JP2001099980A - Nuclear reactor power measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nuclear reactor power measuring device capable of reducing the number of sensitiveness calibrations of a GT sensor while suppressing an error of sensitiveness of the GT sensor within a tolerance range. SOLUTION: This device is provided with gamma ray thermometers 31a to 31i outputting signals corresponding to the temperature change of metal due to gamma rays generated inside a nuclear reactor 2, means 5 and 13a for determining reactor power on the basis of the signals outputted by the gamma ray thermometers 31a to 31i and a sensitiveness of the gamma ray thermometers 31a to 31i, a calibrating means 9 calibrating the sensitiveness of the gamma ray thermometers 31a to 31i, and a means 20 for predicting a future value of the sensitiveness of the gamma ray thermometers 31a to 31i.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reactor power measuring device for measuring a reactor power based on a detection result of a gamma thermometer installed in a reactor core.

[0002]

2. Description of the Related Art In a nuclear power plant, a plurality of fixed-type fission ionization chambers are arranged in a reactor core to measure a neutron flux, and a reactor output is obtained based on the measured neutron flux.
Such a reactor power measurement apparatus using a fixed-type nuclear fission chamber is referred to as a local power area monitoring device (hereinafter abbreviated as LPRM). Fission ionization chamber used in this LPRM (hereinafter referred to as LPRM detector)
As is well known, fissile material (mainly uranium 235)
Is applied to output a signal corresponding to the ionization current due to the ionization action of fission fragments generated by the fission of incident radiation. The LPRM detector, as described above,
Since it is used fixedly installed in the reactor core, the applied fissile material degrades with time due to exposure to radiation, and the detection sensitivity changes. In order to calibrate the detection sensitivity, a γ-ray thermometer (hereinafter, referred to as a GT sensor) that measures a temperature change of a metal due to γ-rays by a thermocouple is installed in a core, and LPRM is performed based on the output and sensitivity of the GT sensor.
Techniques for calibrating the detection sensitivity of a detector are known. GT
As a prior art describing sensitivity calibration of an LPRM detector using a sensor, there is, for example, JP-A-9-236687. The GT sensor is used not only for the calibration of the sensitivity of the LPRM detector but also for obtaining the power distribution of the reactor power.

However, since the sensitivity of the GT sensor changes with time, the sensitivity of the GT sensor itself must be calibrated. The calibration of the sensitivity of the GT sensor is performed based on the output of the GT sensor and the amount of heat generated by the heater at the time when heat is applied to the GT sensor by the heater, as described in the related art. Note that a plurality of GT sensors are provided on a GT rod extending in the axial direction of the core, and the above-described heater is provided for each GT rod.

[0004]

When heat is applied to the GT sensor by a heater as in the prior art described above, if the heater is rapidly heated, the temperature around the thermocouple of the GT sensor becomes extremely high and heat is applied to the thermocouple. Giving stress,
Failure to do so may cause a failure. Therefore, in order to prevent a failure, the current flowing to the heater is increased in a gentle ramp shape, and the heat generated from the heater is controlled so as to gradually increase. Therefore, the time required for the sensitivity calibration of one GT sensor becomes longer. In addition, when there is a transient change in the amount of heat to be detected, the thermocouple of the GT sensor requires several minutes to follow the change and reach an equilibrium state.

[0005] For the above reasons, G using a heater
Calibration of sensitivity of T sensor is about 1 for one GT rod.
It is known that it takes about 0 minutes. For example, if the sensitivity calibration is performed sequentially for all GT rods in the core, it takes 520 minutes (about 9 hours) in a plant having 52 GT rods.

As described above, since the calibration of the sensitivity of the GT sensor takes a long time, it is preferable that the number of times of the calibration of the sensitivity of the GT sensor be as small as possible. However, if the number of times of the sensitivity calibration of the GT sensor is excessively reduced, the error of the sensitivity of the GT sensor increases, and the output error of the LPRM detector whose sensitivity is calibrated based on the output and the sensitivity of the GT sensor also increases. turn into. In addition, the accuracy of the reactor power distribution obtained based on the output and sensitivity of the GT sensor also decreases.
Therefore, it is desired that the error in the sensitivity of the GT sensor be suppressed within a preset allowable range.

An object of the present invention is to provide a reactor power measuring apparatus capable of reducing the number of calibrations of the sensitivity of the GT sensor while keeping the sensitivity error of the GT sensor within an allowable range.

[0008]

A feature of the present invention to achieve the above object is to provide a gamma ray thermometer for outputting a signal corresponding to a change in the temperature of a metal due to gamma rays generated in a nuclear reactor, Means for obtaining a reactor output based on the signal output from the X-ray thermometer and the sensitivity of the γ-ray thermometer, and a reactor power measurement device having calibration means for calibrating the sensitivity of the γ-ray thermometer, There is provided means for predicting a future value of the sensitivity of the γ-ray thermometer.

According to the feature of the present invention, since the future value of the sensitivity of the γ-ray thermometer is predicted, it is possible to predict when the error of the sensitivity of the γ-ray thermometer exceeds the allowable range.
Therefore, it is possible to predict an optimal time for calibrating the sensitivity of the γ-ray thermometer. Therefore, it is possible to reduce the number of times of the calibration of the sensitivity of the GT sensor while suppressing the error of the sensitivity of the GT sensor within an allowable range. it can. Specifically, the sensitivity of the γ-ray thermometer may be calibrated immediately before the error in the sensitivity of the γ-ray thermometer exceeds the allowable range.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a reactor power measuring apparatus according to a preferred embodiment of the present invention. In FIG. 1, a plurality of GT rods 3 are loaded on a core 2 in a reactor 1, and each GT rod 3 is a GT sensor (γ-ray temperature) which is a plurality of differential thermocouples arranged in the core axis direction. 31a-31i and heater 3
Two. Further, a plurality of LPRM detectors 4 a to 4 d are also arranged in the core 2.

First, the structure of the GT rod 3 will be described. FIG. 2 is a sectional view of the GT rod 3. As shown in FIG. 2, the GT rod 3 is composed of a γ-ray heating metal 33 (for example, SU
S) is inserted into a cylindrical outer tube 34, and a plurality of differential thermocouples (GT sensors) 31 and heaters 32 are provided inside the γ-ray heating metal 33.
A plurality of annular spaces are provided between the outer tube 34 and the γ-ray heat generating metal 33 at arbitrary intervals in the axial direction, and the annular spaces are filled with an inert gas (eg, argon gas). By doing so, the thermal conductivity of the annular space is reduced, and the heat insulating chamber 35 is formed.

In the GT rod 3, the γ-ray heating metal 33
Generates heat due to irradiation with radiation by gamma rays generated in the core 2. As shown in FIG. 2, since the outer periphery of the GT rod 3 is cooled by the circulation of the core cooling water, the γ-ray heat generating metal 33 in the portion without the heat insulating chamber 35 generates the core cooling water even if it generates heat by irradiation. The temperature is almost the same as the temperature (actually, slightly higher than the cooling water temperature). On the other hand, since the γ-ray heat generating metal 33 inside the heat insulating chamber 35 is not cooled, the γ-ray heat generating metal 33 is in a high temperature state due to heat generated by radiation irradiation.
As shown in the figure, a high-temperature contact portion 31A and a cold-temperature contact portion 31B of the differential thermocouple 31 are provided in an inner portion of the heat insulating chamber 35 and a portion without the heat insulating chamber 35, respectively. Measure the temperature of. The differential thermocouple 31 outputs a measured voltage corresponding to a temperature difference ΔT measured at the high-temperature contact part 31A and the cold-temperature contact part 31B. That is, the measured voltage indicates the temperature rise of the γ-ray heating metal 33 due to the irradiation of γ-ray radiation.
1 output. Hereinafter, the output signal of the GT sensor 31 is represented by G
Called T signal.

