JPH1039083A - In-furnace information monitoring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an in-furnace information monitoring apparatus by which the measuring accuracy of information on a state inside a nuclear reactor is enhanced and by which the maintenance and inspection of various apparatuses inside a reactor containment vessel is performed easily. SOLUTION: An in-furnace information monitoring apparatus is provided with a stainless steel rod 15 as a heating element which generates heat by gamma rays, with a thermocouple 14 which detects the temperature of the stainless steel rod 15, with a heat insulating material 16 which is fitted to the stainless steel rod 15 and in which argon is sealed, with a cooling flow passage 17 which is installed between the stainless steel rod 15 and the heat insulating material 16 so as to cool the stainless steel rod 15, with a gamma-ray heating evaluation device 19 which evaluates a gamma-ray amount in the position of the stainless steel rod 15 and with a flow-velocity evaluation device 20 by which the flow velocity of cooling water around the stainless steel rod 15 is measured on the basis of the detection output of the thermocouple 14 and that of the gamma-ray heating evaluation device 19.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-reactor information monitoring apparatus for monitoring state information such as a water level, a pressure, a flow rate, a void ratio or a power distribution in a reactor pressure vessel of a boiling water reactor (BWR). It is about.

[0002]

2. Description of the Related Art In a boiling water nuclear power plant, water as a coolant is boiled in a reactor pressure vessel, and the steam is used to directly turn a turbine to generate power.
Since this coolant has a function of cooling the fuel, the reactor is to be shut down when the water level decreases or when the flow rate decreases. In addition, since the pressure in the furnace also affects the temperature of the boiling water, if an abnormality occurs in the furnace pressure, measures such as shutting down the reactor are performed.

[0003] As described above, monitoring of the information inside the reactor of the nuclear reactor is an important item for safely operating the nuclear reactor, and it is necessary to perform monitoring by various methods. However, since the environment in the furnace is a high radiation field, it is difficult to stably operate a normal process sensor. Therefore, it is common to connect a pipe to the reactor pressure vessel, guide the coolant outside the reactor, and monitor a process amount equivalent to this information outside the reactor.

FIG. 13 schematically shows a conventional monitoring device for performing water level measurement. Reactor pressure vessel 1
The inside is filled with water (hereinafter referred to as cooling water) 3 as a coolant for cooling the core 2, and the cooling water 3 boils due to heat generation of the core 2 to become steam 4. The water level of the cooling water 3 needs to be higher than the core 2 for the purpose of reliably performing the cooling function of the core 2. Conventionally, in order to measure this water level, the pressure at each position is guided outside the furnace by a high pressure pipe 5 and a low pressure pipe 6 from the upper and lower positions of the pressure vessel 1, and the differential pressure is measured by a differential pressure gauge 7 installed outside the furnace. doing. Regarding the flow rate and the pressure, the pipes are connected to the pressure vessel 1 and the process amounts thereof are measured using a sensor installed outside the furnace.

[0005]

The in-furnace information monitoring apparatus having the above-described structure has various problems since a pipe is connected to the pressure vessel 1. For example, in the case of water level measurement, it is necessary to frequently perform maintenance and inspection of these pipes in consideration of the possibility of breakage of the low-pressure pipe 6 to confirm that there is no corrosion or the like. In addition, these pipes complicate the arrangement of pipes in the containment vessel, and make it difficult to perform maintenance, inspection, and the like of other equipment during operation of the reactor.

On the other hand, various means have been developed as means for monitoring furnace information by installing sensors in the furnace, and there are various known examples.

[0007] For example, regarding the flow velocity, "Two-Phase Flow-
Monitoring by Analysis ofln-core Neutorn Detector
Noise Signals-A Literature Survey ", AJCStekel
enburg, Ann. Nucl. Energy, Vol. 20, No. 9, pp. 611-21, 1993
(Reference 1) is known. The technique of this document 1 measures the flow velocity between the fluctuations of a pair of neutron sensors installed in the axial direction in the furnace,
Since the correlation is used, there is a problem that accuracy is low and that only an average value between two sensors can be known.

Regarding the water level, US Pat. No. 5,111,904 "I
n-vessel water level monitor forboiling water reac
tors "(US Patent 1) and" Application of Radi
calgamma thermometer Assemblies for Coolant Monito
ring in Ringhals W- PWRs. ", Smith, RD, SKI-B-36-82
(1982) (Reference 2). All of these use a thermocouple, but in the technique of U.S. Pat. No. 1, there is a problem that the value changes depending on the reactor output because the monitoring is performed based on the temperature of the thermocouple. Further, in the technique of Document 2, the sensor signal changes only when the water level comes to the sensor position, but there is a problem that it is impossible to distinguish when the water level is above or below the sensor.

Regarding the void fraction, "The use of Gamma
Thermometer as a MultipurposeSensor ", V. Tosi et al.
(Reference 3) and "A Void Detection System ForBWR
There are known examples such as S ", Lionel Banda (Reference 4). Reference 3
The technology disclosed in Patent Document 4 uses a sensor that measures the heat generated by gamma rays, and measures the void fraction based on fluctuations in the sensor output. The technology described in Document 4 uses a gamma ray detector and a neutron detector, and calculates the ratio based on the respective ratios. It measures the void fraction.

US Pat. No. 5,225,149 entitled "Detection of core thermal hydrau"
There is a known example of "lic oscillations" (U.S. Patent No. 2). In the technology of U.S. Patent No. 2, a neutron sensor and a gamma sensor are used to monitor the void fraction, and a minute vibration of the reactor output is detected based on the change. Things.

Since neutron and gamma ray intensity information in the reactor is the most important information in the reactor, a neutron detector such as a fission counter or a gamma ray detector is inserted into the reactor even at present. And make direct measurements. However, because of the high radiation intensity inside the furnace, most of them are pulled out of the furnace or replaced after a few years of use, and a more reliable in-furnace sensor is desired.

The present invention has been made in view of the above-described circumstances, and aims to improve the accuracy of measuring the state information in the reactor, reduce the number of pipes from the reactor pressure vessel, and further reduce the number of pipes in the containment vessel. It is an object of the present invention to provide an in-furnace information monitoring device that facilitates arrangement of various devices and facilitates maintenance and inspection of those devices.

[0013]

According to a first aspect of the present invention, there is provided an in-reactor information monitoring apparatus which is installed in a reactor core of a nuclear reactor and generates heat by gamma rays, and is attached to the heating element. A thermocouple for temperature detection, and a heat insulator disposed around the heating element to suppress heat release to the surroundings,
A cooling path formed between the heating element and the heat insulating body to allow the cooling of the heating section by flowing a coolant having a flow rate dependent on the ambient flow rate, and the position of the heating element based on the radiation detection of the core. A gamma ray heat generation evaluation device for evaluating a gamma dose, and a flow velocity evaluation device for taking in detection outputs of the thermocouple and the gamma ray heat generation evaluation device and measuring a flow velocity of cooling water around a heating element based on these detection outputs. It is characterized by.

In the present invention, the heating element generates heat due to gamma rays in the furnace, and is insulated by the surrounding heat insulator to be heated to a high temperature. This heat is cooled by a cooling path provided between the heat insulator and the heating element at a rate depending on the flow velocity flowing through the cooling pipe. Then, the flow rate in the furnace can be measured by comparing the calorific value of the gamma ray evaluated by the gamma ray heat generation evaluation device with the temperature measured by the thermocouple. In addition, since the sensor is constituted only by the thermocouple and the sensor structural material installed in the furnace, the flow rate of the cooling water in the furnace can be directly and stably measured.

