JP2871375B2 - Reactor power adjustment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for starting a reactor by operating a control rod, and more particularly, to a system for operating a control rod corresponding to an output state of a neutron flux at the time of starting a reactor, and a neutron. It relates to a bundle instrumentation system.

[0002]

2. Description of the Related Art When starting a nuclear power plant, control rods inserted into a reactor core are gradually pulled out to increase the output of a nuclear reactor. This operation has been performed by an operator. The operator operates the control rods one by one while monitoring the neutron flux n and the reactor period (period) T in order not to give rapid reactivity to the reactor. The relationship between n and T can be expressed by the following equation.
/ T is called the neutron flux change rate.

[0003]

(Equation 1)

However, in recent years, there has been a demand for automating the operation of a plurality of control rods for the purpose of saving labor and shortening the startup time of a nuclear power plant. For example, Japanese Patent Laid-Open Publication No. Sho 63-286793 "Control rod operation system" meets this demand. This conventional example,
When the reactor is changed from the subcritical state to the critical state, the next withdrawal amount of the control rod is determined based on the total amount of control rod withdrawal, the previously operated control rod withdrawal amount, and the reactor cycle. This indicates that the control rod is operated according to the information.

For neutron flux measurement, a conventional neutron source area monitor (SRM) and an intermediate area monitor (IR
M), and a start-up area monitor (SRNM) for monitoring the neutron flux from the neutron source area to the intermediate area has been developed and is being used. The start-up area monitor is sometimes referred to as a wide-range monitor (WRM), that is, a start-up area neutron flux monitor. Neutron detector used for SRNM to detect neutron flux from the neutron source region to the intermediate region (hereinafter referred to as SRNM detector)
Has integrated neutron detectors for the SRM and the IRM so that they can be installed in the reactor core during operation of the nuclear power plant. Conventional neutron detectors for SRM and IRM require a drive mechanism in order to be pulled out of the core when the reactor power reaches a predetermined value.

One example of the SRNM is described in Japanese Patent Application Laid-Open No. Sho 59-180482, entitled "Wide Range Monitor Device". This SRM is provided with a logarithmic campbell unit for measuring a neutron flux in accordance with the Campbell theorem in addition to the conventional SRM and IRM. Then, these outputs are switched, the furnace cycle is calculated based on the switched signals, and the result is output to a period meter. At the time of starting the reactor, as described above, the reactor cycle is an important parameter.

[0007]

The reactor cycle is constantly monitored during the start-up of the plant. If this value falls below a predetermined value, the reactor is scrammed. It is desirable from the viewpoint of stable power supply that unnecessary scrum is not generated even if the reactor cycle is temporarily reduced due to electrical noise or other factors, even if there is no abnormality in the reactor . For this reason, a filter having a time constant of several tens of seconds is provided in the part for calculating the furnace cycle, the furnace cycle is calculated via the output of this filter, and the result is output. The result is output via the Internet.

When the control rod operation is performed based on the furnace cycle output in this manner, the change in the furnace cycle output when the control rod is operated, particularly when the control rod is pulled out, is very slow because of the filter. For this reason, after the control rod withdrawal, it is necessary to wait sufficiently until the furnace cycle becomes stable, confirm the result, and then resume the control rod withdrawal. That is, there is a problem that the time required for the control rod pull-out operation becomes long.

In particular, when a plurality of control rods are simultaneously pulled out, the reactivity becomes larger than that of a single control rod. Therefore, if a plurality of control rods are slightly pulled out, it is necessary to take sufficient time to change the furnace cycle. Monitoring, and then the control rod withdrawal is performed again. In this case, there is a problem that the control rod withdrawal operation time is long because the change in the furnace cycle instruction value is slow despite performing a plurality of control rod operations.

An object of the present invention is to provide a reactor power adjusting device capable of shortening the start-up time of a nuclear reactor.

[0011]

[0012]

[0013]

[0014]

[0015]

[0016]

According to a first aspect of the present invention , there is provided a neutron reactor which is disposed in a nuclear reactor.
Neutron detector to detect neutron flux from source region to intermediate region
Operation means and control rods inserted into the core of the reactor
Control rod driving device and an output signal of the neutron detection means
Means for outputting a first furnace cycle based on the neutron detection
On the basis of the output signal of the discharge means,
Output second reactor cycle with fast response to neutron flux change
Means and the control rod drive based on the second furnace cycle
And control means for outputting a control signal.

According to a second aspect of the present invention which achieves the above object of the present invention,
The feature is that the neutron flux from the neutron source region to the intermediate region is detected.
First reactor cycle based on the output signal of the neutron detection means
Means for outputting a signal based on an output signal of the neutron detection means.
Therefore, the response to the change of the neutron flux is larger than that of the first reactor cycle.
Means for outputting a fast second furnace cycle, said second furnace cycle
Controls the control rods inserted into the reactor core based on
Control means for outputting a control signal to the control rod drive device.
It has been.

According to a third aspect of the present invention which achieves the above object of the present invention,
The features are located in the reactor,
Neutron detection means for detecting a neutron flux up to a region,
Control rod drive for operating control rods inserted into the core of the sub-core
And a first delay element, the output of the neutron detection means.
First furnace affected by the first delay element based on a signal
Means for outputting a period, and a time constant longer than the first delay element
Having a short second delay element, and an output of the neutron detection means.
Second furnace affected by the second delay element based on a signal
Means for outputting a cycle; and
Control means for outputting a control signal to the control rod driving device.
That is.

According to a fourth aspect of the present invention which achieves the above object of the present invention,
The feature is that the neutron flux monitor is activated from the neutron source area.
Output of neutron detection means to detect neutron flux to the intermediate region
Input a force signal and, based on the output signal, change the time constant.
Output multiple furnace cycles affected by multiple delay elements
Is to do.

According to a fifth aspect of the present invention which achieves the above object of the present invention,
The feature is that the neutron flux monitor is activated from the neutron source area.
Output of neutron detection means to detect neutron flux to the intermediate region
Means for outputting a first furnace cycle based on a force signal;
Neutron flux change from the first reactor cycle based on force signal
Means for outputting a second furnace cycle having a fast response to
That is.

According to a sixth aspect of the present invention which achieves the above object of the present invention,
The feature is that the reactor power control device is
Output signal of the neutron detector that detects the neutron flux up to the region
Of the neutron flux than the first reactor cycle obtained based on
Means for outputting a second furnace cycle having a fast response to
The system inserted into the reactor core based on the second reactor cycle
A control signal is output to the control rod drive that operates the control rod.
And means of control.

[0022]

[0023]

According to the first invention, the control means controls the first furnace cycle.
Response to neutron flux changes is based on the second reactor cycle.
Therefore, the control signal is output to the control rod driving device, so that the control rod operation (specifically, the operation of pulling out the control rod and the operation of stopping the extraction) can be performed in a short time in response to the change of the neutron flux in the core. And the start-up time of the reactor can be significantly reduced.

According to the second invention, the control is performed in the same manner as in the first invention.
The control means responds more to neutron flux changes than the first reactor cycle.
The control signal is sent to the control rod drive based on the fast
Output in a short time to change the neutron flux in the core
In response, control rod operation (specifically,
And pull-out stop operation) can be performed when the reactor is started up.
The time can be significantly reduced.

According to the third invention, the control means controls the first delay.
Element affected by the second delay element, which has a shorter time constant than the element
A control signal is output to the control rod drive based on two furnace cycles.
To respond quickly to changes in the neutron flux in the core.
Control rod operation (specifically, control rod withdrawal operation and withdrawal)
Shutdown operation), and the start-up time of the reactor
Can be shortened.

