JPH0136079B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a nuclear reactor power control device that controls the power of a nuclear reactor based on a preset power curve.

In a direct cycle plant such as a boiling water reactor, the void coefficient of reactivity is negative and large, so output can be controlled by a recirculation flow rate control method. That is, if an increase in load is required,
If the recirculation flow rate is increased, the voids in the furnace will decrease, the reactivity will become positive, and the furnace output will increase. Equilibrium is reached when the number of voids increases and the reactivity becomes zero.

Conventionally, a nuclear reactor power control system using such a recirculation flow rate control method is as illustrated in FIG. That is, a represents the output control device, b represents the load setting device, and c represents the recirculation flow rate control system.
The output control device a includes an output pattern generator d and a controller e. For example, when starting a nuclear reactor, an output pattern generator d generates an output request signal C at each time as a function of time based on a preset output target value A and an output change rate B.
Output. Then, the controller e controls the position of the load setter b so that the deviation E of the signal D' fed back from the load setter b with this output request signal C becomes 0, and the output signal from the load setter b is Accordingly, the recirculation flow rate control system c controls the recirculation pump f to adjust the recirculation flow rate. At this time, the flow rate of the recirculation pump f is adjusted so that the deviation signal G between the actual output signal F fed back from the reactor and the load setter signal D becomes 0, so that the flow rate is finally output from the load setter b. This means that the reactor output that meets the requirements will be obtained.

By the way, when increasing the output of a nuclear reactor,
Since the reactor core transitions from a low temperature state to a high temperature state, in order to avoid a rapid temperature rise of the fuel during this power transition period, the core power is increased at an extremely small rate of increase in power, and the metal material of the fuel is sufficiently used. There are cases where operation is performed to reach the output target value after acclimating to the high temperature. This kind of operation that gradually increases the output along a preset output curve is called
This is called PCIOMR operation and is controlled by the reactor power control system described above. However, if, for example, the output control device a malfunctions or the output detector that detects the output signal F fed back from the reactor malfunctions, the output operation along the predetermined output curve will not be performed correctly and the health of the fuel will be affected. It is possible that sex may be impaired. In addition, when such an abnormality occurs, it must be handled manually based on the operator's judgment, but this places a heavy burden on the operator, so it has been desired to automate such a monitoring function.

This invention was made based on the above circumstances, and its purpose is to be able to monitor control abnormalities during the PCIOMR operation, and when an abnormality occurs, an accident signal is automatically output and the operation of the device is stopped. The object of the present invention is to obtain a nuclear reactor power control device that can ensure the integrity of fuel.

The present invention will be described below with reference to an embodiment of the reactor power control system shown in FIGS. 2 and 3. In the figure, 1 is a boiling water nuclear reactor, 2 is a reactor recirculation pump, and the flow rate of this recirculation pump 2 is adjusted by a reactor power control system 3, which will be described below. That is, 4 is an output control device, 5 is a load setting device, and 6 is a recirculation flow rate control system. This recirculation flow rate control system 6 receives an actual output signal F fed back from the reactor 1 and a signal D output from the load setting device 5.
By adjusting the flow rate of the recirculation pump 2 so that the deviation signal G becomes 0, a reactor output that matches the request issued from the load setting device 5 can be obtained.

On the other hand, the output control device 4 is an output pattern generator 7
, a controller 8 and a monitoring device 9. The output pattern generator 7 generates an output request signal C at each time in a time function based on a preset output target value A and an output change rate B.
Output. The controller 8 receives this output request signal C and a signal fed back from the load setting device 5.
The position of the load setting device 5 is controlled so that the deviation E of D' becomes zero.

Further, the monitoring device 9 includes a deviation calculator 10, a first judge 11, and a second judge 12. The arithmetic unit 10 receives an output request signal C output from the output pattern generator 7 and an output signal H from an actual plant output, for example, a generator 13.
A deviation signal I is outputted to the first judgment device 11 by calculating the deviation between the two. This first judgment device 11 judges whether or not this deviation signal I exceeds a tolerance value J, which will be described below, and outputs an accident signal K when the deviation signal I exceeds a tolerance value J. It's summery.

The allowable value J is then set by the second determiner 12. That is, this judgment device 12 inputs the above-mentioned output target value A, output request signal C, and generator output signal H, and as shown in FIG. During the output transition period before one reaches the output target value A, a tolerance value J with a tolerance range of ±2% is given to the output request signal C to the first judge 11, and During steady operation after at least one of the machine output signals H reaches the output target value A, the allowable value J is switched to +0.5% and output to the first judge 11. In other words, during the power transition period when the output is increasing, the core output is low, so the allowable range can be set relatively wide in this way. It is possible to absorb such variations in output. On the other hand, during steady-state operation at high output, especially when the output target value is set to the rated output of the plant, an output greater than the output target value means greater than the rated output, ensuring the integrity of the fuel. Due to the need to do so, it is important to operate within narrow tolerances as described above.

