JP5431143B2 - Radiation measurement equipment - Google Patents

Description

  The present invention relates to a radiation measuring apparatus. Specifically, when the background value based on the radiation dose measurement value fluctuates due to a predetermined external factor at the measurement location of the facility, the alarm measurement value (BG × n) based on the BG value fluctuated due to the external factor is preset. The alarm setting value that has been set is compared, and the alarm setting value that is set in advance based on the comparison result is updated according to the fluctuation of the background value.

  In facilities that handle radiation, such as nuclear power plants, hospitals, and universities, radiation measuring devices for measuring the amount of radioactivity (concentration) in the facilities and equipment are installed. The nuclear power plant will be explained as an example. The radiation measuring device installed in the nuclear power plant is a detector (monitor) installed at a measurement location such as water supply, turbine, or central control room, and detection supplied from the detector. It consists of a display that displays the actual dose rate based on the signal, a recorder that constantly records the displayed numerical data, and a controller that analyzes and stores the data as necessary.

  In the control unit of the radiation measuring apparatus configured as described above, as shown in FIG. 7A, the measured value measured by the detector is compared with a preset alarm setting value, and the measured value is set as an alarm setting. It alerts the operator by issuing an alarm when it exceeds the value. The alarm set value is a value (hereinafter referred to as a background (BG value)) obtained from a measured value (for example, past operation data) at a predetermined measurement location of a nuclear power plant multiplied by n (n is a positive real number). The value is defined as “BG × n times”. Further, as shown in FIG. 7 (B), the BG value is defined by a value obtained by averaging measured values of radiation dose when the reactor is rated output and a certain amount of hydrogen is injected into the reactor. Yes.

  By the way, the structural materials and piping of nuclear reactors use corrosion-resistant members, but when heat is applied, a chromium-deficient region is generated along the grain boundary, and high tensile stress is further applied thereto. Even in high-temperature pure water, when the oxygen concentration is high, local corrosion occurs along the crystal grain boundary, which may lead to stress corrosion cracking.

  Therefore, conventionally, in order to cope with stress corrosion cracking, hydrogen injection, in which hydrogen is injected into the reactor water via a water supply system of a boiling water reactor, has been widely performed. For example, Patent Document 1 proposes a hydrogen injection amount control device that measures the quality of the reactor water flowing out from the pressure vessel and injects hydrogen into the water supply system based on this data. Patent Document 2 proposes a hydrogen injection system that controls the injection amount of hydrogen so that the corrosion potential indicating the degree of the corrosive environment of the metal material and the main steam system dose rate are within a predetermined range. According to these hydrogen injections, stress corrosion cracking can be prevented by reducing the concentration of dissolved oxygen and hydrogen peroxide in the reactor water, improving the water quality environment, and lowering the corrosion potential of the primary structural material. Will be able to.

Japanese Patent Publication No. 7-21554 JP-A-9-222495

However, the conventional hydrogen injection as described above has the following problems. That is, when a neutron hits oxygen in the reactor water of the nuclear power plant described above, radioisotope N-16 is generated. This radioactive isotope N-16 becomes a mixture of volatile nitrogen compounds (HNO ₃ , HNO ₂ , NH ₃ , N _{2 and} others) when hydrogen is injected into the nuclear reactor, and nitrogen compounds (NH ₃ etc.) ) Increase, and a part of it moves to the main turbine system and exhaust gas system together with the main steam. As a result, the radiation level of the turbine building or the like increases, and the indicated values of the main steam monitor and exhaust gas system monitor installed in the main turbine and exhaust gas system fluctuate. Therefore, the BG value used when calculating the above-described alarm set value also varies.

