JPH10221485A - Reactor power measuring instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To guaranty that various data processing based on the outputs of γ-ray thermometers is fully reliable. SOLUTION: A γ-ray temperature measuring system 11 is constituted of γ-ray thermometers 11-1 to 11-k, which measures heat due to local γ-ray in core. The outputs of these γ-ray thermometers are sent out to a γ-ray thermometers signal processor 102 and a soundness judgment part 101. The soundness judgment part 101 judges the soundness of at least a part of the γ-ray thermometers in the γ-ray temperature measuring system 11 based on the outputs of the γ-ray thermometers, various process quantities from a process instrumentation system 12 and data necessary for soundness judgment which are contained in the data base 104. This judgment result is sent out to the γ-ray thermometers signal processor 102 and a soundness judgment results display 105.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nuclear instrumentation system in a nuclear power plant, and more particularly to a γ-fixed nuclear reactor.
The present invention relates to a reactor power measuring device for realizing a reactor power measurement with a (gamma) ray thermometer with high reliability.

[0002]

2. Description of the Related Art In a nuclear reactor, γ
Γ-ray thermometers for measuring heat generated by X-rays, and a plurality of local power detectors (Local Power Range Monitor:
PRM ”) is used to measure the reactor power. For example, Japanese Unexamined Patent Publication No. Hei 7-92294 discloses a configuration of a nuclear instrumentation system in which local power in a reactor calculated from a γ-ray thermometer is used for calibration of LPRM sensitivity.

[0003] LPRM continuously measures the local neutron flux in the core power region, and provides information for protecting the reactor from a local abnormal increase in the reactor power and for monitoring the local power distribution. Etc., from the viewpoint of maintaining the safety of the nuclear power plant,
It plays a very important role.

The measurement principle of a γ-ray thermometer is completely different from that of LPRM which measures a neutron flux using a fissile material, and a temperature rise of a metal due to γ-ray irradiation is detected by a temperature measuring means such as a thermocouple. The gamma dose is obtained from the temperature rise, and the neutron flux is calculated indirectly from this. Therefore, unlike LPRM, there is no need to consider the sensitivity deterioration due to the temporal loss of the fissile material used for measurement.
Since the exposure performance is relatively good, it is always fixedly installed in the furnace.

[0005]

However, according to the above-mentioned prior art, when performing sensitivity calibration of LPRM or various data processing based on the output of a gamma ray thermometer, the measurement using the gamma ray thermometer is performed. However, a specific method for confirming whether or not each γ-ray thermometer is performing a desired operation soundly has not been sufficiently studied.

[0006] As described above, since the gamma ray thermometer has good exposure resistance performance, it cannot be determined that it is uniquely high in reliability, and like general sensors, failures such as short-circuit, disconnection, and drift occur. Can not escape the outbreak.
In particular, in boiling water reactors, voids are generated in the reactor core, and the voids are said to be affected by vibrations, and the performance of the γ-ray thermometer is degraded by receiving this vibration for a long time. It is possible to do.

[0007] Not only for the combination of the LPRM and the γ-ray thermometer, but generally for a system requiring high reliability,
The same high reliability is required for the auxiliary system for calibrating and inspecting the system. For this reason, there is a need for a gamma ray thermometer to provide soundness confirmation means that can guarantee that various data processing based on the gamma ray thermometer output is sufficiently reliable.

An object of the present invention is to provide a reactor power measuring apparatus capable of determining the soundness of a γ-ray thermometer with high reliability.

[0009]

According to the present invention, there is provided a reactor power measuring apparatus for measuring the power of a reactor using a γ-ray thermometer. Database means for associating the output range of the γ-ray thermometer with a database; and determining whether the output of the γ-ray thermometer is within the allowable range stored in the database means. It is configured to include a soundness determination unit for determining soundness.

According to this configuration, when determining the soundness of the γ-ray thermometer, the allowable range is previously stored in a database in association with various process amounts obtained online, and γ is determined based on the allowable range in the database. The soundness of the line thermometer is determined. As a result, the soundness of the γ-ray thermometer can be determined with high reliability.

An object of the present invention is to provide a reactor power measuring apparatus for measuring the power of a reactor using a plurality of γ-ray thermometers arranged in a directional manner.
The present invention is also achieved by a configuration including a soundness determination unit that estimates an output value of a line thermometer based on the output of another γ-ray thermometer and compares the estimated value with the output of the γ-ray thermometer.