According to the fourth invention, the neutron flux monitor in the activation region
Data affected by multiple delay factors with different time constants.
Output the number of furnace cycles,
Each has a different speed of response to neutron flux changes
You. Based on the fastest response furnace cycle among the multiple furnace cycles
Operating the control rods to change the neutron flux in the core
Control rod operation (specifically, control rod
(Pull-out operation and pull-out stop operation).
The start-up time of the reactor can be significantly reduced.

According to the fifth invention, the neutron flux monitor in the activation region
The response to neutron flux changes more than in the first reactor cycle
Since a means for outputting a fast second furnace cycle is provided, the
By operating the control rod based on the second furnace cycle,
Control rod operation in a short time in response to neutron flux changes in the core
(Specifically, control rod pull-out operation and pull-out stop operation)
Can significantly reduce the start-up time of the reactor.
You.

According to the sixth invention, a reactor power control apparatus
However, the response to neutron flux change is faster than the first reactor cycle.
Means for outputting a second furnace cycle, based on the second furnace cycle.
Control means for outputting a control signal to the control rod driving device.
Control in a short time in response to neutron flux changes in the reactor core.
Control rod operation (Specifically, control rod pull-out operation and pull-out stop
Shutdown operation), which significantly increases the reactor start-up time.
Can be shortened.

[0029]

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention, BWR
A reactor power control device applied to the present invention will be described below with reference to FIGS.

The control rods C _{1 to} C _N for controlling the reactor power and the SRNM detectors S _{1 to} S _K for detecting the neutron flux at the time of starting the reactor are arranged in the core inside the reactor pressure vessel 1. I have. FIG. 6 shows an example of arrangement of control rods, SRNM detectors, and fuel assemblies F in the core. FIG. 6 is an example of a core of a BWR that performs gang control rod operation, which will be described later. However, even in a core of a BWR that operates control rods in the core one by one, the arrangement relation of the control rod, the SRNM detector, and the fuel assembly F is also shown. Is the same. Fuel assembly F, as shown in a portion of the enlarged vicinity of SRMN detectors S ₁ in FIG. 6, the control rod C ₁ ~
Four bodies are arranged adjacent to each of C ₄ . Control rods C ₁ -C ₄ are arranged so as to surround the SRMN detector S _1.

The positions of the control rods C _{1 to} C _N in the core axis direction are adjusted by control rod driving devices M _{1 to} M _N connected to the control rods C _{1 to} C _N , respectively. The position of the control rod in the core axis direction is
It is detected by the control rod position detectors P _{1 to} P _N. Control rod drive M ₁ ~M _N in FIG. 1 using the motor as each driving source. However, a hydraulically driven control rod drive device that drives the control rods with hydraulic pressure may be used. Further, the control rod position detectors P _{1 to} P _N in this embodiment
, A synchro transmitter is used. However, a plurality of reed switches may be provided on the control rod, and the position of the control rod in the core axis direction may be detected using these reed switches.

The reactor power control device of the present embodiment
M detectors S _{1 to} S _K , neutron flux monitor (SRN
M) 2 ₁ ~2 _K, and a nuclear power output control means 14, the control rod control system 15 and the control rod drive M ₁ ~M _N.

The SRNMs 2 _{1 to} 2 _K have the same configuration, and include a logarithmic Campbell means 4, a logarithmic coefficient ratio means 5, furnace cycle calculators 8 and 9, a scrum determinator 11, and the like. In addition,
3 is a preamplifier, 6 is switching means, and 7 and 10 are display means.

The furnace cycle calculators 8 and 9 have basically the same configuration as shown in FIG. The furnace cycle calculator 8 includes a filter 8A, a calculator 8D, a filter 8E, and a reciprocal calculator 8H. The filter 8A includes a subtractor 8B and an integrator 8
C, and the filter 8E has a subtractor 8F and an integrator 8G. On the other hand, the furnace cycle calculator 9 has a filter 8A, a calculator 8D, a filter 9E, and a reciprocal calculator 8H. The filter 9E has a subtractor 8F and an integrator 9G. Ta
The time constant of the filter 8A, Tb ₁ is a time constant of the filter 8E, and Tb ₂ are time constants of the filter 9E, S represents a Laplace operator. The time constant Tb ₂ (= τ ₂ ) is
It is set shorter than the time constant Tb ₁ (= τ ₁ ) (that is, τ ₁ > τ ₂ ). Here, the time constant τ ₁ is set to several tens of seconds, and the time constant τ ₂ is set to several seconds.

The output signals of the SRNM detectors S _{1 to} S _K are:
Inputted individually to the corresponding SRNM2 ₁ ~2 _K. SRN
It will be described on the basis of the M function of the SRNM2 _1. SRNM
The output signal of the detector S ₁ is amplified by SRNM2 ₁ preamplifier 3, is input to the logarithmic Campbell means 4 and the logarithmic count rate means 5. The logarithmic Campbell unit 4 outputs to the switching unit 6 a logarithmic Campbell signal for the input signal according to the Campbell's theorem. On the other hand, logarithmic counting rate means 5
Calculates the logarithmic count rate by counting the pulses of the input signal, and outputs it to the switching means 6 as a logarithmic count rate signal. Switching means 6
In general, one of the two signals is selected according to the values of both input signals, and the selected signal is subjected to arithmetic processing to output a neutron flux output signal in the activation region (corresponding to the reactor output)
Is output. The neutron flux output signal n of this activation region is input to the display means 7, the furnace cycle calculator 8, and the furnace cycle calculator 9. The reactor cycle calculators 8 and 9 calculate the reactor cycle of the reactor based on the input signal n. The furnace cycle calculator 9 has a higher responsiveness because the filter time constant is shorter than the furnace cycle calculator 8.

The calculation of the reactor cycle of the nuclear reactor in the reactor cycle calculators 8 and 9 will be described in detail below. First, the furnace cycle calculator 8 will be described. The output signal n output from the switching means 6 is input to the filter 8A. Output signals n ₁ of the output signal n and filter 8A is input to the arithmetic unit 8D. The arithmetic unit 8D uses these input signals to calculate (n
−n ₁ ) / n is calculated. (Nn- ₁ ) represents a differential value dn / dt of (Equation 1). The signal output from the arithmetic unit 8D represents the reciprocal of the furnace cycle T according to (Equation 1). Arithmetic unit 8
The output signal of D is supplied to a reciprocal calculator 8H via a filter 8E.
Is input to The reciprocal calculator 8H calculates the reciprocal of the input signal. As a result, the furnace cycle T is output from the reciprocal calculator 8H. The difference between the furnace cycle calculator 9 and the furnace cycle calculator 8 is that the output signal of the calculator 8D is output through a filter 9E having a shorter time constant than the filter 8E.
H. The reciprocal calculator 8H of the furnace cycle calculator 9 also outputs the furnace cycle.

The reciprocal calculator 8H is provided between the calculator 8D and the filter 8E in the case of the furnace cycle calculator 8, and between the calculator 8D and the filter 9E in the case of the furnace cycle calculator 9. You may.

Since the neutron flux signal output from the SRNM detector contains a minute fluctuation component, the signal n input to the reactor cycle calculator oscillates. Filters 8E and 9E are provided to prevent this vibration.

When an abnormality occurs in the nuclear reactor plant and the reactor cycle becomes shorter than a predetermined value, the nuclear reactor is scrammed and the nuclear reactor is stopped. However, in spite of the fact that the reactor is stable, other electrical noises and the like are mixed into the SRNM to prevent the generation of unnecessary reactor scram caused by the temporary shortening of the reactor cycle T. is necessary. The generation of nuclear reactor scram is undesirable from the viewpoints of reduced utilization of the reactor plant and stable power supply. Occurrence of scram, the unnecessary reactor can be prevented by setting by setting a longer time constant of the filter 8E in furnace cycle calculator 8, that is, the constant tau ₁ filter time 8E to several tens of seconds.