  However, as described above, the alarm set value is fixed at a preset value. Therefore, if the BG value fluctuates due to hydrogen injection, the previously set alarm set value “BG” is set. “× n times” is not always satisfied. Accordingly, when the alarm set value is fixed regardless of whether or not the BG value is changed due to hydrogen injection, when the BG value becomes higher due to hydrogen injection, the value of “BG × n times” approaches the alarm set value. Thus, there is a problem that an alarm is inadvertently issued with a slight change in instruction. On the other hand, when the BG value becomes low due to fluctuations in the amount of hydrogen injection, the value of “BG × n times” is in a direction away from the alarm set value, and the “BG × n times” value originally issues an alarm. There is a problem that the alarm does not occur even though the value is a power value.

  In the above description, the case where the radiation dose of the facility in the reactor fluctuates due to hydrogen injection has been described. However, the radiation dose may vary due to other external factors. Of course, it is necessary to update the alarm set value in consideration of external factors.

  Therefore, the present invention has been made in view of the above problems, and its purpose is to be able to update to an accurate alarm set value when the radiation dose fluctuates due to a predetermined external factor in a nuclear power generation facility. Is to provide a simple radiation measurement apparatus.

In order to solve the above problems, the present invention is a radiation measurement apparatus installed at a predetermined measurement location of a facility, and includes a detection unit that measures the radiation dose at the measurement location, and a radiation dose measured by the detection unit. A control unit that determines whether or not a corresponding measurement value exceeds an alarm setting value indicating a criterion for whether or not to issue a preset alarm, and issues an alarm based on the determination result; the provided, the control unit, when the measured value of the radiation amount by the predetermined external factors in the measurement points is changed, acquires the background value from the measured value corresponding to the amount of radiation measured by detection unit, acquired the After calculating an alarm measurement value for determining whether or not the radiation dose is abnormal based on the background value, multiply the background value by n (a positive real number) / m (a positive real number of 2 or more). (Bag ground value x n / m) If the alarm set value is exceeded, the alarm set value is updated so that the alarm set value becomes the alarm measurement value. If the (bag ground value x n / m) value is less than the alarm set value, the alarm set value it is characterized in that no update.

  In the present invention, for example, when an external factor such as hydrogen injection occurs in a nuclear power plant facility, the measurement value of the radiation dose measured by the detector fluctuates, and the background value (hereinafter referred to as the BG value). It also fluctuates. In the radiation measuring apparatus according to the present invention, when a predetermined external factor occurs, the alarm measurement value is compared with a preset alarm set value, and the preset alarm set value is measured based on the comparison result. Update as the value fluctuates.

  As an update method, when the alarm measurement value (BG × n) based on the BG value fluctuated due to an external factor is less than a preset alarm set value, the alarm set value immediately becomes the alarm measurement value. Updated. In addition, the alarm measurement value (BG × n) based on the BG value fluctuated due to an external factor is equal to or greater than the alarm set value, and a value obtained by multiplying the background value by n / m (BG × n / m) is an alarm. When the set value is exceeded, the alarm set value is updated to become the alarm measured value.

  According to the present invention, an alarm measurement value based on a background value that varies due to an external factor is compared with a preset alarm setting value, and the preset alarm setting value is updated based on the comparison result. Accordingly, it is possible to automatically follow the alarm set value in consideration of fluctuations due to external factors, and to issue an alarm based on a more accurate alarm set value. As a result, the safety in the facility can be improved.

It is a figure which shows the block structural example of the radiation measuring device which concerns on the 1st Embodiment of this invention. It is a figure for demonstrating automatic tracking mode (1st process). It is a figure for demonstrating automatic tracking mode (2nd process). It is a flowchart which shows an example of operation | movement of a radiation measuring device. It is a figure for demonstrating the automatic tracking mode with an upper limiter function. It is a flowchart which shows an example of operation | movement of the radiation measuring device which concerns on the 2nd Embodiment of this invention. It is a figure for demonstrating the alarm alerting process of the conventional radiation measuring device.