According to this configuration, the reference value and the output of the γ-ray thermometer to be determined are determined based on the output of another γ-ray thermometer except for the γ-ray thermometer whose soundness is to be determined. The soundness of the γ-ray thermometer is determined by the comparison. Therefore,
The soundness of the γ-ray thermometer can be determined with high reliability.

It is another object of the present invention to provide a reactor power measuring apparatus for measuring the output of a reactor using an LPRM and a gamma ray thermometer, wherein the output value of the gamma ray thermometer is measured in the vicinity of the gamma ray thermometer. The present invention is also achieved by a configuration including a soundness determination unit for estimating the soundness based on the output of the LPRM disposed in the system and comparing the estimated value with the output of the γ-ray thermometer.

According to this configuration, when judging the soundness of the γ-ray thermometer, the output of the LPRM arranged near the γ-ray thermometer whose soundness is to be judged is used as a reference, and this reference value and the judgment object are used. By comparing the outputs of the γ-ray thermometers, the soundness of the γ-ray thermometer is determined. As a result, the soundness of the γ-ray thermometer can be determined with high reliability.

A further object of the present invention is to provide a reactor power measuring apparatus for measuring the power of a reactor using a gamma ray thermometer, wherein a core power is calculated based on a process value of a process instrumentation system of a reactor facility. The present invention is also achieved by a configuration including a soundness determination unit that compares the calculated core power value with the output of the γ-ray thermometer and determines the soundness of the γ-ray thermometer based on the comparison result.

According to this configuration, the calculated value of the core power calculated by the calculation is used as a criterion for determination, and the soundness of the γ-ray thermometer is determined by comparing the reference value with the output of the γ-ray thermometer to be determined. Therefore, the soundness of the γ-ray thermometer can be determined with high reliability.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing a first embodiment of a reactor power measuring apparatus according to the present invention.

The γ-ray thermometers 11-1 to 11-k and the process instrumentation system 12 are installed in a nuclear reactor.
It is configured to include line thermometers 11-1 to 11-k. The reactor power measurement device includes a soundness determination unit 101 (soundness determination means) and a γ-ray thermometer connected to each of a plurality of γ-ray thermometers 11-1 to 11-k in the γ-ray temperature measurement system 11. Signal processing unit 1
02, γ connected to the γ-ray thermometer signal processing unit 102
It comprises a line thermometer data processing unit 103, a database 104 (database means) connected to the soundness determination unit 101, and a soundness determination result display unit 105.

A γ-ray temperature measuring system 11 composed of γ-ray thermometers 11-1 to 11-k measures heat generated by γ-rays locally in the furnace, converts this into an electric signal, It is output as a total output voltage (hereinafter, referred to as “γ-ray thermometer output”). These γ-ray thermometer outputs are sent to the γ-ray thermometer signal processing unit 102 and the soundness determination unit 101.

The γ-ray thermometer signal processing unit 102 converts the γ-ray thermometer output sent from the γ-ray temperature measurement system 11 into γ-ray thermometer data, and converts the γ-ray thermometer data to γ-ray thermometer data. It has a function of sending it to the processing unit 103. The γ-ray thermometer data is, for example, the in-furnace local output calculated from the γ-ray thermometer output. The γ-ray thermometer data processing unit 103 performs, for example, data processing necessary for the LPRM configuration based on the local power inside the furnace, or calculates the power distribution of the core.

The process instrumentation system 12 sends out various process quantities to the soundness determination unit 101. Soundness determination unit 101
Is the γ-ray thermometer output sent from the γ-ray temperature measurement system 11, the various process quantities from the process instrumentation system 12, and the soundness judgment (or confirmation) stored in the database 104.
Γ-ray thermometers included in the γ-ray temperature measurement system or some of them (here, the γ-ray thermometers targeted for the soundness determination are γ-ray thermometers 11-i Is determined, and the determination result is used as the γ-ray thermometer signal processing unit 10.
2 and a function of sending it to the determination result display unit 102.

The γ-ray thermometer signal processing unit 102 extracts only the output of the normally operating γ-ray thermometer based on the determination result sent from the soundness determination unit 101, Γ-ray thermometer data converted based on the data
The data is sent to the line thermometer data processing unit 103. The soundness determination result display unit 105 has a function of numerically or graphically providing information about which γ-ray thermometer is malfunctioning.

