JPH07174889A - Reactor output automatic control device - Google Patents

Abstract

PURPOSE:To smoothly take automatic control by improving the control precision of a reactor output automatic control device having a function generator, and preventing the output inconsistency of multiple systems. CONSTITUTION:Break point data (x1, y1)-(xn, yn) on the exponential function are selected and set on the memory 21' of a function generator 20' so that the relative error beta obtained when the absolute error epsilon is divided by the exponential function value e<x> becomes the set relative error betao or below. This reactor output automatic control device is provided with an integrated control device, an on-site control device, and a multiplex control rod automating device receiving the internal arithmetic information of other systems and meeting the self- held internal conditions via the AND operation of the internal arithmetic information of the system and the internal arithmetic information of other systems between the multiplex control devices when inputs of individual systems are cross-inputted and a holding mechanism of the internal conditions is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reactor power automatic adjusting device for controlling a reactor power of a nuclear power plant.

[0002]

2. Description of the Related Art In a boiling water nuclear power (BWR) power plant, when power output control is performed by a control rod automation operation, for example, from start-up of a reactor to reaching criticality,
The reactivity control from the reactor rated pressure to the subcritical state, and from the subcritical state to the re-critical state during drywell inspection is performed by the nuclear instrumentation system based on the neutron flux detected by the sensor installed in the reactor. Input more to calculate the estimated reactivity,
Insert / pull out the control rod.

The range of the neutron flux for calculating the estimated reactivity is a very wide range of signals, for example, 10 ^-9 to 10 ² %, and therefore the logarithmic compression is generally performed from the nuclear instrumentation system to the reactor power automatic adjusting device. Is input as a signal of, for example, -9 to 2.

On the other hand, since the neutron flux as an antilogarithm is required for the calculation of the estimated reactivity, it is necessary to use the neutron flux logarithmically compressed in the reactor power automatic adjusting device after converting it to an antilogarithm. . For this reason, generally, a function generator that generates an approximate function of the exponential function e ^x is used to perform conversion from logarithm to antilogarithm.

FIG. 5 shows a configuration example of a conventional automatic reactor power adjusting apparatus using a function generator. The automatic reactor power adjusting apparatus 1 includes a multiplication circuit 10, a function generator 20, and an estimated reactivity calculation circuit. 30, a subtractor 40, a controller 50, and a control rod controller 60.

In FIG. 5, the neutron flux φ in the reactor 70 is
Is input from the sensor 71 to the nuclear instrumentation system 80, and is input as the common logarithmic neutron flux log φ from the nuclear instrumentation system 80 to the multiplication circuit 10 in the reactor power automatic adjustment apparatus 1.

In the automatic reactor power control system 1, the multiplication circuit 10 converts the common logarithmic neutron flux logφ into a natural logarithmic neutron flux lnφ and outputs it to the function generator 20. The function generator 20 calculates a neutron flux φ from the logarithmic neutron flux lnφ by an approximate function of the set exponential function, and outputs it to the estimated reactivity calculation circuit 30. The estimated reactivity calculation circuit 30 inputs the neutron flux φ and calculates the estimated reactivity ρ. Subtractor 4
In 0, the estimated reactivity ρ calculated by the estimated reactivity calculation circuit 30 is subtracted from the target reactivity ρ _t to obtain the deviation signal s1. The controller 50 inputs the deviation signal s1 and outputs a control rod insertion / pulling-out command s2 to the control rod control device 60. The control rod controller 60 controls the control rod insertion / withdrawal command s.
The control rod 72 in the reactor 70 is driven according to 2 to change the reactor output.

Here, the function generator 20 has an exponential function y =
break point data on the ^{_{e x (x 1, y 1}} ) ~ (x n, y n)
And a memory 21 storing only the range necessary for reactivity control,
The minimum range x-axis break point data x _i , x _{i + 1} , including the input value x (= lnφ) of the function generator 20, (i = 1, 2, ..., N)
-1) and its break point numbers i and i + 1 are stored in the memory 21.
X-axis reference circuit 22 and the break point numbers i, i +
The y-axis break point data y _i , y _{i + 1} corresponding to ₁ from the memory 21 and the y-axis reference circuit 23, and the function generator 20.
Input value x, x-axis break point data x _i , x _{i + 1} , and y-axis break point data y _i , y _{i + 1} are input to the function generator 20.
Output value F (x) (i.e., exponential approximation value of the function y = e ^x) composed of first approximation value calculating circuit 24 for calculating a the following equation.

[0009]

F (x) = y _i + (x−x _i ) * (y _{i + 1} −y _i ) / (x _{i + 1} −x _i ) Further, for example, the common logarithmic neutron flux log φ is −9. When input in the range of ~ 2, the natural logarithmic neutron flux lnφ is -2.73 ~
Since the range is 4.61, the input range of the function generator 20 (x
The range) must be set in the -24th to 5th place.