In the calibration of the sensitivity of the GT sensor 31, a current is first supplied to the heater 32 to heat the heater 32. The heat generated by the heater 32 is transmitted to the γ-ray heat generating metal 33, and a voltage corresponding to the temperature difference between the high temperature contact portion 31A and the cold temperature contact portion 31B is output. As described above, the temperature of the γ-ray heat generating metal 33 in the vicinity of the cold / hot contact portion 31B is lowered by cooling with the core cooling water. At this time, the sensitivity of the GT sensor 31 is calibrated according to the value of the GT signal and the current flowing through the heater 32.

Next, the operation of the reactor power measuring apparatus shown in FIG. 1 will be described. In the reactor power measuring device of the present embodiment,
First, the GT rod 3 is loaded into the reactor 1. Since the GT sensor 31 of the loaded GT rod 3 must perform sensitivity calibration, the GT signal output from the GT sensor 31 until the sensitivity calibration is performed. Bypass. The processing will be described below.

Before the GT rod 3 is loaded into the reactor 1, the operator selects "GT rod loading-GT bypass" from the "command menu" displayed on the display means of the man-machine interface 6. Interface 6
Is selected by the input means. By selecting “GT rod loading-GT bypass”, the man-machine interface 6 outputs a bypass command to the calibration management device 7.

The calibration management device 7 to which the bypass command has been input.
Outputs a switch control signal to the signal switch 81, and the signal switch 81 to which the switch control signal is input connects the terminal 81-1 as an input terminal and the terminal 81-3 as an output terminal. . By connecting the terminals 81-1 and 81-3, the signal input to the terminal 81-1 of the signal switch 81 is not output to the process computer 5 but is output to the calibration management device 7. On the other hand, terminal 81-2 which is an output terminal
Outputs a burn-up signal, which is input to the process computer 5. When the burn-up signal is input, the process computer 5 determines that the signal to be input via the signal switch 81 cannot be used.

As described above, after the signal input to the process computer 5 via the signal switch 81 is bypassed, the GT rod 3 is loaded on the nuclear reactor 1. By doing so, it is possible to prevent the process computer 5 from obtaining an erroneous reactor power distribution based on the GT signal output from the GT sensor 31 on which the sensitivity calibration has not been performed.

Next, in the reactor power measuring apparatus of the present embodiment, factory data (factory test data) is input as initial data of the GT sensor 31. The details will be described below. First, before starting the reactor 1, the operator inputs “GT rod loading-factory test data transfer” from the “command menu” displayed on the display means of the man-machine interface 6 by the input means of the man-machine interface 6. At the same time, a recording medium (for example, a floppy disk) on which factory test data is recorded is inserted into the man-machine interface 6. Note that the factory test data recorded on the recording medium is a result of performing a Joule heating test at the time of shipment from the factory to confirm whether the GT sensor 31 satisfies desired performance. In a test loop simulating thermo-hydraulic conditions in the furnace, a large current is applied to the entire GT rod 3 to simulate heating by γ-rays using heat generated by the resistance of the GT rod 3 itself. By this joule heating test, GT
Data on the sensitivity, temperature coefficient, and time constant of the sensor 31 can be obtained. FIG. 3 shows an example of the factory test data. As shown in FIG. 3, the factory test data includes a sensitivity table, a temperature coefficient table, and a time constant table. Each table has a channel a to i of the GT sensor 31 in a row,
No. of GT rod 3 in the row. Has taken. The data of the sensitivity, the temperature coefficient, and the time constant of the corresponding GT sensor 31 are input to each cell of each table.

The man-machine interface 6 reads the factory test data from the recording medium and outputs the read factory test data to the calibration management device 7. The calibration management device 7
When the factory test data is input, an inquiry is made to the operator via the man-machine interface 6 as to whether to use the sensitivity data of the factory test data as the initial sensitivity of the GT sensor 31. When the operator replies to this inquiry to use as the initial sensitivity, the calibration management device 7
Outputs the sensitivity data of the factory test data to the calibration control device 9. The calibration control device 9 stores the input sensitivity data in the sensitivity memory 10 and the sensitivity database 11 in a table format shown in FIG. Note that the sensitivity memory 10 is a storage device that stores only the latest sensitivity data, and the sensitivity database 11 is a storage device that stores the sensitivity data in time series. The sensitivity table stored in the sensitivity database 11 is provided with a label indicating that the data is the date of loading of the GT rod 3 and the data at the time of factory shipment. Further, the calibration management device 7 outputs the temperature coefficient data and the time constant data of the factory test data to the calibration control device 9, and the calibration control device 9 stores the temperature coefficient data and the time constant data in the temperature coefficient / time constant memory 12 Are stored as a temperature coefficient table and a time series table in FIG.

On the other hand, in response to an inquiry from the calibration management device 7, if the operator inputs that the sensitivity data of the factory test data is not used as the initial sensitivity, the calibration management device 7
Sends a command to the calibration control device 9 to store the sensitivity table in which the uncalibration flag is set as the sensitivity data of each GT sensor 31 in the sensitivity memory 10 and the sensitivity database 11. The calibration control device 9 stores a sensitivity table with an uncalibrated flag set in the sensitivity memory 10 and the sensitivity database 11 in accordance with a command from the calibration management device 7. Thus, the factory test data is stored in each storage device.

Subsequently, in the present embodiment, the conditions of the plant parameters necessary for calibrating the sensitivity of the GT sensor 31 are input.

The operator uses the input means of the man-machine interface 6 to select "GT sensor calibration condition input" from the "command menu" displayed on the display means. When the “GT sensor calibration condition input” is selected, the man-machine interface 6 informs the calibration management device 7 that the calibration condition input has been selected. To enter the calibration conditions. The operator follows the instruction displayed on the display means of the man-machine interface 6 to perform the GT
The calibration conditions of the plant parameters required to calibrate the sensor 31 are input by the input means of the man-machine interface 6, and the input calibration conditions are input to the calibration management device 7. The calibration condition of the plant parameter input by the operator is at least LPRM
Value, APRM value, core flow rate, reactor water temperature, recirculation flow rate, reactor pressure, turbine load, feedwater temperature, reactor heat output, permissible values for time-varying combinations of logical product or logical sum, and It is a combination of a logical product or a logical sum of the lower limit value of the recirculation flow rate and the lower limit value of the core flow rate.

Next, the operator gives a plant state monitoring command to the calibration management device 7 via the man-machine interface 6. The calibration management device 7 to which the plant state monitoring command has been given fetches the plant parameters online via the process computer 5 and determines whether or not the GT sensor 31 can be calibrated by comparing with the above-described calibration conditions.
The judgment result is provided to the operator through the man-machine interface 6. The plant parameters such as the reactor pressure value, the recirculation flow value, the core flow value, and the LPRM value are respectively determined by the reactor pressure measurement system 41, the recirculation flow measurement system, the core flow measurement system 43, and the LPRM measurement system. The measured value is input to the process computer 5.

The operator determines whether or not to execute the calibration of the GT sensor 31 based on the result of the determination provided by the man-machine interface 6. 7 outputs a calibration command. At this point, even if the reactor is in a stopped state, if at least one of the water purification system and the residual heat removal system is activated, or if the recirculation pump is operating at the minimum speed, the core flow rate will be lower. Since it is secured and the GT sensor 31 can be calibrated, the operating state of the water purification system and the residual heat removal system and the rotation speed of the recirculation pump are also provided to the operator through the man-machine interface 6 to assist the operator in making the determination. Is done.

When a calibration command is input by the operator in a state where the calibration conditions are satisfied, the calibration management device 7 presents to the operator that the sensitivity calibration of the GT sensor 31 is to be started by the man-machine interface 6 and confirms it. Ask for. If there is no mistake in starting the calibration, the operator approves the confirmation from the calibration management device 7, and the calibration management device 7 starts the calibration in response to the confirmation. On the other hand, if the start of the calibration is incorrect, the operator instructs the cancellation of the start of the calibration by the man-machine interface 6 in response to the confirmation from the calibration management device 7, and the calibration management device 7 receiving the instruction starts the calibration. do not do. In addition, the calibration management device 7
Indicates that when a calibration command is input by an operator in a state where the calibration conditions are not satisfied, a warning is displayed by the man-machine interface 6 to the effect that the calibration command has been input under conditions where calibration is not possible. The operator confirms whether there is any mistake in the calibration command from the operator. On the other hand, if the calibration command is incorrect, the operator instructs the calibration management device 7 to cancel the start of calibration, and if the calibration command is correct, instructs the calibration management device 7 to start calibration. When the start of calibration is instructed, the calibration management device 7 starts calibration.