Next, the operation related to the soundness of the γ-ray thermometer of the reactor power measuring apparatus having the above configuration will be described in detail with reference to the drawings. FIG. 2 shows the soundness determination unit 1
FIG. 2 is a circuit diagram showing a specific configuration of No. 01. The output of the gamma ray thermometer 11-i, which is the target of the soundness determination, is output from the comparator 101A.
And 101C. The other input terminal of the comparator 101A receives the output voltage VH of the reference power supply 101B, and the other input terminal of the comparator 101C receives the output voltage VL of the reference power supply 101D.
Now, assuming that the output of the γ-ray thermometer 11-i is xi, the comparator 1
01A, the output of the γ-ray thermometer 11-i and the reference power supply 101B
(Xi-VH) is calculated, and when the difference becomes negative, the output of the comparator 101A becomes "1".

In the comparator 101C, the reference power source 10
1D and the difference between the output xi of the gamma ray thermometer 11-i (VL-xi
) Is calculated, and when this difference becomes negative, the comparator 10
The output of 1C becomes "1". If the output of at least one of the comparator 101A and the comparator 101C becomes “1”, O
The output of the R circuit 101E becomes "1". That is, as long as the output xi of the γ-ray thermometer 11-i is equal to or higher than VL and equal to or lower than VH by the circuits including the comparators 101A to 101E,
The output of the OR circuit 101E remains "0", but when the output xi of the gamma ray thermometer 11-i falls below or exceeds VL, if the output of the OR circuit 101E becomes "1", the sound is good. Gamma ray thermometer 11-i
A lamp or the like indicating an abnormality of the lamp lights up. At the same time, the switch 102A provided in the γ-ray thermometer signal processing unit 102 is automatically turned “open”, and the output of the γ-ray thermometer 11-i indicating abnormality is output to various signal processing and data processing. Is blocked from being used for In this case, a configuration may be adopted in which the lamp or the like is only turned on and the determination of the interruption of the output of the γ-ray thermometer 11-i indicating the abnormality is left to the operator, and is manually performed. Note that the switch 102A may have a burnout function of fixing the output of the γ-ray thermometer to a specific value when an abnormality is detected. The display on the soundness determination result display unit 105 allows an operator or the like to grasp the state of the γ-ray thermometer.

Further, the above-described soundness judging means may be provided for all the γ-ray thermometers, or one soundness judging means may be shared by a plurality of γ-ray thermometers. Alternatively, the soundness may be sequentially determined by a signal breaker such as a multiplexer.

Next, the reference power supplies 101B and 101D shown in FIG.
Will be described. In places where fission is actively occurring, the heat generated by gamma rays is large. Therefore,
The output of the γ-ray thermometer changes depending on factors that promote and suppress the generation of fission. For example, the curve A in FIG. 3 shows the distribution of the output of the γ-ray thermometer at the position where the control rod is not inserted, and the curve B shows the γ at the position where the control rod is inserted.
3 shows a distribution of a line thermometer output. The reason that the output of the γ-ray thermometer fluctuates around the true value is due to the influence of noise in
This is due to the inherent thermal fluctuation of the line thermometer output.
The distribution of the γ-ray thermometer output according to the position of the control rod is based on statistical data obtained from experimental data and actual operation results on actual equipment,
The heat generated by the line is represented by a theoretical model such as a heat diffusion equation, and is obtained from a Monte Carlo simulation or the like based on the theoretical model.

From this distribution, a range in which the γ-ray thermometer is normal is determined. For example, the standard deviation σ of the distribution and the mean μ
Is calculated, and VH for monitoring a high value is set to a value of [μ + 3σ], and VL for monitoring a low value is set to a value of [μ-3σ]. FIG.
In the example, the normal / abnormal state is determined in the section [VL, VH] at the position where the control rod is not inserted, and the determination is performed in the section [VL, VH] at the position where the control rod is inserted. Of course, besides statistical methods and simulations,
Depending on the experience of operating the plant and the operating rules, VL,
VH may be determined.

Not only the control rod position but also the process amount affecting the fission such as the recirculation flow rate is obtained from the process instrumentation system 12. The output range of the γ-ray thermometer is set in the database 104 in a form corresponding to these processes.
The soundness determination unit 101 searches the database 104 for upper and lower limits [VL, VH] corresponding to the process amount, and determines normal / abnormal. VL and VH are set to the upper and lower limits of the output range of the temperature measuring means (for example, a thermocouple) in the γ-ray thermometer, and when the output falls below the lower limit, a disconnection occurs, and when the output falls below the upper limit, a short circuit occurs. It is also possible to determine that an occurrence has occurred. The data collected in the database 104 may be a list of γ-ray thermometer outputs corresponding to each process amount, or a mathematical expression describing the relationship between each process amount and the γ-ray thermometer output. You may. Alternatively, it may be a knowledge database that derives a γ-ray thermometer output from each process amount.