Hereinafter, the best mode for carrying out the invention (hereinafter referred to as an embodiment) will be described.
<1. First Embodiment>
[Configuration example of radiation measurement equipment]
First, an example of the configuration of the radiation measuring apparatus 100 according to the present invention will be described. The radiation measuring apparatus 100 according to the present invention is applicable to facilities using radiation such as nuclear power plants, hospitals, universities, etc., and external factors such as hydrogen injection performed to prevent the occurrence of applied corrosion cracking. When this occurs, an automatic follow-up mode is provided in which a preset alarm set value is updated in accordance with a measured value that varies due to an external factor. Below, the case where the radiation measuring device 100 which concerns on this invention is applied to a nuclear power station is demonstrated.

  As shown in FIG. 1, the radiation measuring apparatus 100 includes a control unit 10, a display unit 20, a recording unit 22, an alarm unit 24, an operation unit 26, a memory unit 28, a detection unit 30, and an amplification unit 32. Each of the control unit 10, the display unit 20, the recording unit 22, the alarm unit 24, the operation unit 26, the memory unit 28, and the amplification unit 32 is provided in the central control room, and the detection unit 30 performs predetermined measurement of the nuclear power generation facility. It is installed at the location.

  The detection unit 30 includes, for example, a detector (monitor) such as an ionization chamber type, a GM counter type, a scintillation type, and a semiconductor type, and measures (continuously monitors) the radiation dose at the measurement location, and is obtained by measurement. The measured value is supplied to the amplifying unit 32. In this example, the main steam monitor (radiation monitor) installed in the upstream main steam pipe is shown as the detection unit 30 (see FIG. 1). The amplifying unit 32 adjusts the output balance of the measurement values supplied from the detection unit 30 or amplifies the measurement values and supplies them to the control unit 10. A preamplifier may be separately provided on the detection unit 30 side.

  The display unit 20 displays the radiation dose rate at the measurement location of each facility based on the detection signal (measurement value) supplied from the detection unit 30 via the control unit 10. The display method may be digital display or analog display. The recording unit 22 records the radiation dose and the like at the measurement location of each facility during operation based on the detection signal (measured value) supplied from the detection unit 30 via the control unit 10. The recording method may be a paperless type or a paper type for recording on paper by inkjet or the like. An operator deployed in the central control room can check whether there is an abnormality in the radiation dose by periodically checking the indicated value on the display unit 20 and the recorded value on the recording unit 22.

  The alarm unit 24 is configured by a speaker, for example, and issues an alarm in the central control room or the like based on an audio signal supplied from the control unit 10 when the radiation dose exceeds an alarm set value at a predetermined measurement location. That is, when the measured value of the radiation dose is recorded as an abnormal rise, the operator provided in the central control room or the like is alerted by an alarm.

  The operation unit 26 includes, for example, a keyboard and a mouse, and is provided in the vicinity of the display unit 20, the main board of the central control room, and the like. The operation unit 26 performs switching (selection) of the automatic follow-up mode and the fixed mode, operation of each device, and the like. The operation unit 26 generates an operation signal according to a user input operation and supplies the operation signal to the control unit 10. For example, when the radiation amount at the measurement location varies due to external factors such as hydrogen injection and the automatic tracking mode is selected by the user, an operation signal corresponding to the automatic tracking mode is generated and supplied to the control unit 10.

  The memory unit 28 is configured by, for example, a semiconductor memory or an HDD (Hard Disk Drive), and stores measurement data measured by the detection unit 30. For example, as will be described later, an average value obtained by averaging measured values acquired at a predetermined period in the automatic tracking mode is stored.

  The control unit 10 includes a CPU (Central Processing Unit) 12, a ROM (Read Only Member) 14, and a RAM (Random Access Memory) 16. The ROM 14 records various programs for operating the radiation measurement apparatus 100. The RAM 16 temporarily stores and holds data obtained when the CPU 12 performs various processes. The CPU 12 executes a program stored in the ROM 14 and controls each unit so that the radiation measuring apparatus 100 performs a desired operation.

