JP2007064635A - Monitoring device and monitoring method for nuclear reactor state - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a penetration part of a reactor pressure vessel, especially, a penetration part on a position lower than the core, while monitoring the nuclear reactor state with sufficient accuracy; and also to reduce exchange frequency of a detector. <P>SOLUTION: In this monitoring device for monitoring the nuclear reactor state, a neutron flux, a cooling water temperature, γ rays generated from an activated material or the like are detected by a detector assembly 8 disposed inside a reactor container 1 on the outside in the horizontal direction of the core 2, and an output from the detector assembly 8 is transferred to a signal processing means 9 from a through hole on the furthermore upside than the core, and a core heat output distribution is calculated by an output distribution evaluation means 10, and the cooling water flow rate is estimated by a flow rate estimation means 11 from the cooling water temperature, the core heat output and a reactor heat balance. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a reactor state monitoring apparatus and a reactor state monitoring method.

  In general, the core of a power generating reactor is constituted by a large number of elongated fuel assemblies arranged in a substantially cylindrical shape inside a reactor vessel. In the core, the fuel assembly whose temperature has risen due to the energy generated by the fission reaction heats the coolant passing through the core. The energy given to the coolant is sent directly or indirectly to the turbine and contributes to power generation.

  A detector inserted through a through-hole of a reactor pressure vessel is usually installed inside the reactor core (see, for example, Patent Document 1). By measuring the neutron flux in the core with this detector, the power of the reactor can be directly monitored. Patent Document 2 discloses a technique for obtaining a thermal output distribution of a core by measuring gamma rays generated from a nitrogen isotope having a mass number of 16 contained in cooling water. Patent Document 3 discloses a technique for evaluating the thermal power distribution of the core by arranging a gamma ray or neutron flux sensor between the inner surface of the reactor vessel and the core.

  In a boiling water reactor, heated cooling water boils, and an air-water interface between saturated steam and cooling water is formed in the reactor pressure vessel. Pressure differences at different axial positions in the reactor pressure vessel can be measured and converted to the position of the air-water interface, that is, the mass-converted water level of the reactor pressure vessel (see, for example, Patent Document 4). In order to measure this pressure difference, it is necessary to penetrate the instrumentation piping through the reactor pressure vessel. Usually, a plurality of instrumentation pipes for detecting the water level are installed in order to improve measurement accuracy and make the measuring instrument redundant.

  For the purpose of not interfering with the reactor internal structure in the reactor pressure vessel, such instrumentation piping penetrates below the core of the reactor pressure vessel.

The flow rate of the cooling water flowing through the core can be obtained from the pressure difference between the upper and lower positions of the core support plate that supports the core (see, for example, Patent Document 5). Further, the flow rate can be obtained from the heat balance of the reactor by measuring the cooling water temperature at the core inlet. Regardless of which method is used to determine the flow rate of cooling water, instrumentation piping that penetrates the reactor pressure vessel is required.
JP 2001-228282 A JP 05-203782 A Japanese Patent No. 2647573 JP 2000-65978 A JP 2003-66180 A

  Reactor power, coolant flow rate and coolant temperature, and variation (distribution) due to these locations are important information for controlling the reactor. However, it is desirable that the number of pipes penetrating the reactor vessel, such as an instrument pipe for inserting a detector for measuring the reactor power, the coolant flow rate, and the coolant temperature, be as small as possible. In particular, when the pipe connected to the penetration part of the reactor vessel located below the core breaks, it becomes difficult to fill the reactor core with the coolant. It should be reduced as much as possible.

  Moreover, since the detector disposed in the core has a high neutron irradiation amount, the detector is rapidly deteriorated and the replacement frequency of the detector is high. For the purpose of reducing the number of pipes that pass through the reactor vessel and reducing the frequency of detector replacement, it is conceivable to monitor the reactor with a detector arranged outside the reactor core. If it is only disposed outside the core, the measurement accuracy may be reduced and sufficient monitoring may not be possible.

  Therefore, the present invention can reduce the number of penetrations of the reactor pressure vessel, in particular, the penetrations at a position lower than the reactor core, and the detector replacement frequency while monitoring the state of the reactor with sufficient accuracy. The purpose is to do so.

  In order to achieve the above object, the present invention provides a reactor state monitoring apparatus for monitoring the state of a nuclear reactor, a transmission means for transmitting a signal through a penetration part of the reactor vessel, and an inner side of the reactor vessel. A radiation detector, output evaluation means for calculating a thermal output of the reactor based on a signal output from the radiation detector and transmitted by the transmission means, and disposed inside the reactor vessel A coolant temperature measuring means for measuring the temperature of the coolant, a coolant temperature measured by the coolant temperature measuring means and transmitted by the transmitting means, the thermal power calculated by the power evaluating means and the heat of the reactor And a flow rate estimating means for estimating the flow rate of the coolant flowing through the core based on the balance.

  Further, the present invention provides a reactor state monitoring apparatus for monitoring a state of a nuclear reactor, a transmission means for transmitting a signal through a penetration portion of the reactor vessel, and a radiation detector disposed inside the reactor vessel. Output evaluation means for calculating the thermal output of the nuclear reactor based on a signal output from the radiation detector and transmitted by the transmission means, and at least two places, and a part of the coolant is activated A gamma ray detector set for detecting gamma rays generated from the activated radioactive material and a ratio of gamma ray intensity detected by the gamma ray detector set, a distance between the gamma ray detectors and a half-life of the radioactive material A flow rate evaluation means for calculating a flow rate of the coolant flowing through the core, a heat output calculated by the power evaluation means, a flow rate of the coolant calculated by the flow rate evaluation means, and the original Based on the heat balance of the furnace, and having a coolant temperature estimating means for estimating the temperature of the coolant, a.