In the above description, the comparison was made using the physical quantity of the output voltage of the γ-ray thermometer, but the present invention is not limited to the output voltage. Intermediate physical quantities at the time of converting the output of the γ-ray thermometer to the output in the furnace performed by the γ-ray thermometer signal processing unit 102 include a calorific value by γ-rays, a γ dose, a neutron flux density, and the like.

As described above, the soundness determination unit 101 having the structure shown in FIG. 2 can determine the soundness of the γ-ray thermometer with a simple structure.

FIG. 4 shows a second embodiment of the reactor power measuring apparatus according to the present invention. The overall configuration is the same as that of FIG. 1, but the configuration of FIG. 1 determines the soundness using the outputs of the γ-ray thermometers 11-1 to 11-k, whereas in FIG. The soundness determination unit 101 takes in intermediate physical quantities from the output of the γ-ray thermometer processed by the thermometer signal processing unit 102 to the furnace output, and determines the soundness.

In the description of the above embodiment, the soundness judgment is performed based on the output of the gamma-ray thermometer obtained at each time. However, the database 104 stores the time-series data of the output of the gamma-ray thermometer. Then, a form in which soundness determination is performed may be adopted. A gamma ray thermometer often uses a thermocouple as a temperature measuring means, but if the sheath tube containing the gamma ray thermometer is deformed due to pressure or the like, the internal thermocouple is also deformed. The thermoelectromotive force of the pair changes. When the deformation of the thermocouple proceeds irreversibly, a drift occurs in the output of the γ-ray thermometer. The cause of this drift may be various factors such as deformation due to heat and deterioration due to radiation exposure of the thermocouple. So, to detect drift,
The properly sampled γ-ray thermometer output or the physical quantity converted by the γ-ray thermometer signal processing unit 102 is used as the soundness determination unit 1.
01 in the database 104 in time series,
Soundness is determined based on the time-series data.

FIG. 5 is a γ-ray thermometer output characteristic diagram for explaining a method of judging soundness based on time-series data. Time t
0 to t10, the output of the γ-ray thermometer is stored in the database 10
4 is the sampling time. If the output of the γ-ray thermometer at time t is x (t),

[0034]

## EQU1 ## By calculating x (ti + 1) -x (t) [i = 0, 1,...], The increasing tendency (or decreasing tendency) of the γ-ray thermometer output can be obtained. If the operation state of the plant is constant, errors and thermal fluctuations caused by the measurement are canceled in the time average. If a drift has occurred, as in this example, x (ti + 1) -x
It can be seen that the average of (ti) does not become 0, and a drift occurs that diverges in the positive direction. The fact that the operation state of the plant is constant from time t0 to time t10 can be known from the control rod position and the process amount such as the recirculation flow rate obtained from the process instrumentation system 12.

The time series data stored in the database 104 is not limited to the output of the γ-ray thermometer, but is an intermediate physical quantity until the output of the furnace processed by the γ-ray thermometer signal processing unit 102 is derived.

Next, an embodiment in which the outputs of the γ-ray thermometers are compared with each other to detect an abnormality of the γ-ray thermometer will be described.

FIGS. 6 (a), 6 (b) and 6 (c) show, at a certain point in time, the outputs of a plurality of γ-ray thermometers in a specific coordinate system in the furnace, for example, in the vertical direction of the core or in the radial direction of the core. FIG. Here, the coordinate points where these γ-ray thermometers are arranged are z1 to z11, and the γ-ray thermometers 11-1 to 11-1
-k is represented by γ1 to γ11. Here, the description will be made on the assumption that the γ-ray thermometer (γ5) is abnormal.
In the first stage of the soundness determination algorithm based on the inter-comparison of the gamma ray thermometer outputs, the outputs of the gamma ray thermometers arranged in a specific direction in the furnace are listed. In this specific direction, a coordinate system in the vertical direction or system direction can be used as described above, or as another example, a spiral curve in the vertical axis direction can be used. Such a fixed direction is called a z-axis.

In the second stage of the determination algorithm, the outputs of these gamma-ray thermometers are estimated from the outputs of at least two gamma-ray thermometers adjacent on the z-axis. FIG.
(A) and (b) show the outputs of three γ-ray thermometers γ5 to γ7 based on the outputs of adjacent γ-ray thermometers indicated by pairs of (γ4, γ6) and (γ6, γ8), respectively. Is explained. This estimation value calculation is performed for all γ-ray thermometers on the z-axis.

