate output module to generate the feedforward value of the pressure controller.

[0066] In the rate output module RATL in the embodiment of the present invention, HL is the up rate (IN is up from small to large), LL is the down rate (IN is down from large to small), OC of the pressure controller PID is the feedforward value, SP is the pressure setting value, PV is the actual pressure value, and the deviation between the setting value SP and the actual value PV is calculated as the controller output value AV after proportional integral operation. The pressure control trigger module is implemented by an RS trigger. When the deviation between the pressure setting value and the actual value is less than 50%, and the R terminal is false, when the emergency shutdown of the valve control mode generates the RB action triggering falling edge or the pressure control button is put into operation according to actual needs, the pressure control mode is put into operation. It should be noted that when the R terminal of the RS trigger is false and the S terminal is true, the output Out is true; when R is true, Out is false; when the R terminal is false and the S terminal is false, the output Out remains in the previous state.

[0067] In the embodiment of the present invention, when the steam of stack 1 or stack 2 does not enter the steam turbine, the power operation of stack 1 or stack 2 is false. In this case, the quick release button will not be put into operation, "stack 1 shutdown" and "stack 2 shutdown" are false, and the feedforward value OC is equal to 0. Only when the steam of stack 1 and stack 2 enter the steam turbine, the power operation of stack 1 and stack 2 are true, the quick release button can be put into operation, and the double stacks are operated with one machine power. In this case, an emergency shutdown condition occurs. After the shutdown of stack 1 or stack 2 is true, the OC value changes from 0 to a negative value (for example, -35) at a rate of 100 / cycle. After a period of time, the main steam pressure stabilizes near the set value under the pressure control feedforward and feedback. When the operator resets the emergency shutdown interlock instruction of the reactor protection system or the quick release button is manually exited, the shutdown of stack 1 or stack 2 will be reset to false, and then the OC value will recover from a negative value to the initial value of 0 at a small rate of 0.0001 / cycle. By setting the change of the feedforward value, rapid response and smooth recovery can be achieved during the shutdown and signal reset processes, thereby improving the safety, stability and reliability of the system.

[0068] In the embodiment of the present invention, the valve adjustment instruction generation module includes:

[0069] A total valve position reference value output unit, used to obtain a total valve position reference value based on a pressure control value output by a pressure controller in a pressure control mode, or to generate a total valve position reference value based on a preset valve control target value and an RB rate in a valve control mode in a valve control mode;

[0070] The valve control command output unit is used to input the total valve position reference value into a preset valve control flow function and then output the valve control command.

[0071] Specifically, Figure 3As shown, when SW=true when the pressure control mode is put into use, the selection module 5 outputs In2, which corresponds to the In1 input of the selection module 6. The pressure control value of the pressure controller is sequentially input into the total valve position reference value output unit and the function f(x1) of the total valve position reference value and the throttle opening. The function is obtained after correction during the unit power increase process, thereby obtaining the corresponding throttle opening, which is used as the throttle command to make the throttle act to respond to the main steam pressure fluctuation. When SW=false in the valve control mode, the selection module 5 obtains the valve control target value inputted by In1 (the valve control target value is manually set by the operator according to actual needs) and outputs it to In1 of the selection module 6, and the output value of the pressure control automatically tracks the preset valve position target value. If an emergency shutdown condition occurs, based on the RB action signal, SW=true of selection module 6, the total valve position reference value decreases at the RB rate (the current total valve position reference value is multiplied by the RB rate (less than 1) and then output) to In2 of selection module 6, and is sequentially input into the total valve position reference value output unit and the function f(x1) of the total valve position reference value and the regulating valve opening to obtain the corresponding regulating valve opening, until the total valve position reference value is less than the output value of f(x), that is, the regulating valve is closed at the RB rate until it is closed below the total valve position reference value corresponding to the remaining stack power, the RB action signal is reset, the pressure controller is automatically put into operation, and the main steam pressure is regulated by the proportional-integral action.

[0072] The device provided by the embodiment of the present invention is as follows: Figure 4 As shown, it also includes: a two-level three-out-of-two logic module, which is used to generate an emergency shutdown signal based on the auxiliary contacts of the emergency shutdown interlocking water pump stop instruction and the network quantity of the DCS, and generate a 1# stack shutdown signal and / or a 2# stack shutdown signal under the premise that the quick release button is put into use and the total valve position parameter is greater than a preset percentage.