  Further, the control unit 10 executes the fixed mode or the automatic tracking mode based on the operation signal corresponding to the mode selection supplied from the operation unit 26. In the fixed mode, it is determined whether the measurement value according to the radiation dose measured by the detection unit 30 exceeds an alarm setting value indicating a criterion for whether or not to issue a preset alarm, An alarm is issued based on the judgment result. In the automatic tracking mode, the measurement value of the radiation dose is monitored for fluctuation due to external factors such as hydrogen injection at the measurement location, and when the measurement value fluctuation is detected, the measurement corresponding to the radiation dose measured by the detection unit 30 is performed. A BG value is acquired from the value, and an alarm measurement value (BG × n) for determining whether or not the radiation dose is abnormal based on the acquired BG value is calculated. Then, the calculated alarm measurement value is compared with a preset alarm setting value, and the alarm setting value preset based on the comparison result is updated in real time according to the fluctuation of the measurement value.

[Automatic tracking mode]
Next, the automatic tracking mode will be described in detail. As described above, the automatic tracking mode is a (BG × n) value based on the changed BG value and a preset alarm when the radiation dose (BG value) changes due to external factors such as hydrogen injection. In this mode, the fixed alarm set value is updated to a (BG × n) value in accordance with the comparison result with the set value. In this automatic tracking mode, the first process when the BG value after hydrogen injection fluctuates in a direction away from the preset alarm set value, and the BG value after hydrogen injection approaches the preset alarm set value. And a second process in the case of changing in the direction of

First, the first process will be described.
(1) An n value for multiplying the BG value is set in advance. The n value is the same value as the n value used when calculating the alarm set value, and is a coefficient used when determining whether or not the alarm set value serving as a reference for issuing an alarm is exceeded.
(2) The measurement value measured by the detection unit 30 is acquired, for example, at a cycle of 10 seconds, and the acquired measurement value is stored in the memory unit 28 of the control unit 10. The reason for setting the period to 10 seconds is that the time constant is about 10 seconds, and the time constant varies depending on the object to be measured.
(3) Of the latest 40 measured values stored in the memory unit 28, excluding “measured values for 5 times after measuring the maximum value” and “measured values for 5 times after measuring the minimum value” The average value of the acquired 30 measurement values is calculated, and the average value is stored in the memory unit 28 as the BG value. In order to perform accurate measurement (until it decays to the original value), the measurement time of about 5 times the time constant is excluded from the five measurements after measuring the maximum and minimum values. Because it is necessary to remove. Thereby, it is possible to prevent the set value from inadvertently fluctuating with respect to abnormal movement (noise) that changes in a spike shape.
(4) Multiply the set n value by the calculated BG value to calculate a (BG × n) value after hydrogen injection.
(5) When the preset alarm set value exceeds the (BG × n) value calculated in (4) above, the alarm set value is immediately followed automatically and updated to the (BG × n) value. This is because the BG value after the hydrogen injection is lower than the reference BG value set in advance, and accordingly, the (BG × n) value after the hydrogen injection is also lower than the alarm set value. This is because there is a problem that the alarm is not issued even though the set value is reached. For example, as shown in FIG. 2, when the BG value is between point A and point B, the (BG × n) value after hydrogen injection is less than the alarm set value, so the alarm set value immediately after hydrogen injection ( BG × n) value. On the other hand, when the BG value is before point A and after point B, the (BG × n) value after hydrogen injection is equal to or higher than the alarm set value, so that the alarm set value is maintained at a preset value (fixed). To do.
(6) The (BG × n) value is rounded by rounding off the calculation result of the (BG × n) value after hydrogen injection at the decimal point x-th place (the value of x is preset). Thereby, it is possible to reliably satisfy the (BG × n) value while ensuring safety.