At the start of calibration, the calibration management device 7
First, the output terminal of the signal switch 81 is securely connected to the terminal 81-3.
Make sure it is on the side. This is because the output terminal of the signal switch 81 may be switched to the terminal 81-2 due to the influence of noise. When the output terminal is on the terminal 81-2 side, a switching control signal is output from the calibration management device 7 to the signal switch 81, and the output terminal of the signal switch 81 is switched to the terminal 81-3. .
As described above, the terminal 81-1 of the signal switch 81 and the terminal 8
In the state where 1-3 is connected, a burn-up signal is output from the terminal 81-2 to the process computer 5, and in the state where the burn-up signal is input, the process completion signal is outputted to the process computer 5. Is output to the calibration management device 7.

Next, the calibration management device 7 includes a calibration control device 9
A terminal 82-1 which is an input terminal of the signal switch 82.
And the terminal 82-3 as an output terminal. According to this instruction, the calibration control device 9 outputs a switching control signal to the signal switch 82 so as to connect the terminals 82-1 and 82-3 of the signal switch 82. When the terminals 82-1 and 82-3 of the signal switch 82 are connected, a signal input to the terminal 82-1 of the signal switch 82 is input to the calibration control device 9 via the terminal 82-3. And
A burn-up signal is output from one terminal 82-2. The burn-up signal output from the terminal 82-2 is input to the calorific value converters 13a and 13b, and the calorific value converters 13a and 13b to which the burn-up signal is input similarly output a burn-up signal.

The burn-up signals output from the calorific value converters 13a and 13b are input to the terminals 83-1 and 83-2, which are input terminals of the signal switch 83, and are also input to the deviation monitoring device 14. You. The burn-up signal input to the signal switch 83 is supplied to a terminal 83-3 of the signal switch 83.
Is output to the terminal 81-1 of the signal switch 81. The burnup signal input to the signal switch 81 is
-3 to the calibration management device 7.

Upon receiving the burn-up signal from the signal switch 81, the calibration management device 7 instructs the deviation monitoring device 13 to switch the input terminal of the signal switch 83. Upon receiving the instruction, the deviation monitoring device 13 operates the signal switch 8.
3, a switching control signal is output, and the signal switch 83 to which the switching control signal is input switches input terminals. When the switching of the input terminals is completed, the deviation monitoring device 13 sets the input terminals of the signal switch 83 to the terminals 83-1 and 83-2.
Which terminal has been switched to is output to the calibration management device 7. The input terminals are terminals 83-1 and 83-2.
In either case, a burn-up signal is input to the calibration management device 7 via the signal switch 81.

The calibration management device 7 converts the burn-up signal output from the signal switch 82-2 into a heating value conversion device 13
It is confirmed that input has been made from each of the route from a and the route from the calorific value conversion device 13b, and that the switching of the signal switch 83 by the deviation monitoring device 14 has been correctly performed. When this confirmation is completed, the calibration management device 7
Causes the display means of the man-machine interface 6 to display "GT signal bypass completed".

When the bypass of the GT signal is completed, the calibration management device 7 asks the operator via the man-machine interface 6 whether to execute a self-diagnosis to confirm whether the operation of the device required for performing the calibration is possible or not. When the operator responds to this inquiry that the self-diagnosis is performed, the calibration management device 7 instructs the calibration control device 9 to perform the self-diagnosis. In addition, the calibration management device 7
Command the self-diagnosis to the calibration control device 9 and display "calibration control device-self-diagnosis" on the display means of the man-machine interface 6.

The calibration controller 9 to which the self-diagnosis command has been input
First, a diagnosis is made as to whether there is a disconnection or a short circuit in a signal line (hereinafter, referred to as a GT signal measurement line) from the GT sensor 31 to the calibration control device 9 via the GT signal processing device 15 and the signal switch 82. This diagnosis is performed in the following procedure.

The GT signal processor 15 captures the GT signals output from all the GT sensors 31 loaded in the reactor core 2 and converts the captured GT signals into a signal switch 82.
Is input to the calibration control device 9 via the. Calibration control device 9
Divides the acquired GT signals into a plurality of groups according to the positions of the GT sensor 31 in the core axis direction and the core diameter direction.

FIG. 4 shows an example of grouping the GT sensors 31. FIG. 4 is a view of the core 2 viewed from above or below, and the core 2 is divided into regions D1 to D5 in the radial direction. GT included in each of the regions D1 to D5
The sensors 31 are further divided into channels a to i to form one group. By grouping in this way, if there is no abnormality in the GT signal measurement line, the GT signals obtained in each group have substantially the same value.

Next, the difference between the values of the GT signals for each group is calculated for each GT signal. Then, the difference is compared with a preset allowable value. If the obtained difference is larger than the allowable value, it means that an abnormal value GT signal is included in the group. FIG.
9 shows an example of a table summarizing differences obtained in group 2-d. The group 2-d is a group including the GT sensors of the channel d among the GT sensors arranged in the area D2. In FIG. 5, the GT sensor No. of the GT sensors included in the group 2-d and the value of the GT signal obtained by the GT sensor are set in each of the row item and the column item, and the difference between each GT signal is calculated. And the cell where the column intersects. The calibration control device 9 creates such a table from the fetched GT signals, compares the value of each cell in the table with an allowable value, and checks for a GT signal indicating an abnormality. FIG.
In the example, the allowable value set in advance is ± 0.05, and among the difference values shown in each cell, those exceeding the allowable value are marked with “*”. In FIG. 5, when searching for a GT sensor whose difference value exceeds the allowable value, 2
It can be seen that the GT sensors 8-29 and 52-37 most frequently exceed the allowable values. That is, 28-
It can be seen that there is some abnormality in the GT signal measurement line of the GT sensor 29 and the GT signal measurement line of the GT sensor 52-37. Although some other GT sensors exceed the permissible value, the combination with the GT sensor other than the GT sensor of 28-29 and the GT sensor of 52-37 does not exceed the permissible value. It can be determined that the sensor is not abnormal.

The calibration control device 9 outputs the table of FIG. 5 to the calibration management device 7 for the group including the abnormal GT sensor 31. The calibration management device 7 presents the table to the operator through the man-machine interface 6. The difference value exceeding the allowable value is displayed in red for easy identification. Further, the calibration management device 7 uses the man-machine interface 6 to handle the abnormal GT sensor 31 (1) bypass, (2) substitute with another GT signal, (3) use as it is, Is selected by the operator.

When the operator selects (1), the calibration management device 7 instructs the calibration control device 9 to bypass the GT signal from the abnormal GT sensor.
The calibration control device 9 sets a value indicating a failure in a cell to which a GT signal of the abnormal GT sensor 31 is input in the sensitivity table stored in the sensitivity memory 10 and the sensitivity database 11.

When the operator selects the option (2), the calibration management device 9 substitutes (2-1) the GT signal of another GT sensor belonging to the same group with respect to the setting of the substitute value of the GT signal. 2-2) Substituting the average value of GT signals of other GT sensors belonging to the same group, (2-
3) The operator is presented with four choices of substituting the average value of the GT signals of the GT sensors arranged above and below, and (2-4) setting an expression for calculating the substitute value by the operator.

When the operator selects the option (2-1), the calibration management device 7 inquires of the operator which GT sensor 31 in the same group substitutes the GT signal. The operator is the GT sensor N of the substitute GT sensor.
is input to the calibration management device 7 through the man-machine interface 6. The calibration management device 7 outputs the input GT sensor No. to the calibration control device 9 and
Inputs a substitution expression for substituting the input GT signal of the GT sensor No. into a cell in the sensitivity table stored in the sensitivity memory 10 and the sensitivity database 10 in which a value indicating a failure is set. For example, the GT sensor "36-
To substitute the GT signal of “05-05b” with the GT signal of “44-05b”, “= (44-05b)” is input as an expression into the cell of “36-05b” in the table.

