JPH0385491A - Controlling device for nuclear reactor output - Google Patents

Abstract

PURPOSE:To make an output temperature of a nuclear reactor controllable to a predetermined temperature value according to an operational condition by correcting a withdrawal rate and an insertion rate of a control rod which are set by comparing a target controlling value with its changing rate, in comparison with regulating conditions of each process vale. CONSTITUTION:A standard fuzzy control part 19a is fed a nuclear reactor outlet temperature TP from a temperature detector 11, and a target temperature value TS of the nuclear reactor outlet and a target changing rate value DTS of the nuclear reactor outlet from an output value setter 19, and therewith a withdrawal or an insertion rate VR of a control rod 15 is set by a fuzzy inference. Subsequently, a restricted fuzzy control part 19b is fed a nuclear reactor inlet temperature TI from a temperature detector 18, a neutron flux level N from a neutron flux detector 12 and a process value of a coolant piping temperature THP from a temperature detector 17, and then corrects the rate VR set by the control part 19a, by the fuzzy inference and consequently feeds a demand signal V of a control rod driving rate to a control rod drive mechanism 14. In this way, from a critical condition to a high output operation of a nuclear reactor 1, its output temperature can be stably controlled and an operational controllability of a plant can be improved.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention relates to a nuclear reactor power control device, and in particular, a device for controlling the reactor outlet temperature to a predetermined value by manipulating the position of control rods. Regarding nuclear reactor power control equipment.

(Prior Art) A conventional nuclear reactor power control device will be described with reference to FIG. 17.

A nuclear reactor 1 houses a reactor core 1a, which generates heat due to a nuclear fission chain reaction and heats a primary coolant flowing within the reactor. The heated primary coolant is sent to the intermediate heat exchanger 3 via the high temperature side pipe 2, and transfers heat to the secondary coolant through heat exchange. The primary coolant whose temperature has been lowered by heat exchange is returned to the reactor 1 through the low temperature side pipe 4. Such circulation of the primary coolant is performed by a circulation pump 5 interposed in the low temperature side piping 4.

On the other hand, the secondary coolant whose temperature has been increased by heat exchange in the intermediate heat exchanger 3 is sent through the high temperature side pipe 6 to the steam generator 7 which is a load heat exchanger. Here, a case will be described in which a steam generator fan is used as an example of a load heat exchanger, but an air cooler and other cooling systems have a similar cooling system configuration. The secondary coolant whose temperature has been lowered by heat exchange in the steam generator 7 is returned to the intermediate heat exchanger 3 through the low temperature side pipe 8. Such circulation of the secondary coolant is performed by a circulation pump 9 interposed in the low temperature side piping 8.

The reactor output is controlled by the reactor output control device 13 using the output setting value from the output setting device 10, the reactor outlet temperature from the temperature detector 11, and the neutron flux level from the neutron flux detector 12. It will be done. Reactor power control device 1
3 uses the reactor exit temperature from the temperature detector 11 as a feedback signal, processes the neutron flux level from the neutron flux detector 12 as an auxiliary signal, and uses the control rod drive speed command signal obtained as a result to drive the control rods. Output to mechanism 14. Control rod drive mechanism 1 into which the control rod drive speed command signal is input
4 adjusts the reactor output by inserting and removing the control rods 15 into and from the reactor core 1a.

(Problems to be Solved by the Invention) In the conventional reactor power control device 13, during critical to low power operation, the reactor exit temperature is controlled particularly during system temperature rise, where the response of the reactor exit temperature to control rod operations is slow. It was difficult to automatically control to a predetermined value depending on the operating state. For this reason, the operator manually operated the control rods 15 during the critical to low output operation. However, since the content of the operation is influenced by the experience and skill of the operator, there is a problem in that the output control characteristics are influenced by the operator's skill and the like from critical to low output operation.

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a nuclear reactor power control device capable of stably automatically controlling the reactor power, including low power operation. .

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a reactor power control device that outputs a control rod drive speed command signal to a control rod drive mechanism to control the output of a nuclear reactor, in which a reactor outlet temperature is input. A prescribed fuzzy control unit that compares the control target value and control target change rate of the reactor exit temperature and sets the control rod withdrawal or insertion speed by fuzzy reasoning, and the reactor inlet temperature, neutron flux level,
Various process quantities related to the reactor, such as coolant piping temperature, are input and compared with the constraint conditions of these process quantities, and the control rod withdrawal or insertion speed set by the above-mentioned prescribed fuzzy control unit is corrected by fuzzy reasoning. The system is equipped with a constraint fuzzy control section.

(Operation) In the present invention, the predetermined fuzzy control unit inputs the reactor outlet temperature, compares the control target value of the reactor outlet temperature with the control target change rate, and sets the control rod withdrawal or insertion speed by fuzzy reasoning. Then, the constraint fuzzy control unit inputs various process quantities surrounding the reactor, such as reactor inlet temperature, neutron flux level, and coolant piping temperature, compares them with the constraint conditions of these process quantities, and uses fuzzy reasoning to create a prescribed fuzzy control unit. Corrects the control rod withdrawal or insertion speed set in , and outputs the control rod drive speed command signal obtained as a result to the control rod drive mechanism. Therefore, the reactor outlet temperature can be stably controlled to a predetermined value depending on the operating state from the critical state to high power operation of the reactor.