According to a second aspect of the present invention, in the in-furnace information monitoring apparatus, the gamma ray heat generation evaluation apparatus evaluates the amount of gamma ray heat generation at the position of the heating element by calculation correction using the output of a radiation detector installed inside or outside the reactor. It is characterized by that.

In the present invention, the output of the radiation detector installed in the reactor pressure vessel or outside the reactor pressure vessel is used to calculate and correct the gamma ray heat generation at the position where the heating element is installed in the reactor. The quantity can be evaluated.

According to a third aspect of the present invention, there is provided an in-furnace information monitoring apparatus, comprising: a heating element which is installed in a reactor core of a nuclear reactor and generates heat by gamma rays; A pair of heat insulators, and a cooling path formed between the heat generator and one of the heat insulators to cool a heat generating portion by flowing a coolant having a flow rate dependent on an ambient flow rate; A first thermocouple for detecting a temperature of a portion of the heat generating body that is in contact with the heat insulating body and the cooling path, and a temperature of a portion of the heat generating body that is in contact with the heat insulating body and not in contact with the cooling path; The detection outputs of the second thermocouple and the first and second thermocouples are fetched, and the temperature difference between the two temperature measurement sites of the heating element stored in advance and the flow rate of the cooling water around the heating element are stored. With reference to characteristic data indicating the relationship between And having a flow rate evaluation device for measuring the flow rate of the cooling water in.

In the present invention, the cooling effect of the cooling pipe, ie, the flow velocity in the furnace, is measured by comparing the temperature of the heating element without the cooling pipe with the temperature of the heating element with the cooling pipe. can do.

According to a fourth aspect of the present invention, there is provided an in-furnace information monitoring apparatus in which a thermocouple having two contacts is provided in place of the thermocouple according to the third aspect, and one of the contacts is connected to a heat insulator and a cooling path. The temperature measuring device is characterized in that it is disposed at a portion for measuring the temperature of a heating element that is present, the other contact is in contact with a heat insulator, and is disposed at a portion for measuring the temperature of the heating element that is not in contact with a cooling passage.

In the present invention, the output of the thermocouple can be directly obtained as an output depending on the flow velocity flowing through the cooling pipe.

According to a fifth aspect of the present invention, the in-furnace information monitoring apparatus is characterized in that it has a heater portion which is in contact with the heating element which generates heat by gamma rays and generates heat by electricity.

In the present invention, even when the reactor power is low and the amount of generated gamma rays is small, the flow velocity can be measured by utilizing the heat generated by the heater.

According to a sixth aspect of the present invention, there is provided an in-furnace information monitoring apparatus, comprising: a heating element which is installed in a reactor core of a nuclear reactor and generates heat by gamma rays; a thermocouple for temperature detection attached to the heating element;
A heat insulator connected to the heating element, the heat insulation effect of which changes according to the ambient pressure, based on the detection output of the thermocouple reflecting the furnace pressure by changing the heat insulation effect of the heat insulator according to the furnace pressure. A pressure evaluation device for measuring the pressure in the furnace.

In the present invention, when the temperature of the heating element changes due to the pressure, the temperature is measured by a thermocouple by utilizing the fact that the heat insulation effect varies depending on the pressure. The gamma ray evaluated by a gamma ray heat generation evaluation apparatus is used. The pressure in the furnace can be directly measured from the difference between the calorific value and the calorific value measured by the thermocouple.

According to a seventh aspect of the present invention, there is provided an in-furnace information monitoring apparatus, comprising: a heating element which is installed in a reactor core of a nuclear reactor and generates heat by gamma rays; a first heat insulator whose heat insulation effect changes according to ambient pressure; A second heat insulator whose heat insulation effect does not change accordingly, a first thermocouple for detecting a temperature of a portion of the heating element insulated by the first heat insulator, and a second heat insulator which is insulated by the second heat insulator A second thermocouple for detecting the temperature of the heating element portion, and a furnace based on the difference in the heat insulation effect of the first and second heat insulators with respect to the ambient pressure by taking in the detection outputs of the first and second thermocouples. A pressure evaluator for measuring a furnace pressure based on a temperature difference between two temperature measuring portions of the heating element obtained from detection outputs of the first and second thermocouples reflecting internal pressure. Features.

In the present invention, the temperature of the heating element surrounded by the pressure change heat insulator whose heat insulation effect changes depending on the pressure;
The temperature of the heating element surrounded by the heat insulator whose heat insulation effect does not change with pressure is measured by each thermocouple, and the furnace pressure can be measured based on the difference.

[0027] In the in-furnace information monitoring apparatus according to the eighth aspect, the heat insulator whose heat insulating effect changes according to the ambient pressure has a cavity inside, and the volume of the hollow portion changes due to the external pressure. The thermal conductivity changes with pressure.

The in-furnace information monitoring apparatus according to a ninth aspect of the present invention is characterized in that the in-furnace information monitoring device has a heater section which generates heat by electricity at a position in contact with a heating element which generates heat by gamma rays.

In the present invention, even when the amount of heat generated by the gamma ray is small and the output of the reactor is low, the pressure in the reactor can be measured by using the heat generated by the heater.

According to a tenth aspect of the present invention, there is provided an in-furnace information monitoring apparatus, wherein a heating element which is installed in a reactor core and which generates heat by gamma rays, a thermocouple for temperature detection attached to the heating element, A heat insulator disposed around and suppressing heat release to the surroundings, a DC measuring device for measuring a DC component of the output of the thermocouple, and an AC measuring device for measuring an AC component of the output of the thermocouple, A water level evaluation device for evaluating a water level of the cooling water in the furnace from measurement results of the DC measurement device and the AC measurement device.

In the present invention, in the sensor described in the above-mentioned known document 2, the difference in signal fluctuation between when the sensor is immersed in the cooling water and when the sensor is not immersed is monitored by an AC measuring device. Thereby, the position of the water level with respect to the sensor can be determined. That is, when a sensor is present in water, the sensor output fluctuates greatly due to the effect of voids in the water, but the fluctuation of the signal is reduced in the atmosphere.

An in-furnace information monitoring apparatus according to an eleventh aspect is characterized in that a heater portion that generates heat by electricity is provided inside the heating element that generates heat by gamma rays.

In the present invention, even when the amount of heat generated by the gamma ray is small and the output of the reactor is low, the pressure in the reactor can be measured by using the heat generated by the heater.

According to a twelfth aspect of the present invention, there is provided an in-furnace information monitoring apparatus, comprising: a heating element installed in a reactor core of a nuclear reactor and generating heat by gamma rays; a thermocouple for temperature detection attached to the heating element; A heat insulator that is disposed around and suppresses heat release to the surroundings; a first thermocouple that detects the temperature of the portion of the heating element that is heated by the heat insulating effect of the heat insulator; and a heat insulator that is not insulated by the heat insulator A second thermocouple for detecting a temperature of the heating element, a gamma ray change monitoring device for monitoring a change in a difference between detection outputs of the first and second thermocouples, and a first and second thermocouple. A corrector that corrects the change in the detection output with a parameter that depends on the structure of the heating element and the heat insulator, a neutron monitoring device that measures a neutron component in the furnace, and the outputs of the neutron monitoring device and the corrector are captured. Monitor changes in output ratio And having a that output change monitoring device.

