JPS6337918B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a nuclear reactor heating control device, and particularly to a nuclear reactor heating control device that is optimal for suppressing the rate of increase in reactor water temperature within a specified range in a nuclear reactor plant.

In conventional boiling water nuclear power plants, nuclear heating is performed by operators manually operating control rods. In this case, operators must operate the control rods according to a predetermined control rod withdrawal sequence to ensure that the temperature of the reactor water reaches the rate of temperature rise (55°C/Hr) specified in the operating technical specifications. So as not to exceed
Heating operations are being carried out while being monitored.

FIG. 1 is a system diagram showing an example of a conventional nuclear power plant.

A reactor core 2 and control rods 3 are installed inside the nuclear reactor 1, and the control rods 3 are controlled in a predetermined manner by a control rod drive mechanism 4. The steam generated in reactor 1 is
Steam that is supplied to the turbine 5 via the turbine stop valve 7 and has completed its work is sent to the condenser 6 and used as water supply again. Further, the turbine bypass steam is bypassed to the condenser 6 via the turbine bypass valve 8 . In this bypass operation, when a predetermined temperature increase rate is exceeded, the pressure in the main steam pipe corresponding to this temperature increase rate is detected by the pressure detector 9, the pressure control device 10 is controlled based on this, and the turbine The bypass valve 8 is opened to bypass the steam generated in the reactor 1 to the condenser 6, thereby suppressing the rate of temperature rise.
At this time, the operator stops withdrawing the control rods 3 or inserts them to suppress the nuclear reaction in the core 2 and restore the temperature to a specified rate of increase.

However, such an operation has the following problems.

(a) Since the operational burden at plant start-up is large, in order to operate while observing the temperature rise constraint conditions, it is necessary to
Requires skilled technique.

(b) It is difficult to know the rate of temperature change more accurately than with conventional instrumentation, and strict adherence to constraint conditions is not desirable from the standpoint of operational efficiency.

SUMMARY OF THE INVENTION An object of the present invention is to provide a nuclear reactor heating control device that can perform effective heating operations while observing constraint conditions and can reduce the operational burden on operators during heating operations.

The features of the present invention include means for determining the temperature of reactor water in a nuclear reactor, and first deviation calculation means for determining a temperature deviation signal that is the deviation between the reactor water temperature obtained by the temperature determining means and a target temperature. , means for calculating a temperature rise rate by inputting the reactor water temperature obtained by the temperature calculating means, and a second deviation calculation for calculating a temperature rise rate deviation signal that is a deviation between the temperature rise rate and a target temperature rise rate. and a low value for selecting and outputting a lower value deviation signal from among the temperature deviation signal output from the first deviation calculation means and the temperature increase rate deviation signal output from the second deviation calculation means. outputting a control rod withdrawal command when the absolute value of the deviation signal output from the priority circuit and the low value priority circuit is greater than or equal to a dead zone setting value and the deviation signal is positive;
control rod operation determination means for outputting a control rod insertion command when the deviation signal is negative; and control rod selection sequence control means for selecting a control rod based on the command output from the control rod operation determination means. and a control rod drive control means that can be operated by

FIG. 2 is a block diagram showing an embodiment of the present invention. In FIG. 2, the same members used in FIG. 1 are given the same reference numerals.

The actual temperature of the reactor is measured by a temperature detector 12 attached to the suction part of the recirculation pump 11, and a temperature setting device 13 is used to maintain the temperature at a desired temperature.
The temperature deviation is calculated. On the other hand, the measured temperature is used in a differentiator 15 to determine the actual temperature increase rate, and then compared with the temperature increase rate setter 14 to determine a deviation. Temperature setting device 13, temperature rise rate setting device 1
4 is a potentiometer that outputs a setting signal. This deviation passes through an integrator 16 and becomes a temperature rise rate deviation. The low value priority circuit 17 selects the low value of these two temperature deviation and temperature increase rate deviation signals. The low value priority circuit 17 is provided so that the temperature increase rate deviation signal is given priority at first, and when the reactor is heated to near the target temperature, the temperature deviation is given priority.

The deviation signal selected by the low value priority circuit 17 determines the operation amount of the control rod according to the deviation amount.
This determination is made by the control rod operation determining section 18.
FIG. 3 shows the control algorithm of this control rod operation determination section 18. Calculated temperature deviation
Control rod operation is determined when TDEF satisfies the following equation.

｜TDEF｜＞ε ……(1) TDEF＞0: Control rod 1 notch withdrawn ……(2) TDEF＜0: Control rod 1 notch inserted ……(3) In other words, the absolute value of temperature deviation is ε (dead zone) If it is above, the direction of withdrawal/insertion of the control rod is determined in accordance with the positive/negative value. In this case, the amount of withdrawal and insertion is all one notch, and after one notch operation is completed, the calculation of the temperature deviation is repeated again, and the next control rod operation is determined.