FIGS. 6A to 6C illustrate a method of calculating the estimated value by linearly interpolating the outputs of adjacent γ-ray thermometers. Figure 6 shows linear interpolation.
To explain the case of (a) as an example, in the section [z4, z6], an estimation based on the idea that the output of γ4 and the output of γ6 are connected by a straight line, and the output in that section is interpolated. This is a method of calculating a value.

As the estimated output value y5 of γ5, the output of γ4 and the output of γ6 are connected by a straight line, and the output on the straight line corresponding to the position of z5 is used. Similarly, γ6
Output estimated value y6 ′ and γ7 output estimated value y7 ′, respectively.
6 (b) and 6 (c). Although not shown, the same applies to γ1 to γ4 and γ8 to γ11. However, γ1 and γ2 located at both ends on the z-axis cannot be interpolated as described above. In this case, extrapolate the outputs of γ1 and γ3,
In the case of γ11, the outputs of γ9 and γ10 may be extrapolated. γ
In the case of 1 to γ4 and γ8 to γ11, it can be easily understood that each estimated value becomes a value close to the actually measured output.

At the completion of the second stage of the determination algorithm, two values, ie, the actually measured value of each γ-ray thermometer and the estimated output value calculated by the above method, have been obtained. An output difference d between the output of the thermometer and the estimated output is calculated.

That is, the output difference di between the output yi of the i-th γ-ray thermometer (γi) and the estimated value yi 'is determined by the following equation.

[0043]

## EQU2 ## di = | yi-yi '|

When these output differences di are plotted for each γ-ray thermometer, they are as shown in the graph of FIG.

In the fourth stage of the determination algorithm, it is determined which γ-ray thermometer is malfunctioning based on the graph of FIG. As is clear from the graph of FIG. 7, the output difference d of γ5 set as malfunction is significantly higher than the output difference of other γ-ray thermometers. However, although not larger than the output difference of γ5, the output difference between γ4 and γ6 is also larger than the output difference of other γ-ray thermometers. This is γ4
And γ5, which is the common neighbor to
This is because the output estimates of γ4 and γ6 were affected by this. However, the simultaneous failure of γ4 and γ6 means that the probability of malfunction is extremely low because the γ-ray thermometers 11-1 to 11-k are configured in a parallel system from the viewpoint of measurement. For these reasons, a comprehensive judgment is made to determine that γ5 exhibits an abnormality or abnormality.

FIG. 8 shows the output characteristics of the γ-ray thermometer when there is a local core power rise abnormality near z5. Even when there is such an output abnormality, according to the above determination algorithm, for example, the output value of γ4 and γ
By looking at the output difference between the output value y5 of γ5 estimated from the output value of 6 and the actually measured value y5 of γ5, it can be seen that γ5 has not detected an abnormality in the output rise, so that γ5 is out of order. Can be determined.

The power of the core changes according to the control rod insertion pattern. When the control rod is inserted, the core power decreases because neutrons are absorbed by the control rod.

FIG. 9A shows the case where the control rod is not inserted (curve C) and the case where the control rod is inserted at 50% (curve C-50) and 75% (curve C-75). 4 shows an example of a change in core power. How much the control rod is inserted can be known from the output of the process instrumentation system 12. Even when the control rod is inserted, for example, FIG.
As can be seen from the γ-ray thermometer γ5 in (b), it is possible to detect an abnormality whose output is shown to be high regardless of the position where the control rod is inserted. Of course, also at the core position above the position where the control rod is inserted, as described above, the γ-ray thermometer calculated from the γ-ray thermometer output other than the γ-ray thermometer under consideration is used. The soundness can be confirmed by comparing the estimated output value with the actual output.

In the above description, linear interpolation of adjacent γ-ray thermometer outputs when obtaining the estimated output value of the γ-ray thermometer has been described. However, the outputs of three or more adjacent γ-ray thermometers are fitted by a curve. It is also possible. As a method of applying a curve, a well-known method such as spline interpolation can be used.

Next, an embodiment for judging the soundness of the γ-ray thermometer using the output of the LPRM will be described. FIG.
Numeral 0 indicates a third embodiment of the reactor power measuring apparatus according to the present invention, and the same reference numerals are used for the same components as those in FIG.

