JPH0221296A - Controlling of fast breeder reactor system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a method for controlling a fast breeder reactor plant.

(Prior art) In a fast breeder reactor plant, an evaporator (or steam generator,
The main steam generated by heat exchange with the secondary sodium system in (the same applies hereinafter) passes through the main steam control valve and is supplied to the turbine for power generation, and then is returned to water in the condenser and sent to the feedwater heater.
After being heated here, it is sent to the evaporator again.

By the way, in such a fast breeder reactor plant, the valve opening degrees of the turbine bypass valve and the main steam control valve of the turbine bypass system are controlled by the turbine speed control system (hereinafter referred to as E) Ic:Elcc
tro Hydraulic Controller
), load loss occurs,
the difference between the generator load and the turbine output by more than a predetermined value,
For example, if a difference of (40%/10 milliseconds) or more occurs, the power/load imbalance relay (hereinafter referred to as PLUR) of this EHC will operate, instantly opening the main steam control valve fully in a few milliseconds, and Rapidly shuts off steam flowing into the turbine.

Thereafter, by canceling PLUR, the power plant is operated to maintain the output equivalent to the load within the power plant.

By the way, since feedwater heaters generally use turbine extracted steam as a heating source, due to the above-mentioned PLUR operating range, when the output state is equivalent to the internal load of the power plant, the internal pressure will decrease due to a decrease in turbine exhaust pressure. , the temperature of the water supplied to the evaporator will drop.

To prevent this, in the output operation state equivalent to the load in the power plant, drain water from the steam water separator is used to secure a heating source for the feed water heater via a flash tank, and the feed water temperature is maintained at a predetermined value. A control method has been proposed to maintain the

(Problems to be Solved by the Invention) However, with the above-mentioned conventional method, there are cases where the steam separator drain valve becomes stuck or the pressure control system of each feed water heater malfunctions, or when the steam generated in the flash tank During the time it is introduced into the feedwater heater, the feedwater heater remains without a heating source, and is no longer able to meet the temperature conditions required for plant operation. There was a risk of inviting

The present invention has been made to solve the above-mentioned problems, and is a fast breeder reactor plant control method capable of alleviating the thermal shock of the steam generator feed water nozzle section caused by the drop in feed water temperature during load loss. The purpose is to provide

[Structure of the Invention] (Means for Solving the Problems) That is, the fast breeder reactor plant control method of the present invention includes:
A first control signal for controlling the feed water temperature to a predetermined temperature is created from the feed water temperature information, and a first control signal for controlling the feed water flow rate to a predetermined flow rate is created from the feed water flow rate information and the evaporator or steam generator outlet steam temperature information. 2 control signals are created, the first and second control signal output values are compared, the lower signal output 1st shift is selected, and based on this selected control signal, the main water supply flow rate control valve is opened. It is characterized by controlling the degree.

(Function) In the fast breeder reactor plant control method of the present invention having the above configuration, the value of the first control signal for controlling the feed water temperature to a predetermined temperature created from the feed water temperature information, the feed water flow rate information and the evaporation Compare the value of the second control signal for controlling the feed water flow rate to a predetermined flow rate, which is created from the steam temperature information at the outlet of the steam generator or the steam generator, and adjust the opening degree of the main feed water flow rate control valve based on the lower output value. Control. Therefore, even when load loss occurs, the water supply temperature can be maintained at a predetermined temperature, and thermal shock at the evaporator water supply nozzle can be alleviated. Furthermore, control signals can be switched bumplessly.

(Example) An example of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 2 shows a schematic configuration of a fast breeder reactor power plant. Main steam generated by exchanging heat with a secondary sodium system in an evaporator 1 passes through a steam separator 2, and then The steam passes through the superheater 3, flows through the main steam pipe 5 in which the main steam control valve 4 is inserted, is introduced into the turbine 6, and is used for power generation.

The steam after rotating the turbine 6 is returned to water in the condenser 7, and the steam is removed in the deaerator 8, and then the feed water is heated by a feed water pump driven by a pump driving turbine 9. After being sent to the vessel 11 and heated there, it is sent to the evaporator 1 again through the water supply pipe 13 in which the main water supply flow rate control valve 12 is inserted.

Further, the steam/water separator 2 is connected to a flash tank 15 via a drain valve 14.
The steam introduced into the condenser 7, deaerator 8, feed water heater 1
1 respectively.