Next, the second process will be described.
(1) The method of setting the n value, sampling the measured value, and calculating the BG value and the (BG × n) value are the same as the processes (1) to (4) of the first process described above.
(2) The (BG × n / m) value is calculated by multiplying the BG value after hydrogen injection by n / m. Here, n / m is multiplied by the BG value when the BG value after hydrogen injection is fluctuating upward from a preset reference BG value. This is because the range until the alarm issuance approaches and becomes narrower (because it goes in a harsh direction), so the urgency to immediately follow the alarm set value is low. Note that “m” is a real number equal to or greater than 2, and the update timing of the alarm set value can be made earlier by selecting a large “m”.
(3) When the (BG × n / 2) value exceeds the alarm set value, the alarm set value is updated to a (BG × n) value. For example, as shown in FIG. 3, when “m” is set to 2, when the BG value is between point C and point D, the alarm set value is updated to (BG × n) value, and the BG value is Before C and after point D, the alarm set value is fixed to a preset value.
(4) The (BG × n) value is rounded by rounding off the calculation result of the (BG × n) value after the hydrogen injection at the decimal point x-th place (the value of x is preset). Thereby, it is possible to reliably satisfy the (BG × n) value while ensuring safety.

[Fixed mode]
Next, the fixed mode will be described. The fixed mode is a mode in which the alarm set value is fixed to the initially set value regardless of whether or not the radiation dose varies, and is the same mode as the alarm determination process using the alarm set value of the conventional radiation measuring apparatus 100. is there. This fixed mode is, for example, a monitoring / alarm mode set during normal operation where no external factor such as hydrogen injection occurs.

[Operation example of radiation measurement equipment]
Next, an example of the operation of the radiation measuring apparatus 100 when the user selects the automatic tracking mode when hydrogen is injected into the reactor water via the water supply system of the nuclear power plant will be described. It is assumed that the fixed mode is selected until the automatic tracking mode is selected.

  As shown in FIG. 4, in step S10, the control unit 10 determines whether or not the automatic tracking mode is selected. If it is determined that the automatic tracking mode has been selected, the process proceeds to step S20. If it is determined that the automatic tracking mode has not been selected, normal fixed mode processing is executed.

  In step S <b> 20, the control unit 10 calculates a (BG × n) value based on the actual measurement value during operation measured by the detection unit 30 installed in the nuclear power generation facility. In this example, for example, a BG value is calculated based on a measurement value from the detection unit 30 installed in the upstream main steam pipe, and the value is calculated by multiplying the BG value by n (BG × n). Note that the method of calculating the (BG × n) value is the same process as (1) to (4) of the first process described above. When the (BG × n) value is calculated, the process proceeds to step S30.

  In step S30, the control unit 10 determines whether or not the (BG × n) value after hydrogen injection is less than a preset alarm set value. If it is determined that the (BG × n) value after hydrogen injection is less than the preset alarm set value, the process proceeds to step S40, and the (BG × n) value after hydrogen injection is not less than the preset alarm set value. If it is determined, the process proceeds to step S50.

  If the control unit 10 determines in step S40 that the (BG × n) value after hydrogen injection is less than the preset alarm setting value, the control unit 10 immediately updates the alarm setting value to a (BG × n) value. For example, as shown in FIG. 2, when the (BG × n) value after hydrogen injection is lower than the preset alarm set value, the preset alarm set value becomes the (BG × n) value. Update as follows.

  On the other hand, when it is determined that the (BG × n) value after hydrogen injection is not less than the preset alarm set value, the control unit 10 calculates based on the BG value after hydrogen injection in step S50 (BG × n / 2) Determine whether the value exceeds the alarm set value. If it is determined that the (BG × n / 2) value after hydrogen injection exceeds the alarm set value, the process proceeds to step S60. On the other hand, if it is determined that the (BG × n / 2) value after hydrogen injection does not exceed the alarm set value, it is determined by the monitor that the BG value remains within the normal range even after hydrogen injection. Continue monitoring.

  In step S60, when the control unit 10 determines that the (BG × n / 2) value after hydrogen injection exceeds the alarm set value, the control unit 10 updates the alarm set value to the (BG × n) value after hydrogen injection. . For example, as shown in FIG. 3, when the (BG × n / 2) value exceeds the preset alarm set value, the preset alarm set value is (BG × n) value after hydrogen injection. Update to be

  When such a series of processes in the automatic tracking mode is completed and the fluctuation of the radiation dose due to hydrogen injection is attenuated (stopped), the automatic tracking mode is switched to the fixed mode. And the control part 10 measures the radiation dose of the measurement location in a plant | facility in fixed mode, and continues monitoring whether the (BGxn) value based on this exceeded the alarm setting value.