[0073] like Figure 5 As shown, the emergency shutdown signal of the high-temperature reactor is an inter-island signal between the reactor and the conventional island. The extended relay auxiliary contacts of the emergency shutdown interlock feedwater pump stop command generate "Emergency Shutdown 1", "Emergency Shutdown 2" and "Emergency Shutdown 3". Since the relay is energized under normal working conditions, in order to increase the reliability of the emergency shutdown signal, the DCS network quantity emergency shutdown A and emergency shutdown B are used to perform a two-level three-out-of-two configuration. When the quick release button is put into use and the total valve position reference value is greater than 20%, the 1# stack shutdown signal and the 2# stack shutdown signal are generated and sent to the RS trigger through a 2s pulse to generate the RB action signal.

[0074] In the nuclear reactor shutdown system, the accuracy and reliability of the signal are crucial. The two-level three-to-two logic module means that the signal needs to go through two layers of screening. First, in each level of the three-to-two logic, at least two of the three input signals need to appear at the same time to trigger the next action. The two-level setting further improves fault tolerance. If a three-to-two module of the first level fails, the second level can still screen and judge the signal. Assuming that a channel of the first level has an erroneous output due to hardware aging, the second level can comprehensively judge whether the shutdown interlock should be triggered based on the output of other normal channels. Moreover, the fault can be easily located and isolated. When the system is abnormal, by monitoring each channel of the two-level three-to-two logic module, it can quickly determine which channel or which level has a problem, so that timely maintenance and replacement can be carried out without affecting the basic functions of the entire shutdown system.

[0075] The device provided by the embodiment of the present invention is as follows Figure 4 As shown, it also includes: a total valve position reference value calculation module corresponding to the remaining stack power and an RB action reset logic module,

[0076] RB action reset logic module is used to trigger the RB action signal to automatically reset when the deviation between the pressure setting value and the actual value is less than the preset value and the main steam pressure reaches a steady state after a preset delay time; or,

[0077] When the total valve position reference value is less than the output value of the total valve position reference value calculation module corresponding to the remaining stack power, the RB action signal is triggered to automatically reset; or,

[0078] When the automatic reset of the RB action signal fails, after the quick release button is manually exited or the operator resets the emergency shutdown interlock instruction of the reactor protection system, the 1# stack shutdown signal or the 2# stack shutdown signal is reset, triggering the RB action reset; the embodiment of the present invention manually exits the quick release button and resets the emergency shutdown interlock instruction of the reactor protection system. These two conditions take into account the situation of manual intervention, so that the operator can trigger the reset by these means when judging that the system can be safely restored to operation, thereby increasing the controllability and reliability of the system;

[0079] When the total valve position reference value is less than the total valve position reference value corresponding to the remaining stack power output by the total valve position reference value calculation module, the RB action signal is triggered to automatically reset. This mechanism takes into account the reasonable matching relationship between stack power and valve position to ensure the stable operation of the system.

[0080] The embodiment of the present invention triggers the RB action signal reset through the above multiple conditions, so that the system can avoid being in an abnormal state for a long time. If the RB action (rapid power reduction action) is not reset for a long time, it will bring human traps to the operator's operation, which may cause the reactor to abnormally shut down. The embodiment of the present invention can restore the normal power regulation function of the system in time under the premise of ensuring safety by setting a reasonable reset mechanism, prevent other safety problems caused by overprotection, and enable the system to resume normal steam production and power generation as soon as possible under the premise of safety, thereby improving the performance and efficiency of the entire system.

[0081] like Figure 5 As shown, when the deviation between the pressure setting value and the actual value is less than 0.13MPa, and after a delay of 2 minutes, when the main steam pressure reaches a steady state, the RS trigger is triggered to automatically reset the RB action signal; or, when the total valve position reference value is less than the total valve position reference value corresponding to the remaining stack power, the RS trigger is triggered to automatically reset the RB action signal, or when the automatic reset of the RB action signal fails, manually exit through the quick release button or when the operator resets the emergency shutdown interlock instruction of the reactor protection system, the 1# stack is shut down or the 2# stack is shut down and reset, triggering the RB action reset.

[0082] The total valve position reference value calculation module corresponding to the remaining stack power in the embodiment of the present invention includes:

[0083] The remaining stack power calculation unit of the 1# stack is used to calculate the remaining stack power of the 1# stack according to the 1# stack shutdown signal, the 1# stack power operation signal and the 1# stack power;

[0084] The remaining stack power calculation unit of the 2# stack is used to calculate the remaining stack power of the 2# stack according to the 2# stack shutdown signal, the 2# stack power operation signal and the 2# stack power;

[0085] The total valve position reference value output unit corresponding to the remaining stack power is used to add the remaining stack power of stack 1 and the remaining stack power of stack 2 and input the result into the function of the reactor dual stack power percentage and the total valve position reference value to obtain the total valve position reference value corresponding to the remaining stack power.