(Embodiment) An embodiment of the nuclear reactor power control device according to the present invention will be described with reference to the accompanying drawings.

In FIG. 1, the same parts as in FIG. 17 are given the same reference numerals, and redundant explanation will be omitted. Reactor 1 has core 1a.
A control rod 15 is provided in the reactor core 1a so that it can be inserted and removed by a control rod drive mechanism 14. A temperature detector 11 for measuring the reactor outlet temperature and a temperature detector 17 for measuring the pipe temperature are connected to the primary coolant high temperature side pipe 2 connected to the reactor 1. A temperature detector 18 for measuring the reactor inlet temperature is connected to the primary coolant low temperature side pipe 4. Note that reference numeral 12 indicates a neutron flux detector that measures the neutron flux level, and this neutron flux detector 12 is arranged around the nuclear reactor 1.

The reactor power control device 19 receives the reactor outlet temperature from the temperature detector 11, the piping temperature from the temperature detector 17, the reactor inlet temperature from the temperature detector 18, and the neutron flux level and output from the neutron flux detector 12. After inputting the reactor outlet temperature target value and the reactor outlet temperature change rate target value from the setting device 10 and performing arithmetic processing, a control rod drive speed command signal is output to the control rod drive mechanism 14 to adjust the reactor output. is designed to be controlled.

FIG. 2 shows a block diagram of the reactor power control device 19. The reactor power control device 19 is a prescribed fuzzy control section 19
a and a constraint fuzzy control section 19b. The specified fuzzy control unit 19a inputs the reactor outlet temperature T1, the reactor outlet temperature target value T8, and the reactor outlet temperature change rate target value DT8, and sets the withdrawal or insertion speed VR of the control rod 15 by fuzzy reasoning. . The constraint fuzzy control unit 19b inputs the process variables of the reactor inlet temperature Tl, the neutron flux level N, and the coolant pipe temperature THP,
The speed of withdrawal or insertion of the control rod 15 set by the prescribed fuzzy control section 19a is corrected by fuzzy reasoning, and the control rod drive speed command (2) obtained as a result is output to the control rod drive mechanism 14.

Next, the processing in the prescribed fuzzy control section 19a will be explained with reference to FIG.

First, reactor outlet temperature T1, reactor outlet temperature target value T8
and reactor outlet temperature change rate target value DT,
Based on these, the reactor outlet temperature change rate DT is calculated. Next, reactor outlet temperature target value T8 and reactor outlet temperature T
Calculate the deviation T8TP (temperature deviation) between Determine the grade, negative less (NS) grade and negative greater (NB) grade.

Next, the deviation DT8-DT between the reactor outlet temperature change rate target value DT and the reactor outlet temperature change rate DT.

(Temperature change rate deviation) and substituted the deviation into the membership function shown in Figure 5, positive and large (P B) grade, positive and small (ps) grade, zero (ZO) grade, negative small (NS) grade and negative large (
NB) Find the grade.

Then, the fuzzy control rule shown in FIG. 6 is executed to determine the change width DV of control rod speed and the membership function corresponding thereto. Note that if the control rod speed change width DV is positive and large (
P B) Fuzzy set, positive and small (p s) fuzzy set, fuzzy set of zero (zO), negative and small (NS)
It is assumed that the fuzzy set and the negative large (NB) fuzzy set are defined by the membership functions shown in FIG. Next, the membership functions of each control rod speed change width DV obtained by executing each fuzzy rule are synthesized, and the center of gravity is set as the control rod speed change width DvR. For example, in a grade with a temperature deviation of 0.7, the temperature change rate deviation is 0 in PB.
．． In the case of PS with grade 4, the change width DV of control rod speed is a positive and small value (PS), and its membership function is the minimum value 0 of the grade with temperature deviation PH and the grade with temperature change rate PS. The function form shown in Fig. 8 has a maximum value of .4.

In addition, if the temperature deviation is 0.3 in the grade PS and the temperature change rate deviation is 0.6 in the grade zO, the control rod speed change range DV is set to zero (20), and its membership function is the temperature deviation is the minimum value of the PS grade and the temperature change rate is the minimum value of the zO grade. 3 is the maximum. The function form shown in FIG. 9 is assumed. Therefore, as shown in FIG. 10, the membership function in FIG. 8 and the membership function in FIG. 9 are combined, and the center of gravity DvR is set as the range of change in control rod speed. Then, the change width Dv of the control rod speed obtained for the current control rod speed ■1
Add R and set the control rod speed VR.

Next, regarding the processing of the constraint fuzzy control unit 19b, the 11th
This will be explained according to the diagram.