The LPRM measurement system 13 is composed of LPRM-1 to -RM, and sends an LPRM output to the LPRM signal processing unit 106. The LPRM signal processing unit 106 converts the LPRM output obtained from the LPRM measurement system into LPRM data and outputs the LPRM data to the soundness determination unit 101. Of course, the LPRM data, which is the result of the LPRM signal processing unit 106, is sent to a higher-level nuclear instrumentation system and used in various forms. The soundness determination unit 101 compares the local core output obtained from the γ-ray thermometer signal processing unit 102 with the local core output obtained from the LPRM signal processing unit 106 to determine the soundness of each γ-ray thermometer. judge.

In the case of using the γ-ray thermometer, the conventional apparatus performs calibration of the LPRM whose sensitivity has deteriorated based on the local core power calculated from the output of the γ-ray thermometer. On the contrary, this embodiment is characterized in that the soundness of the γ-ray thermometers 11-1 to 11-k is determined from the deterioration of the LPRM. In the embodiment of FIG. 10, the contents of the processing performed by the soundness determination unit 101 will be described below.

As described above, LPRM-1 to LPRM-m
Is degraded over time. The degree of degradation generally depends on how much neutrons have been exposed. FIG.
(A) shows a change with time of deterioration of sensitivity of LPRM. Generally, the sensitivity degradation with respect to time is a monotonically decreasing function, but is shown here by a straight line for ease of explanation. If the sensitivity deterioration exceeds the limit value α, a new LP
Exchanged for RM. L placed in the furnace under the same initial conditions
Even with PRM, the degree of deterioration differs depending on the amount of neutrons exposed. For example, the degree of deterioration is different between the core center where the neutron flux is dense and the upper / bottom part where the neutron flux is sparse, and when the control rod is inserted, the neutrons are absorbed by the control rod and the progress of the deterioration is slow.

If the factors affecting the sensitivity deterioration of the LPRM are recorded temporally, the current LPR can be changed from the initial state.
The degree to which the sensitivity of M has deteriorated can be calculated back. For example, as shown in FIG. 11 (b), the operation is started at time t0, the control rod is inserted at t1, and the sensitivity is degraded by r in the LPRM after the current time t2. If this deterioration is corrected, the core power at the position where the LPRM is arranged can be obtained, although the accuracy of the LPRM is not as good as the initial accuracy.

Thus, the soundness of the γ-ray thermometer can be confirmed by comparing the sensitivity-corrected LPRM output with the output of the γ-ray thermometer arranged near the LPRM. FIG. 12 illustrates this comparison method. LPRM-1 to LPRM-4 are LPRM outputs whose sensitivity has been corrected as described above. Z in this case
The axis is preferably in the core vertical axis direction or radial direction from the relationship between the LPRM arrangement position and the γ-ray thermometer arrangement position. Usually, the number of gamma thermometers installed in the furnace is LPRM
More than the number of. Therefore, the local output calculated based on the output of the γ-ray thermometer and the local output based on the output of the LPRM are, as shown in FIG.
The output from the PRM will be scattered at appropriate intervals.

When there is an LPRM disposed near the position of the γ-ray thermometer under consideration, for example, as shown in the figure, the output y5 of the γ-ray thermometer (γ5) and By comparing the output y5 of LPRM-2, γ
5 malfunctions can be detected.

FIG. 13 shows a fourth embodiment of the present invention. In FIG. 13, the same reference numerals are used for the same components as those described in each of the above-described embodiments, and thus redundant description will be omitted. A process signal processing unit 14 is connected between the process instrumentation system 12 and the soundness determination unit 101. The process signal processing unit 14 processes the process amounts −1 to −n output from the process instrumentation system 12 and outputs the processed process amounts to the soundness determination unit 101. The soundness determination unit 101 obtains a core output based on information from the process signal processing unit 14, and determines the soundness of the γ-ray thermometer by comparing the core output with a measurement value of the γ-ray thermometer.

The total power of the core can be easily calculated from the difference between the enthalpy of the medium such as the coolant flowing into the core and the enthalpy of the medium (coolant) flowing out. In addition,
These enthalpies can also be calculated using the feedwater flow rate, the recirculation flow rate, the coolant temperature, and the like. Now, the total power of the core can also be obtained as the sum of the local powers.

That is, if the total core power obtained from the enthalpy difference and the control rod insertion pattern are known, it is possible to calculate how much local core power is output. The soundness of the γ-ray thermometer can be confirmed by comparing the core power distribution obtained from the enthalpy difference with the local core power using the output of the γ-ray thermometer. FIG. 14 shows a comparison of core power for soundness confirmation used in the embodiment shown in FIG. It will be clear that, by way of example, a malfunction of γ5 can be detected by an algorithm similar to the one described above.