The furnace cycle signal, which is the output of the furnace cycle calculator 8, is provided by a display means 10 for displaying the furnace cycle and the scrum discriminator 1
1, and other devices not shown. The scram determiner 11 outputs a trip signal for scramming the reactor when the input reactor cycle is equal to or less than a predetermined value. This trip signal is input to the scrum processing device 12a. The scrum processing devices 12a to 12n
NM2 Besides trip signal from ₁ to 2 _K, and enter the other input signal Ua which is a scrum factor, and carrying out arithmetic processing, and controls scram solenoid valve (not shown), plant abnormally atoms Scrum the furnace.

The furnace cycle calculator 9 is provided for performing a control rod operation based on an output signal (furnace cycle signal) of the furnace cycle calculator 9. In the control rod operation, the ability to quickly grasp the magnitude of the change in the neutron flux associated with the control rod operation after execution of the control rod operation is to quickly determine the result of the control rod operation and to quickly predict the execution of the next control rod operation. It is important to do. In addition, when the change of the neutron flux due to the operation of the control rod is slowly grasped, there is a possibility that the operation of the control rod is excessively performed. An important parameter of the neutron flux at the start-up of the reactor, especially during operation until the reactor reaches criticality, is the reactor cycle. Therefore, the furnace cycle calculator 9 that outputs the furnace cycle for operating the control rod,
As described above, the filter 8 of the furnace cycle calculator 8 can monitor the change of the furnace cycle after operating the control rod in a short time.
A filter 9 having a time constant τ ₂ shorter than the time constant τ _{1 of} E
E is provided. Each of the filters in the furnace cycle calculators 8 and 9 is an n-order delay element (n is an integer), and the filters 8A, 8A
E and 9E are specifically first-order lag elements.

The nuclear power control means 14 is provided by the SRNM 2 ₁
Furnace periodic signal output from the furnace cycle calculator 9 provided to 2 _K, and the recirculation flow rate and other signals Ub reactor power, etc.
Enter The nuclear power control means 14 calculates based on these furnace cycle signals and other input signals Ub, and outputs a control operation command signal to the control rod control device 15. The control rod control device 15 to which the control operation command signal has been input is controlled by the control rod position signal U detected by the control rod position detectors P _{1 to} P _N.
While monitoring c, according to the control rod operation sequence information (not shown), the corresponding motor drive devices LD _{1 to} LD _N
Control. The motor driving devices LD _{1 to} LD _N controlled by the control rod control device 15 drive the motors of the corresponding control rod driving devices M _{1 to} M _N. Therefore, the target control rod is moved to the target position in the core axis direction by the corresponding control rod drive device. The control rod operation according to the control rod operation sequence information is described in, for example, Japanese Patent Application No.
No. 6304.

Here, the content of the processing executed by the nuclear power output control means 14 to output the control operation command signal is as follows.
This will be described in detail with reference to FIG.

Step 21 sets an initial value and sets a variable i to 0.
To This variable i is for indicating whether or not the control rod withdrawal command is output. That is, if the variable i is 0, it means that the control rod withdrawal command is not output from the nuclear power output control means 14. On the contrary,
When the variable i is 1, it means that the nuclear power output control means 14 is outputting the control rod withdrawal command. Step 22
Takes the furnace cycle output from the furnace cycle calculator 9 and selects the shortest furnace cycle among the taken furnace cycles. The selected shortest furnace cycle is the furnace cycle handled in the processing after step 23 of the nuclear power output control means 14 in the present embodiment. Determining the furnace cycle is whether the reference value above T ₁ at step 23. If the furnace cycle is the reference value above T _1,
Control rod can be pulled out. For this reference value T _1,
The below-mentioned reference value T ₂ is a value that defines the stop of the control rod withdrawal. That is, the furnace cycle if below the reference value T _2, the control rod withdrawal is stopped. These reference values are shown in FIG. The reference values T ₁ and T ₂ can be easily determined from the analysis results and the operation results of the reactor plant up to the present. For example, the reference value T ₁ 200 seconds, the reference value T ₂ is 100 seconds.

If the determination in step 23 is "YES", the control rod can be pulled out, so that a control rod withdrawal command is output to the control rod controller 15 in step 24. Once output, the control rod withdrawal command is continuously output until a control rod withdrawal stop command is output. Step 25 sets the variable i to one. Step 26 determines whether the reactor power has reached its target value. The target value of the reactor power is a reactor power that is an important breakpoint in operation management at the time of starting the reactor such as a reactor criticality. The reactor power is obtained by another device, not shown, based on the neutron flux at the time of reactor startup detected by all SRNM detectors. When the reactor power reaches the target value, a control rod withdrawal stop command is output to the control rod controller 15 in step 27. If it is determined in step 26 that the reactor power has not reached the target value, the process returns to step 22 and the subsequent processes are repeated.

[0047] Now, in step 23 described above, when the furnace cycle is not in above T _1, the step 28
Move on to processing. Although the furnace cycle has a negative value,
This value is treated as a T ₁ or more. In step 28, the variable i
Is 1 or not. The determination in step 28 is “NO”
If it is, the process of step 26 is executed, and if the determination is “YES”, in step 29 the furnace cycle is set to the reference value T ₂
It is determined whether or not: If the determination in step 29 is "N
If "O", the process of step 26 is performed. In other words, although a control rod in withdrawal, furnace cycle shows that greater than the reference value T ₁ or less and the reference value T _2. Therefore, it is not necessary to stop the control rod withdrawal.

If the determination in step 29 is "YES", a control rod withdrawal stop command is output to the control rod controller 15 in step 30. Thus, the operation of pulling out the control rod is stopped. A step 31 sets a variable i to 0. Once the control rod pullout stop command is output in step 30, the control rod pullout stop command is continuously output until the control rod pullout command is output.

[0049] If step 28 is "NO", the variable i is an even by control rod withdrawal is not being performed 0, moreover the withdrawal of the control rods to the furnace cycle is less than the reference value T ₁ Since it is not necessary, the process of step 26 may be executed.

The nuclear power output control means 14 shown in FIG.
The control rod operation performed based on the above processing will be specifically described with reference to FIG. At step 24, the time 0 is set based on the control rod withdrawal command output from the nuclear power output
When the control rod withdrawal is started, the furnace cycle is shortened as the control rod is withdrawn. Control rod withdrawal is continued until the furnace cycle reaches the reference value T _2. At time t _a when the furnace cycle reaches the reference value T ₂ , the control rod withdrawal is stopped. However, the furnace cycle, although temporarily shorter than the reference value T _2, gradually longer over time than that. The reason for temporarily furnace cycle is shorter than the reference value T ₂ are, nuclear power control unit 1
This is because there is a time delay from the output of the control rod withdrawal stop command from 4 to the stop of the control rod. Control rod withdrawal until the furnace cycle reaches the reference value T ₁ is longer than the reference value T ₂ are are stopped. Again, the furnace cycle reaches T _1,
Control rod withdrawal resumes. Here, the time t _b after, the temporary furnace periodically rises above the reference value T ₁ is due to the time delay from the control rod withdrawal command from nuclear output control means 14 is output to the control rod is operated Things.
Furnace cycle shown in FIG. 4, of the furnace cycle output from each furnace cycle calculator 9 SRNM2 ₁ ~2 _K, shows the values obtained by selecting the shortest value in step 22. Since use of the furnace cycle, which is the output of the furnace cycle calculator 9 with a short filter 9E time constant, when the reactor is subcritical, after the control rod withdrawal stop, the reference value T ₁ furnace cycle from the reference value T ₂ The elapsed time until the rise of the control rod is short, and the control rod withdrawal can be resumed quickly. Therefore, the interval of the control rod withdrawal operation can be shortened, and the start-up time of the reactor can be significantly reduced.