In the function generator 20 described above, x =
There is no error at x _i or x = x _{i + 1} , but x _i <x
In the range of <x _{i + 1} , the difference ε with the true exponential value y = e ^x

[Equation 2] ε = | F (x) −e ^x | is generated as an absolute error of the function generator 20.

Therefore, the break point data (x ₁ , y ₁ ) to
(X _n , y _n ) is set so that the maximum value of the absolute error is equal to or less than the setting error ε _o .

For example, between (x ₁ , y ₁ ) and (x ₂ , y ₂ ) shown in FIG. 6, the exponential function e ^x and its approximate function F
The maximum value ε _max of the absolute error ε with (x) is _{calculated as} follows.

The straight line connecting (x ₁ , y ₁ ) and (x ₂ , y ₂ ) is

Since y = y ₁ + (x−x ₁ ) * (y ₂ −y ₁ ) / (x ₂ −x ₁ ), the absolute error ε is

## EQU4 ## ε = (x−x ₁ ) (y ₂ −y ₁ ) / (x ₂ −
x ₁₎ a + y ₁ -e ^x. x _z where ε is maximum is

Dε / dx = (y ₂ −y ₁ ) / (x ₂ −x ₁ ) −e ^x = 0

X = ln {(y ₂ −y ₁ ) / (x ₂ −x ₁ )} = x _z . Therefore, the maximum value ε _max of ε is

## _EQU7 ## ε _max = (x _z −x ₁ ) * (y ₂ −y ₁ ) / (x ₂ −x ₁ ) + y ₁ −ex ^x = [ln {(y ₂ −y ₁ ) / (x ₂ -x _1)} -x _{1] (y 2 -y 1) / (} x 2 -x 1) + y 1 - a _{(y 2 -y 1) / (} x 2 -x 1).

A conventional reactor power adjusting apparatus 1 shown in FIG.
So as this way epsilon _max obtained is equal to or less than epsilon _o, break point data _{(x 1, y 1) ~} (x n,
y _n ) has been determined, and the value shown in the memory 21 is ε _o =
Range of 0.01, x: When set to -24 to 5, the number of break points n at this time is 90 points. FIG. 7 is a graph showing the break point data in this case. The graph in the dotted line is a reduced view.

In the conventional reactor power regulator described above, for example, the common logarithmic neutron flux from the nuclear instrumentation system 80 is used.
When log φ changes from log 10 ^{-9 to} log 10 ^-8 (%), the natural logarithmic neutron flux lnφ changes from -0.73 to -18.42. Therefore, the output of the x-axis reference circuit 22 is x ₁ = -24 x ₂ = -4.5262207 i = 1, and the output of the y-axis reference circuit 23 is y ₁ = 3.77513 × 10 ^-11 y ₂ = 1.08214 × 10 ^-2 . Therefore, the output value F (x) of the first-order approximate value calculation circuit 24 is F (−20.73) = 1.8171464 × 10 ⁻³ F (−18.42) = 3.1008186 × 10 ⁻³ from the formula [Equation 1].

Absolute error ε of the function generator 20 at this time
Are respectively ε (-20.73) = | F (-20.73) -e- ^20.73 | = 0.0018 ε (-18.42) = | F (-18.42) -e- ^18.42 | = 0.0031 from the formula [Equation 2]. In both cases, the setting error ε _o = 0.01 or less.

Further, for example, the common logarithmic neutron flux log φ
But if you change the ^{log 10 → log 10 2 (%} ), natural logarithm neutron flux Lnfai is 2.303 → 4.605, and the output of the x-axis reference circuit 22, when the lnφ = 2.303, x
₂₅ = 2.2454394 x ₂₆ = 2.3326269 i = 25 lnφ = 4.605, x ₇₄ = 4.6009570 x ₇₅ = 4.6290820 i = 74, and the output of the y-axis reference circuit 23 is lnφ = 2.303, y ₂₅ = 9.4445640 y ₂₆ = When 10.304976 lnφ = 4.605, y ₇₄ = 99.579570 y ₇₅ = 102.420. Therefore, the output value F (x) is F (2.303) = 10.0126025 F (4.605) = 99.9878849 from the formula [Formula 1]. The absolute error ε of the function generator 20 at this time is ε (2.303) = | F (2.303) −e ^2.303 | = 0.008 ε (4.605) = | F (4.605) −e ^4.605 | = 0.005, and both are setting errors ε _o = 0.01 or less.