The soundness judgment result display unit 105 simply displays
The γ-ray thermometers 11-1 to 11-k not only indicate “normal”, “abnormal”, etc., but also FIGS. 3, 5, 6, 7, and It is also possible to present graphical information indicating the core output as the basis for the determination as shown in FIG. Of course, a mode in which only numerical information is presented may be used.

The output of the γ-ray thermometer is fetched online and stored in a database, and the output of the γ-ray thermometer obtained online is compared with the corresponding γ-ray thermometer fetched in the past and made into a database. There may be an example in which there is provided a soundness determining means for determining and displaying the soundness of the γ-ray thermometer.

Further, according to the present invention, by combining a plurality of soundness judgment methods of the embodiment described above, soundness judgment with higher reliability becomes possible.

The present invention can be implemented by hardware, software, or
It is also possible to combine both.

[0064]

As described above, according to the present invention, the output allowable range of the γ-ray thermometer is made into a database in association with various process amounts obtained online, and the output of the γ-ray thermometer is stored in the database. Determine the soundness of the γ-ray thermometer by whether it is within the allowable range of, or,
The core power is calculated based on the process value obtained by the process instrumentation system of the reactor equipment, the calculated core power is compared with the output of the γ-ray thermometer, and the soundness of the γ-ray thermometer is determined based on the comparison result. Since the soundness is determined, the soundness of the γ-ray thermometer can be determined with high reliability. Therefore, the sensitivity calibration of LPRM using the output of the γ-ray thermometer, γ
Data processing using a line thermometer can be performed with high reliability.

The present invention is also directed to a reactor power measuring apparatus for measuring the power of a reactor using a plurality of γ-ray thermometers arranged in a directional manner.
Since the output value of the gamma ray thermometer was estimated based on the output of another gamma ray thermometer, and the estimated value was compared with the output of the gamma ray thermometer to determine the soundness, the gamma ray temperature was determined. It is possible to determine the soundness of the meter with high reliability. Further, sensitivity calibration of LPRM using the output of the γ-ray thermometer and highly reliable data processing using the γ-ray thermometer can be performed.

Further, the present invention relates to a reactor power measuring apparatus for measuring the power of a reactor using an LPRM and a γ-ray thermometer, wherein the output value of the γ-ray thermometer is measured in the vicinity of the γ-ray thermometer. Is estimated based on the output of the LPRM disposed in the system, and the estimated value is compared with the output of the γ-ray thermometer to determine the soundness. Can be determined.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of a reactor power measuring apparatus according to the present invention.

FIG. 2 is a circuit diagram showing a specific configuration of a soundness determination unit 101.

FIG. 3 is an explanatory diagram showing a method of setting a γ-ray output range for soundness determination.

FIG. 4 is a block diagram showing a second embodiment of the reactor power measuring apparatus according to the present invention.

FIG. 5 is a γ-ray thermometer output characteristic diagram for explaining a soundness determination method based on time-series data.

FIG. 6 is a graph showing outputs of a plurality of γ-ray thermometers on a specific coordinate system in a furnace at a certain time.

FIG. 7 is a graph showing an example of detecting an abnormal γ-ray thermometer.

FIG. 8 is an output characteristic diagram of a γ-ray thermometer when there is a local core abnormality.

FIG. 9 is an output characteristic diagram showing a change in core power when a control rod is not inserted and when a control rod is inserted.

FIG. 10 is a block diagram showing a third embodiment of the reactor power measuring apparatus according to the present invention.

FIG. 11 is an explanatory diagram for explaining a change with time of the sensitivity deterioration of the LPRM and a sensitivity deterioration after a predetermined time has elapsed.

FIG. 12 shows the local output and LP based on the output of a γ-ray thermometer.
It is explanatory drawing for judging soundness by comparing the local output based on RM output.

FIG. 13 is a block diagram showing a fourth embodiment of the present invention.

FIG. 14 is a graph for explaining a method of determining soundness by comparing with a core power distribution.