In the void fraction estimating method described in the above-mentioned reference 3, the void fraction is evaluated using a high-speed neutron detector and a gamma ray detector. By taking advantage of the fact that the time response characteristics with respect to the output of neutron measurement are greatly different by measuring in the above manner, the rising portion of the thermocouple output is detected, and the rising portion is corrected by a corrector to obtain the void ratio in Reference 3. The estimation method can be applied. ADVANTAGE OF THE INVENTION According to this invention, the structure of the gamma ray sensor inserted in a furnace can be simplified, and the reliability can be improved compared with the technique described in the literature 3.

According to a thirteenth aspect of the present invention, there is provided an in-furnace information monitoring apparatus, comprising: a heating element which is installed in a reactor core and which generates heat by gamma rays; and a heat insulator which is disposed around the heating element and suppresses heat release to the surroundings. And a first thermocouple for detecting a temperature of a portion of the heating element which is heated to a high temperature due to a heat insulating effect of the heat insulating body;
A second thermocouple for detecting a temperature of a portion in direct contact with water in the furnace, a gamma ray evaluator for evaluating an average gamma ray flux from detection outputs of the first and second thermocouples, and a neutron in the furnace A neutron evaluator that removes a gamma ray component obtained from the gamma ray evaluator as a noise component from the component and extracts only a neutron component.

In the present invention, it is possible to correct the gamma ray component measured by the neutron monitoring device by using the gamma ray intensity obtained by measuring the calorific value of the gamma ray with a thermocouple, whereby the neutron component can be corrected. A small signal can be detected.

According to a fourteenth aspect of the present invention, there is provided the in-furnace information monitoring apparatus, wherein the heating element is provided in the reactor core and generates heat by gamma rays, a thermocouple for temperature detection attached to the heating element, A sensor part is constituted by a heat insulator which is disposed around and suppresses heat release to the surroundings, a plurality of the sensor parts are arranged in a core axis direction in the furnace, and the inside of the furnace is determined based on a thermocouple output of each sensor part. An axial gamma ray distribution monitoring device that stores an axial power distribution, and a normal value of the power distribution shape and a power distribution shape that appears when the reactor is abnormal are stored in advance, and the output of the axial gamma ray distribution monitoring device is stored. And an abnormality detector for detecting an abnormality of the reactor by using the abnormality detector.

In the present invention, by applying each sensor unit as a gamma thermometer, the gamma ray distribution in the axial direction is measured, and the shape of the output distribution in the axial direction is monitored, so that when the control rod is pulled out. , Early detection of abnormal axial power distribution that causes thermo-hydraulic output vibration that is likely to occur when the recirculation pump trips, and based on the detection result, it is possible to perform operations that do not cause output vibration Becomes

The in-furnace information monitoring apparatus according to a fifteenth aspect, wherein the abnormality comparator evaluates a rate of change from a past output distribution using an output of the axial gamma ray distribution monitoring apparatus, and evaluates the rate of change from the rate of change. It is characterized by detecting an abnormality.

In the present invention, when the control rod is pulled out,
Anomalous output in the axial direction, which may cause thermal hydraulic output vibration that is likely to occur when the recirculation pump is tripped, is detected early by predicting from the change rate, and operations that do not cause output vibration are performed early. Can be performed.

The in-furnace information monitoring device according to claim 16, wherein the abnormality comparator evaluates a rate of change from a past power distribution in the furnace by using an output of the axial gamma ray distribution monitoring device. The rate of change is corrected by a prediction filter determined from the structure of the heating element, the heat insulator, and the thermocouple, a current power distribution of gamma rays in the furnace is estimated, and an abnormality is detected from the estimated value.

In the present invention, the thermal response of the gamma thermometer is corrected by the prediction filter and the speed is increased, so that the accurate value of the gamma ray distribution can be predicted at an early stage, and the abnormal output in the axial direction can be detected at an early stage. Thus, an operation that does not cause output vibration can be performed early.

[0044]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a furnace information monitoring apparatus according to the present invention will be described below with reference to the drawings. The following embodiment is applied to a boiling water reactor.

[First Embodiment] (FIGS. 1 to 3) FIG. 1 is a system configuration diagram showing an in-furnace information monitoring apparatus according to the present embodiment, and FIG. 2 (A) shows the inside of the furnace shown in FIG. FIG. 3B is an enlarged view showing a structure of a temperature measuring portion in the information monitoring apparatus, and FIG. FIG. 3 is an explanatory view showing the temperature distribution of the thermometer and the measurement principle of the flow rate of the cooling water in the furnace.

As shown in FIG. 1, the in-furnace information monitoring apparatus of the present embodiment is basically provided in a reactor core 12 with a stainless steel rod 15 as a heating element that generates heat by gamma rays, and is attached to the stainless steel rod 15. A thermocouple 14 for detecting the temperature, a heat insulator 16 disposed around the stainless steel bar 15 for suppressing heat release to the surroundings, and formed between the stainless steel bar 15 and the heat insulator 16 depending on the ambient flow rate. A cooling path 17 for cooling the heat generating portion by flowing cooling water 13 at a flow rate; a gamma ray heat generation evaluating device 19 for evaluating the gamma dose at the stainless steel bar 15 based on radiation detection of the core; and a thermocouple 14 And a flow velocity evaluation device 20 which takes in the detection outputs of the gamma ray heat generation evaluation device 19 and measures the flow velocity of the cooling water 13 around the stainless steel rod 15 based on these detection outputs. That. The gamma ray heat generation evaluation device 20
The output of a neutron detector 18 which is a radiation detector installed in the reactor core 12 is used to evaluate the calorific value of the gamma ray at the position of the stainless steel rod 15 by calculation correction.

More specifically, as shown in FIG. 1, a reactor core 12 composed of fuel rods (not shown) is provided inside a reactor pressure vessel 11, and a cooling water 1 for cooling the reactor core 12 is provided.
3 circulates. In the core 12, a stainless steel rod 15 having a contact of a chromel-alumel thermocouple 14 provided therein is inserted vertically. A cylindrical heat insulator 16 filled with argon gas is mounted around the upper end of the stainless steel rod 15. A cooling channel 17 for cooling the stainless steel rod 15 is formed between the stainless steel rod 15 and the heat insulator 16. That is, FIG.
As shown in (B), the heat insulator 16 is made of a stainless steel rod 15.
It is configured in a cylindrical shape as a stainless steel tube that wraps the
An argon gas 16b is accommodated therein, and a cooling channel 17 is provided on the stainless steel rod 15 side.

Next, the operation of the present embodiment will be described. In this embodiment, the output of the neutron detector 18 inserted into the reactor core 12 for monitoring the output of the reactor is input to the gamma ray
To evaluate the calorific value. In addition, it can also be estimated from the thermal output of the reactor, neutrons outside the reactor, gamma ray sensors, outputs of thermocouples and the like. The gamma ray heat generation evaluation result and the output of the thermocouple 14 are input to the flow velocity evaluation device 20. The stainless steel bar 15 is heated by gamma rays in the furnace and is insulated from the surrounding cooling water 13 by the heat insulator 16, so that the temperature becomes high. Assuming that the normal reactor water temperature is 285 ° C, the temperature varies to about 330 ° C due to gamma ray heat generation, although it depends on the intensity of gamma rays and the structure of the heat insulator.