However, the accuracy P for the true value is P (-20.73) = ε (-20.73) / e ^-20.73 = 1.8 × 10 ⁸ (%) P (-18.42) = ε (-18.42) / e ^-18.42 = 3.1 × 10 ⁷ (%) P (2.303) = ε (2.303) / e ^2.303 = 0.08 (%) P (4.605) = ε (4.605) / e ^4.605 = 0.005 (%) and small neutron flux φ The accuracy in the area is very poor.

Therefore, the reactor power automatic adjusting apparatus using such a function generator has a problem in that the control accuracy is extremely poor and good control cannot be performed.

This is because the setting error ε _o is larger than the true value, and it is necessary to make the setting error ε _o smaller in order to obtain good control. However, for example, if the setting error ε _o = 1.0 × 10 ⁻¹⁰ , sufficient control accuracy can be obtained, but the number of break point data is about 10,000, the capacity of the memory 21 becomes enormous, and the memory usage efficiency deteriorates. Not only that, the x-axis reference circuit 22 and the y-axis reference circuit 23 that refer to the break point data in the memory also need to handle a large amount of memory data, so that the processing speed thereof decreases and it is necessary for control. It may not be possible to ensure responsiveness.

By the way, for the purpose of shortening the plant start-up time and reducing the load on the operator as described above, in the reactor power automatic adjusting device for automatically operating the control rods used for the power adjustment of the reactor, In order to prevent malfunction of the control rod at the time of one failure, the control system from the sensor that detects the process amount (for example, neutron flux detector) to the motor drive device that drives the control rod to the field controller that issues the drive signal System is being implemented.

FIG. 8 shows an example of a duplex structure of a conventional automatic reactor power adjusting apparatus in such a multiplexing system.
In this dual reactor power automatic adjusting device, the process amount p is measured by the sensors S _A and S _B installed in the plant.
_A and p _B are detected, and the control rod automation device 100A, 10
Input to 0B respectively.

The control rod automation devices 100A and 100B are
Sensor S _A, performing process variable p _A, control operation by the control calculator by entering the p _B containing integral element to match the target value a performs predetermined processing from S _B, operates the operation result The commands e _A and e _B are output to the transmission lines T _1A and T _1B .

The integrated control devices 200A and 200B respectively input the operation commands e _A and e _B from the transmission lines T _1A and T _1B , and also input signals from other control devices (not shown) to perform calculations. The calculation results are used as drive commands f _A and f _B , and the site control devices 300A _i and 300B _i (i = 1, 2,
, N; n is the number of control rods) and is output via transmission lines T _2A and T _2B .

The field controllers 300A _i and 300B _i are
It is installed for each control rod, and the drive commands f _A and f _{B are set.}
Is input from each of the transmission lines T _2A and T _2B to drive the corresponding control rod, the motor drive signals g _iA and g _iB are output to the motor drive device 400, and the motor drive device 400 outputs the motor drive signals. The control rod driving motor M is driven by the logical product of g _iA and g _iB (hereinafter referred to as AND), that is, when the motor driving signals match, and the control rod 72 in the reactor 70 is operated.

In such a conventional duplex system, the control rod is driven when the outputs of both systems match, and when the outputs do not match, the drive of the control rod is interrupted and the current state is maintained.

However, regarding automatic output adjustment by the control rod, it is necessary to consider not to interrupt the operation of the control rod in addition to the conventional prevention of erroneous operation. That is, since the control rod operation command for automatic output adjustment is output by the feedback control via the controller including the integral element in the control rod automation device 100 as described above, both systems of the duplex system are output. If the outputs do not match and the drive of the control rod is interrupted, the feedback control is not performed satisfactorily, so that a problem arises that automation is excluded.

Therefore, it is necessary to prevent the control rod operation from being interrupted, and it is therefore necessary to make the outputs of both systems of the duplex system, that is, the motor drive signals coincide.

However, in the conventional dual structure in which the upper controller shown in FIG. 8 and the lower motor driver on site are completely vertically divided and independent, even if each controller operates normally, the input signal In some cases, the outputs of both systems do not match due to the difference in the generation timing and the input / output timing of each control device.

The above problems due to the conventional configuration will be described with reference to FIG.

FIG. 9 shows the main configuration of the control rod automation device 100. In FIG. 9, the process amount p input from the sensor S is processed by the processing circuit 101, and the control rod position command b is calculated in the control calculator 102 based on the deviation from the target value a. In the judgment circuit 103, if the deviation between the control rod position command b and the actual control rod position c is negative, the command d ₁ for driving the control rod 72 in the insertion direction is set to 1, and if the deviation is positive, it is pulled out. The command d ₂ for driving in the direction is set to 1, and if the deviation is within a predetermined value, the command to maintain the current condition is d ₁ = d ₂ = 0.
Output {d ₁ , d ₂ }).