When the operator selects the option (2-2), the calibration management device 7 sends the GT signal of the abnormal GT sensor 31 to another G of the same group to the calibration control device 9.
An instruction is given to substitute the average value of the T signal. The calibration control device 9 inputs the substitution expression representing the average value of the GT signal of the group to the cell in which the value indicating the failure is set in the sensitivity table of the sensitivity memory 10 and the sensitivity database 11. For example, the GT signal of the GT sensor “36-05b” is combined with “28-05b” and “44” belonging to the same group.
When the average value of “−05b” is substituted, “36−
For the cell of “05b”, “= (((28-05b) + (44
-05b)) / 2) ".

When the operator selects the option (2-3), the calibration management device 7 sends the GT signal of the abnormal GT sensor 31 to the calibration control device 9 to transmit the GT signal of the abnormal GT sensor 31 to the GT. An instruction is given to substitute the average value of the GT signals of the GT sensors 31 arranged vertically on the rod 3. The calibration control device 9 inputs the substitution expression representing the average value of the GT signals of the GT sensors 31 arranged above and below to the cell in which the value indicating the failure in the sensitivity table of the sensitivity memory 10 and the sensitivity database 11 is set. I do. For example, G
When the GT signal of the T sensor “36-05b” is substituted by the average value of the upper and lower GT sensors “36-05a” and “36-05c”, “=” is applied to the cell of “36-05b”.
(((36-05a) + (36-05c)) / 2) ". When there is no GT sensor that can be substituted in the vertical direction, the calibration management device 7 gives the operator the No sensor "and prompts you to re-enter your options.

When the operator selects the option (2-4), the calibration management device 7 requests the operator to input an assignment formula. The operator inputs the substitution expression through the man-machine interface 6, and the calibration management device 7 determines whether the substitution expression input by the operator is correct. If there is an error in the substitution expression, the operator is informed that there is an error in the substitution expression, and a re-input is requested. If the substitution expression is correct, the substitution expression is presented to the operator, and a message for confirming whether or not to substitute the abnormal GT sensor 31 GT signal by the substitution expression is presented. When the operator confirms that there is no mistake in the substitution formula, he or she inputs the fact that there is no mistake to the calibration management device 7 through the man-machine interface 6, and when there is a mistake, inputs the substitution formula again. The calibration management device 7 instructs the calibration control device 9 to substitute the GT signal of the abnormal GT sensor 31 with the substitution formula input by the operator. The calibration control device 9 sets a cell in the sensitivity memory 10 and the sensitivity table of the sensitivity database 11 in which a value indicating a failure is set,
Enter the substitution expression entered by the operator.

When the operator selects the option (3) from the above-mentioned options regarding the handling of the GT signal of the abnormal GT sensor 31, the calibration management device 7 instructs the operator to bypass the GT signal of the abnormal GT sensor 31. Inquires whether or not to perform the substitute value processing. If there is no mistake in the selection, the operator inputs that fact through the man-machine interface 6. Calibration management device 7
Is the G of the abnormal GT sensor 31 with respect to the calibration control device 9.
A command is issued to use the T signal as it is. The calibration control device 9 does not perform processing on the sensitivity memory 10 and the sensitivity database 11. As described above, the abnormality of the GT signal measurement line is diagnosed, and how to handle a GT signal indicating an abnormal value due to the abnormality of the GT signal measurement line is determined.

Next, in this embodiment, diagnosis of the heater 32 is performed. Hereinafter, the method will be described.

The calibration controller 9 issues a command to the heater power allocator 16 to allocate the heater power 17 to the heater 32 in the GT rod 3. The heater power allocation device 16 is composed of a group of switches for controlling the allocation of the heater power sources 17 and the heaters 32. One heater power source 17 and all the heaters 32 can be connected by the switches of the heater power allocation device 16. .
These switches are controlled by an assignment command from the calibration control device 9, and their patterns are predetermined.

FIG. 6 shows the connection relationship between the switches in the heater power supply allocating device 16 and the heater power supplies 17 and 32. In FIG. 6, a plurality of heater power supplies 17 are provided.
And two of the plurality of heaters 32
An example is a book. Heater power supply 17A and heater 32A
Can be connected via a switch 16A-1, and the heater power supply 17A and the heater 32B can be connected via a switch 16A-2. Further, the heater power supply 17B and the heater 32A can be connected via a switch 16B-1.
The heater power supply 17B and the heater 32B are connected to a switch 16B-2.
Can be connected via.

In FIG. 6, when the switch 16A-1 is closed, a current is supplied from the heater power supply 17A to the heater 32A. When the switch 16A-1 is closed, the other switches connected to the heater power supply 17A, including the switch 16A-2, and the other switches connected to the heater 32A, including the switch 16B-1, It is open. When the switch 16B-2 is closed, the heater power supply 17B
Supplies a current to the heater 32B. Switch 16B
-2 is closed, the other switches connected to the heater power supply 17B, including the switch 16B-1, and the heater 32B, including the switch 16A-2.
The other switches connected to are open.
The calibration control device 9 sequentially switches these switches according to a predetermined pattern so that current is supplied to all the heaters 32.

The calibration controller 9 is a current pattern generator 18
Is instructed to create a test current pattern. The current pattern creating device 18 creates a test current pattern, and issues a command to the heater power supply 17 to supply a current according to the pattern to the heater 32. The heater power supply 17 supplies a test current to the heater 32 according to the test current pattern created by the current pattern creation device 18.

The heater power supply 17 measures a test current value and a voltage value when the test current is supplied to the heater 32. The value of the test current passed by the heater power supply 17 and the value of the voltage at that time are transmitted to the calibration control device 9 via the current pattern creation device 18. The calibration control device 9 calculates the resistance value of the heater 32 for each GT rod 3 from the assignment command transmitted to the heater power assignment device 16 and the test current value and voltage value obtained from each heater power source 17. The calibration control device 9 stores the calculated resistance value for each GT rod 3. After obtaining the resistance values of all the heaters 32, these resistance values are compared with the standard resistance values determined from the specifications of the heater 32. Among the obtained resistance values, the heater 32 whose difference from the standard value is equal to or larger than a predetermined allowable value is determined to be abnormal.

The calibration control device 9 transmits the resistance value of the heater 32 and the determination result of the abnormality to the calibration management device 7. The calibration management device 7 displays the resistance value of the heater 32 and the determination result of the abnormality on the display means of the man-machine interface 6. Then, for the operator, G having the heater 32 which is abnormal
Regarding how to process the GT signal of the GT sensor 31 in the T rod 3, (1) bypass all GT signals, (2) GT of the GT sensor 31 in another GT rod 3
Two alternatives are provided. When the operator selects (1) from this option, the calibration management device 7 instructs the calibration control device 9 to bypass the GT signal of the GT sensor in the GT rod 3 having the abnormal heater 32. . First, the calibration control device 9 excludes the abnormal heater 32 from the assignment target of the assignment command to the heater power assignment device 16 so as to exclude the current supply to the abnormal heater 32. Further, the calibration controller 9 sets the sensitivity data corresponding to the GT sensor 31 in the GT rod 3 having the abnormal heater 32 to a value indicating a heater failure in the sensitivity tables of the sensitivity memory 10 and the sensitivity database 11.

On the other hand, when the operator selects (2), the calibration management device 7 requests the operator to select the GT rod 3 to substitute. The operator uses the man-machine interface 6 to replace the GT rod 3 having the abnormal heater 32 with the GT rod N of the GT rod 3.
Enter o. After confirming whether the GT rod No. input by the operator is correct, the calibration management device 7 sends the GT rod 3 having the abnormal heater 32 to the calibration control device 9.
A command is issued to substitute the GT signal obtained from the GT sensor 31 inside the GT sensor 31 in the GT rod 3 into which the GT rod No. has been input by the operator. The calibration control device 9 includes a GT having an abnormal heater 32.
The substitution expression is input to the sensitivity memory 10 and the sensitivity table of the sensitivity database 11 so that the sensitivity data of the GT sensor 31 in the rod 3 can be substituted by the GT signal of the GT sensor 31 in the substitute GT rod 3. For example, when the heater 32 of the GT rod 36-05 is abnormal, this GT
When trying to substitute the GT signal of the rod with the GT signal of the 44-05 GT rod, the sensitivity data of the channel a of the GT rod 36-05 contains "= (44-05a)".
Similarly, the substitution expression “= (44-05b)” is input for the channel b.
The same applies to channel c to channel i.