FIG. 3 shows the axial temperature distribution at the center of the stainless steel bar 15. Since the thermocouple 14 is disposed substantially at the center of the heat insulator 16, it is possible to measure the highest temperature. However, a cooling channel 17 is provided between the heat insulator 16 and the stainless steel rod 15, and the stainless steel rod 15 is cooled depending on the surrounding flow rate. I do.

The curve P in FIG. 3 is the axial temperature distribution at the center position of the stainless steel bar 15 when the cooling channel 17 is not provided, and the curve Q in FIG. It is a temperature distribution in the axial direction at the center position of the stainless steel bar 15 when provided.

The temperature evaluation of the thermocouple position in the stainless steel bar 15 in the case where the cooling flow path 17 is not provided is performed by using the output of the neutron detector 18 in the reactor core 12 by using the output of the neutron detector 18 in the sensor position. It is done by evaluating. The flow velocity evaluation device 20 compares the evaluation result calculated from the calorific value of the gamma ray with the output of the thermocouple 4 cooled by the cooling flow path 17 to obtain the cooling flow path 1.
The flow rate in the cooling water 7 is determined, and the flow rate of the surrounding cooling water 13 can be evaluated.

As described above, according to the present embodiment, by inserting a sensor having a simple structure combining the stainless steel bar 15 and the thermocouple 14 into the furnace, it is possible to measure the flow velocity stably in the furnace. It becomes possible. In addition, since the measurement can be performed directly, the measurement speed can be improved as compared with the conventional flow velocity measurement outside the furnace. Further, since the number of sensors provided outside the reactor can be reduced, maintenance outside the reactor pressure vessel can be easily performed.

[Second Embodiment] (FIGS. 4 and 5) The in-reactor information monitoring apparatus of the present embodiment monitors the flow rate of cooling water in a nuclear reactor. FIG. 4 is a system configuration diagram showing the in-furnace information monitoring apparatus according to the present embodiment, and FIG. 5 is a flow rate of cooling water in the furnace monitored by the in-furnace information monitoring apparatus shown in FIG. 4 and detected by a differential thermocouple. FIG. 4 is a characteristic diagram showing a relationship with a temperature difference.

As shown in FIG. 4, in this embodiment, a stainless steel rod 15 as a heating element which is installed in the reactor core 12 and generates heat by gamma rays is basically provided at different positions around the stainless steel rod 15. A heat insulating body 16 (16c, 16d) for suppressing heat release to the surroundings, and a stainless steel rod 1
5 and one of the heat insulators 16d, a cooling flow path 17 for flowing the cooling water 13 at a flow rate depending on the surrounding flow rate to cool the heat generating portion, and two contact points 14a and 14
b, one contact 14a is arranged at a portion for measuring the temperature of the stainless steel rod 15 in contact with the other heat insulator 16d and the cooling channel 17, and the other contact 14b is connected to one heat insulator 1
6c in contact with the thermocouple 14.

In this embodiment, each contact 14a, 1
4b, the detected output is taken in, and reference is made to characteristic data indicating the relationship between the previously stored temperature difference between the two temperature measurement sites of the stainless steel rod 15 and the flow rate of the cooling water 13 around the stainless steel rod 15, The configuration includes a flow velocity evaluation device 20 that measures the flow velocity of the cooling water 13 around the stainless steel rod 15. In addition, it has a heater 21 that contacts the stainless steel bar 15 that generates heat by gamma rays and generates heat by electricity.

More specifically, as shown in FIG. 4, a stainless steel rod 15 that generates heat by gamma rays is provided with a heater 21 that generates heat by electricity and a thermocouple 14.
Has a high contact 14a and a low contact 14b. For example, when a chromel-alumel thermocouple is applied as the thermocouple 14, a differential thermocouple that is connected in the order of chromel, alumel, and chromel and that outputs a temperature difference at a contact point of the two chromel alumels is applied. Stainless steel rod 1 including high contact 14a and low contact 14b of thermocouple
5, around a pair of heat insulators 16c and 16d
Is attached, and the cooling passage 17 is provided only in one heat insulator 16d.
Is provided.

The configuration is not limited to this, and a configuration using two sets of thermocouples may be used. That is, the first thermocouple is a thermocouple attached to a stainless steel bar and detects the temperature of the portion of the stainless steel bar 15 where the heat insulator 16 and the cooling channel 17 are in contact, and the second thermocouple is connected to the heat insulator. And cooling channel 1
This is a thermocouple for detecting the temperature of the stainless steel bar 15 not in contact with 7. In addition to the thermocouple, a configuration for obtaining a temperature difference between two points, such as using a speed difference of an ultrasonic wave, may be applied. This temperature difference is determined by the flow rate evaluation device 2
Input to 0.

Next, the operation of the present embodiment will be described. In the above configuration, substantially the same heat insulators 16c and 16d
Are wound around the stainless steel bar 15 in the same state, so that the heat generated by gamma rays and the heat insulating effect can be obtained in substantially the same manner in the portion of the stainless steel bar 15 surrounded by the heat insulators 16c and 16d. Then, due to the cooling effect of the cooling channel 17 provided in the heat insulator 16d, the high contact point 1 of the thermocouple 14 is formed.
A temperature difference occurs in a portion of the stainless steel bar 15 around the low contact 4b and the low contact 14b. This temperature difference is measured as a temperature difference between the high contact point 14a and the low contact point 14b of the differential thermocouple 14, and is converted into a flow velocity in the flow velocity evaluation device 20.

When the power of the reactor is low, the gamma ray intensity is weak, so the calorific value of the gamma ray is small, and this temperature difference may not be generated. In this case, the stainless steel rod 15 is provided by the heater 21 built in the stainless steel rod 15. 15 can be heated and similar measurements can be made. If the flow rate can be evaluated by another measuring instrument, the failure of the sensor unit can be diagnosed by evaluating the response due to the heating of the heater 21.

FIG. 5 shows an example of the output characteristic of the differential thermocouple with respect to the flow rate of the cooling water 13 around the stainless steel rod 15 when using the heater heating. By storing the relationship between the flow velocity and the temperature difference between the differential thermocouples in the flow velocity evaluation device 20, the temperature difference measured by the thermocouple can be converted into the flow velocity.

According to the above-described second embodiment, it is not necessary to evaluate the calorific value of gamma rays using a neutron detector or the like in the furnace, and the flow rate of the cooling water 13 in the furnace can be measured only from the thermocouple output. become. Further, by incorporating the heater 21, the failure of the sensor unit can be detected, and the flow rate of the cooling water can be monitored even when the reactor power is low.

[Third Embodiment] (FIG. 6) The in-reactor information monitoring device of the present embodiment monitors the pressure in the reactor, and FIG. 6 is a system configuration diagram showing the in-reactor information monitoring device. It is.

As shown in FIG. 6, this embodiment basically includes a stainless steel rod 15 installed in the core 12 and generating heat by gamma rays, a first heat insulator 16e whose heat insulation effect changes according to the ambient pressure, and One contact (low contact 14b) of the thermocouple 14 for detecting the temperature of the portion of the stainless steel bar 15 insulated by the second heat insulator 16f whose heat insulation effect does not change according to the ambient pressure and the first heat insulator 16e And another contact (high contact) 14 of the thermocouple 14 for detecting the temperature of the portion of the stainless steel bar 15 insulated by the second heat insulator 16f.
a, and the stainless steel obtained from the detection output of the thermocouple 14 reflecting the furnace pressure due to the difference in the heat insulating effect of the first and second heat insulators with respect to the ambient pressure by taking in the detection output of each contact 14a, 14b of this thermocouple. And a pressure evaluator 24 for measuring the pressure in the furnace based on the temperature difference between the two temperature measuring portions of the rod 15.