Since process signals such as the process quantities p _A and p _B or the control rod positions c _A and c _B are input to the corresponding control rod automation devices 100A and 100B,
The control rod automation devices 100A, 100B may differ due to differences in sensor mounting positions, individual sensor characteristics, etc., or differences in the operation cycles of the multiplexed control rod automation devices 100A, 100B.
It may be input to B as a different feedback signal.

As a result, there is a case in which a pull-out command or an insertion command is generated in one operation command e _A , and the other operation command e _B is maintained as it is, and the operation commands e _A and e _{B of} both systems do not match. .

Another case in which the outputs of both systems do not match will be described with reference to FIG. FIG. 10 shows the main circuits of the integrated control devices 200A and 200B.

As shown in FIG. 10, switches SWA, S
When the condition is satisfied and self-maintained by momentary input such as WB input, due to the difference in the duration of the switch inputs sw _A and sw _B and the calculation cycle of the integrated control devices 200A and 200B, only one integrated control device There are cases where internal conditions are met. In this case, the control rod automation device 100A, 1
In some cases, when the operation commands e _A and e _B are input from 00B, the drive commands f _A and f _{B of} both systems do not match.

In FIG. 10, assuming that r _A and r _B are reset conditions and their inverse signals are r _A ′ and r _B ′, internal conditions l _A and l _{B of the} integrated control devices 200A and 200B are assumed.
Is a logical expression

## EQU8 ## It can be expressed as l _A = (sw _A + l _A ) · r _A ′ l _B = (sw _B + l _B ) · r _B ′. In addition, the integrated control devices 200A, 2
When the drive commands f _A and f _B output from 00B are expressed by a logical expression,

F _A = e _A · l _A f _B = e _B · l _B

Here, in both systems, the pre-stage controller input e _A
= E _B = 0 and the internal condition l _A = l _B = 0, only the pre-stage control device input e _A changes to 0 → 1, and further only the switch input sw _A changes to 0 → 1. The condition l _A is from the formula [Equation 8]

[Mathematical formula-see original document] l _A = (sw _A + l _A ) · r _A ′ = (1 + 0) · 1 = 1 and the internal condition l _B remains 0, so the internal conditions l _A and l _B of both systems do not match. Become. Therefore, the drive commands f _A and f _{B for} both systems are also calculated from the formula [Equation 9].

[Mathematical formula-see original document] f _A = e _A · l _A = 1.1 · 1 = 1 f _B = e _B · l _B = 0 · 0 = 0, which is a disagreement.

Then, the switch input sw _B changes (0 →
Then, 1), the internal condition 1 _B becomes 1 as well as 1 _A, and when the preceding stage controller input e _B changes (0 → 1), the drive command f _B also becomes 1 and coincides with the drive command f _A.

Thus, the switch input sw _A (s
Internal condition l _A (l _B ) of the system in which w _B ) has changed (0 → 1)
Change, only the drive command f _A (f _B ) of the system where the front stage controller input e _A (e _B ) and the switch input sw _A (sw _B ) of the one system have changed (0 → 1) changes. The outputs of the systems do not match (f _A ≠ f _B ).

As described above, the on-site control device 30 in the subsequent stage
0A _i and 300B _i input drive commands f _A and f _B , respectively, and output motor drive signals g _1A and g _1B . The motor drive device 400 drives the motor by ANDing the motor drive signals g _1A and g _1B. Therefore, if the motor drive signals g _1A and g _1B do not match, the control rod is not driven.

When the drive of the control rod is interrupted, the loop of the control rod automation control is in a state equivalent to the open state, so it is necessary to interrupt the automatic operation in order not to saturate the integral element of the controller.

[0042]

SUMMARY OF THE INVENTION According to the present invention, if the memory capacity of the function generator is set to an appropriate size, satisfactory control accuracy cannot be obtained. Conversely, if an attempt is made to obtain sufficient control accuracy, the memory capacity of the memory will be reduced. In order to solve the former problem of the prior art that the value becomes more than an appropriate size, the reactor output having a high-precision function generator that minimizes the memory capacity and obtains good control accuracy. An object is to provide an automatic adjusting device.

Further, in order to solve the problem of the latter multiplex system in the prior art, the present invention prevents the output discrepancy of each system due to the generation timing of the input signal and the input / output timing of each control device, and the control rod. It is an object of the present invention to provide a reactor power automatic adjusting device in which the automatic operation of (1) is smoothly performed.

