JPS59155796A - Automatic power control device for atomic power plant - 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 [Technical Field of the Invention] The present invention relates to improvements in automatic output adjustment devices for nuclear power plants.

[Technical use of the invention] In recent years, with the increasing proportion of nuclear power plants in the electric power system, nuclear power plants are no longer limited to base load operation, but are now undergoing load following operation, automatic frequency control (hereinafter referred to as FC) operation, etc. There is an increasing need to perform output adjustment operations.

On the other hand, in boiling water reactors, for example, as a core thermal output control method to adjust the output, the density is changed by changing the flow rate of the core, which has a neutron moderating function, and thereby the core thermal output A recirculation flow rate control method that changes the neutron absorption rate, and a control rod operation method that changes the core thermal output by inserting and removing control rods, which are neutron absorbers, from the reactor core.
5 and its daughter nucleus Zenon 135 are produced,
Since this Zenone 135 is a neutron absorbing substance, when the core thermal output is changed, the Zenone concentration also changes temporally and spatially. Therefore, when transitioning from high-power operation in the daytime to low-power operation at night during load-following operation, or vice versa, the fluctuations in the xenone concentration distribution and the associated fluctuations in the power distribution must be taken into consideration when adjusting the reactor core. It is necessary to adjust the flow rate and operate the control rods.

For example, when a load following operation is performed only by adjusting the core flow rate, the core thermal output, core flow rate, iodine concentration, and xenone concentration change as shown in FIG. 1. In the figure, time is plotted on the horizontal axis, and core thermal output, core flow rate, xenone concentration, and iodine concentration are plotted on the vertical axis. Curve a is core thermal output, curve A is core flow rate, and curve C is xenone concentration. , and the curve d shows the temporal variation of the iodine concentration.

As is clear from the figure, lowering the core flow rate lowers the core thermal output, and increasing the core flow rate increases the core thermal output. In addition, in order to maintain a constant power output, the core flow rate must be increased or decreased in response to the increase or decrease in the xenone concentration, and the power distribution also changes over time as the xenone concentration distribution changes and the core flow rate changes. spatially variable.

In addition, in boiling water reactors, the relationship between core thermal output and core flow rate is regulated in order to maintain the integrity of the nuclear fuel and various equipment, and the reactor must be operated within these limits. There must be.

FIG. 2 does not show such a limited range; the horizontal axis shows the core flow rate, the vertical axis shows the core thermal output, and the shaded area is the operating range of the reactor.

Furthermore, in order to maintain the integrity of the nuclear fuel, the output distribution when the nuclear fuel is run-in in advance is hereinafter referred to as the PC envelope. Changes in the output distribution are permitted only within the range (not shown).

Therefore, when load following operation is performed in a nuclear power plant, it is required to comply with the above-mentioned two restrictions on the core flow rate and core thermal power distribution as the operation limit value 3-.

On the other hand, compared to AFCFC12 load following operation, the amount of change in core thermal output is small at maximum, about 5%, and the change time is also 5%.
Since the change in xenone concentration is almost negligible, and the amount of change in output is also small, it is possible to operate only by controlling the recirculation flow rate.

However, even when applying AFCFCl2, it is required to comply with the operational limit values for the core thermal output, core flow rate, and core thermal power distribution described above, but when applying AFCFCl2 under constant power operation, In this case, since the xenone concentration hardly changes, there is little change in the core state, and the margin for the operating limit value is also constant.
It is possible to know the possible output adjustment range in advance, and the AFC operation is easy.

[Problems in the Background Art] However, in the conventional automatic output adjustment device of a nuclear power plant, when AFCFCl2 is applied in addition to 4n4- during load following operation, the Zenon i11 degree increases as the core thermal output changes. Since it constantly changes, the xenone concentration,
The core flow rate and power distribution are constantly changing, and the amount of margin relative to the operating limit value is also constantly changing.