The heat insulator 16e, whose heat insulating effect changes according to the ambient pressure, has a cavity inside, and the volume of the cavity changes due to the external pressure, and the thermal conductivity changes according to the pressure. At a position in contact with the stainless steel rod 15 that generates heat by gamma rays, a heater 21 that generates heat by electricity is provided.

More specifically, as shown in FIG. 6, the stainless steel rod 15 that generates heat by gamma rays includes a heater 21 that generates heat by electricity, and a high contact 14a and a low contact 14b of the thermocouple 14. These are substantially the same as those of the second embodiment.

A constant heat insulator 16f whose thermal insulation effect hardly changes due to pressure (water pressure) is connected around the high contact 14a of the thermocouple 14, while a thermal insulation effect is provided around the low contact 14b by water pressure. Changing pressure change insulator 1
6e is connected. The pressure-changing heat insulator 16e is constituted by a pressure hole 23b for guiding pressure therein, a pressure cylindrical portion 22b expanded by the pressure, and an argon gas 16b for heat insulation sealed in the pressure cylindrical portion 22b. .

On the other hand, the unchanging heat insulator 16f includes a pressure hole 23a for introducing pressure therein, a pressure cylindrical portion 22a which expands with the pressure guided by the pressure hole 23a, and a pressure cylindrical portion 22a.
a, and an argon gas 16b sealed in a. The output of the thermocouple 14 is input to the pressure evaluation device 24.

In the above configuration, the pressure cylindrical portion 22b
Expands outward due to the pressure in the pressure hole 23b. Thereby, the heat insulation effect around the low contact point 14b of the thermocouple 14 is reduced. On the other hand, since the pressure cylindrical portion 22a has a sufficient thickness so that the rate of expansion due to the pressure in the pressure hole 23a is small, the pressure does not change the heat insulating effect of the high contact 14a. In this case, the pressure change heat insulator 16e is
Since the thickness of the pressure cylinder is thinner than that of the non-changing heat insulator 16f, the heat generated by the gamma ray in that portion is reduced. However, by adjusting the reduced amount by the heat insulation thickness in contact with the stainless steel rod 15, the furnace pressure is reduced. Can be obtained. That is, the thermocouple output is converted into the furnace pressure by the pressure evaluation device 24. The heater 21 is used for measuring the pressure in the reactor by heating the stainless steel rod 15 when the reactor output is low, as in the second embodiment.

According to this embodiment, the temperature difference between the parts of the stainless steel rod 15 where the heat insulation effect differs based on the difference in the heat insulation effect due to the pressure inside the reactor is measured by utilizing the heat generated by the gamma ray of the nuclear reactor. It is a simple sensor that combines a thermocouple with high radiation resistance and a stainless steel bar, and can measure the pressure inside the furnace in a stable state.

[Fourth Embodiment] (FIGS. 7 and 8) The in-reactor information monitoring apparatus of the present embodiment monitors the level of cooling water in a nuclear reactor. FIG. 7 is a system configuration diagram showing the configuration of the present embodiment, and FIG. 8 is a characteristic diagram thereof.

As shown in FIG. 7, in the present embodiment, basically, a stainless steel bar 15 that generates heat by gamma rays, a thermocouple 14 attached to the stainless steel bar 15 for temperature detection, and around the stainless steel bar 15. A heat insulator 16 that is provided and suppresses heat release to the surroundings; a DC measuring device 25 that measures a DC component of the output of the thermocouple 16; an AC measuring device 26 that measures an AC component of the output of the thermocouple 14; A water level evaluation device 27 that evaluates the water level of the cooling water in the furnace from the measurement results of the DC measurement device 25 and the AC measurement device 26.

More specifically, as shown in FIG. 7, a high contact 14a and a low contact 14b of a differential thermocouple 14 are arranged in a stainless steel rod 15, and the stainless steel rod
A heat insulator 16 is provided around the stainless steel rod 15 so that the high contact 14a becomes hot due to the heat generated by the heat sink. The stainless steel rod 15 to which the heat insulator 16 is attached is inserted into the cooling water 13 in the furnace. The output of this thermocouple 14 is
It is guided outside the furnace and is input to the DC measuring device 25 and the AC measuring device 26. These measurement results are input to the water level evaluation device 27, respectively. In such a configuration, the high contact 14 a and the low contact 14
b and the temperature changes.

FIG. 8 shows the temperature of the high contact 14a and the low contact 14b with respect to the water level, and the differential thermocouple 1 as the temperature difference.
4 is shown. When the water level is higher than the low contact 14b, the high contact 14a has a higher temperature than the low contact 14b due to the heat insulating effect of the heat insulator 16. In addition, in the boiling water reactor, voids are generated in the cooling water 13 nearer to the water surface, but as a result of the evaluation, the low contact 14b directly in contact with the cooling water 13 is affected by the voids in the water. The output fluctuates,
This fluctuation was found to be larger than that of the high contact 14a surrounded by the heat insulator 16.

On the other hand, when the water level of the cooling water 13 is located below the low contact 14 b, the temperature rises because the low contact 14 b is not cooled by the cooling water 13. Due to this temperature rise, the low contact 14b becomes higher in temperature than the high contact 14a insulated by the heat insulator 16, and the output of the differential thermocouple 14 is inverted. Further, when the water level of the cooling water 13 falls below the high contact 14a, neither the high contact 14a nor the low contact 14b is cooled, so that the high contact 14a surrounded by the heat insulator 16 has a higher temperature, and the output of the differential thermocouple 14 Is also a positive value. Traditionally,
The water level of the cooling water and the rate of change of the water level were estimated only by the positive / negative reversal of the output of the differential thermocouple, but whether the water level is above the low junction or below the high junction is determined. However, there is a problem that the output cannot be determined because all outputs of the differential thermocouple are positive.

On the other hand, in the configuration of the present embodiment, the DC component of the signal is monitored by the DC measuring device 25 so that the same function as in the related art is provided, and the fluctuation component of the thermocouple output is reduced by the AC measuring device 26. By monitoring, these judgments became possible. That is, when the fluctuation component is equal to or higher than the reference, it is considered that the influence of the void of the cooling water 13 is present, and thus the water level of the cooling water 13 can be determined to be above the low contact point 14b.

The amount of fluctuation makes it possible to determine the amount of voids and to what extent the water level of the cooling water 13 is at the top. These are performed by the water level evaluation device 27. In this method, a heater (not shown) is built in the stainless steel rod 15 so that a similar determination can be made using the heater heat even when the reactor output is low.

According to the above-described fourth embodiment, a sensor having a simple structure combining a thermocouple 14 having high radiation resistance and a stainless steel bar 15 is inserted into the furnace by utilizing the gamma ray heat generation of the reactor, By monitoring the AC and DC components of the output, the water level in the furnace can be monitored continuously.

[Fifth Embodiment] (FIGS. 9 and 10) FIG. 9 shows the configuration of this embodiment. This in-reactor information monitoring device measures the void fraction and minute neutron flux in the reactor.