[0044]

[Means for Solving the Problems] [Claim 1]
The invention described is a reactor that inputs neutron flux from a sensor installed in a nuclear reactor by logarithmically compressing it with a nuclear instrumentation system, calculates estimated reactivity and inserts / extracts control rods in the reactor. In the output automatic adjustment device, the logarithmic value of the neutron flux logarithmically compressed by the nuclear instrumentation system is input, and the ratio of the difference between the approximate value and the true value of the neutron flux to the true number to the true value is less than or equal to a predetermined value. According to the break point data of the exponential function that is preselected and set as described above, a function generator that calculates a neutron flux that is a true number from the logarithmic value of the neutron flux that has been input, and is converted to a true number by this function generator. Estimated reactivity calculation circuit that estimates the reactivity from the neutron flux, and control that calculates the control rod insertion / extraction operation command based on the deviation between the reactivity output from this estimated reactivity calculation circuit and the target reactivity Specially equipped with To.

In the invention described in [Claim 2], from the sensor for detecting the process amount related to the reactor output to the on-site control device for driving and controlling the control rod at the operating end are multiplexed,
A control device connected in multiple stages hierarchically inputs the output of the sensor or the control device of the previous stage and performs an arithmetic operation, and sequentially outputs it to the control device of the subsequent stage, and when the outputs of the control devices of each system of the final stage match. The reactor power automatic adjusting apparatus for driving the operating end is characterized in that it is provided with means for matching the input signals of the respective control devices in the same hierarchy for each control device of each hierarchy.

Further, in the invention described in [Claim 3], in the above configuration, the internal operation information of the control device of the other system in the same hierarchy is taken in, collated with the internal operation information of the control device of the own system, and It is characterized in that it is provided with a means for matching the internal condition of self-holding in the system.

[0047]

With the former configuration, a highly accurate function generator can be obtained which has the minimum required memory capacity and can secure the required accuracy in any region regardless of the size of the neutron flux. As a result, the controllability of the reactor power automatic adjustment device can be improved.

In the latter configuration, if the control devices of the respective systems have the same capability and ignore the calculation timing on the premise of the same processing, basically the same calculation result will be obtained if the input information is the same. As means for matching the outputs of the systems, the process amount and the input signal from the pre-stage device or from the outside are similarly input to the control device of each system.
Then, the control device of each system takes in the input signal by AND.

As a result, even when the process amount of the single system or only the input signal from the pre-stage device or the outside is changed, the same input signal is input to all the control devices of the respective systems, and each control device individually and independently. By taking in the input signals of the other system by AND, the timings of establishment / non-establishment of the input states between the multiplex control devices can be matched.

Further, when the multiplex control device has a storage element which holds an internal condition by an instantaneous input signal such as an operation switch input and holds itself, the multiplex control devices are made to match the internal condition. As means, the internal operation information of the other system is mutually fetched, and the internal condition of the own system is calculated by ANDing the internal operation information of the own system and the internal operation information of the other system. That is, the internal condition of each system that holds itself is satisfied when the conditions of all internal calculation information are satisfied, and the internal condition is not satisfied for each system because the condition of the internal calculation information of the other system or its own system is not satisfied, and the condition is satisfied at the same timing. , Make it unfulfilled.

In this way, the input signals of each system are matched,
The outputs of the multiplex control devices can be synchronized at all times by matching the timings of the establishment / non-establishment of the self-holding outputs of the control devices of the respective systems.

[0052]

Embodiments of the present invention will be described below with reference to the drawings. The same parts as those of the conventional example are designated by the same reference numerals, and the duplicated description will be omitted.

FIG. 1 shows an embodiment of a reactor power automatic adjusting apparatus 1'of the present invention, which is made in comparison with the prior art shown in FIG. 5, and is different from the prior art shown in FIG. , The true value of the absolute error ε instead of the conventional function generator 20 incorporating the breakpoint data so that the difference between the approximate value and the true value (absolute error ε) is less than or equal to the set value (set error ε _o ). The function generator 20 'incorporating the break point data is used so that the ratio (hereinafter, referred to as relative error β) to the constant value (hereinafter, referred to as set relative error β _o ) is equal to or less than a constant value (hereinafter referred to as set relative error β _o ).

That is, in this embodiment, the break point data (x ₁ , y ₁ ) to (x _n , y _n ) set in the memory 21 ′ of the function generator 20 ′ have the absolute error ε as true. Maximum value β of relative error β obtained by dividing by exponential function value e ^x
_It is determined that _max is less than or equal to the set relative error β _o .

For example, between (x ₁ , y ₁ ) and (x ₂ , y ₂ ) shown in FIG. 6, the exponential function e ^x and its approximate function F are used.
The maximum value β _max of the relative error β with respect to (x) is obtained below.