  As described above, according to the first embodiment, even when the background value fluctuates due to external factors such as hydrogen injection, a (BG × n) value based on the fluctuating background value is set in advance. The alarm setting value that has been set is compared, and the alarm setting value that is set in advance according to the comparison result is automatically followed (updated). As a result, it is possible to reset the alarm setting value to an optimum value in consideration of fluctuations due to external factors, and to issue an alarm more accurately. As a result, the operation of the nuclear power generation facility can be executed more safely.

  In addition, automatic tracking mode and fixed mode can be selected arbitrarily, so even if the measured value (indicated value) rises or falls due to an abnormality in the plant or equipment, the alarm setting can be set by mistake by selecting the fixed mode. Control that values do not follow automatically can be executed. As a result, the nuclear power generation facility can be operated more accurately and safely.

<2. Second Embodiment>
In the second embodiment, an upper limit value is set in the automatic follow-up mode described in the first embodiment, and control is performed so that the alarm set value is automatically updated to be equal to or higher than the upper limit value. In addition, the same code | symbol is attached | subjected to the component which is common in the radiation measuring device 100 demonstrated in 1st Embodiment mentioned above, and detailed description is abbreviate | omitted.

[Automatic tracking mode with limiter function]
The radiation measuring apparatus 100 has an automatic tracking mode with a limiter function. In this automatic tracking mode with a limiter function, the alarm setting value that is updated according to the change in radiation dose due to external factors is updated within the normal range (within an allowable range that does not cause a safety problem). The upper limiter value is provided separately from the alarm set value. For example, as shown in FIG. 5, when the (BG × n / 2) value after hydrogen injection exceeds the alarm set value, the alarm set value is automatically updated to the (BG × n) value after hydrogen injection. . However, in the present embodiment, since the upper limit value is preset, the BG value is not updated to (BG × n) between point E and point F, but is limited (changed) to the upper limit value. Is done. On the other hand, when the BG value is from point C to point E and from point F to point D, the (BG × n) value after hydrogen injection is less than the upper limit value, so that (BG × n) value as described above. Updated to

[Operation example of radiation measurement equipment]
Next, an example of the operation of the radiation measuring apparatus 100 when the automatic follow-up mode is selected when hydrogen is injected into the reactor water through the water supply system of the nuclear power plant will be described. In the second embodiment, the processing from step S100 to step S140 shown in FIG. 6 is the same as the processing from step S10 to step S50 shown in FIG. 4 described in the first embodiment. Therefore, the description is simplified. As shown in FIG. 6, in step S100, the control unit 10 determines whether or not the automatic tracking mode is selected. If it is determined that the automatic tracking mode has been selected, the process proceeds to step S110. If it is determined that the automatic tracking mode has not been selected, normal fixed mode processing is executed.

  In step S110, the control unit 10 calculates a (BG × n) value based on the actual measurement value during operation from the detection unit 30 installed in the nuclear power plant facility.

  In step S120, the control unit 10 determines whether the (BG × n) value after hydrogen injection is less than a preset alarm set value. If it is determined that the (BG × n) value after hydrogen injection is less than the preset alarm set value, the process proceeds to step S130, and the (BG × n) value after hydrogen injection is not less than the preset alarm set value. If it is determined, the process proceeds to step S140.

  In step S130, when the control unit 10 determines that the (BG × n) value after hydrogen injection is less than the preset alarm set value, the control unit 10 immediately updates the alarm set value to the (BG × n) value.