The effect of the present embodiment will be specifically described below.

[0052] Figure 5 is the reactor during startup, the control rod is limited to showing the results of analyzing the change of the furnace period for withdrawal, pull out tens cm to one particular control rod until time t _1, then 3 shows changes in the furnace cycle when the control rod withdrawal is stopped. The furnace cycle indicated by the solid line is the output of the furnace cycle calculator 8. The furnace cycle indicated by the broken line is the output of the furnace cycle calculator 9. FIG. 5 shows the furnace cycle obtained based on the output of the SRNM detector adjacent to the drawing control rod and the furnace cycle obtained based on the output of the SRNM detector located at a position away from the drawing control rod. Is shown.

As is clear from FIG. 5, the furnace cycle calculator 9
Has a faster response than the furnace cycle output from the furnace cycle calculator 8 and changes in response to control rod operation. For example, during the period from 0 to t ₁ second, the furnace cycle is reduced together with the control rod withdrawal, and after the control rod withdrawal is completed (t
_{After 1} ), the furnace cycle is rising. In particular, the furnace cycle calculated based on the output signal of the SRNM detector adjacent to the control rod to be withdrawn has a considerably low value at time t ₁ , and the change in the furnace cycle after time t ₁ is not significant. since t ₁ of the previous more slowly, it can be seen reactor close to the critical state. On the other hand, the furnace cycle output from the furnace cycle calculator 8, the inclination of the even furnace cycle after time t ₁ has decreased in different.

As described above, by monitoring the reactor cycle output from the reactor cycle calculator 9, the change state of the neutron flux with respect to the operated control rod, that is, the state (reaction) of the reactor can be quickly grasped.

Therefore, by operating the control rods based on the furnace cycle output from the furnace cycle calculator 9, the control rod withdrawal operation interval can be further safely reduced.
A reactor cycle calculator 8 for the safety system of the reactor,
The furnace cycle calculator 9 for the service system of the furnace is provided separately.
Therefore, the safety of the reactor can be further improved.

The nuclear power control means 14 controls each SRNM2
The furnace cycle output from the furnace cycle calculator 9 of _{1 to} 2 _K is input, and a control rod operation command is created and output by a calculation based on the shortest furnace cycle selected from these input furnace cycles. By doing so, it becomes possible to pull out control rods with further enhanced safety of the reactor.

In particular, in a method of operating a plurality of control rods described later at a time, that is, in a so-called gang operation of control rods (hereinafter simply referred to as a gang operation), not only one SRNM detector but also a plurality of SRNM detectors is used. Against SRN
There is a control rod withdrawal adjacent to the M detector. Therefore, each control rod operation, the shortest furnace cycle of the furnace cycle outputted from the furnace cycle calculator 9 SRNM2 ₁ ~2 _K is different from each other. Therefore, by always selecting the shortest furnace cycle of these furnace cycles and operating the control rods based on the selected furnace cycle, the synergy with the high-speed response provided in the furnace cycle calculator 9 provides It is possible to shorten the interval of the control rod withdrawal operation and further enhance the safety of the plant.

In this embodiment, the necessity of the scrum is determined by using the output of the furnace cycle calculator 8 having the filter 8E having a long time constant (on the order of several tens of seconds). Unnecessary scrum can be avoided in the event that is temporarily reduced. For this reason, the operating rate of the nuclear reactor is improved. As a matter of course, judging the necessity of the scrum using the output of the furnace cycle calculator 8 can perform the scram when it is necessary in an abnormal situation.

[0059] described above embodiments, the reactor power control unit 14, based on the shortest (smallest) reactor period selected from the furnace cycle, which is the output of the furnace cycle calculator 9 SRNM2 ₁ ~2 _K To output a control rod withdrawal command.
The control rod withdrawal command can be output by a method different from that of the above-described embodiment. The following two cases can be considered as this method.

Case 1: The next shortest furnace cycle is selected excluding the shortest furnace cycle, and a control rod withdrawal command is output based on this furnace cycle.

Case 2: A plurality of input furnace cycles are weighted averaged, and a control rod withdrawal command is output using the calculated result.

First, case 1 will be described. this is,
One SRNM detector and one SRNM fail,
This is a method for avoiding that the furnace cycle output from the SRNM becomes extremely short, thereby stopping the control rod withdrawal. When implementing this case, the nuclear power control means 14 selects a furnace cycle shorter than the shortest furnace cycle among the furnace cycles input in step 22 of FIG. The control rod withdrawal command is output based on the furnace cycle.

Next, the method of Case 2 will be described. For this purpose, it is necessary to explain the change in the neutron flux when the control rod is pulled out. Therefore, first, the positional relationship between the control rod and the SRNM detector will be described, and then the change in the neutron flux when the control rod is withdrawn under these conditions will be described. Finally, a description will be given of calculating a weighted average of a plurality of furnace periods input based on the result.

Control rods and SRNM in BWR core
FIG. 6 shows the arrangement of the detectors. Square unit D is 1
4 shows four fuel assemblies F arranged around a body cross-shaped control rod C _i (i = 1 to N). This core has 840 fuel assemblies F and 205 (N = 20).
5) The control rod Ci is provided. D entered in unit D
Numerals 1 to D4 show examples of the gang control rod operation group numbers. For example, there are 26 control rods in group D1, and these control rods are operated at one time. The group D5 and subsequent groups, which are the fifth group, are omitted. In the gang operation, a control rod group is selected in consideration of the symmetry of the core. As a result, the control rods are pulled out of the reactor relatively uniformly, so that the local neutron flux peak is lower than when the control rods are pulled out one by one, and the input reactivity per control rod withdrawal amount Can be reduced. At the time of starting the reactor, if the gang operation is performed so that the input reactivity becomes the same as when the control rods are pulled out one by one, the time required to make the reactor critical can be reduced.

The SRNM when the control rods of group D1 in FIG. 6 are pulled out from the entire insertion position to the front pull-out position.
FIG. 7 shows an analysis result of the neutron flux signal output from the detectors S ₈ and S ₁₀ and the core average neutron flux signal. The values of the neutron flux in FIG. 7 are normalized with the neutron flux in the initial state being 1. The output signal of SRNM detectors S ₁₀ substantially matches the change in the core average neutron flux. On the other hand, SRNM
The output signal of the detector S ₈ is largely changed than the variation of the core average neutron flux. The reason is, when the control rod D1 groups are drawn by gang operation, the control rods of the unit Da adjacent SRNM detectors S _8, changes from full insertion state into total withdrawal state, is blocked by the control rod until it which was neutrons is to become as measured by SRNM detectors S _8. Measured value itself of SRNM detectors S ₈ is the correct one is a localized phenomenon. Group D1
This phenomenon that occurs when the control rod of the
The same is true for the M detectors S ₁ , S ₂ , S ₄ , S ₅ and S ₆ . Since the reactor cycle T is the reciprocal of the rate of change of the neutron flux per unit time, as shown in (Equation 1), the vicinity of the installation of the SRNM detector in FIG.
Furnace cycle is the shortest in H, yet it can be seen that the shortest furnace cycle of SRNM detectors S _8. When the shortest furnace cycle among these furnace cycles is used, control rod withdrawal and control rod withdrawal stop are repeated more than necessary, and the start-up time of the reactor becomes longer.