Since the relative error β = ε / e ^x , substituting the equation [Equation 4],

Equation 12] _{β = {(x-x 1} ) (y 2 -y 1) / (x 2 -x 1) + y 1} is / e ^x -1. x _z where β is maximum is

Dβ / dx = [(y ₂ −y ₁ ) / (x ₂ −x ₁ ) − {(x−x ₁ ) (y ₂ −y ₁ ) / (x ₂ −x ₁ ) + y ₁ }. ] / E ^x = 0,

X = {y ₂ * (x ₁ +1) -y ₁ * (x ₂ +1)} / (y ₂ −y ₁ ) = x _z .

Therefore, this x _z is _converted to x in the equation [Equation 12].
The value β substituted for is the maximum value β _max .

Next, the operation of this embodiment will be described.

In the above configuration, when the set relative error β _o is β _o = 0.01, the break point data (x ₁ , y ₁ ) to (x _n , y _n ) set in the memory 21 ′ are as shown in FIG. The value is as shown in 1, and the number of break points n is 110.
In addition, FIG. 2 shows the graph of this break point data. The graph in the dotted line is a reduced view.

Using such break point data, the common logarithmic neutron flux logφ from the nuclear instrumentation system is log10 ⁻⁹ → log
When changed to 10 ^-8 (%), the logarithmic neutron flux lnφ is -207.73 →
18.42. Therefore, the output of the x-axis reference circuit 22 is x ₁₃ = -20.785217 x ₁₄ = -20.517318 i = 13 when lnφ = -20.73, x ₂₁ = -18.642028 x ₂₂ = -18.374130 i = 21 when lnφ = -18.42 Therefore, the output of the y-axis reference circuit 23 is y ₁₃ = 9.3992852 × 10 ^-10 y ₁₄ = 1.2286882 × 10 ^-9 lnφ = -18.42 when lnφ = -20.73, and y ₂₁ = 8.0143767 × 10 ^-10 y ₂₂ = 1.0476509 × 10 ^-8 . Therefore, the output value F (x) of the first-order approximate value calculation circuit 24 is F (−20.73) = 9.99445141 × 10 ⁻¹⁰ F (−18.42) = 1.00549381 × 10 ⁻⁸ from the equation [Formula 1].

Also, for example, the common logarithmic neutron flux logφ
However, when log10 → log10 ² (%) is changed, the logarithmic neutron flux lnφ becomes 2.303 → 4.605, so the x-axis reference circuit 22
Output when the lnφ = 2.303, when _{x 99 = 2.2537813 x 100 = 2.5216717} i = 99 lnφ = 4.605, the output of _{x 107 = 4.3969144 x 108 = 4.6648111} i = 107 next, y-axis reference circuit 23, lnφ = When 2.303, y ₉₉ = 9.5236799 y ₁₀₀ = 12.449391 lnφ = 4.605, when y ₁₀₇ = 81.199937 y ₁₀₈ = 106.14553. Therefore, the approximate value F (x) is F (2.303) = 10.0612103 F (4.605) = 99.98298285 from the formula [Formula 1].

Compared with the conventional example shown in FIG. 5, the accuracy P (= β × 100) for the absolute error ε and the true value in the region where the neutron flux is small is ε (-20.73) = 0.0018, P in the conventional example. (-20.73) = 1.8 × 10 ⁸ (%) ε (-18.42) = 0.0031, P (-18.42) = 3.1 × 10 ⁷ (%) In this embodiment, ε (-20.73) = 0.0615 × 10 ^-10 , P (-20.73) = 0.62 (%) ε (-18.42) = 0.0048 × 10 ^-8 , P (-18.42) = 0.48 (%), and the reactor power automatic adjusting device of this embodiment is better than the conventional example. You can get much higher accuracy.

The accuracy P for the absolute error ε and the true value in the region where the neutron flux is large is ε (2.303) = 0.008, P (2.303) = 0.08 (%) ε (4.605) = 0.005, P in the conventional example. (4.605) = 0.005 (%) In this example, ε (2.303) = 0.057, P (2.303) = 0.57 (%) ε (4.605) = 0.593, P (4.605) = 0.59 (%), which is the same as the conventional example. The absolute error ε is larger than
The accuracy P for the true value is the same as in the region where the neutron flux is small,
The precision required for control can be sufficiently obtained.

The number of break point data is 90 in the conventional example.
The number of points is 110 in this embodiment, which is almost the same.

As described above, according to this embodiment, it is possible to ensure the required control accuracy in any neutron region without increasing the memory capacity, and to perform reliable and favorable control.

In the above embodiment, the setting relative error β _o is set to 0.01, but the setting relative error β _o may be set to another value.

The multiplication circuit 10 for obtaining the natural logarithm from the common logarithm is not always necessary, and the multiplication circuit 10 can be omitted if the exponential function is an exponential function whose base is 10.