[0086] like Figure 5As shown, the remaining stack power of the 1# stack is obtained by switching module 1 and selection module 7, and the remaining stack power of the 2# stack is obtained by switching module 2 and selection module 8. The two are added and input into the function f(x2) of the reactor dual stack power percentage and the total valve position reference value to obtain the total valve position reference value corresponding to the remaining stack power. The embodiment of the present invention considers the shutdown signal, power operation signal and actual power of the 1# stack and the 2# stack respectively, and can calculate the remaining stack power of each reactor more comprehensively and accurately. The remaining stack power of the two stacks is added and input into a specific function to obtain the total valve position reference value, which fully considers the comprehensive power situation of the entire system, so as to ensure that the total valve position reference value can reflect the overall demand of the dual stack system, thereby achieving more effective control of the system.

[0087] It should be noted that switching module 1 and switching module 2 are rate switching modules, RT is the rate, the default is 1 / cycle, when SW=true, the rate increases from 0 to 1# stack power or 2# stack power at 1 / cycle; when SW=false, the rate decreases from 1# stack power or 2# stack power to 0 at 1 / cycle.

[0088] The embodiment of the present invention further provides a method for controlling the main steam pressure under the emergency shutdown condition of a high temperature gas-cooled reactor, based on the device in the above embodiment, comprising:

[0089] When the dual-stack with one unit operates normally, the turbine control system is in pressure control mode, with 1# stack power operating and 2# stack power operating, the total valve position reference value is greater than the preset percentage value, the quick release button is in operation, and the feedforward value of the pressure controller is 0; when an emergency shutdown condition occurs, the RB action signal is triggered based on the generated 1# stack shutdown signal and / or 2# stack shutdown signal, and the turbine regulating valve is quickly closed to the opening corresponding to the remaining stack power through the feedforward effect, and the pressure is maintained near the preset target pressure by the pressure control proportional integral feedback effect of the pressure controller. When the deviation between the pressure set value and the actual value is less than the preset value, and after the preset delay time, the RB action signal is triggered to automatically reset after the main steam pressure reaches a steady state.

[0090] When two reactors with one unit are operating normally, the turbine control system switches the control mode to valve control mode according to the unit status requirements. The total valve position reference value is equal to the preset valve position target value, and the output value of the pressure control automatically tracks the preset valve position target value. If an emergency shutdown condition occurs, the RB action signal is triggered based on the generated 1# stack shutdown signal and / or 2# stack shutdown signal, and the total valve position reference value decreases at the RB rate, and the regulating valve is closed to control the pressure until the total valve position reference value is less than the total valve position reference value corresponding to the remaining stack power. The RB action signal is triggered to automatically reset, the pressure controller is automatically put into operation, and the main steam pressure is adjusted by the proportional integral effect.

[0091] The method provided in the embodiment of the present invention can realize that when dual reactors are operating with one unit power, the turbine throttle command can be quickly reduced under DEH pressure control or valve control mode, thereby reducing the large fluctuation of steam pressure, ensuring that the fluctuation of steam main pipe pressure is within the allowable range, and ensuring that the other reactor continues to operate normally and stably with load.

[0092] Specifically, the 1# stack shutdown signal or the 2# stack shutdown signal is generated based on a two-level three-out-of-two logic module, specifically, the emergency shutdown signal is generated based on the auxiliary contacts of the emergency shutdown interlock feedwater pump stop instruction and the network quantity of the DCS, and under the premise that the quick release button is put into operation and the total valve position reference value is greater than the preset percentage, the 1# stack shutdown signal and / or the 2# stack shutdown signal is generated to improve the reliability of the signal.

[0093] In the embodiment of the present invention, when the automatic reset of the RB action signal fails, manual exit is performed through the quick release button, or when the operator resets the emergency shutdown interlock instruction of the reactor protection system, the 1# stack shutdown or 2# stack shutdown is reset, triggering the RB action reset.

[0094] Specifically, when the operator resets the emergency shutdown interlock command of the reactor protection system or manually exits the quick release button, the "1# stack shutdown" or "2# stack shutdown" falling edge is triggered, and the RB action signal is automatically reset to false. The present invention not only considers the automatic reset of the RB action signal after the steam pressure control is stabilized under valve control and pressure control, but also considers the manual exit of the quick release button and the reset of the emergency shutdown interlock command of the reactor protection system. These two conditions take into account the situation of manual intervention, so that the operator can trigger the reset through these means when judging that the system can be safely restored to operation, thereby increasing the controllability and reliability of the system.