  On the other hand, when it is determined that the (BG × n) value after hydrogen injection is not less than the preset alarm set value, the control unit 10 calculates (BG × n / n) based on the BG value after hydrogen injection in step S140. 2) Determine whether the value exceeds the alarm set value. If it is determined that the (BG × n / 2) value after hydrogen injection exceeds the alarm set value, the process proceeds to step S150. On the other hand, if it is determined that the (BG × n / 2) value after hydrogen injection does not exceed the alarm set value, it is determined by the monitor that the BG value remains within the normal range even after hydrogen injection. Continue monitoring.

  In step S150, when the control unit 10 determines that the (BG × n / 2) value after hydrogen injection exceeds the alarm set value, the (BG × n) value after hydrogen injection is a preset upper limiter. Determine whether the value is exceeded. When it is determined that the (BG × n) value exceeds the upper limit value, the process proceeds to step S160, and when it is determined that the (BG × n) value does not exceed the preset upper limit value, the process proceeds to step S170. move on.

  If the control unit 10 determines in step S160 that the (BG × n) value exceeds the upper limit value, the alarm setting value is updated to the upper limit value. For example, as shown in FIG. 5, since the (BG × n) value exceeds the preset alarm set value between the point E and the point F of the BG value, the alarm set value is limited to the upper limit value. To do.

  On the other hand, when the control unit 10 determines in step S170 that the (BG × n) value does not exceed the upper limit value, the alarm setting value is updated to the (BG × n) value. For example, as shown in FIG. 5, since the (BG × n) value is less than the upper limit value between point C to point E and point F to point D of the BG value, the alarm set value is set to (BG Xn) Update to value.

  As described above, according to the present embodiment, by providing the upper limit value, the alarm set value can be automatically followed within an appropriate range, and the safety can be further improved.

  It should be noted that the technical scope of the present invention is not limited to the above-described embodiments, and includes those in which various modifications are made to the above-described embodiments without departing from the spirit of the present invention. For example, in the first embodiment described above, two modes of the automatic follow-up mode and the fixed mode are provided so that the user can select one of the modes according to the occurrence of an external factor. It is not limited to this. For example, a configuration in which only the automatic tracking mode is provided may be adopted.

DESCRIPTION OF SYMBOLS 10 ... Control part, 20 ... Display part, 22 ... Recording part, 24 ... Alarm part, 26 ... Memory part, 30 ... Detection part, 100 ... Radiation measuring device

Claims (4)

A radiation measurement device installed at a predetermined measurement location of a facility,
A detector for measuring the radiation dose at the measurement location;
It is determined whether or not the measurement value according to the radiation dose measured by the detection unit exceeds a preset alarm value indicating whether or not to issue a preset alarm, and the determination result And a control unit that issues an alarm based on
The controller is
If the measured value of the radiation amount by the predetermined external factors in the measuring position is changed, it acquires the background value from the measured value corresponding to the measured radiation dose by the detection unit, based on the background values obtained After calculating an alarm measurement value for determining whether or not the radiation dose is abnormal , the background value is multiplied by n (a positive real number) / m (a positive real number of 2 or more) (bag) When the ground value × n / m) value exceeds the alarm set value, the alarm set value is updated so that the alarm set value becomes the alarm measurement value, and the (bag ground value × n / m) value The radiation measuring apparatus is characterized in that the alarm setting value is not updated when is less than the alarm setting value . The controller is
The alarm setting value is updated so that the alarm setting value becomes the alarm measurement value when the alarm measurement value based on the background value changed by a predetermined external factor is less than the alarm setting value; The radiation measuring apparatus according to claim 1 , wherein The controller is
A limiter value for limiting the alarm set value within an allowable range is provided, and it is determined whether the alarm measurement value exceeds the limiter value, and the alarm measurement value exceeds the limiter value according to the determination result. when it is determined that there radiation measuring device according to claim 1 or 2, characterized in that updating the alarm set value to the limiter value. The alarm setting value determined by the control unit is a value obtained by multiplying the background value obtained by past operation data at the measurement location of the facility and n (n is a positive real number),
4. The alarm measurement value is a value obtained by multiplying a background value during actual operation of the facility by n (n is a positive real number) . The radiation measuring apparatus according to one item .

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