When the self-diagnosis of the heater 32 is completed in this way, the calibration control device 9 transmits the diagnosis result to the calibration management device 7. Then, the calibration management device 7 provides a diagnosis result to the operator via the man-machine interface 6.

As described above, when the diagnosis of the device necessary for the calibration is completed and the setting of the treatment when there is an abnormality is completed, the calibration management device 7 displays “GT calibration” on the display means of the man-machine interface 6. "Wait" is displayed, and waits for a calibration execution command from the operator. The operator gives a calibration execution command to the calibration management device 7 via the man-machine interface 6. Upon receiving the calibration execution command, the calibration management device 7 displays “GT sensor calibrating” on the display means of the man-machine interface 6. Then, a command is issued to the calibration control device 9 to execute calibration of the sensitivity of the GT sensor 31. After issuing a calibration execution command to the calibration control device 9, the calibration management device 7 fetches plant parameters from the process computer 5 and monitors time fluctuations of the fetched plant parameters. This monitoring of the plant parameters is continued until the sensitivity calibration of all GT sensors 31 is completed.

The calibration control device 9 to which the calibration execution command is input from the calibration management device 7 transmits an assignment command for assigning the heater power supply 17 and the heater 32 to the heater power assignment device 16. When the heater power allocation device 16 receives the allocation command, the switch in the heater power allocation device 16 is set to closed or open in a predetermined pattern, and the allocation of the heater power 17 and the heater 32 is completed. When the allocation of the heater power supply 17 is completed, the heater power allocation device 16 transmits an allocation completion signal to the calibration control device 9.

Upon receiving the assignment completion signal from the heater power assignment device 16, the calibration control device 9 instructs the current pattern creation device 18 to create a current pattern to be applied to the heater 32. . The current pattern creation device 18 sends the current pattern creation command to the calibration control device 9.
, A current pattern to be applied to the heater 32 is created. When the creation of the current pattern is completed, a current pattern creation completion signal indicating that the creation of the current pattern is completed is transmitted to the calibration control device 9.

When receiving the current pattern creation completion signal, the calibration control device 9 instructs the current pattern creation device 18 to transmit the current pattern to the heater power supply 17. The current pattern creation device 18 that has received the command transmits the current pattern to the heater power supply 17.

The heater power supply 17 is connected to the current pattern creation device 1
8 is amplified to a predetermined calibration current, and supplied as a calibration current to the heater 32 allocated by the heater power allocation device 16. The heater power supply 17 measures the value of the calibration current actually passed to the heater 32, and transmits the measured value of the calibration current to the calibration control device 9 via the current pattern creation device 18. The calibration control device 9 stores the value of the calibration current sent from the current pattern creation device 17 in the calibration database 19.

The heater 32 supplied with a predetermined calibration current
Generates a heat amount in the GT rod 3 according to the magnitude of the current. The amount of heat generated in the GT rod 3 diffuses in the GT rod 3 according to a temperature gradient in which a heat flow occurs. When the heat flow reaches the vicinity of the GT sensor 31, the temperature in the vicinity increases. The GT sensor 31 outputs a GT signal corresponding to the temperature rise. The GT signal output from the GT sensor 31 is input to the GT signal processing device 15. The nine GT sensors 31 in the GT rod 3
Signals output from the same GT signal processing device 1
5 is input.

FIG. 7 is a block diagram showing the configuration of the GT signal processing device 15. The GT signals of the nine GT sensors 31 input to the GT signal processing device 15 are
Sampled in order by 151. The sampled GT signal is converted to an analog-to-digital converter (A / A / D).
D) 152 to a digital signal. The GT signal converted to a digital signal is subjected to noise removal processing by a digital signal processing device (DSP) 153. The GT signal that has been subjected to the noise removal processing is output to the GT sensor 3
The data is stored in the storage area 154 corresponding to each of the channels a to i.

The calibration control device 9 includes a GT signal processing device 15
The GT signal stored in the storage area 154 of the GT rod 3 is periodically fetched via the signal switch 82, and the GT rod 3
Is stored in the calibration database 19.

The heater power supply 1
7 is completed, and the heater power supply 1 for the heater 32 of the GT rod 3 to be calibrated is completed.
When the application of the calibration current from 7 is completed, the current pattern creation device 18 sends a signal indicating the completion of the application of the calibration current to the calibration control device 9. When receiving the signal indicating the completion of the application of the calibration current from the current pattern creation device 18, the calibration control device 9 compares the calibration current value stored in the calibration database 19 with the GT.
The sensitivity of the GT sensor 31 is calculated based on the signal. Hereinafter, a method of calculating the sensitivity of the GT sensor 31 will be described.

First, the algorithm for calculating the sensitivity of the GT sensor 31 will be described. In this embodiment, the GT sensor 3
The fact that the output value of 1 (the value of the GT signal) follows (Equation 1) is used.

[0064]

U = S (1 + αU) W (Equation 1) where U: GT sensor output (GT signal) [mV], W:
γ-ray calorific value [W / g], α: temperature coefficient [mV-1],
S: Sensor sensitivity [mV / (W / g)]. By solving this (Equation 1) for the γ-ray heating value W, (Equation 2) is obtained.

[0065]

(Equation 2)

This (Equation 2) is obtained by calculating γ from the GT sensor output U.
This is a conversion formula for converting a calorific value W by a line.

Conversely, solving Equation (1) for the GT sensor output U yields Equation (3).

[0068]

(Equation 3)

This (Equation 3) is given by γ given when the reactor power is constant (even if the reactor is stopped).
It shows the output of the GT sensor with respect to the linear heating value W. In this (Equation 3), assuming that the heating value ΔW by the heater is added so as to be added to the γ-ray heating value W, and the output of the GT sensor is also increased by ΔU accordingly, the heating value ΔW given by the heater And GT responding to it
The ratio ΔU / ΔW of the increase amount ΔU of the sensor output has a value close to the differential coefficient dU / dW of (Equation 3).

When the differential coefficient dU / dW of (Equation 3) is actually obtained, (Equation 4) is obtained.

[0071]

(Equation 4)

Further, when (Equation 4) is solved for the sensitivity S,
(Equation 5) is obtained.

[0073]

(Equation 5)

In this (Equation 5), dU / dW is the ratio ΔU / ΔW of the heat generation amount ΔW given by the heater and the increase amount ΔU of the GT sensor output responding thereto, and the heat generation amount W is used to heat the heater. The sensitivity S can be obtained by inputting the heat value by the γ-ray obtained from the previously measured GT signal.

The calibration control device 9 of this embodiment includes a heater 32
The GT signal, the sensitivity of the GT sensor 31, and the temperature coefficient α before heating are extracted from the calibration database 19, the sensitivity memory 10, and the temperature coefficient / time constant memory 12, respectively.
The calorific value W is obtained based on (Equation 2). Further, the calibration control device 9 retrieves the GT signal after heating the heater 32 from the calibration database 19, and calculates the difference between the GT signal before heating the heater 32 and the GT signal after heating, that is, ΔU Ask for. Further, the calibration control device 9 takes out the value of the calibration current stored in the calibration database 18 and calculates the amount of heat ΔW generated by the heater 32 based on the calibration current value. Then, the sensitivity S of the GT sensor is calculated from (Equation 5) based on W, ΔU, and ΔW obtained in this manner and the temperature coefficient α fetched from the temperature coefficient / time constant memory 12. The calibration control device 9 transmits the calculated sensitivity S of the GT sensor 31 to the calibration management device 7. The calibration management device 7 displays the sensitivity S of the GT sensor 31 to the operator via the man-machine interface 6. The operator checks the sensitivity S of the GT sensor 31, and if there is no abnormality in the sensitivity S, continues the GT sensor 31 of the next GT rod 3.
A command is issued to the calibration management device 7 via the man-machine interface 6 to obtain the sensitivity for On the other hand, if the operator finds that the calculated sensitivity S is abnormal, the calibration management device 7 via the man-machine interface 6 calculates the sensitivity of the GT rod 3 including the abnormal GT sensor 31 again. Command.