As shown in FIG. 9, the present embodiment basically includes a stainless steel rod 15 installed in a reactor core and generating heat by gamma rays, and a heat generated by the stainless steel rod 15 connected to the stainless steel rod 15. A heat insulator 16 that insulates the inside of the cooling water 13, a high contact point 14 a of a thermocouple 14 that detects the temperature of the portion of the stainless steel bar 15 that is heated by the heat insulating effect of the heat insulator 16, and is not insulated by the heat insulator 16. A gamma ray change monitoring device 28 that monitors a change in the difference between the low contact 14b of the thermocouple 14 that detects the temperature of the stainless steel bar 15 and the detection output of the two contacts 14a and 14b.
A compensator 30 for compensating a change in the detection output of each contact 14a, 14b of the thermocouple with a parameter depending on the structure of the stainless steel bar 15 and the heat insulator 16, and a neutron change monitoring device for measuring a neutron component in the furnace 29, and a void evaluator 31 as an output change monitoring device that captures the outputs of the neutron change monitoring device 29 and the corrector 30 and monitors a change in the ratio of the outputs.

Further, a gamma ray evaluator 32 for evaluating the average gamma ray flux from the detection output of the thermocouple 14, and a neutron component obtained by removing the gamma ray component obtained as a noise component from the neutron component in the furnace by the gamma ray evaluator 32 And a neutron evaluator 33 for extracting only the neutrons.

More specifically, as shown in FIG. 9, a reactor core 12 composed of fuel rods (not shown) is formed inside a reactor pressure vessel 11, and cooling water 1 for cooling the reactor core 12 is formed.
3 are circulating. Inside the core 12, a stainless steel rod 1 including a high contact 14a and a low contact 14b of the differential thermocouple 14 is provided.
5 is inserted, and a heat insulator 16 in which an argon gas 16b is sealed is provided around the stainless steel rod 15.
The output of the differential thermocouple 14 is supplied to the gamma ray change monitor 2
8 and its output is input to the rise corrector 30.

On the other hand, the output of the neutron detector 18 installed near the high contact 14a is input to the neutron change monitoring device 29. The output of the rise corrector 30 and the output of the neutron change monitoring device 29 are input to a void evaluator 31, and the output of the thermocouple 14 is input to a gamma ray evaluator 32. The output of the neutron detector 18 is input to the neutron flux evaluator 33.

Next, the operation of the present embodiment will be described. In the above configuration, the stainless rod 15 is heated by gamma rays in the furnace and is insulated from the surrounding cooling water 13 by the argon gas 16b, so that the portion of the stainless rod 15 insulated by the argon gas 16b has a high temperature. By arranging the high junction 14a of the thermocouple at this position and arranging the low junction 14b of the thermocouple 14 at a position not insulated by the argon gas 16b, the amount of heat generated by gamma rays, that is, the output in proportion to the gamma ray intensity, Obtained as thermocouple output. This principle is the same as that shown in each of the above-mentioned embodiments, and there is a gamma thermometer known as a means for measuring gamma rays in the furnace.

On the other hand, the output of the neutron detector 18 installed close to the high contact 14a is monitored by the neutron change monitoring device 29.

The operation of each monitoring device will be described with reference to FIGS. 10 (A), 10 (B) and 10 (C). First, in the neutron change monitoring device 29, the output of the neutron detector is shown in FIG.
When it changes as shown by 0 (A), its rise angle Z1 is measured. Similarly, the output of the thermocouple is detected by the gamma ray change monitoring device 28 as shown in FIG. 10B, and the characteristics such as the angle Z2 are recorded. Although these angles depend on the response time of the sensor and the response time of the measurement circuit, the response time of the neutron change monitoring device 29 is set to be sufficiently earlier than the observed rise. However, since the output of the thermocouple 14 has a slow response, the output of the gamma ray change monitoring device 28 is output later than the actual change of the gamma ray. Therefore, the output of the gamma ray change monitoring device 28 is further input to the rise corrector 30 and corrected by the rise corrector 30. That is, the rise corrector 30
In this example, characteristics such as the structure of the stainless steel bar 15 are stored, and a prediction filter process corresponding to an inverse function of those characteristics is performed. It is sufficient to use a theoretically established filter such as a Kalman filter for such a prediction filter. FIG. 10C shows the output of the rise correction device.

The outputs of these change monitoring devices 28 and 29 are monitored by a void evaluator 31 for the ratio of the rising angles. It is known that the peripheral void ratio can be monitored based on the fluctuation amount of the neutron flux and the fluctuation amount of the gamma ray. However, in the configuration of the present embodiment, the gamma ray change monitoring device 28 is used.
In addition, it is possible to estimate the peripheral void ratio from the ratio of the change rate of the rising angle of the output of the neutron change monitoring device 29.

On the other hand, the average gamma ray flux at the position of the high contact point 14 a is evaluated by the gamma ray evaluator 32 and is input to the neutron flux evaluator 33. The neutron flux evaluator 33 evaluates the gamma ray component of the output of the neutron detector 18 from the evaluated gamma ray flux and the gamma ray sensitivity of the neutron detector 18,
The gamma ray component is removed from the output of the neutron detector 18 and only the neutron component is extracted. Thereby, it is possible to measure a minute neutron flux.

When a fission detector is used as the neutron detector 18, the neutron sensitivity of the neutron detector 18 which has been inserted into the reactor for a long period of time is low because the neutron sensitivity is reduced by the neutron irradiation dose. However, by performing such a correction, the neutron flux can be monitored even with the neutron detector 18 having low neutron sensitivity, and the life of the neutron detector 18, that is, the time for loading the neutron in the reactor, Can be lengthened.

According to the fifth embodiment, a sensor having a simple structure in which a stainless steel bar 15 and a thermocouple 14 are combined is inserted into the furnace and its output is corrected, so that the void ratio and the void rate in the furnace are corrected. A small neutron flux can be measured.

[Sixth Embodiment] (FIGS. 11 and 12) This embodiment monitors the power distribution in the axial direction of the core. FIG. 11 is a system configuration diagram showing the configuration of the in-furnace information monitoring device according to the present embodiment, and FIG. 12 is a diagram showing the principle thereof.

As shown in FIG. 12, the present embodiment basically includes a stainless steel bar 15 installed in a core 11 and generating heat by gamma rays, a thermocouple 14 attached to the stainless steel bar 15 for temperature detection, A gamma thermometer 34 as a sensor unit is constituted by the heat insulator 16 which is disposed around the stainless steel bar 15 and suppresses heat release to the surroundings,
A plurality of gamma thermometers 34 arranged in the axial direction of the core in the furnace, and an axial gamma ray distribution monitoring device 35 for storing an axial power distribution in the furnace based on the thermocouple output of each gamma thermometer 34; A distribution abnormality detector 36 that stores in advance the normal value of the distribution shape and the shape of the power distribution that appears when the reactor is abnormal, and detects the abnormality of the reactor using the output of the axial gamma ray distribution monitoring device. is there.

The distribution abnormality detector 36 uses the output of the axial gamma ray distribution monitoring device 35 to evaluate the rate of change from the past output distribution, and detects an abnormality from the rate of change.

The distribution abnormality detector 36 evaluates the rate of change with respect to the past power distribution in the furnace using the output of the axial gamma ray distribution monitoring device 35, and evaluates the rate of change with the stainless steel rod 15.
The correction is performed by a prediction filter determined from the structures of the heat insulator 16 and the thermocouple 14, the current gamma ray output distribution in the furnace is estimated, and an abnormality is detected from the estimated value.