The largest change in the neutron flux in the section ΔH is due to the fact that the SRNM detector Si is provided at the position shown in FIG. This is because neutrons that had been shielded by the control rod until then are measured by the SRNM detector. In addition, 1
6 is a control rod handle, and 17 is an SRNM detector insertion tube.

Therefore, in order to avoid the above problem, S
When the control rod adjacent to the RNM detector is pulled out and the upper end of the control rod is near the position of the SRNM detector, the output from the furnace cycle calculator 9 is output based on the output signal of the SRNM detector. For example, a calculation result obtained by multiplying a furnace cycle to be performed by a weighting coefficient (correction coefficient) r shown in FIG. 9 and a furnace cycle output from the furnace cycle calculator 9 based on other output signals of the SRNM detector. The average is calculated and used as the furnace cycle. These calculations are performed by the nuclear power control unit 14.
The furnace cycle handled in the process of FIG. 3 is defined as this furnace cycle. Thus, the furnace cycle in accordance with the output of SRNM detectors S ₈ in FIG. 7 is substantially the same value as the core average. Therefore, since the nuclear power control means 14 outputs the control rod withdrawal command obtained by the calculation using the furnace cycle obtained by the weighted average, it does not output the control rod withdrawal stop command more than necessary, The startup time of the reactor can be further reduced.

The weight coefficient r shown in FIG. 9 is an example. The weighting coefficient r is a furnace cycle obtained by the neutron flux change of SRNM detectors S ₈ of FIG. 8, a value obtained as the substantially identical to the furnaces period obtained by the neutron flux variation in the core average, further This is a value obtained by performing linear approximation. The reason why the result of the linear approximation is used is that the calculation process becomes easy. If the processing capability of the nuclear power output control means 14 is high and there is room for processing, linear approximation may not be used.

Another embodiment of the present invention which achieves the function of Case 2 described above will be described below. This embodiment has the same configuration as the embodiment of FIG. 1 except for the configuration of the reactor power control means 14. That is, the present embodiment is obtained by replacing the reactor power control means in the embodiment of FIG. 1 with the reactor power control means 14A shown in FIG. The configuration of the reactor power control means 14A in this embodiment will be described with reference to FIG.

The reactor power control means 14A is provided with the SRNM2
Weight calculation means 14a _{1 to} 14a _K , which are separately connected to each of the furnace cycle calculators 9 of _{1 to} 2 _K and multiply the furnace cycle output from the furnace cycle calculator 9 by a weight coefficient r, and addition calculation means 14a ₁
Averaging means 14b for performing an averaging process on the output signals of .about.14a _K , the reactor cycle which is the output of the averaging means 14b, and other input signals Ub (recirculation flow rate, reactor output, etc.) Ub
Control rod withdrawal judging unit 14c for outputting a control rod withdrawal command and control rod withdrawal stop command based on the bets, the function generating means 14d ₁ ~14d _K and the adjacent control rod withdrawal judging means 14
having e ₁ ~14e _K. Function generating means 14d ₁ ~14d _K
And the adjacent control rod withdrawal judging means 14e ₁ ~14e _K are provided, one to the corresponding sum arithmetic unit 14a ₁ to 14A _K. The control rod withdrawal determination means 14c executes the processing of FIG. In this case, step 22 is the average calculation means 14b
The process for taking in the furnace cycle output from is performed, and the selection of the short furnace cycle as described above is not performed.

Adjacent control rod withdrawal determination means 14e _{1 to} 14e
e _K is the upper end of the control rod being pulled out of the four control rods adjacent to the corresponding SRNM detector.
This is to determine which position in the height direction (see FIG. 8) passes the M detector. Adjacent control rod withdrawal judging means 14e ₁ ~14e _K is applicable SRNM detectors axially position 14f ₁ ~14f _K of four control rods adjacent
And the top of the control rod being pulled out and SRNM
The relative distance between the detector (corresponding to the horizontal axis of FIG. 9), and outputs it to the function generator 14d ₁ ~14d _K control rod in the pulling corresponds to the information that is which. Function generating means 14d ₁ ~14d _K is a weighting coefficient r in accordance with the outputted the leaving early distance from the appropriate adjacent control rod withdrawal judging means 14e ₁ ~14e _K, corresponding addition operation means 14a ₁ to 14
and outputs it to a _K. Function generating means 14d ₁ ~14d _K
, For example, the function shown in FIG. 9 is assigned.

[0072] Incidentally, for example, with respect to SRNM detectors S _8, initially drawn by the control rod of the adjacent control rods is a control rod of the group D1. The second control rod to be withdrawn is the control rod of group D4. When the control rods of the group D1 are pulled out, the weight coefficient r may be a value shown in FIG. However, when the group D4 is pulled out, the function becomes a function of the relative distance and the weight coefficient r different from FIG. For example, the weight coefficient r has a minimum value of 0.7 and a maximum value of 1.0. Therefore, it is necessary to prepare the function shown in FIG. 9 for every four control rods adjacent to the SRNM detector. These functions are provided for each function generating means 14d ₁ ~14d _K.

As described above, the furnace cycle output from each of the furnace cycle calculators 9 of the SRNMs 2 ₁ to 2 _K is corrected, and control rod withdrawal is determined based on the corrected furnace cycle. The control rod withdrawal stop command is no longer output from the reactor power control device 14, and the start-up time of the reactor can be further reduced as compared with the embodiment of FIG.

The function shown in FIG.
It is necessary to create in advance for each control rod adjacent to the NM detector. When this analysis is difficult or the accuracy is not sufficient, the reactor power control means 14A may be configured as shown in FIG. 11 without using the weighted average of the reactor cycle. Reactor power control means 14B of FIG.
Is, SRNM2 ₁ ~2 averaging process as is the average calculating unit 14b of the furnace cycle output from the furnace cycle calculator 9 _K, control the average furnace cycle obtained by the average calculation unit 14b bar withdrawal judging means 14c.

In this embodiment, the furnace cycle obtained by the averaging means 14b is shorter than the furnace cycle based on the core average neutron flux, but the furnace cycle based on the output of the SRNM detector adjacent to the control rod being withdrawn. Longer than. For this reason, the frequency of outputting the control rod withdrawal stop command in this embodiment is as shown in FIG.
, But less than the configuration of FIG. 1 in which the reactor power control means 14B is applied in place of the reactor power control means 14, the start-up time of the reactor plant is slightly longer than that of the embodiment of FIG. The configuration of the output control device is simplified.

The reactor power control means for selecting the minimum value of the furnace cycles from the respective furnace cycle calculators 9 of the SRNMs 2 _{1 to} 2 _K and determining the control rod withdrawal command is shown in FIG. It is only necessary to replace the means 14b with the minimum value selecting means.

FIG. 12 shows another embodiment of the reactor power control apparatus.
Shown in The reactor power control means 14D of this embodiment is the same as that shown in FIG.
This is obtained by adding a furnace cycle editing unit 14g and a display unit 14h to the configuration of FIG. The furnace cycle editing means 14g is an SRN
M2 ₁ to 2 furnace cycle from each furnace cycle calculator 9 _K, and the average calculating unit 14b furnace cycle average obtained in (furnace cycle used to determine the control rod withdrawal instruction; labeled S _T in FIG. 13) Create information for display. The display means 14h displays this display information. FIG. 13 shows an example of information displayed on the display unit 14h.