Reactor power control system 3 configured as above
In this case, the output target value A and the output change rate B are input to the output pattern generator 7, and an output request signal C at each time is output. Then, as described above, based on this output request signal C and the feedback signal D' from the load setting device 5, the position of the load setting device 5 is controlled by the controller 8, and the position of the load setting device 5 is controlled based on the load setting device signal D and the feedback signal D' from the load setting device 5. The flow rate of the recirculation pump 2 is adjusted by the recirculation flow rate control system 6 based on the feedback output signal F from the recirculation pump 2. That is, the operation of the recirculation pump 2 is controlled according to a predetermined output pattern that changes from moment to moment based on a preset output target value A and an output change rate B.

Then, during the output transition period until the output target value is reached, the output request signal C and the generator output signal H are compared in the first judgment unit 11 within the tolerance range of ±2% as described above. When an abnormality exceeds this allowable range, an accident signal K is output, and the output control device 4 immediately stops operation when this accident signal K is output.

On the other hand, during high output operation after reaching the output target value A, the narrow tolerance range of +0.5% is input to the first judge 11 as the judgment reference value, and the output request signal C
A comparison is made between the output signal H and the generator output signal H. In the event of an abnormality exceeding this allowable range, an accident signal K is output as in the above-mentioned output transition period, and the operation of the output control device 4 is stopped.

Therefore, it is possible to prevent damage to the fuel due to abnormal output in the event that the output control device 4 malfunctions or the feedback signal from the reactor becomes abnormal, which is effective in ensuring the integrity of the fuel. . Furthermore, during steady operation at high output, which greatly affects the health of the fuel, the output is checked within a narrow tolerance range, which is extremely effective in preventing fuel damage during high output.

In addition, in this example, the deviation tolerance range between the output target value and the actual plant output was set to ±2% and 0.5%, but in short, these tolerance ranges ensure the integrity of the fuel during reactor operation. Because it is set based on a value that takes into account a sufficient safety factor,
Various modifications can be made for each plant without being restricted by the numerical values of the embodiments, and implementation can be carried out with the optimum values. Furthermore, in the above embodiment, the generator output is used as the actual plant output, but for example, the turbine inlet pressure, main steam flow rate, feed water flow rate, reactor thermal output, etc.
It is of course also possible to use process signals that are related to the output of the plant.

As explained above, the present invention is provided with a monitoring device in an output pattern generator that outputs an output request signal at each time based on a preset output target value and output change rate. The system compares the deviation between the output request signal and the actual plant output, and outputs an accident signal when this deviation exceeds a predetermined allowable value. Therefore, sufficient fuel integrity is ensured during PCIOMR operation, and control abnormalities can be automatically monitored, greatly reducing the burden on operating personnel. Furthermore, after at least one of the output request signal and the actual plant output reaches the output target value, the above-mentioned monitoring device judges a control abnormality using a narrower tolerance value than the output transient period before the output target value is achieved. It is extremely effective in preventing fuel damage during high-power operation, and has great effects in improving the safety of nuclear reactors and automating control, such as by improving the accuracy of output control.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing a conventional reactor power control system, Fig. 2 is a schematic diagram of a reactor power control system showing an embodiment of the present invention, and Fig. 3 is a time chart showing changes in the allowable range. be. 4... Output control device, 7... Output pattern generator, 9... Monitoring device, 10... Deviation calculator, 11
...first judge, 12...second judge.

Claims (1)

[Claims] 1. An output pattern generator that outputs an output request signal at certain times to a recirculation flow control system via a load setting device based on a preset output target value and output change rate; A monitoring device that compares the deviation between the output request signal output from the output pattern generator and the actual plant output with a predetermined tolerance value and outputs an accident signal when the deviation exceeds the tolerance value, During steady operation after at least either the output request signal or the actual plant output has reached the output target value, this monitoring device compares the deviation with a tolerance value in a narrower range than in the previous output transient period. A nuclear reactor power control device characterized in that it makes a judgment. 2. The monitoring device includes a deviation calculator that calculates the deviation between the output request signal and the actual plant output;
a first judger that compares and judges the deviation signal output from the deviation calculator with the above-mentioned allowable value; and a second judger that replaces the above-mentioned allowable value when the above-mentioned output request signal or actual plant output reaches the above-mentioned output target value. 2. The nuclear reactor power control device according to claim 1, characterized in that it is configured to include a second determination device. 3 The first judger determines that the output request signal is ±2%,
Also, during steady operation after achieving the output target value, +0.5%
3. The nuclear reactor power control system according to claim 2, wherein the comparative judgment is made using the permissible value as the allowable value.