More specifically, in FIG. 11, a reactor core 12 composed of fuel rods is provided inside the reactor pressure vessel 11, and cooling water 13 for cooling the reactor core 12 is circulated. Inside the reactor core 12, a stainless steel rod 15 generating heat by gamma rays and a heat insulator 16 containing an argon gas 16b are provided.
And a thermocouple 16 for measuring the temperature difference between the temperature of the portion of the stainless steel rod 15 insulated by the argon gas 16b and the temperature of the portion not insulated by five points in the axial direction of the core 12. Gamma thermometer 34 is inserted. This gamma thermometer 3
The outputs of five sensor units provided in the axial direction of the four cores 12 are input to an axial gamma ray distribution monitoring device 35, and the output is input to a distribution abnormality detector 36.

Next, the operation of the sixth embodiment will be described.

In the above configuration, the gamma thermometer 3
The gamma ray flux at five axial positions of the core 12 in which the respective sensor units 4 are disposed is the gamma ray distribution monitoring device 35 in the axial direction.
Is calculated based on the output of each sensor unit. This output is compared with an abnormality distribution stored in advance by a distribution abnormality detector 36. If the output is equal to or greater than the judgment criterion, the output distribution shape in the axial direction of the core is judged to be abnormal, and the distribution is distributed to the reactor safety system. An abnormal output 37 is output. As a method for determining this abnormality, for example, as shown in FIG. 12A, a gamma ray intensity distribution is calculated for a gamma ray flux at a certain point, and an abnormality is output when the amount of change in the distribution exceeds a certain reference. . In FIG. 12A, the distribution with respect to the upper sensor unit is compared. When the amount of change of the measured value S with respect to the normal value R is compared with the abnormality determination criterion T for determining abnormality, the amount of change at the sensor unit position Y5 is greater than the abnormality determination criterion T.

In the abnormality determination method shown in FIG. 12B, the change rate of the gamma ray flux S1 at each measured position of the sensor unit is obtained from the normal value R considered to be normal, and the change rate is determined as the abnormality determination reference. If it exceeds T, it is determined to be abnormal.
In this abnormality determination method, the gamma ray flux S1 is detected at the sensor position Y4.
Is a value equal to or greater than the abnormality determination criterion T.

Further, the abnormality determination method shown in FIG. 12 (C) is an improvement in that the time response is slow because the response of the gamma thermometer 34 measures heat. The gamma thermometer 34 responds to the change in the measured value S2.
Using the inverse function of the sensor response calculated from the above structure as a prediction filter, the measured value S2 is corrected, the predicted value U is calculated, and an abnormality is determined from the amount of change in the value. FIG.
In (C), the predicted value of the gamma ray flux exceeds the abnormality determination criterion T at the sensor unit positions Y3, Y4, Y5, and it is determined that there is an abnormality. If it is determined that the distribution is abnormal, the distribution abnormality detector 36 outputs a distribution abnormality output 37. Note that the gamma thermometer 34 may have various shapes such as a type including a heater, and the abnormality determination method of the present embodiment can be applied to those shapes. In addition, as a device for detecting a shape abnormality, a device for recognizing a shape graphically is also included. The abnormality criterion T predicts a predicted change in the power distribution in the axial direction, such as control rod withdrawal of a nuclear reactor, and determines an appropriate value from the change range.

According to the sixth embodiment described above, the gamma thermometer 34 is constructed by arranging sensor parts having a simple structure in which the stainless steel bar 15 and the thermocouple 14 are combined in the core in the axial direction of the core. From the change in the power distribution shape of the gamma ray at the position, the power distribution abnormality which causes the vibration of the reactor power can be detected at an early stage.

[0100]

According to the present invention, by inserting a sensor having a simple structure combining a stainless steel rod and a thermocouple into the reactor, the flow rate, water level, pressure, void ratio,
It is possible to measure minute neutron flux and directly measure the information inside the reactor, thereby improving the measurement accuracy of the parameters inside the reactor and improving the piping connected to the reactor pressure vessel. And the number of operations for maintenance and inspection of those pipes can be reduced.

Further, by continuously measuring the gamma ray heating value in the reactor at a plurality of points in the axial direction of the reactor core, it is possible to monitor the abnormal shape of the power distribution which causes the output vibration of the reactor, and to detect this early stage. Thus, appropriate measures can be realized at an early stage. Therefore, an excellent effect that the reliability and operability of the reactor itself can be improved is achieved.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram showing a first embodiment of an in-furnace information monitoring device according to the present invention.

2 (A) is an enlarged view showing a structure of a temperature measuring portion in the in-furnace information monitoring device shown in FIG. 1, and FIG. 2 (B) is a cross sectional view of the above (A).

FIG. 3 is an explanatory diagram showing a temperature distribution of a thermometer portion of the in-furnace information monitoring device shown in FIG. 1 and a measurement principle of a flow rate of cooling water in the furnace.

FIG. 4 is a system configuration diagram showing a second embodiment of the in-furnace information monitoring device according to the present invention.

5 is a characteristic diagram showing a relationship between a flow rate of cooling water in the furnace monitored by the furnace information monitoring device shown in FIG. 4 and a temperature difference detected by a differential thermocouple.

FIG. 6 is a system configuration diagram showing a third embodiment of the in-furnace information monitoring device according to the present invention.

FIG. 7 is a system configuration diagram showing a fourth embodiment of the in-furnace information monitoring apparatus according to the present invention.

FIG. 8 is an explanatory diagram showing the relationship between the level of cooling water in the furnace and the temperature output of the thermocouple, which are monitored by the furnace information monitoring device shown in FIG. 7;

FIG. 9 is a system configuration diagram showing a fifth embodiment of the in-furnace information monitoring apparatus according to the present invention.

10 (A), (B) and (C) are explanatory diagrams showing the measurement principle of the in-furnace information monitoring device shown in FIG.

FIG. 11 is a system configuration diagram showing a sixth embodiment of the in-furnace information monitoring apparatus according to the present invention.

12 (A), (B), and (C) are explanatory diagrams showing a method for detecting an abnormality in an axial power distribution in a furnace applied to the in-furnace information monitoring apparatus shown in FIG.

FIG. 13 is a system configuration diagram showing an example of a conventional in-furnace process amount measuring device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Reactor pressure vessel 12 Reactor core 13 Cooling water 14 Thermocouple 14a High contact 14b Low contact 15 Stainless steel rod 16 Insulator 16a Stainless tube 16b Argon gas 16c Insulator 16d Insulator 17 Cooling tube 18 Neutron detector 19 Gamma ray heat generation device 20 Flow velocity evaluation device 21 Heater 22a Pressure cylinder portion 22b Pressure cylinder portion 23a Pressure hole 23b Pressure hole 24 Pressure evaluation device 25 DC measurement device 26 AC measurement device 27 Water level evaluation device 28 Gamma ray change monitoring device 29 Neutron change monitoring device 30 Rise correction device 31 Void evaluator 32 Gamma ray evaluator 33 Neutron flux evaluator 34 Gamma thermometer 35 Axial gamma ray distribution monitoring device 36 Distribution abnormality detector 37 Distribution abnormality output

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location G21C 17/02 GBBC 17/10 GBDF

Claims (16)