According to such a display, in addition to the effect shown in FIG. 11, it is possible to grasp the values of the respective furnace periods while comparing them at once. In addition, if the furnace cycle is displayed with the horizontal axis as a time axis instead of a bar graph, that is, a so-called trend display has an effect that how the furnace cycle changes with the passage of time can be grasped at once. In the example of FIG. 13, set values relating to control rod operation and plant protection are also displayed. Withdrawal authorization corresponds to the reference value T _1, indicates that it is possible the output of the control rod withdrawal command. The pull-out stop indicates that a control rod pull-out stop command can be output. Withdrawal inhibition indicates that control rod withdrawal is prevented when the reactor cycle falls below this value to protect the reactor. The display of FIG. 13 is also made for manual operation of the control rod. Scrum indicates that if the reactor cycle falls below this value, the reactor will be scrammed. However, the furnace cycle used for judging withdrawal prevention and scrum is the furnace cycle output from the furnace cycle calculator 8. Therefore, the furnace cycle editing means 14g needs to input the furnace cycle output from the furnace cycle calculator 8 without passing through the average calculating means 14b. Displaying the set values of the pull-out prevention and the scrum is effective for the operator to roughly understand the margin for the operation of the reactor protection function for the control rod operation. In particular, when the control rod is manually pulled out, the control rod operation can be performed while observing the behavior of the reactor plant by looking at the display information, so that the burden on the operator can be reduced.

It is needless to say that the effect of the embodiment of FIG. 1 can be obtained by applying the configuration of FIG. 12 to the reactor power control means 14 of FIG.

[0080] The average calculation unit 14b of Figure 12, addition operation means 14a ₁ to 14A _K and average calculation means 14b or instead of the minimum value selection computing unit described above.

The furnace cycle editing means 14g and display means 14h of FIG. 12 are separately provided in the embodiment of FIG. 1 so that each furnace cycle can be set with respect to the set value of the reactor protection (control rod withdrawal prevention, scram). It is easy to grasp how much the value has a margin. In this case, furnace cycle editing means 14g is, SRNM2 ₁ ~2 _K furnace cycle output from the furnace cycle calculator 8 and 9, and reactor power control unit 1
The shortest furnace cycle selected in step 22 of step 4 is input to create the above display information. By providing the display means 14h near the means for operating the control rods and displaying the information as shown in FIG. 13, the operator can easily monitor the furnace cycle or judge the manual operation of the control rods. In addition, by displaying the state of the neutron flux together with the operating state of the reactor plant, monitoring at the time of starting the plant becomes easy.

When the reactor power control means shown in FIGS. 10 and 11 is used, the average reactor cycle output from the averaging means 14b is replaced with the reactor cycle editing means instead of the shortest reactor cycle selected in step 22. Enter 14g.

The furnace cycle editing means 14g and the display means 14h
Another embodiment in which is provided separately from the embodiment of FIG. 1 will be described below. FIG. 14 shows an operation control panel used in the present embodiment. This operation control panel has, as display means, a large-screen display device 18 that shows the state of the entire reactor plant, and a touch-operable small-screen display device (CRT) 35 provided in the operation control panel 19. The large screen display device 18 has large display screens 18A to 18C. 19A is an operation switch group. Although not shown, the furnace cycle editing means 14
g is a furnace cycle output from the furnace cycle calculator 8 and 9 of SRNM2 ₁ ~2 _K, and enter the shortest furnace cycle selected in step 22 of the reactor power control unit 14, in FIG. 15 for example The display information shown is created and displayed on a predetermined large display screen of the large screen display device 18. In FIG.
The left side of the point is information related to control rod operation, and the right side of the point A is information on neutron flux. In this way, by displaying both information together, the operation state of the control rod and the change state of the neutron flux can be viewed together,
It is possible to predict the state of the plant, whether or not the next control rod operation is possible, or the driving amount thereof.

In FIG. 14, the large screen display screen 18
B shows the entire plant information (schematic plant information from the reactor to the generator), and the large screen display screen 18A shows trend information of important parameters. FIG.
5 is displayed on the large screen display screen 18C. If other information is to be displayed on the large screen display screen 18C, the furnace cycle editing means 14g displays the display information of FIG.

The display information based on the output of the furnace cycle calculator 9 among the display information created by the furnace cycle editing means 14g is displayed on the small screen display device 35, and the display information based on the output of the furnace cycle calculator 8 is displayed on the small screen display device 35. The information may be displayed on the large screen display device 18.

Another embodiment of the reactor power control apparatus according to the present invention will be described with reference to FIG. This embodiment is different from the embodiment of FIG. 1 in that the furnace cycle calculators 8 and 9 shown in FIG.
Is that the furnace cycle calculator 36 integrated except for the filters 8E and 9E is provided. Furnace cycle calculator 3
As shown in FIG. 17, the device 6 has the same configuration as that of FIG.
The reciprocal of the furnace cycle T output from the calculator 8D is input to the reciprocal calculator 8H. Furnace cycle T, which is the output of reciprocal calculator 8H, is input to filters 8E and 9E. As in the embodiment of FIG. 1, the time constant τ ₁ of the filter 8E is set to several tens of seconds, and the time constant τ ₂ of the filter 9E is set to several seconds. The output of the filter 8E is output to the display means 10 and the scrum discriminator 11. The output of the filter 9E is input to the reactor power control means 14.

This embodiment can provide the same effects as the embodiment of FIG. Further, in the present embodiment, a part of the configuration of the furnace cycle calculators 8 and 9 in FIG. 1 is integrated, so that the configuration can be simplified. In particular, when the SRNM is configured using a microcomputer system, the SNM shown in FIGS.
Most of the functions of the RNM can be achieved by software. Therefore, in the present embodiment in which a part of the configuration of the furnace cycle calculators 8 and 9 is integrated, the amount of software of the SRNM can be reduced and the processing speed is increased. However, in this embodiment, a part of the reactor cycle calculator 8 that outputs a reactor cycle to the safety protection system and a part of the reactor cycle calculator 9 that outputs the reactor cycle to the reactor power control means which is a service system Therefore, the reliability of the furnace cycle calculator 36 must be significantly higher than that of each furnace cycle calculator of FIG. If the reactor cycle calculator 36 fails, the scram of the reactor may be affected.

FIG. 18 shows a reactor power control apparatus according to another embodiment of the present invention. In this embodiment, the filter 9E is
Each component having the same configuration as the filter 9E without being provided in the RNM
Filter 9E ₁ ~9E _K corresponding to SRNM but on the reactor power control means 37. Filter 9E ₁ ~9E _K
Inputs the output of the reciprocal calculator 8H of each SRNM. Reactor power controller 37 includes a reactor power control unit 14 to input filter 9E ₁ ~9E _K, and the respective outputs of the filters 9E ₁ ~9E _K. The SRNM requires high responsiveness, but when the SRNM is configured using a microcomputer system, the responsiveness of the SRNM greatly depends on the software processing speed of the microcomputer system. Therefore, as a means for increasing the responsiveness of SRNM, the reactor power control means filters 9E ₁ ~9E _K 37
The configuration of the present embodiment provided therein is extremely effective. This embodiment can also obtain the same effect as the embodiment of FIG.

The configuration shown in FIG. 18 can be applied to the embodiment shown in FIG. That is, removing the filter 9E provided in each furnace cycle calculator 9 SRNM2 ₁ ~2 _K, filter 9E ₁ ～9E having the same configuration as the filter 9E
_K is provided in the reactor power control means 14 similarly to the reactor power control means 37. This can increase the responsiveness of the SRNM2 ₁ ~2 _K for the embodiment of FIG.