[0095] It should be noted that, in the embodiment of the present invention, after the 1# stack shutdown signal and / or the 2# stack shutdown signal is generated, the feedforward value of the pressure controller changes from 0 to a preset negative value at a first preset rate; when the operator resets the reactor protection system emergency shutdown interlock instruction or manually exits the quick release button, after the 1# stack shutdown signal or the 2# stack shutdown signal is reset, the feedforward value of the pressure controller recovers from the preset negative value to the initial value 0 at a second preset rate, and the second preset rate is much smaller than the first preset rate.

[0096] For example, after the emergency shutdown of the 1# reactor, "1# reactor shutdown" and "RB action" are both true; select module 1 to output In2, that is, the 1# reactor power before shutdown; select module 2 to output the 1# reactor power before shutdown; the rate module outputs the total valve position reference corresponding to the 1# reactor power that needs to be subtracted at a rate of 100 / cycle, that is, the OC value changes from 0 to a negative value (for example, -35) at a rate of 100 / cycle; the main steam pressure tends to stabilize under the feedback of the feedforward instruction OC and the pressure controller; when the 2# reactor is shut down in an emergency, "2# reactor shutdown" and "RB action" are both true; select module 3 Output In2, i.e., the power of stack 2 before shutdown; select module 4 to output the power of stack 2 before shutdown; the rate module outputs the total valve position reference corresponding to the power of stack 2 that needs to be subtracted at a rate of 100 / cycle, i.e., the OC value changes from 0 to a negative value at a rate of 100 / cycle; the main steam pressure tends to be stable under the feedback of the feedforward command OC and the pressure controller; when the operator resets the emergency shutdown interlock command of the reactor protection system or exits the quick release button, "Stack 1 shutdown" or "Stack 2 shutdown" is reset to false, and the OC value recovers from a negative value to the initial value of 0 at a small rate of 0.0001 / cycle.

[0097] The embodiment of the present invention can respectively achieve rapid response and smooth recovery during shutdown and signal reset by setting the above feedforward value changes, thereby improving the safety, stability and reliability of the system.

[0098] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A main steam pressure control device for a high temperature gas-cooled reactor under emergency shutdown conditions, characterized in that: The steam turbine control system used in dual-reactor with one machine includes: A total valve position reference value output module corresponding to the shutdown power of the stack, used to calculate the total valve position reference value corresponding to the shutdown power of the stack 1# and the stack 2# in a pressure control mode based on the shutdown signal of the stack 1# and / or the shutdown signal of the stack 2#; A rate output module is provided, which is used to obtain a total valve position reference value corresponding to the shutdown power and generate a corresponding feedforward value of a pressure controller; A pressure controller, configured to output a pressure control value based on a preset pressure setting value, an actual pressure value, and the feedforward value; The pressure control trigger module is used to switch the valve control mode to the pressure control mode when an emergency shutdown occurs in the valve control mode or the pressure control button is put into operation; The valve regulating instruction generation module is used to generate a valve regulating instruction based on the pressure control value output by the pressure controller in the pressure control mode, or based on the preset valve position target value in the valve position mode and the RB rate after the emergency shutdown triggers the RB action, so as to make the valve regulating action respond to the main steam pressure fluctuation.

2. The device according to claim 1, characterized in that The total valve position reference value output module corresponding to the shutdown power includes: The shutdown power calculation unit of the 1# stack is used to calculate the shutdown power of the 1# stack according to the shutdown signal of the 1# stack, the power operation signal of the 1# stack and the power of the 1# stack; A shutdown power calculation unit of the 2# stack, used for calculating the shutdown power of the 2# stack according to the shutdown signal of the 2# stack, the power operation signal of the 2# stack and the power of the 2# stack; The total valve position reference value output unit corresponding to the shutdown power is used to add the shutdown power of the 1# stack and the shutdown power of the 2# stack, input the sum into the function of the reactor dual stack power percentage and the total valve position reference value, obtain the total valve position reference value corresponding to the shutdown power, and then invert it.

3. The device according to claim 1 or 2, characterized in that: The valve adjustment instruction generation module includes: A total valve position reference value output unit is used to obtain a total valve position reference value based on a pressure control value output by a pressure controller in a pressure control mode, or to generate a total valve position reference value based on a preset valve control target value and an RB rate after an emergency shutdown triggers an RB action in a valve control mode; The valve control command output unit is used to input the total valve position reference value into a preset valve control flow function and then output the valve control command.

4. The device according to claim 1, characterized in that Also includes: The two-level three-out-of-two logic module is used to generate an emergency shutdown signal based on the auxiliary contacts of the emergency shutdown interlock feedwater pump stop instruction and the network quantity of the DCS, and to generate a 1# stack shutdown signal and / or a 2# stack shutdown signal under the premise that the quick release button is put into operation and the total valve position parameter is greater than a preset percentage.