The calibration management device 7, which has been instructed to calculate the sensitivity of the next GT rod 3, transmits the sensitivity S of the GT sensor whose sensitivity has been calculated to the sensitivity memory 10 and the sensitivity database to the calibration control device 9. 11 is instructed to store in a table format. Upon receiving the instruction, the calibration control device 9
The calculated sensitivity S is overwritten on the sensitivity table in the sensitivity memory 10, and a new sensitivity table is created and stored in the sensitivity database 11. The sensitivity database 11
, The sensitivity table is labeled with the date of the calibration.

When the storage of the sensitivity S of the GT sensor whose calibration has been completed in the sensitivity memory 10 and the sensitivity database 11 is completed, the calibration controller 9 sets the GT rod 3 to be calibrated next.
In order to apply a current to the heater 32 inserted in the
An allocation command is transmitted to the heater power allocation device 16 to switch a switch in the heater power allocation device 16. When the allocation of the heater power supply 17 to the GT rod 3 to be calibrated next is completed by switching the switch in the heater power allocation device 16, the calibration controller 9
Instructs the current pattern creation device 18 to create a current pattern. The current pattern creation device 18 that has received the command creates a current pattern and outputs it to the heater power supply 17. The heater power supply 17 supplies a calibration current to the heater 32 according to the input current pattern.

As described above, the calibration control device 9 determines the calibration current applied to the heater 32 and the G current from the GT sensor 31.
The T signals are fetched in time series and stored in the calibration database 19. When the application of the calibration current is completed, the calibration control device 9 sets the GT according to the above (Equation 5).
After the sensitivity S of the sensor is calculated and the operator's confirmation is obtained, the calculated sensitivity S is input to the sensitivity memory 10 and the sensitivity database 11. As described above, each GT rod 3
The sensitivity S is calculated for the GT sensor 31 of FIG. When the sensitivities S of all the GT sensors 31 are stored in the sensitivity memory 10 and the sensitivity database 11, the calibration management device 7 displays a message “calibration completed” on the man-machine interface 6.
Thus, the calibration of the sensitivity of the GT sensor 31 is completed.

After confirming that the sensitivity calibration of all GT sensors 31 has been completed, the operator inputs a heating value conversion start command from the man-machine interface 6 to the calibration management device 7. Upon receiving the heat generation amount conversion start command, the calibration management device 7 issues a command to the calibration control device 9 to switch the output terminal of the signal switch 82 from the terminal 82-3 to the terminal 82-2. Upon receiving the command, the calibration control device 9 changes the output terminal to the signal switch 82 from the terminal 82-3 to the terminal 82.
A switching control signal is issued to switch to -2. The signal switch 82 to which the switching control signal is input changes the output terminal to the terminal 8
Switch from 2-3 to terminal 82-2. When receiving the heat generation amount conversion start command, the calibration management device 7 connects the input terminal of the signal switch 83 to the terminal 83-
Issue a command to set it to 1. Upon receiving the command, the deviation monitoring device 14 connects the input terminal to the terminal 83-
A switching control signal is issued so as to be 1. The signal switch 83 to which the switching control signal is input has an input terminal of the terminal 83-1.

The output terminal of the signal switch 82 is connected to the terminal 82-2.
When the switch is made, the burn-up signal output from the terminal 82-2 is not transmitted, and the calorific value conversion device 13
a and 13b fetch the GT signal stored in the storage area 154 of the GT signal processing device 15.

The calorific value converter 13a reads the sensitivity S from the sensitivity memory 10 and converts the temperature coefficient α into the temperature coefficient /
GT signal U, sensitivity S
Based on the temperature coefficient α and the temperature coefficient α, the calorific value W in the GT sensor 31 is obtained by the above (Equation 2).

The calculated calorific value W is calculated by the calorific value converter 1.
The data is stored in a memory in the memory 3a in correspondence with each GT sensor 31. In the sensitivity table of the sensitivity memory 10,
In the cell corresponding to the GT sensor 31 that has been found to be abnormal by the above-described diagnosis, a value indicating “failure” is input, or an assignment formula for obtaining a substitute value is input. When the sensitivity data has a value indicating “failure”, the calorific value conversion device 13a stores a value indicating “failure”. If the substitution expression is input, a substitute value is calculated according to the substitution expression, and the calculated value is stored in the memory as the heat generation amount W of the GT sensor 31.

The calorific value W obtained by the calorific value converter 13a is input to the calibration management device 7 via the signal switch 83 and the signal switch 81. Since the input terminal of the signal switch 83 is the terminal 83-1, the output of the calorific value conversion device 13b is not input to the calibration management device 7.
The calibration management device 7 presents the calorific value W of each GT sensor 31 to the operator through the man-machine interface 6.
At this time, the G value of the GT sensor 31 using the substitute value is used.
T sensor No. Is received from the calibration control device 9 and the man-machine interface 6 displays which GT sensor of the failed GT sensor is substituted by the GT signal of which GT sensor. Further, the failed GT sensor 31
Is displayed as "failure-bypass". For the calorific value W of the normally functioning GT sensor, the calorific value W is displayed in green, the calorific value W as a substitute value is displayed in yellow, and “failure-bypass” is displayed in red.

The calibration management device 7 executes the GT
The calorific value W of the sensor 31 is obtained, and a graph in which the calorific value W of each GT sensor 31 is plotted on the time axis is presented to the operator through the man-machine interface 6. In addition, according to the instruction of the operator, the time average value and variance of each heating value and the average value and variance in the group shown in FIG. 4 are calculated and presented to the operator.

The operator confirms the information on these calorific values presented on the man-machine interface 6,
It is confirmed whether each GT sensor 31 performs a desired operation and whether the conversion of the GT signal into the calorific value is correctly executed. When this confirmation is completed, the operator issues a GT sensor operation command to the calibration management device 7 via the man-machine interface 6 so as to output the calorific value to the process computer 5.

Upon receiving the GT sensor operation command from the man-machine interface 6, the calibration management device 7 changes the output terminals of the signal switch 81 from the terminal 81-3 to the terminal 81-.
2 to output a switching control signal. Also,
It notifies the process computer 5 that the GT signal (heat generation amount) is available.

The output terminal of the signal switch 81 is the terminal 81-2.
When the mode is switched to, the burn-up signal output from the terminal 81-2 stops, and the calorific value data output from the calorific value converter 13a is input to the process computer 5.
The process computer 5 includes a calorific value conversion device 13 continuously over time.
The calorific value data is fetched from a.

The process computer 5 converts the captured calorific value data into power densities per unit length or unit volume in the four fuel assemblies surrounding the GT sensor by using a core performance calculation program in the process computer 5. In this conversion, a response coefficient that associates the calorific value data with the output density of the fuel assembly is used. This response coefficient can be obtained by a so-called Monte Carlo simulation. In other words, a method is used in which the fuel rods in the fuel assembly are set as gamma-ray sources, a large number of gamma-rays are randomly emitted from the source, and a statistical study is made of how much of the gamma-rays reaches the GT sensor. Used. The process computer obtains the power density distribution of the core 2 as described above, and outputs the obtained power density distribution to the calibration management device 7. The calibration management device 7
The input power density distribution is converted to a man-machine interface 6
Is displayed on the display means.

Next, in the present embodiment, the calibration management device 7 asks the operator via the man-machine interface 6 to judge whether or not to predict the future value of the sensitivity of the GT sensor 31. The operator selects “do not perform sensitivity prediction” when not predicting the sensitivity of the GT sensor 31, and selects “perform sensitivity prediction” when predicting the sensitivity.