FIG. 19 shows a reactor power control apparatus according to another embodiment of the present invention. In this embodiment, the furnace cycle calculator 36 is used.
Filter 9E is connected to the reciprocal calculator 8H of
The output of E is controlled by the reactor power control means 14 and the filter 8E _1.
Is entered. The output of the filter 8E ₁ is input to the display unit 10 and the scram determiner 11. Time constant of the filter 8E ₁ is a time constant and a time constant and a constant was synthesized filter time 8E ₁ filter 9E is set to be the same as the time constant of the filter 8E. This embodiment has the same effect as the embodiment of FIG.

FIG. 20 shows a reactor power control apparatus according to another embodiment of the present invention. This embodiment is different from the embodiment of FIG. 1 in that a switch 38 is provided downstream of the reactor cycle calculators 8 and 9, and the output signal of the switch 38 is output to the reactor power control
Is different. Switching of the switch 33 is controlled by a switching signal 39 output from the switching means 6. The switching means 6 has a switching determiner 6A and a switch 6B as shown in FIG. The switching determiner 6A receives the outputs of the logarithmic Campbell means 4 and the logarithmic coefficient rate means 5 and outputs a switching signal 39 based on these outputs.
That is, the switching judging unit 6A outputs the output signal of the logarithmic Campbell means 4 when the output signal of the logarithmic count rate means 5 becomes equal to or more than a predetermined value, and outputs the logarithmic signal when the output signal of the logarithmic Campbell means 4 becomes less than another predetermined value. A switching signal 39 for switching the switch 6B is output so that the output signal of the counting rate unit 5 is output from the switching unit 6. The switching signal 39 is the switch 6
Used to control switching between B and 38. Switching means 6 except that switching signal 39 is output to switch 38
Is used in the switching means 6 of each of the above-described embodiments including FIG.

Since the switches 6B and 38 perform the same operation based on the switching signal 39, when the output signal of the logarithmic count rate means 5 is output from the switching means 6, the furnace cycle which is the output of the furnace cycle calculator 9 is output. The signal is input to the reactor power control means 14, and the switching means 6 supplies the logarithmic Campbell means 4.
Is output, the reactor cycle signal, which is the output of the reactor cycle calculator 8, is input to the reactor power control means 14.

The output signal of the logarithmic Campbell means 4 makes the furnace cycle longer than the output signal of the logarithmic counting means 5.
Therefore, when the output signal of the logarithmic cambell means 4 is output from the switching means 6, it is better to perform control rod withdrawal determination based on the furnace cycle signal output from the furnace cycle calculation circuit 8 to increase the noise margin. I can take it. For this reason, a switch 38 is provided, and when the output signal of the logarithmic Campbell means 4 is output from the switching means 6, the reactor cycle signal output from the reactor cycle calculation circuit 8 is input to the reactor power control means 14. . This embodiment also produces the effects obtained in the embodiment of FIG.

Up to now, the embodiment in which the reactor power control means automatically determines the control rod operation based on the reactor cycle output from each SRNM has been described, but this reactor power control means is provided. It is possible that the operator does not operate the control rod manually.
Corresponding to such cases, SRNM2 ₁ shown in FIG. 1
Is input to the furnace cycle is the output of the furnace cycle calculator 9 to 2 _K in a furnace cycle editing means 14 g. Furnace cycle editing means 14g
Performs the processing described in the embodiment of FIG. 12, for example, to create display information relating to the furnace cycle. The display information created individually is displayed on the display unit 14h. The operator
By manually performing the control rod operation while watching the furnace cycle output from the furnace cycle calculator 9 displayed on the display means 14h, there is an effect that the interval of the control rod withdrawal operation can be shortened. This is because, as described above, the time constant of the filter 9E in the furnace cycle calculator 9 is short, and the furnace cycle information having a high response to the control rod operation is displayed on the display means 31.
This is because it can be displayed on the screen.

This embodiment is different from the SRNM 2 ₁ to SRNM 21 shown in FIG.
2 _K is connected to the SRNM detectors S _{1 to} S _K of FIG. When the operator manually performs the pull-out operation of the control rod, the operation is performed by operating the corresponding switch of the operation switch group 19A of the operation control panel 19 in FIG.

The embodiment of FIG. 23 uses the SRNM shown in FIG.
2 ₁ to 2 reactor output of each filter 9E of _K periods editing means 14
g to create display information. This embodiment is different from the furnace cycle calculator 8 and the furnace cycle calculator 9 shown in FIG.
Are integrated, and the configuration of the SRNM is simplified in terms of hardware or software.

The embodiment of FIG. 24 uses the SRNM shown in FIG.
The output of each switch 38 of 2 _{1 to} 2 _K is output to the furnace cycle editing means 14.
g to create display information. When the furnace cycle greatly changes in accordance with the control rod operation, the display means 14h displays the furnace cycle output from the furnace cycle calculator 9 having high responsiveness, and the furnace cycle does not change much with the control rod operation. Since the furnace cycle output from the furnace cycle calculator 8 is sometimes displayed, the burden on the operator for determining the control rod operation can be reduced.

The means for operating the control rod based on the furnace cycle has been described above. The relationship between the reactor cycle and the reactivity of the reactor is shown in (Equation 2). Instead of the furnace cycle calculators 8, 9, and 36 in the above-described embodiment, a reactivity calculator that executes the calculation of (Equation 2) may be used. In this way, the same effect as that of the corresponding embodiment can be obtained by the reactivity calculator according to each embodiment described above.

[0099]

(Equation 2)

Here, δk / k is the reactivity, L ₁ is the average lifetime of neutrons, and k is the effective multiplication factor. This (Equation 2) is described in "Reactor" P54 (Kyoritsu Shuppan, first edition of 1972).

For example, in the embodiment shown in FIG. 1, the furnace cycle calculators 8 and 9 are replaced by a first reactivity calculator including a reactivity calculator and a filter 8E and a second reactivity calculator including a reactivity calculator and a filter 9E. This is a reactor power control device that is replaced with a reactivity calculator. Each reactivity calculating means inputs the power of the SRNM detector and executes the calculation of (Equation 2). In the first and second reactivity calculators, each filter receives the output of the reactivity calculator. The scrum determiner 11 receives the first reactivity, which is the output of the first reactivity calculator, and determines the scrum. The reactor power control means 14 inputs the second reactivity, which is the output of the second reactivity calculator, and outputs a control rod withdrawal command.

Further, in the embodiment shown in FIG. 16, the reactor power control unit is obtained by replacing the reactor cycle calculator 36 with the reactivity calculating means.

[0103]

According to the features of the present invention, the control rod operation (specifically, the operation of pulling out the control rod and the operation of stopping the extraction) can be performed in a short time in response to the change of the neutron flux in the core. In addition, the start-up time of the reactor can be significantly reduced.

[0104]

[0105]

[0106]

[0107]

[0108]

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a reactor power control device according to a preferred embodiment of the present invention.

FIG. 2 is a detailed configuration diagram of a reactor power control unit 14 of FIG.

FIG. 3 is an explanatory diagram of a processing procedure executed by a reactor power control means 14;

FIG. 4 is an explanatory diagram showing a relationship between a furnace cycle and control rod withdrawal.

FIG. 5 is an explanatory diagram showing effects of the embodiment of FIG. 1;

FIG. 6 is an explanatory diagram showing an arrangement state of control rods and SRNM in a core.

FIG. 7 is a characteristic diagram showing a neutron flux distribution in a core axis direction at the time of control rod withdrawal.

FIG. 8 is an explanatory diagram showing a positional relationship between an SRNM detector and a control rod in a core axis direction.