5. The device according to claim 4, characterized in that Also includes: The total valve position reference value calculation module corresponding to the remaining stack power and the RB action reset logic module, where: RB action reset logic module is used to trigger the RB action signal to automatically reset when the deviation between the pressure setting value and the actual value is less than the preset value and the main steam pressure reaches a steady state after a preset delay time; or, When the total valve position reference value is less than the output value of the total valve position reference value calculation module corresponding to the remaining stack power, the RB action signal is triggered to automatically reset; or, When the automatic reset of the RB action signal fails, after the quick release button is manually exited or the operator resets the emergency shutdown interlock command of the reactor protection system, the 1# stack shutdown signal or the 2# stack shutdown signal is reset, triggering the automatic reset of the RB action signal.

6. The device according to claim 5, characterized in that The total valve position reference value calculation module corresponding to the remaining stack power includes: The remaining stack power calculation unit of the 1# stack is used to calculate the remaining stack power of the 1# stack according to the 1# stack shutdown signal, the 1# stack power operation signal and the 1# stack power; The remaining stack power calculation unit of the 2# stack is used to calculate the remaining stack power of the 2# stack according to the 2# stack shutdown signal, the 2# stack power operation signal and the 2# stack power; The total valve position reference value output unit corresponding to the remaining stack power is used to add the remaining stack power of stack 1 and the remaining stack power of stack 2 and input the result into the function of the reactor dual stack power percentage and the total valve position reference value to obtain the total valve position reference value corresponding to the remaining stack power.

7. A method for controlling the main steam pressure of a high temperature gas-cooled reactor under emergency shutdown conditions, characterized in that: Based on the device described in any one of claims 1 to 6, the method comprises: When the dual-stack with one unit is operating normally, the turbine control system is in pressure control mode, the 1# stack power is operating and the 2# stack power is operating, the total valve position reference value is greater than the preset percentage value, the quick release button is in operation, and the feedforward value of the pressure controller is 0; when an emergency shutdown condition occurs, the RB action signal is triggered based on the generated 1# stack shutdown signal and / or 2# stack shutdown signal, and the turbine regulating valve is quickly closed to the opening corresponding to the remaining stack power through the feedforward effect, and the pressure is maintained near the preset target pressure by the pressure control proportional integral feedback effect of the pressure controller. When the deviation between the pressure set value and the actual value is less than the preset value, and after the preset delay time, the RB action signal is triggered to automatically reset after the main steam pressure reaches a steady state; When the dual-stack with one unit operates normally, when the turbine control system switches the control mode to the valve control mode according to the unit status requirements, the total valve position reference value is equal to the preset valve position target value, and the output value of the pressure control automatically tracks the preset valve position target value. If an emergency shutdown condition occurs, the RB action signal is triggered based on the generated 1# stack shutdown signal and / or 2# stack shutdown signal, the total valve position reference value decreases at the RB rate, and the regulating valve is closed to control the pressure until the total valve position reference value is less than the total valve position reference value corresponding to the remaining stack power. The RB action signal is triggered to automatically reset, the pressure controller is automatically put into operation, and the main steam pressure is adjusted by the proportional integral effect.

8. The method according to claim 7, characterized in that The process of generating the No. 1 stack shutdown signal and / or the No. 2 stack shutdown signal includes: generating the emergency shutdown signal based on the auxiliary contacts of the emergency shutdown interlock feedwater pump stop instruction and using the network quantity of the DCS, and generating the No. 1 stack shutdown signal or the No. 2 stack shutdown signal under the premise that the quick release button is put into operation and the total valve position reference value is greater than a preset percentage.

9. The method according to claim 7, characterized in that: Also includes: When the automatic reset of the RB action signal fails, manually exit through the quick release button or when the operator resets the emergency shutdown interlock instruction of the reactor protection system, the 1# stack shutdown or 2# stack shutdown is reset, triggering the automatic reset of the RB action signal.

10. The method according to claim 9, characterized in that When the No. 1 stack shutdown signal or the No. 2 stack shutdown signal is generated, the feedforward value of the pressure controller changes from 0 to a preset negative value at a first preset rate; when the operator resets the reactor protection system emergency shutdown interlock instruction or manually exits the quick release button, and the No. 1 stack shutdown signal or the No. 2 stack shutdown signal is reset, the feedforward value of the pressure controller recovers from the preset negative value to the initial value 0 at a second preset rate, and the second preset rate is much smaller than the first preset rate.

Images