Therefore, when attempting to apply AFCFCl2 within the operating limit even in a state such as during load following operation,
If an attempt is made to set the AFCFCl2 power adjustment range in advance, the AFCFCl2 power adjustment range must be adjusted according to the power adjustment range of the core state with the smallest margin during load following operation, and the AF
C. The disadvantage is that the operating capacity is significantly limited, and the ability of the automatic output adjustment device of the nuclear power plant cannot be fully utilized, making it difficult to respond to changes in power demand.

[Purpose of the Invention] The present invention has been made to deal with such conventional drawbacks, and is to improve the automatic output of a nuclear power plant by making it possible to improve the efficiency of AFCFCCl2 as much as possible during load following operation in a nuclear power plant. The purpose is to provide a regulating device.

[Summary of the Invention] In other words, the present invention calculates core thermal output, power distribution, etc. by inputting plant quantities such as core flow rate, core pressure, and neutron flux from each side cover installed in the reactor. Compare the output signal from the pro wrestling calculation device and this process calculation device with predetermined reactor operation limit values such as core flow rate, power distribution, and core thermal output, and output the maximum variation range of -C generator output. an AFC signal limiting device that limits and outputs an AFC request signal according to an output signal from the output change width calculating device; It is characterized by being equipped with a generator output adjustment device that adjusts the generator thermal output during operation, and performs automatic control of, for example, recirculation flow rate necessary for load following operation, as well as automatic control of recirculation flow rate when AFC operation is required. The system automatically determines the range in which AFC operation is possible while constantly monitoring the state of the core during load following operation, and automatically controls the core within this range.

[Embodiment 1 of the invention The details of the present invention will be explained below with reference to the drawings.

FIG. 3 is a block diagram showing an embodiment of the automatic output adjustment device for a nuclear power plant according to the present invention.

In the figure, °C code 1 is, for example, a boiling water nuclear coupler reactor, and inside this reactor 1 there are various controls (
(not shown) is provided, and the output of this M-side lid is connected to the process calculation device 2.

The process calculation device 2 calculates the core thermal output, power distribution, iodine and xenone concentration distribution, etc. based on the signals indicating various plant gates input from the measuring instruments of the reactor 1, and outputs the corresponding data signals. is configured to output.

This process calculation device 2 is configured to perform calculations at a cycle of about one hour when the output is held constant, such as during base load operation, and at even smaller intervals during load following operation.

Outputs of the process calculation device 2, ie, output data signals such as the core thermal output, the power distribution of the core thermal output, and the core flow rate, are input to the power change range calculation device 3.

This output change range calculation device 3 calculates the input core thermal output,
Data signals such as power distribution and core flow rate are compared with predetermined operating limit values for core thermal output and core flow rate as shown in Figure 2 above to determine the operating margin, and power generation is performed within this margin. AFC signal limiting device 4 calculates the machine output change amount.
It has a function to output to.

In addition, in order to obtain the generator output change amount corresponding to the margin of each data, the output change width calculation device 3 calculates the change rate of the core thermal output, power distribution, and core flow rate with respect to the generator output change amount of the output level. It is configured to store a preset relational expression as a function and output the amount of change using this.

The AFC signal restriction device 4 receives an AFC request signal A output from a power dispatch center (not shown), etc., and limits the AFC request signal A by comparing it with the output signal from the output change range calculation device 3. Then, this limited AFC request signal is output to the output adder 5.

8- The output adder 5 adds the load following operation request signal B output from the load pattern generator 6 and the restricted AFC request signal from the AFC signal limiting device 4, and outputs the output from the generator as a load request signal. It has a function of outputting to the output adjustment device 7.

The generator output adjustment device 7 is connected to a recirculation flow rate control system 8 that controls the core thermal output of the reactor 1, and compares the output detection signal C from the actual generator with the output from the output adder 5. Then, a control signal is outputted to the recirculation flow rate control system 8 so that both signals match.

The automatic output adjustment device for a nuclear power plant of the present invention configured as described above operates as follows.

First, plant variables such as core flow rate, core pressure, and neutron flux are detected by measuring instruments placed in the nuclear reactor 1 and input into the process calculation device 2 . The core thermal output, power distribution, iodine and xenone concentration distribution, etc. are calculated in the process calculation system M2, and are added to the output change range calculation device 3 using various plant quantities as data signals, and the core heat output and the core heat A margin is determined by comparing the predetermined operation limit value for the output phase division, and the amount of change in generator output that is possible within this margin is calculated. It is input to the restriction device 4.