When the operator selects “execution of sensitivity prediction”, the calibration management device 7 issues a command to the sensitivity prediction device 20 via the calibration timing calculation device 21 to predict the sensitivity. The sensitivity prediction device 20 that has received the sensitivity prediction command predicts the sensitivity of the GT sensor 31 based on the sensitivity data stored in the sensitivity database 11, and stores the predicted sensitivity in the predicted sensitivity memory 22.

A method of estimating the sensitivity in the sensitivity estimating device 20 will be described below. In this embodiment, the sensitivity S is predicted according to (Equation 6).

[0092]

S (t) = S ₁ + S ₂ exp (−μt) (Equation 6) where S (t) is sensitivity at time t, S ₁ is saturation sensitivity, S ₂ is transient sensitivity, and μ is The time constant, exp (), is an exponential function based on natural logarithm. S ₁ , S ₂ , and μ are model parameters specific to the GT sensor 31 to be subjected to sensitivity prediction, and identifying them is the first stage of sensitivity prediction.

In the sensitivity estimation after the sensitivity calibration has been performed once, the sensitivity is estimated using the sensitivity data obtained by the calibration and the factory test data. Assuming that the time t = 0 is the time when the calibration is performed, the sensitivity S obtained by the calibration is S = S ₁ + S ₂ . However, as is, three unknown parameters S ₁ ,
Since S ₂ and μ cannot be identified, the sensitivity data of the factory test data is used as S ₁ and the time constant data is used as μ. By giving the S _1, the sensitivity was obtained in S ₂ calibration S
Obtained by subtracting the sensitivity S ₁ is a factory test data from.

The sensitivity predicting apparatus 20 changes the sensitivity in the equation (6) where S ₁ , S ₂ , and μ identified as described above are substituted, thereby obtaining the sensitivity up to the end of one operation cycle of the reactor 1. Calculate the future value of S. Sensitivity prediction device 2
0 indicates that the calculated future value of the sensitivity S is stored in the predicted sensitivity memory 22, and the future value of the sensitivity S calculated by the calibration management device 7 via the calibration time calculation device 21 and (Expression 6)
The values of S ₁ , S ₂ , and μ assigned to are output. The calibration management device 7 uses the man-machine interface 6 to execute S ₁ , S
_2. A graph showing the time change of the values of μ and the future value of the sensitivity S is presented to the operator.

FIG. 8 is an example of a graph showing the time change of the future value of the sensitivity S obtained by the sensitivity prediction device 20.
In the graph of FIG. 8, the vertical axis represents sensitivity S and the horizontal axis represents time t. As shown in FIG. 8, the sensitivity S of the GT sensor 31
Decreases over time.

When the calibration management apparatus 7 presents the operator with a graph showing the result of the sensitivity future value prediction, the operator requests the operator to determine whether to calculate the calibration time. The operator selects “Calibration time calculation unnecessary” when not calculating the calibration time, and selects “Execute calibration time calculation” when calculating the calibration time.

When the calibration management device 7 receives an instruction to execute calibration timing calculation from the operator, the calibration management device 7 firstly gives the operator an allowable value εs of a sensitivity error that may be caused by a change in sensitivity.
Prompts you to enter At this time, the calibration management device 7 also presents a reference value of the allowable value εs. When the reference value presented by the calibration management device 7 is set to the allowable value εs, the operator inputs the reference value through the man-machine interface 6,
When a different allowable value from the reference value is determined, the value is input through the man-machine interface 6. The calibration management device 7 calculates the tolerance value εs of the sensitivity error into the calibration time calculation device 21.
And sends a command to the calibration time calculation device 21 to calculate the calibration time.

Next, a description will be given of a method of calculating the calibration time by the calibration time calculating device 21 in the present embodiment. As described above, the sensitivity S is represented by (Equation 6) as a function of the time t. When this (Equation 6) is solved for time t, (Equation 7) is obtained.

[0099]

(Equation 7)

What the calibration timing calculation device 21 wants to obtain is the time required for the sensitivity S calibrated at the time t = 0 to change and the error to reach the allowable value εs.
S-εs may be substituted for S (t) in (Equation 7). (Equation 8) is obtained by this substitution, and the time t obtained by this (Equation 8) is the time required for the sensitivity to change from S to S-εs, that is, the time for performing the next calibration.

[0101]

(Equation 8)

By substituting S−2εs for S (t) in (Equation 7), the calibration time two times ahead can be obtained.
By substituting S−3εs for S (t), the calibration timing three times ahead can be obtained. When the calibration time calculating device 21 calculates the time to perform the next calibration according to the above (Equation 8), it transmits this to the calibration management device 7. The calibration management device 7 displays the obtained calibration time on the graph showing the time change of the future value of the sensitivity S via the man-machine interface 6. FIG.
It is an example of the graph which displayed the calibration time on the time change of the predicted future value of the sensitivity S. As shown in the figure, the sensitivity S is the allowable value ε.
The calibration time is set at the time when the value decreases by s.

As described above, from the prediction result of the future value of the sensitivity S, a time when the sensitivity S decreases by the allowable value εs is obtained, and the time is set as the calibration time, so that the error of the sensitivity S is always kept below the allowable value εs. Can be kept. By keeping the error of the sensitivity S equal to or less than the allowable value εs, the error of the heating value W obtained based on the sensitivity S and the error of the reactor output obtained based on the heating value W fall within a predetermined range. Can be suppressed. In this embodiment, the allowable value s of the error of the sensitivity S is given. However, the allowable value of the error of the calorific value W or the allowable value of the error of the reactor output is given, and the sensitivity S is determined from the allowable value. May be calculated.

The calibration management device 7 presents the graph shown in FIG. 8 to the operator, and automatically performs the calibration of the GT sensor 31 when the next calibration time comes, or The operator issues a calibration command or requests a selection.

If the operator wants the GT sensor 31 to be automatically calibrated, the "automatic calibration when the calibration time has come"
Select When the operator "Calibration time comes, automatic calibration"
Is selected, the calibration management device 7 sets the calibration time calculation device 2
At the next calibration time calculated by 1, the calibration of the GT sensor is automatically performed.

Next, the calibration management device 7 informs the operator of the GT based on the heat value obtained based on the predicted sensitivity.
Check whether signal abnormality monitoring is performed. When the operator instructs the calibration management device 7 to perform the abnormality monitoring, the calibration management device 7 instructs the calorific value conversion device 13b using the GT signal and the predicted sensitivity future value to generate the future value of the calorific value. Command to ask for.

The calorific value conversion device 13b is provided with the calibration management device 7
, The future value of the sensitivity stored in the predicted sensitivity memory 22 is fetched, and the future value of the calorific value is calculated based on the fetched future value of the sensitivity and the GT signal given from the GT signal processor 15. I do. The calculation of the future value of the calorific value is performed based on (Equation 2). The calculated future value of the calorific value is stored in the memory of the calorific value converter 13b in association with the GT sensor 31.

Next, the calibration management device 7 controls the deviation monitoring device 1
4 to monitor the difference between the calorific value calculated by the calorific value converter 12a and the future value of the calorific value calculated by the calorific value converter 12b. Upon receiving the command, the deviation monitoring device 13 captures the calorific value data from the calorific value conversion device 12a,
Data of the future value of the calorific value is fetched from 2b. Then, a deviation between the captured calorific value and a future value of the calorific value is calculated.
Further, the deviation monitoring device 13 generates a heat value and a future value of the heat value,
And the calculated deviation is transmitted to the calibration management device 7. The calibration management device 7 graphically displays the calorific value and the future value of the calorific value and the deviation provided from the deviation monitoring device 13 on a time axis.

The calibration management device 7 provides the operator with
When the difference between the calorific value and the future value of the calorific value increases, the operator is asked whether the future value of the calorific value is automatically transmitted to the process computer 5. When the operator replies that the future value of the calorific value is automatically transmitted to the process computer 5 when the deviation increases, the calibration management device 7 instructs the operator to input an allowable value of the deviation. At this time, the calibration management device 7 presents a reference value of the deviation allowable value.
If the operator enters to use the reference value as is,
The calibration management device 7 sets the reference value as the allowable value of the deviation. When the operator sets a value other than the reference value, the operator inputs the set value via the man-machine interface 6.