[Claims] 1. A heating element installed in a reactor core of a nuclear reactor and generating heat by gamma rays, a thermocouple for temperature detection attached to the heating element, and a heat release disposed around the heating element and radiating heat to the surroundings. A cooling path formed between the heat generating element and the heat insulating body, the cooling path having a flow rate dependent on an ambient flow rate to cool the heat generating section, and radiation detection of the core section. A gamma ray heat generation evaluation device that evaluates the gamma dose at the position of the heating element based on the detection output of the thermocouple and the gamma ray heat generation evaluation device, and measures the flow velocity of the cooling water around the heating element based on these detection outputs. An in-furnace information monitoring device comprising a flow velocity evaluation device. 2. The gamma ray heat generation evaluating apparatus evaluates a gamma ray heat generation amount at the position of the heating element by calculation correction using an output of a radiation detector installed inside or outside a nuclear reactor. The in-furnace information monitoring device according to claim 1. 3. A heating element installed in the core of the nuclear reactor and generating heat by gamma rays, and a pair of heat insulators arranged around the heating element at different positions to suppress heat release to the surroundings; A cooling path formed between the heat generating element and one of the heat insulating bodies and configured to flow a coolant having a flow rate depending on an ambient flow rate to cool the heat generating unit is in contact with the heat insulating body and the cooling path. A first thermocouple for detecting a temperature of the heating element portion, a second thermocouple for detecting a temperature of the heating element portion that is in contact with the heat insulator and not in contact with the cooling path, and Taking in the detection output of the second thermocouple, and referring to characteristic data indicating the relationship between the temperature difference between the two temperature measurement sites of the heating element and the flow rate of the cooling water around the heating element which are stored in advance. Measure the flow velocity of the cooling water around the heating element An in-furnace information monitoring device comprising a flow velocity evaluation device. 4. A thermocouple having two contacts is provided in place of the thermocouple according to claim 3, and the one contact is provided at a portion for measuring the temperature of the heat generating body with which the heat insulator and the cooling path are in contact. 4. The in-furnace information monitoring apparatus according to claim 3, wherein the contact point is disposed, and another contact point is disposed at a portion where the temperature of the heating element not in contact with the heat insulating body is measured. 5. The in-furnace information monitoring apparatus according to claim 1, further comprising a heater portion which comes into contact with the heating element which generates heat by gamma rays and generates heat by electricity. 6. A heating element installed in the core of a nuclear reactor and generating heat by gamma rays, a thermocouple for temperature detection attached to the heating element, and an insulation effect connected to the heating element and depending on ambient pressure. A heat insulator that changes, and a pressure evaluation device that measures a furnace pressure based on a detection output of the thermocouple reflecting a furnace pressure by changing a heat insulating effect of the heat insulator according to a furnace pressure. Characteristic furnace information monitoring device. 7. A heating element installed in the core of a nuclear reactor and generating heat by gamma rays, a first heat insulating body whose heat insulating effect changes according to ambient pressure, and a second heat insulating material whose heat insulating effect does not change according to ambient pressure. A heat insulator, a first thermocouple for detecting the temperature of the portion of the heating element insulated by the first heat insulator, and a temperature detection of the portion of the heating element insulated by the second heat insulator The first and second thermocouples, and the first and second thermocouples, which take in the detection outputs of the first and second thermocouples and reflect the in-furnace pressure due to the difference in the heat insulating effect of the first and second heat insulators with respect to the ambient pressure. And a pressure estimating device for measuring a furnace pressure based on a temperature difference between two temperature measuring portions of the heating element obtained from detection outputs of the two thermocouples. 8. The heat insulator whose heat insulating effect changes according to the ambient pressure has a cavity inside, the volume of the hollow portion changes according to the external pressure, and the heat conductivity of the heat insulator changes according to the pressure. The in-furnace information monitoring device according to claim 6, wherein: 9. The in-furnace information monitoring apparatus according to claim 6, further comprising a heater section that generates heat by electricity at a position in contact with a heating element that generates heat by gamma rays. 10. A heating element installed in a core of a nuclear reactor and generating heat by gamma rays, a thermocouple for temperature detection attached to the heating element, and a heat release disposed around the heating element and radiating heat to the surroundings. Insulating body that suppresses, a DC measurement device that measures the DC component of the output of the thermocouple, an AC measurement device that measures the AC component of the output of the thermocouple, and the measurement results of the DC measurement device and the AC measurement device And a water level evaluation device for evaluating the water level of the cooling water in the furnace. 11. The in-furnace information monitoring apparatus according to claim 10, wherein a heater section that generates heat by electricity is provided inside a heating element that generates heat by gamma rays. 12. A heating element installed in a reactor core of a nuclear reactor and generating heat by gamma rays, an insulating body connected to the heating element and insulating heat generated in the heating element with cooling water in the reactor; A first thermocouple for detecting the temperature of the portion of the heating element that is heated to a high temperature due to the heat insulating effect of the body, a second thermocouple for detecting the temperature of the portion of the heating element that is not insulated by the heat insulating member, and a first thermocouple. A gamma ray change monitoring device for monitoring a change in the difference between the detection outputs of the second thermocouple, and a change in the detection output of the first and second thermocouples corrected by a parameter depending on the structure of the heating element and the heat insulator. A neutron monitoring device for measuring a neutron component in the reactor, and an output change monitoring device for capturing the outputs of the neutron monitoring device and the corrector and monitoring a change in the ratio of the outputs. Furnace information monitoring device . 13. A heating element installed in a reactor core of a nuclear reactor and generating heat by gamma rays, a heat insulating element disposed around the heat generating element to suppress heat release to the surroundings, and a high temperature due to the heat insulating effect of the heat insulating element. A first thermocouple for detecting a temperature of a portion of the heating element, a second thermocouple for detecting a temperature of a portion directly in contact with water in the furnace, and a first thermocouple and a second thermocouple. A gamma ray evaluator that evaluates an average gamma ray flux from the detection output, and a neutron evaluator that extracts only a neutron component by removing a gamma ray component obtained from the gamma ray evaluator as a noise component from a neutron component in the furnace. An in-furnace information output monitoring device, characterized in that: 14. A heating element installed in a reactor core of a nuclear reactor and generating heat by gamma rays, a thermocouple for temperature detection attached to the heating element, and a heat release disposed around the heating element and emitted to the surroundings. And a plurality of sensor units are arranged in the core axis direction in the furnace, and an axis for storing the axial output distribution in the furnace based on the thermocouple output of each sensor unit. A direction gamma ray distribution monitoring device, an abnormality in which a normal value of the shape of the power distribution and a shape of the power distribution appearing when the reactor is abnormal are stored in advance, and an abnormality of the reactor is detected using the output of the axial gamma ray distribution monitoring device. A furnace axial output abnormality monitoring device, comprising: a detector. 15. The abnormality comparator evaluates a rate of change from a past output distribution using an output of the axial gamma ray distribution monitoring device, and detects an abnormality from the rate of change. The in-furnace information monitoring device described in the above. 16. An abnormality comparator evaluates a rate of change from a past power distribution in a furnace using an output of an axial gamma ray distribution monitoring device, and evaluates the rate of change with the heating element, the heat insulator, and the thermocouple. 15. The in-furnace information monitoring apparatus according to claim 14, wherein the correction is performed by a prediction filter determined from the structure of (1), a current gamma ray output distribution in the furnace is estimated, and an abnormality is detected from the estimated value.