First, the control rod speed ■1 obtained by the prescribed fuzzy control unit 19a, the reactor inlet temperature T1, and the high temperature side piping temperature TII
Read P and neutron flux level N.

Here, the control rod speed 2 is assumed to be a fuzzy set defined by the membership function shown in FIG.

Next, the reactor inlet temperature T1, high temperature side piping temperature TH-, and neutron flux level N are shown in FIGS. 13(A) and 13(B).

The membership function shown in (C) is just right (M
EDIUM) or too large (BIG). TIL and THPL in Figures 13 (A) to (C)
”L are operational limit conditions for the reactor inlet temperature T11, high temperature side piping temperature THP', and neutron east level N, respectively, and are determined in advance.

Then, the fuzzy control rule shown in FIG. 14 is executed, and as shown in FIG. 15, the new membership function of R and v
Define the membership function of z.

Here, vz is a fuzzy set defined by a membership function centered at 0.0, as shown in FIG. In other words, the membership function of vR is
The minimum value (LM) of the grade, which is DIUM, is maximized. Further, the membership function of v2 has a form in which the maximum value (LB) of the grade, which is the BIG of each process, is maximized.

Therefore, as shown in FIG. 16, the membership function of vR and the membership function of v2 are combined and their center of gravity V is used as the control rod speed command.

In this way, according to the above embodiment, an appropriate control method is set based on the behavior of the reactor outlet temperature after the control rod operation is performed. Also, it is now possible to automatically control the reactor outlet temperature to a predetermined value depending on the operating status.
Automatic control of reactor output from criticality to high-power operation can be performed stably. In addition, the burden on the operator is reduced,
This solves the problem that output control characteristics are influenced by the experience and skill of the operator, and improves operational controllability.

〔Effect of the invention〕

The present invention provides a predetermined fuzzy control unit that inputs the reactor outlet temperature, compares the control target value and control target change rate of the reactor outlet temperature, and sets the control rod withdrawal or insertion speed by fuzzy reasoning; By inputting various process quantities surrounding the reactor, such as the reactor inlet temperature, neutron flux level, and coolant piping temperature, and comparing them with the constraint conditions of these process quantities, the control rods set in the above-mentioned fuzzy control section are determined by fuzzy reasoning. Equipped with a constraint fuzzy control unit that corrects the withdrawal or insertion speed, it is possible to stably control the reactor output from the reactor criticality to high power operation.
It is possible to improve plant operation controllability.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a nuclear reactor equipment equipped with an embodiment of the reactor power control device according to the present invention, Fig. 2 is a block diagram showing the above embodiment, and Fig. 3 is a prescribed fuzzy diagram in the above embodiment. A processing flow diagram of the control unit, FIG. 4 is a diagram showing the membership function serving as a criterion for the deviation between the reactor outlet temperature and the reactor outlet temperature target value in the above embodiment, and FIG. FIG. 6 is a diagram showing the membership function that serves as a criterion for determining the deviation from the furnace outlet temperature change rate target value. FIG. 6 is a diagram showing the fuzzy control rules provided in the prescribed fuzzy control section in the above embodiment. FIG. A diagram showing a membership function for determining the range of change in control rod speed in the embodiment, FIG. 8 is a diagram showing an example of a membership function in which the range of change in control rod speed is a positive and small value in the above embodiment, FIG. 9 is a diagram showing an example of a membership function in which the width of change in control rod speed is zero in the above embodiment, and FIG. 10 is a diagram showing an example of composition of membership functions with a width of change in control rod speed in the above embodiment. , FIG. 11 shows a processing flow diagram of the constrained fuzzy control unit in the above embodiment, and membership functions for determining the control rod speed, reactor inlet temperature, high temperature side piping temperature, and neutron flux level in the twelfth embodiment. Figure, 14th
The figure shows fuzzy control rules provided in the constrained fuzzy control section in the above embodiment, and FIG. FIG. 16 is a diagram showing an example of the composition of the membership function of control rod speed in the above embodiment. FIG. 17 is a diagram showing a nuclear reactor equipment equipped with a conventional reactor power control device. FIG. l... Nuclear reactor, 1a... Core, 10... Output setting device, 11... Temperature detector, 12... Neutron flux detector, 14... Control rod drive mechanism, 15...・Control rod, 17
．． 18... Temperature detector, 19... Nuclear reactor power control device, 19a... Regulation fuzzy control section, 19b... Constraint fuzzy control section.

Claims (1)

[Claims] In a reactor power control device that outputs a control rod drive speed command signal to the control rod drive mechanism to control the reactor output, the reactor outlet temperature is input and the control target value and control target change rate of the reactor outlet temperature are calculated. A predefined fuzzy control unit that sets the control rod withdrawal or insertion speed using fuzzy reasoning, and inputs various process variables around the reactor such as reactor inlet temperature, neutron flux level, and coolant piping temperature. Reactor power control characterized by comprising a constraint fuzzy control unit that compares with the process quantity constraint conditions and corrects the control rod withdrawal or insertion speed set by the prescribed fuzzy control unit based on fuzzy reasoning. Device.