On the other hand, the main steam pipe 5 includes a turbine bypass pipe 1 which branches from the upstream side of the main steam control valve 4 and is connected to the condenser 7.
6 is provided, and a turbine bypass valve 17 is inserted into this turbine bypass piping 16. In addition,
The turbine bypass capacity is, for example, 50%.

By the way, since the feedwater heater 11 normally heats the feedwater to, for example, about 240° C. using extracted steam from the turbine 6, during load-equivalent operation at the time of load loss, the turbine exhaust pressure decreases, causing a decrease in the internal pressure. , the water supply temperature will drop.

Therefore, in order to prevent the supply water temperature from decreasing in such a case, the following control is performed in this embodiment. Figure 1 shows the schematic configuration of the control circuit for realizing the method of this embodiment. Then, the low value selection circuit (LVG) 20 has
The first control signal 30 and the second control signal 40 are input, and the control signal with the lower value is selected and sent through the phase compensation circuit 21 as the main water supply flow rate and four-node valve opening request signal 22. Output.

The above-mentioned first control signal 30 is generated by the feed water temperature signal 31 and the feed water temperature set to Based on the deviation from the set value 32, the proportional circuit 33
and is created by the integrating circuit 34. Note that the feed water temperature set value 32 is a value lower than the temperature during normal rated operation (
For example, if the water supply pump trip signal is 150° C. or lower, it is set to 170° C.), and is set to be input to the LVG 20 as the first control signal 30 or a positive signal in a normal operating state.

The second control signal 40 is used during normal operation, and is generated by the proportional circuit 43 and the integral circuit 44 based on the deviation between the evaporator outlet steam temperature signal 41 and the evaporator outlet steam temperature set value 42. and a signal produced by the proportional circuit 48 based on the deviation between the output signal from the function generator 46 based on the feed water flow set point 45 and the feed water flow signal 47 .

That is, in the above control circuit, during normal operation, LVG2
0 selects the second control signal 40, and this second control signal 40 controls the opening degree of the main water supply flow rate control valve 12 so that the water supply flow rate becomes a predetermined flow rate. Then, when a turbine load loss or the like occurs and the feed water temperature drops to a certain degree, the LVG 20 selects the first control signal 30, and this first control signal 30 controls the main feed water temperature so that the feed water temperature reaches a predetermined temperature. The opening degree of the flow control valve 12 is controlled.

Therefore, even when the turbine load is lost, the water supply IA
temperature can be maintained at a predetermined temperature, and thermal shock at the evaporator water supply nozzle can be alleviated. Furthermore, control signals can be switched bumplessly.

[Effects of the Invention] As explained above, according to the fast breeder reactor plant control method of the present invention, the value of the first control signal for controlling the feed water temperature to a predetermined temperature created from the feed water temperature information; The value of the second control signal for controlling the feed water flow rate to a predetermined flow rate created from the feed water flow rate information and the evaporator or steam generator outlet steam temperature information is compared, and the main feed water meteor is determined based on the lower output value. Controls the opening degree of the control valve. Therefore, even when load loss occurs, the water supply temperature can be maintained at a predetermined temperature, and thermal shock at the evaporator water supply nozzle can be alleviated. Furthermore, control signals can be switched bumplessly.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a control circuit for explaining one embodiment of the method of the present invention, and FIG. 2 is a diagram showing the configuration of a fast breeder reactor plant. 20...Low value selection circuit 21...Phase compensation circuit 22...Main water supply flow rate control valve opening request signal 30... ...First control signal 31...
...... Feed water temperature signal 32...... Feed water temperature set value 33... Proportional circuit 34... Integral circuit 40... ...Second control signal 41...
...Evaporator outlet steam temperature signal 42...
・Evaporator outlet steam temperature set value 43... Proportional circuit 44... Integral circuit 45... Feed water flow rate set value 46...・・・
...Function generator 47...Water supply flow rate signal 48...Proportional circuit

Claims (1)

[Claims] (1) Create a first control signal for controlling the feed water temperature to a predetermined temperature from the feed water temperature information, and control the feed water flow rate to the predetermined flow rate from the feed water flow rate information and the evaporator or steam generator outlet steam temperature information. Compare the first and second control signal output values to select the lower signal output value, and adjust the main water flow rate based on the selected control signal. A method for controlling a fast breeder reactor plant, characterized by controlling a valve opening degree.