[Explanation of symbols]

 Reference Signs List 11 γ-ray temperature measurement system 11-1 to 11-k γ-ray thermometer 12 Process instrumentation system 13 Local core power measurement (LPRM measurement system) 101 Soundness judgment unit 102 γ-ray thermometer signal processing unit 103 γ-ray thermometer Data processing unit 104 Database 105 Soundness determination result display unit 106 LPRM signal processing unit 107 Process signal processing unit LPRM-1 to LPRM-m Local core power meter

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshiyuki Hirayama 5-2-1, Omika-cho, Hitachi City, Ibaraki Prefecture Inside the Omika Plant, Hitachi, Ltd. (72) Inventor Shunsuke Dai 3-chome, Omika-cho, Hitachi City, Ibaraki Prefecture No. 1 Inside Hitachi, Ltd. Hitachi Plant (72) Inventor Yukihisa Fukasawa 3-1-1 Omikacho, Hitachi City, Ibaraki Prefecture Inside Hitachi, Ltd. Hitachi Plant (72) Inventor Masao Miyake Omika, Hitachi City, Ibaraki Prefecture 5-2-1, Machi-cho, Omika Plant, Hitachi, Ltd. (72) Inventor Yuji Yamazawa 4--6, Kanda Surugadai, Chiyoda-ku, Tokyo Hitachi, Ltd.

Claims (14)

[Claims] 1. A reactor power measuring device for measuring the output of a reactor using a gamma ray thermometer, wherein an allowable range of the output of the gamma ray thermometer is stored in a database in association with various process amounts obtained online. Database means, the γ
A reactor power measuring device, comprising: a soundness judging means for judging the soundness of the γ-ray thermometer based on whether or not the output of the ray thermometer is within an allowable range stored in the database means. . 2. The reactor power measuring apparatus according to claim 1, wherein said allowable range is set based on a result of statistically processing sample values of said γ-ray thermometer stored in said database means. . 3. The reactor power measuring apparatus according to claim 1, wherein the process amount is an output of the gamma ray thermometer, a control rod insertion position, a gamma dose, or a neutron flux density. 4. The soundness determination means includes: first comparison means for comparing an output of a gamma ray thermometer to be determined with a threshold value indicating an upper limit value of the set range; Second comparing means for comparing the output of the totaling device with a threshold value indicating the lower limit value of the set range, and the output of the first comparing means and the second comparing means.
2. The reactor power measuring apparatus according to claim 1, further comprising OR logic means for calculating a logical sum with an output of said comparing means. 5. The soundness judging means includes switch means for interrupting application of the output of the γ-ray thermometer to the γ-ray thermometer signal processing section based on the output change of the OR logic means. The reactor power measuring device according to claim 4, wherein 6. The soundness judging means includes a judgment result display unit for judging and displaying soundness of the γ-ray thermometer based on an output change of the OR logic means. Reactor power measurement equipment. 7. A reactor power measuring device for measuring the power of a reactor using a plurality of gamma thermometers arranged in a direction, wherein the output value of the gamma thermometer to be determined for soundness is determined. A reactor power measuring device comprising: a soundness determining unit that estimates based on the output of another γ-ray thermometer and compares the estimated value with the output of the γ-ray thermometer. 8. The γ-ray thermometer, wherein the other γ-ray thermometers are a plurality of γ-ray thermometers disposed on both sides or in the vicinity of the γ-ray thermometer to be judged as soundness. 7. The reactor power measuring device according to 7. 9. A reactor power measuring device for measuring the power of a reactor using a local power detector (LPRM) and a γ-ray thermometer, wherein an output value of the γ-ray thermometer is measured in the vicinity of the γ-ray thermometer. Reactor power measurement, comprising: a soundness determination means for estimating the soundness based on the output of the LPRM disposed in the apparatus and comparing the estimated value with the output of the gamma-ray thermometer. apparatus. 10. The reactor power measuring apparatus according to claim 9, wherein the LPRM used for the estimation is corrected for the deterioration of the sensitivity before the comparison judgment is performed. 11. A reactor power measuring device for measuring the power of a reactor using a gamma ray thermometer, wherein a core power is calculated based on a process value obtained by a process instrumentation system of a reactor facility,
Compare this core power calculation value and the output of the γ-ray thermometer,
A reactor power measuring device comprising a soundness judging means for judging the soundness of the γ-ray thermometer based on the comparison result. 12. The reactor power measuring apparatus according to claim 11, wherein the core power is calculated based on a difference between an enthalpy of a medium flowing into the core and an enthalpy of a medium flowing out of the core. 13. The reactor power measuring apparatus according to claim 12, wherein the medium is a coolant, feed water, or recirculated water. 14. The output of a γ-ray thermometer is fetched online and stored in a database, and the output of the γ-ray thermometer is compared with the corresponding γ-ray thermometer fetched in the past and stored in a database. A nuclear reactor power measuring apparatus, comprising: a soundness determining unit configured to determine and display the soundness of the γ-ray thermometer.