Further, the present invention can be similarly applied to a controller having not only an exponential function but also another function generator.

FIG. 3 shows an embodiment of the reactor power automatic adjusting apparatus of the present invention made to the prior art illustrated in FIG. The present embodiment is different from the conventional example of FIG. 8 in that the process quantities p _A from the sensors S _A and S _B ,
Input both p _B and take the AND (hereinafter referred to as cross input) control rod automation devices 101A and 101B
And integrated control devices 201A and 201B for cross-inputting the respective outputs of the control rod automation devices 101A and 101B via transmission lines T _1A and T _1B , and integrated control devices 201A and 20B.
Field controllers 301A _i and 301B _i (i = 1, 1) for cross-inputting the respective outputs of 1B through transmission lines T _2A and T _2B .
2, ..., N; n is the number of control rods. Further, when the control rod automation devices 101A and 101B and the integrated control devices 201A and 201B have a storage element such as an operation switch input that holds an internal condition by an instantaneous input signal and holds itself, a multiplexing control device is provided. (In this embodiment, the duplication control device), the internal operation information of the other system is mutually fetched, and the internal operation information of the own system and the internal operation information of the other system are ANDed to establish the internal condition for self-holding. To do so.

Next, the operation of this embodiment will be described.

In the above configuration, the control rod automation device 1
01A, 101B, integrated control devices 201A, 201B,
And the control devices of the respective layers of the site control devices 301A _i and 301B _i cross-input the outputs of both systems in the preceding stage, and control rod automation devices 101A and 101B, and the overall control device 2
When 01A and 201B have a self-holding mechanism for internal conditions, the internal operation information of the other system is taken into each other and AND of the internal operation information of both systems is used to determine the internal condition for self-holding.

Taking the centralized control devices 201A and 201B as a representative, the cross input and the acquisition of the internal calculation information will be described with reference to FIG.

In FIG. 4, integrated control devices 201A, 2
01B inputs the respective outputs e _A and e _B from the preceding stage control device (that is, the control rod automation devices 101A and 101B) together, and ANDs them to obtain cross inputs m _A and m _B.
When these cross inputs m _A and m _B are expressed by a logical expression,

[Expression 15] m _A = e _A · e _B m _B = e _A · e _B Further, if the internal conditions l _A and l _B are expressed by a logical expression,

[Number 16] becomes a _{l A = (sw A + l} A) · (sw B + l B) · r A 'l B = (sw B + l B) · (sw A + l A) · r B'. Furthermore, when the drive commands f _A and f _B are expressed by a logical expression,

F _A = m _A · l _A f _B = m _B · l _B

If the output e _B of the control rod automation device 101B is 0 and only the output e _A of the control rod automation device 101A changes (0 → 1),

[Mathematical formula-see original document] m _A = m _B = e _A · e _B = 1 · 0 = 0, and the inputs m _A and m _B of both systems match.

When only the switch input sw _A changes from 0 to 1, the internal conditions l _A and l _{B become}

[Formula 19] l _A = (sw _A + l _A ) · (sw _B + l _B ) · r _A ′ = (1 + 0) · (0 + 0) · 1 = 0 l _B = (sw _B + l _B ) · (sw _A +1 _A ) · r _B ′ = (0 + 0) · (1 + 0) · 1 = 0, and the internal conditions l _A and l _B of both systems are not satisfied and coincide with each other.

In this state, when the switch input sw _B further changes (0 → 1),

[Formula 20] l _A = (sw _A + l _A ) · (sw _B + l _B ) · r _A ′ = (1 + 0) · (1 + 0) · 1 = 1 l _B = (sw _B + l _B ) · (sw _A + l _A ) · r _B ′ = (1 + 0) · (1 + 0) · 1 = 1 The internal conditions l _A and l _B of both systems are satisfied in agreement.

When the output e _B of the control rod automation device 101B also changes (0 → 1), the cross inputs m _A and m _B are

Since m _A = m _B = e _A · e _B = 1 · 1 = 1, the drive commands f _A and f _B are

[Formula 22] f _A = m _A · l _A = 1 · 1 = 1 f _B = m _B · l _B = 1 · 1 = 1, and both systems necessarily match (f _A = f _B ). .

As described above, when the input information is different due to the difference in the process input amount due to the mounting position of the sensor or the individual characteristics or the difference in the input / output timing between the multiplexed control devices, conventionally, the input information is different between the multiplexing devices. Although there is a case where the outputs of the above-mentioned are inconsistent with each other, in the present embodiment, since the same information is inputted, the inconsistency of the outputs between the multiplexers does not occur.