The control rod to be operated is determined by the control rod selection sequence control section 19. This uses the control rod selection sequence used in conventional control rod value minimizers (RWM). RWM has the function of preventing control rod withdrawal/insertion when the reactor power is low (25% or less), and monitors that control rod withdrawal/insertion is performed according to the correct control rod selection sequence. . That is, the control rod to be operated is selected here, and this control rod is selected based on the operation determination described above.
You can decide whether to pull it out or insert it one by one.

The selected control rod and the direction of operation (withdrawal/insertion) are displayed on the display device 20 to notify the operator. Further, the control rod drive control device 21 automatically drives the selected control rod to perform a heating operation of the nuclear reactor.

FIG. 4 is an explanatory diagram of the control operation of the present invention. Fourth
In the figure, the dotted line characteristic shows the target temperature increase curve, and the solid line characteristic shows the reactor water temperature.

For a given target temperature and rate of increase,
At the control start stage, priority is given to the deviation of the target temperature increase rate, and control rod withdrawal commands are continuously output. As a result, the temperature increase rate reaches the target value, and the withdrawal command is no longer output. Thereafter, the actual temperature increase rate becomes smaller than the target value again, and at that point the control rod withdrawal command is output again. Heating is continued by repeating such control operations.
Temperature deviation is given priority near the target temperature, and control is performed to maintain the reactor water temperature constant at the target temperature. If for some reason the temperature rise rate exceeds the target temperature rise rate, a control rod insertion command is output at that point, and a corrective action is taken to lower the temperature rise rate and maintain the target temperature rise rate. It is done.

As described above, according to the embodiments of the present invention, the heating operation of the nuclear reactor can be performed effectively while observing the constraint of the temperature increase rate. That is, since the low value priority circuit 17 is provided, the temperature can initially be increased while maintaining the set value of the temperature increase rate by operating the control rods based on the temperature increase rate deviation signal.
It becomes possible to proactively control the temperature rise by taking differential factors into consideration. Therefore, effective heating operation can be performed while observing the constraint conditions.

In addition, the control rod operation determination unit 18
The control rod driving device 21 automatically operates the control rod selected by the control rod selection sequence control section 19 according to the control rod operation amount determined as described above based on the output of step 7. Since the control rods can be operated automatically in this way, the operational burden on the operator during heating operations can be significantly reduced. Furthermore, by automatically operating the control rods in this way, the operational burden on the operator is reduced, and
Since the details of automatic driving operations are also displayed, monitoring by the operator is facilitated.

As an embodiment of the present invention, a method of setting the target temperature using a temperature setting device has been described, but in the actual heating process, the pressure is often kept constant. In such a case, a pressure setting device can be used instead of a temperature setting device, the saturation temperature can be calculated from the set pressure, and similar control can be executed.

According to the present invention, since a low value priority circuit is provided, heating operation can be performed using the temperature increase rate deviation signal in advance of the temperature deviation signal, and effective heating operation can be performed while observing the constraint conditions. Become. Further, the control rod drive control means determines the control rod selected by the control rod selection sequence control means based on the control rod operation command obtained by the control rod operation determination means, that is, the output of the low value priority circuit. Since the system is automatically operated based on control rod operation commands, the operational burden on the operator during heating operations can be significantly reduced.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of a nuclear power plant, Fig. 2 is a block diagram of an embodiment of the present invention, Fig. 3 is a control algorithm of the control rod operation determination section according to the present invention, and Fig. 4 is an explanation of control operation of the present invention. It is a diagram. 1... Nuclear reactor, 2... Reactor core, 3... Control rod, 4
... Control rod drive mechanism, 11 ... Recirculation pump, 1
2...Temperature detector, 13...Temperature setting device, 14...
...Temperature rise rate setting device, 15...Differentiator, 16...
Integrator, 17...Low value priority circuit, 18...Control rod operation determination section, 19...Control rod selection sequence control section, 20...Display device, 21...Control rod drive control device.

Claims (1)

[Claims] 1 means for determining the temperature of reactor water in a nuclear reactor; first deviation calculating means for determining a temperature deviation signal that is the deviation between the reactor water temperature obtained by the temperature determining means and a target temperature; and determining the temperature. means for calculating a temperature rise rate by inputting the reactor water temperature obtained by the means; a second deviation calculation means for calculating a temperature rise rate deviation signal that is a deviation between the temperature rise rate and a target temperature rise rate; a low value priority circuit that selects and outputs a low value deviation signal from among the temperature deviation signal output from the first deviation calculation means and the temperature increase rate deviation signal output from the second deviation calculation means; When the absolute value of the deviation signal output from the low value priority circuit is greater than the dead band setting value and the deviation signal is positive, a control rod withdrawal command is output, and when the deviation signal is negative, the control rod is removed. control rod operation determining means for outputting an insertion command; and control rod drive control means for operating the control rod selected by the control rod selection sequence control means based on the command output from the control rod operation determining means. Reactor heating control equipment.