FIG. 9 shows the relative distance between the upper end of the control rod and the SRNM detector;
FIG. 9 is an explanatory diagram illustrating an example of a relationship with a weight coefficient.

FIG. 10 is a configuration diagram of another embodiment of the reactor power control means.

FIG. 11 is a configuration diagram of another embodiment of the reactor power control means.

FIG. 12 is a configuration diagram of another embodiment of the reactor power control means.

FIG. 13 is an explanatory diagram showing an example of display information displayed on a display unit 14h of FIG.

FIG. 14 is a configuration diagram of a plant operation control panel having large-screen and small-screen display devices.

15 is an explanatory diagram showing an example of information displayed on the large screen display device of the plant operation control panel in FIG.

FIG. 16 is a configuration diagram of a reactor power control device according to another embodiment of the present invention.

FIG. 17 is a detailed configuration diagram of the furnace cycle calculator of FIG. 16;

FIG. 18 is a configuration diagram of a reactor power control device according to another embodiment of the present invention.

FIG. 19 is a configuration diagram of a reactor power control device according to another embodiment of the present invention.

FIG. 20 is a configuration diagram of a reactor power control device according to another embodiment of the present invention.

21 is a configuration diagram of the switching means 6 of FIG.

FIG. 22 is a configuration diagram of a neutron flux monitor in an activation area according to another embodiment of the present invention.

FIG. 23 is a configuration diagram of another embodiment of a neutron flux monitor in an activation area.

FIG. 24 is a configuration diagram of another embodiment of a neutron flux monitor in an activation area.

[Explanation of symbols]

S _{1 to} S _K ... SRNM detector, C _{1 to} C _N ... control rods, M ₁ to
M _N : control rod driving device, P _{1 to} P _N : control rod position detector,
2 _{1 to} 2 _K ... neutron flux monitor (SRNM) in the activation region, 8,
9,36 ... furnace cycle calculator, 8A, 8E, 9E ... filter, 14 ... reactor power control device, 15 ... control rod control device, 14a ₁ to 14A _K ... weighting calculating means, 14b ... average calculation means.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroki Sano 7-2-1, Omika-cho, Hitachi City, Ibaraki Pref. Energy Research Laboratory, Hitachi, Ltd. (72) Inventor Hiromi Maruyama 7-2, Omika-cho, Hitachi City, Ibaraki Prefecture No. 1 Hitachi, Ltd. Energy Research Laboratory (72) Inventor Fuku ▲ Saki ▼ Koji 7-2, Omika-cho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd. Energy Research Laboratory (72) Inventor Kazuhiko Ishii Hitachi City, Ibaraki Prefecture 5-2-1, Omikacho Hitachi, Ltd. Omika Factory (72) Inventor Yuichi Higashikawa 3-1-1, Samachi, Hitachi, Ibaraki Pref. Hitachi, Ltd. Hitachi, Ltd. Hitachi Plant (72) Inventor Yukihisa Fukasawa Ibaraki Hitachi, Ltd. Hitachi Plant, 3-1-1, Sachimachi, Hitachi City Hitachi, Ltd. (56) References Akira 62-250396 (JP, A) JP Akira 60-152989 (JP, A) JP Akira 50-146796 (JP, A) (58 ) investigated the field (Int.Cl. ^6, DB name) G21C 7 / 08 G21C 17/00 G21C 17/14

Claims (13)

(57) [Claims] 1. A neutron detecting means disposed in a nuclear reactor and detecting a neutron flux from a neutron source region to an intermediate region, a control rod driving device for operating a control rod inserted into a core of the nuclear reactor, the on the basis of the output signal of the neutron detector
Means for outputting one reactor cycle, and output of the neutron detection means
The neutron flux changes more than the first reactor cycle based on the signal.
Means for outputting a second furnace cycle having a fast response to the second furnace cycle;
Control means for outputting a control signal to said control rod drive device based on two reactor cycles.
Adjustment device. 2. A neutron flux from a neutron source region to an intermediate region.
Reactor based on the output signal of the neutron detection means for detecting
Means for outputting a period, and an output signal of the neutron detection means
The neutron flux change more than the first reactor cycle based on
Means for outputting a second furnace cycle having a fast response,
Control rods inserted into the reactor core
Control means for outputting a control signal to a control rod driving device,
A reactor power adjusting device comprising: 3. A neutron source region disposed in a nuclear reactor.
A neutron detecting means for detecting a neutron flux up to the inter-region,
A control rod drive that operates a control rod inserted into the core of the reactor
And a first delay element, wherein the neutron detection means
The second signal affected by the first delay element based on the output signal
Means for outputting one furnace cycle, and a time longer than the first delay element
A second delay element having a short constant;
The second signal affected by the second delay element based on the output signal
Means for outputting two furnace cycles, and based on the second furnace cycle.
Control means for outputting a control signal to the control rod driving device.
A reactor power adjusting device, comprising: 4. The time constant of the first delay element is 10 seconds or more and 1
Less than 00 seconds, and the time constant of the second delay element is 1 second or less.
4. The element according to claim 3, wherein the time is less than 10 seconds.
Reactor power adjustment device. 5. The control means according to claim 1 , wherein said second furnace cycle is a first furnace cycle.
Start pulling out the control rod when it exceeds a certain value
Outputting a control signal to the control rod driving device;
Is less than or equal to a second set value that is smaller than the first set value.
Control signal to stop pulling out the control rod when
2. An output to a control rod driving device.
A reactor power adjusting device according to any one of to 4 above. 6. The control device according to claim 1, wherein said neutron detecting means is provided in plurality.
The means is based on output signals of the plurality of neutron detection means.
The average value of a plurality of second furnace cycles obtained by
Control signal to the control rod drive based on the average value
6. The method according to claim 1, wherein
On-board reactor power adjustment device. 7. A display device for displaying the second furnace cycle.
The method according to any one of claims 1 to 6, wherein
Reactor power adjustment device. 8. A nuclear reactor scrubber based on the first reactor cycle.
2. A system according to claim 1, further comprising means for judging a system.
A reactor power adjusting apparatus according to any one of claims 7 to 7. 9. A neutron flux from a neutron source region to an intermediate region
The output signal of the neutron detection means for detecting
Based on the force signal, the shadow of multiple delay elements with different time constants
Characterized by outputting a plurality of affected furnace cycles.
Moving region neutron flux monitor. 10. Neutrons from a neutron source region to an intermediate region
First based on the output signal of the neutron detection means for detecting the flux
Means for outputting a furnace cycle; and
Faster response to neutron flux change than the first reactor cycle
Means for outputting two furnace cycles.
Moving region neutron flux monitor. 11. Neutrons from a neutron source region to an intermediate region
Calculated based on the output signal of the neutron detector that detects the flux
Response to neutron flux change than the first reactor cycle
Means for outputting a fast second furnace cycle;
Control rods inserted into the reactor core
Control means for outputting a control signal to the control rod driving device.
A reactor power control device characterized by the above-mentioned. 12. The control means according to claim 1 , wherein said second furnace cycle is a first furnace cycle.
Start pulling out the control rod when it exceeds the set value.
And outputs a control signal to the control rod driving device.
The period becomes equal to or less than a second set value smaller than the first set value.
Control signal to stop pulling out the control rod when
2. An output to said control rod driving device.
2. The reactor power control device according to 1. 13. A neutron detecting means, comprising:
Controlling means based on the output signals of the plurality of neutron detecting means.
Average of a plurality of second furnace cycles obtained by
Control signal to the control rod drive based on the average value obtained.
13. The method according to claim 11, wherein the output is performed.
A reactor power control apparatus according to any one of the above.