Also, when the condition is satisfied by momentary input such as switch input and self-holding is performed, the internal operation information of another multiplexing control device is input and collated with the internal operation information of its own system. Since the result is self-held as an internal condition, the internal conditions of both systems do not differ, and in this case also, no mismatch occurs in the outputs between the multiplexers.

Therefore, it is possible to prevent the automatic operation of the control rod from being interrupted due to the output deviation between the multiplexers, and it is possible to perform the smooth control operation.

[0081]

As described above, according to the present invention,
By using a function generator that incorporates the breakpoint data so that the relative error β is less than or equal to the set relative error β _o , the required memory capacity is minimized and the neutron flux value can be adjusted to any region regardless of the size. It is possible to perform high-precision control that obtains the required accuracy. Further, since the capacity of the required memory can be minimized, the processing speed of the x-axis reference circuit and the y-axis reference circuit that refers to the memory does not decrease, and the responsiveness required for control can be secured.

Further, according to the present invention, each input from the multiplexer of the preceding stage is cross-inputted, and further internal calculation information is taken in as necessary, so that the process amount of a single system and the external input can be obtained. , Even if only the internal calculation information is different, the internal conditions, operation commands, and drive commands between the multiplexed control devices are always satisfied / failed at the same timing.
The outputs of both systems can be matched more reliably without being influenced by the process amount, the generation timing of external input, etc. and the input / output timing of each control device, and the automatic operation of the control rod is less likely to be interrupted. It is possible to perform various control operations.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a reactor power automatic adjusting apparatus equipped with a function generator of the present invention.

FIG. 2 is a memory 21 'of the reactor power automatic adjusting apparatus of FIG.
It is the graph which plotted the inside break point data.

FIG. 3 is a block diagram showing an embodiment of a multiple reactor power automatic adjusting apparatus of the present invention.

FIG. 4 is a diagram showing a main configuration of an integrated control device of the automatic reactor power adjustment system of FIG.

FIG. 5 is a block diagram showing a conventional example for the present invention illustrated in FIG.

6 is a graph showing an exponential function e ^x and the relationship between the approximate straight line.

FIG. 7 is a graph in which breakpoint data in a memory 21 of the automatic reactor power control system of FIG. 5 is plotted.

FIG. 8 is a block diagram showing a conventional example for the present invention illustrated in FIG.

9 is a block diagram showing a main configuration of a conventional control rod automation device of FIG.

FIG. 10 is a diagram showing a main configuration of a conventional integrated control device of FIG.

[Explanation of reference numerals] 1, 1 '......... Automatic reactor power adjusting device 10 ......... Multiplier circuit 20, 20' ......... Function generator 21, 21 '......... Memory 22 ......... X-axis reference circuit 23 ………… y-axis reference circuit 24 ………… first-order approximation value calculation circuit 30 ………… estimated reactivity calculation circuit 50 ………… controller 60 ………… control rod controller 70 ………… reactor 71 ………… Sensor 72 ... Control rod 80 ... Nuclear instrumentation system 100, 101 ... Control rod automation device 200, 201 ... Overall control device 300, 301 ... Site control device 400 ... Motor drive device

Claims (3)

[Claims] 1. A nuclear reactor in which a neutron flux from a sensor installed in a nuclear reactor is logarithmically compressed and input by a nuclear instrumentation system, an estimated reactivity is calculated, and a control rod in the reactor is inserted or withdrawn. In the automatic output adjustment device, the logarithmic value of the neutron flux logarithmically compressed by the nuclear instrumentation system is input, and the ratio of the difference between the approximate value and the true value of the neutron flux to the true number to the true value is equal to or less than a predetermined value. According to the break point data of the exponential function that is selected and set in advance, a function generator that calculates a neutron flux that is a true number from the input logarithmic value of the neutron flux, and a function generator that converts the neutron flux to a true number An estimated reactivity calculation circuit that estimates the reactivity from the generated neutron flux, and calculates the control rod insertion / extraction operation command based on the deviation between the reactivity output from this estimated reactivity calculation circuit and the target reactivity And a controller for A reactor power automatic adjusting device characterized in that 2. A control device that is multiplexed from a sensor that detects a process amount related to reactor output to a field control device that drives and controls a control rod at an operating end, and that is hierarchically connected in multiple stages is a control device of the sensor or the control device of the preceding stage. Control of each layer in the reactor power automatic adjustment device that drives the operating end by matching the output from the control device of each system in the final stage An automatic reactor power adjusting apparatus comprising means for matching input signals of respective control apparatuses in the same hierarchy for each apparatus. 3. The automatic reactor power control system according to claim 2, wherein internal operation information of a control device of another system in the same hierarchy is fetched,
An automatic reactor output adjusting device comprising means for matching internal operation information of a control device of its own system to match internal conditions held by each system.