The AFC signal restriction device @ 4 compares the manually inputted AFC request signal with the AFC operational range output from the specific force change width calculation device 3, and outputs an AFC request signal that is limited to the AFC operational range or less. The output adder 5 adds the request signal B for load following operation input from the load pattern generator 6 to the adder 5, and outputs the final load request signal to the generator output horn adjustment device 7. Ru.

Then, in the generator output adjustment device M7, the input load request signal and the output detection signal C from the actual generator are compared, and a control signal is output to the core flow control system 8 so that the two match. This controls the core flow rate and changes the core thermal power to respond to load fluctuations via the desired core thermal power.

If only load following operation is performed while the AFC request signal ratio is not input to the AFC signal limiting device 4, the AFC request signal applied via the AFC signal limiting device 4 becomes zero and the load pattern generator 6 outputs the AFC request signal to the AFC signal limiting device 4. Only the load following operation request signal B is applied to the generator output adjustment device 7 via the output adder 5, and is compared with the actual generator output C, and a control signal is sent to the core flow rate control system 8 so as to match them. is output, ensuring load following operation.

In addition to load following operation, A-C of the present invention also provides AF
Not only performs C operation, but also performs AFC during constant output operation.
It is also possible to perform only the operation, and the AFC request request signal ratio is output to the output adder 5 via the AFC signal limiting device 4.

[Effects of the Invention] The automatic output adjustment device for a nuclear power plant of the present invention described above includes a process calculation device that calculates and outputs the plant quantity of a nuclear reactor, and an output signal from this process calculation device and the operation of the plant quantity. an output change width calculation device that outputs the maximum change width of the generator output by comparing the output change width with a limit value; an AFC signal restriction device that limits the AFC request signal using the output signal from the output change width calculation device 11-; Since the reactor is equipped with a generator output adjustment device that adjusts the generator thermal output of the reactor according to the output signal from the AFC signal restriction device, it is only possible to automatically control, for example, the recirculation flow rate in order to implement load following operation. If UAFC operation is necessary, it is possible to calculate the possible output change range according to the core state during operation, and automatically perform AFC operation within the output change range when UAFC operation is required. , AFC operation can be performed efficiently without impairing the integrity of nuclear fuel.

Therefore, the operating efficiency of the nuclear power plant can be maximized.

[Brief explanation of the drawing]

Figure 1 is a characteristic diagram showing temporal changes in core thermal output, core flow rate, xenone concentration, and iodine concentration during load following operation, Figure 2 is a diagram showing the reactor operable range, and Figure 3 is a diagram showing the present invention. 1 is a block diagram showing an example of an automatic output adjustment device for a nuclear power plant. 12- 1......Reactor 2...Process calculation device 3...
......Output change width calculation device 4...
・・・・・・AFC signal restriction device 5・・・・・・・・・
... Output adder 6 ...... Load pattern generator 7 ...... Generator output adjustment device 8 ...... ... Recirculation flow city control system agent Patent attorney Suyama Sa - KomapafflOR

Claims (2)

[Claims] (1) A process calculation device that calculates and outputs core heat output, power distribution, etc. by inputting plant quantities such as core flow rate, core pressure, and neutron flux from various measuring instruments installed in the reactor, and this process Output signal from calculation device and core flow rate,
An output change width calculation device that outputs the maximum change width of the generator output by comparing it with predetermined reactor operation limit values such as the power distribution and core thermal output, and output power from this output change width calculation device.
AFC that limits and outputs the AFC request signal depending on the signal
A nuclear power plant characterized by comprising: a signal limiting device; and a generator 111 power adjusting device that adjusts the heat output of the N generator during load following operation of the nuclear reactor using the output signal from the AFC signal limiting device. Automatic output adjustment device for power generation plants. (2) An automatic output adjustment device for a nuclear power plant according to claim 1, wherein the generator output adjustment device is configured to control recirculated raw ore of a nuclear reactor.