The calibration management device 7 transmits the input allowable value of the deviation to the deviation monitoring device 14. The deviation monitoring device 14
The received allowable value of the deviation is constantly compared with the deviation, and when the deviation exceeds the allowable value of the deviation, the signal switch 83 switches the input terminal from the terminal 83-1 to the terminal 83-2. A switching control signal is output. The signal switch 83 to which the switching control signal is input changes the input terminal to the terminal 83-.
2, and the future value of the calorific value output from the calorific value converter 12b is input to the process computer 5 in place of the calorific value output from the calorific value converter 13a.

As described above, the GT sensor 31
Calibration of the sensitivity, calculation of the future value of the sensitivity, setting of the calibration time, and the like are performed. Then, when the set calibration time comes or when a calibration command is given by the operator, the calibration management device 7 starts calibration of the sensitivity of the GT sensor 31 again. The procedure of the sensitivity calibration is as described above. The newly obtained sensitivity is stored in the sensitivity memory 10 and the sensitivity database 11, and the calorific value conversion device 13a
Is a sensitivity memory 10 in which the latest sensitivity data is always stored.
The calorific value is converted based on the sensitivity data.

As in the case of the first calibration, when the second calibration is completed, the sensitivity prediction device 20 predicts the sensitivity. In the prediction of the sensitivity at this time, in addition to the sensitivity S data obtained in the second calibration, factory shipping data and the sensitivity S data obtained in the first calibration can be used. That is, in the second sensitivity estimation, two data on the sensitivity S are obtained. If only the time constant μ is given by the factory shipment data, S ₁ , S
_Since there are two data of the sensitivity S for two unknowns of 2, S ₁ and S ₂ can be identified in the manner of solving the simultaneous linear equations.

Similarly, in the third sensitivity prediction after the third calibration of the GT sensor, three data items relating to the sensitivity S are obtained, and the unknowns are converted into three prediction models. A unique solution can be obtained.

Further, in the fourth and subsequent sensitivity predictions, more data on the sensitivity S than the unknown is obtained. Next, the fourth and subsequent sensitivity predictions will be described. In the present embodiment, in the prediction of the sensitivity after the fourth time,
An algorithm consisting of the following steps is used.
This is a contrivance that the sensitivity S (t) of (Equation 6) is linear with respect to S ₁ and S ₂ but non-linear with respect to μ.

The initial approximate value of the parameter μ is set to μ1 (μ = μ1 + δ).

This μ1 is substituted into (Equation 6) to obtain (Equation 9).

[0117]

S (t) = S ₁ + S ₂ {exp (−μ1t) −δtexp (−μ1t)} (Expression 9) In (Expression 9), X ₁ = exp (−μ1t) and X ₂ = t
If exp (−μ1t), S ₃ = S ₂ δ, (Equation 10) is obtained.

[0118]

S (t) = S ₁ + S ₂ X ₁ −S ₃ X ₂ (Equation 10) (Equation 10) is a multiple regression equation composed of _two independent variables (X ₁ , X ₂ ). Therefore, S ₁ , S ₂ , and S ₃ are obtained in accordance with a known method of calculating a multiple regression coefficient.

From the obtained S ₂ and S ₃ , δ is calculated as δ = S
Determined by the ₃ / S _2.

By repeating the above steps until δ becomes sufficiently small, it is possible to predict the future value of the sensitivity S in consideration of the fact that the sensitivity S is nonlinear with respect to μ. As described above, in the reactor power measuring apparatus according to the present embodiment, since the future value of the sensitivity is predicted based on the calibrated sensitivity of the GT sensor 31, it is necessary to determine when the sensitivity error exceeds the allowable value. Can be predicted. Then, based on the predicted future value of the sensitivity and the allowable value of the sensitivity error, it is possible to determine the next optimal time as the calibration time. Therefore, it is possible to reduce the number of times of the sensitivity calibration of the GT sensor 31 while keeping the sensitivity error of the GT sensor 31 within an allowable range.

In this embodiment, the case where the GT signal is used for calculating the reactor power distribution is described.
It is also possible to calibrate the sensitivity of the LPRM sensor based on the T signal.

[0122]

According to the present invention, it is possible to reduce the number of times the GT sensor sensitivity is calibrated while keeping the sensitivity error of the GT sensor within an allowable range.

[Brief description of the drawings]

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

FIG. 2 is a structural view of a GT rod 3 of FIG.

3 is a diagram showing an example of a sensitivity table, a temperature coefficient table, and a time constant table stored in a sensitivity memory 10 and a temperature coefficient / time constant memory 12 of FIG.

FIG. 4 is a diagram illustrating an example of grouping of GT sensors 31;

FIG. 5 is an example of a table summarizing GT signal differences between GT sensors in the same group.

FIG. 6 is a configuration diagram of a heater power allocation device 16 of FIG. 1;

FIG. 7 is a configuration diagram of a GT signal processing device 15 of FIG. 1;

FIG. 8 is an example of a graph showing a temporal change in sensitivity displayed on the man-machine interface 6 of FIG. 1;

[Explanation of symbols]

1. Nuclear reactor, 2. Core, 3. GT rod, 4. LPRM
Detector, 5: Process computer, 6: Man-machine interface, 7: Calibration management device, 9: Calibration control device, 10 ...
Sensitivity memory, 11: Sensitivity database, 12: Temperature coefficient / time constant memory, 13a, 13b: Heat generation amount conversion device, 1
4: Deviation monitoring device, 15: GT signal processing device, 16: Heater power allocation device, 17: Heater power source, 18: Current pattern creation device, 19: Calibration database, 20: Sensitivity prediction device, 21: Calibration time calculation device 22: prediction sensitivity memory, 81, 82, 83: signal switch.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazuhiko Ishii 5-2-1 Omikacho, Hitachi City, Ibaraki Prefecture Inside the Omika Works, Hitachi, Ltd. (72) Inventor Takeshi Nozaki 3-chome, Sachimachi, Hitachi City, Ibaraki Prefecture No. 1 F-term in Hitachi, Ltd. Hitachi Works (reference) 2G075 AA03 BA03 CA08 DA01 EA09 FA18 FB05 FB07 FB15 FB18 FC06 FD01 GA16 GA34

Claims (5)

[Claims] 1. A gamma ray thermometer for outputting a signal corresponding to a change in temperature of a metal due to a gamma ray generated in a nuclear reactor, a signal output from the gamma ray thermometer, and sensitivity of the gamma ray thermometer. A reactor power measuring device having means for obtaining a reactor power based on the above, and a calibrating means for calibrating the sensitivity of the γ-ray thermometer, comprising: a predicting means for predicting a future value of the sensitivity of the γ-ray thermometer. A reactor power measuring device, characterized in that: 2. A time for calibrating the sensitivity of the γ-ray thermometer based on a future value of the sensitivity of the γ-ray thermometer predicted by the predicting means and a preset allowable value for the sensitivity. 2. The reactor power measuring apparatus according to claim 1, further comprising a calibration time determining means for determining. 3. The apparatus according to claim 2, further comprising display means for displaying a future value of the sensitivity predicted by said prediction means and a time at which the calibration of the sensitivity determined by said calibration time determination means is performed. Reactor power measurement device as described. 4. A first calorific value conversion means for obtaining a calorific value in said γ-ray thermometer based on the sensitivity calibrated by said calibrating means, and said γ based on a future value of sensitivity predicted by said predicting means. A second calorific value converting means for calculating a calorific value in the linear thermometer; and a deviation calculating means for calculating a deviation of the calorific value calculated by the first calorific value converting means and the second calorific value converting means. The reactor power measuring apparatus according to claim 3, wherein the display means displays the deviation obtained by the deviation calculation means. 5. The reactor power measuring apparatus according to claim 2, wherein said calibration means calibrates the sensitivity of said γ-ray thermometer at a time determined by said calibration time determination means.