  Further, the present invention provides a reactor state monitoring apparatus for monitoring a state of a nuclear reactor, a transmission means for transmitting a signal through a penetration portion of the reactor vessel, and a radiation detector disposed inside the reactor vessel. Output evaluation means for calculating a thermal output of the nuclear reactor based on a signal output from the radiation detector and transmitted by the transmission means; and a temperature of the coolant disposed inside the nuclear reactor vessel A temperature measuring means for measuring the temperature, a gamma ray detector set for detecting gamma rays generated from the radioactive material that is disposed at least in two places and activated by a part of the coolant, and detected by the gamma ray detector set Flow rate evaluation means for calculating the flow rate of the coolant flowing through the core based on the ratio of the gamma ray intensity to be performed, the distance between the gamma ray detectors and the half-life of the radioactive material, Based on the heat output calculated by the force evaluation means, the coolant temperature measured by the coolant temperature measurement means, and the coolant flow rate calculated by the flow rate evaluation means, the heat output, the coolant temperature, and the coolant flow rate Correction means for correcting at least one of the above.

  Further, the present invention provides a reactor state monitoring apparatus that monitors a state of a nuclear reactor, and reaches a gas enclosure tube disposed inside the reactor vessel and the outside of the reactor vessel through the gas enclosure tube. A radiation detector for detecting the radiation to be output; and an output evaluation means for calculating a thermal output of the nuclear reactor based on a signal output from the radiation detector.

  Further, the present invention provides a reactor state monitoring apparatus that monitors a state of a nuclear reactor, and reaches a gas enclosure tube disposed inside the reactor vessel and the outside of the reactor vessel through the gas enclosure tube. A gamma ray detector set for detecting gamma rays generated from the radioactive substance, a ratio of gamma ray intensity detected by the gamma ray detector set, a distance between the gamma ray detectors, and a half-life of the radioactive substance. And a flow rate evaluation means for calculating the flow rate of the coolant flowing through the core.

  Further, the present invention provides a reactor state monitoring method for monitoring a state of a nuclear reactor, wherein the intensity of radiation is detected by the reactor vessel and based on a signal transmitted through a penetration portion of the reactor vessel, An output evaluation step for calculating the heat output of the reactor, a coolant temperature measurement step for measuring the temperature of the coolant inside the reactor vessel, a heat output calculated in the output evaluation step, and a measurement in the coolant temperature measurement step And a flow rate estimating step for estimating the flow rate of the coolant flowing through the core based on the temperature of the coolant and the thermal balance of the reactor.

  Further, the present invention provides a reactor state monitoring method for monitoring a state of a nuclear reactor, wherein the intensity of radiation is detected by the reactor vessel and based on a signal transmitted through a penetration portion of the reactor vessel, The output evaluation process to calculate the heat output of the gamma ray, and the gamma rays generated from the radioactive material in which a part of the coolant was activated in at least two places, the ratio of the intensity of these gamma rays, the place where gamma rays are detected A flow rate evaluation step for calculating a flow rate of the coolant flowing through the core based on the distance between the two and the activation material, a heat output calculated in the power evaluation step, and a coolant calculated in the flow rate evaluation step And a coolant temperature estimation step for estimating the coolant temperature based on the flow rate of the reactor and the thermal balance of the reactor.

  Further, the present invention provides a reactor state monitoring method for monitoring a state of a nuclear reactor, wherein the intensity of radiation is detected by the reactor vessel and based on a signal transmitted through a penetration portion of the reactor vessel, An output evaluation process for calculating the heat output of the reactor, a coolant temperature measurement process for measuring the temperature of the coolant inside the reactor vessel, and a radioactive material in which a part of the coolant is activated in at least two places A flow rate evaluation step of detecting a gamma ray to be detected, and calculating a flow rate of the coolant flowing through the core based on a ratio of the intensity of these gamma rays, a distance between locations where gamma rays are detected, and a half-life of the radioactive material And the heat output calculated in the output evaluation step, the coolant temperature measured in the coolant temperature measurement step, and the coolant flow rate calculated in the flow rate evaluation step. And having a correction step of correcting at least one of the flow rate of wood, a.

  According to the present invention, while monitoring the state of the reactor with sufficient accuracy, it is possible to reduce the penetration portion of the reactor pressure vessel, particularly the penetration portion at a position lower than the reactor core, and to reduce the replacement frequency of the detector.

  An embodiment of a reactor state monitoring apparatus according to the present invention will be described with reference to the drawings. A boiling water reactor (BWR) will be described as an example unless otherwise specified, but other types of reactors are also applicable. In addition, the same code | symbol is attached | subjected to the same or similar structure, and the overlapping description is abbreviate | omitted.

[Embodiment 1]
FIG. 1 is a configuration diagram of a reactor state monitoring apparatus according to Embodiment 1 of the present invention.

  The reactor pressure vessel 1 has a substantially cylindrical shape and is arranged so that its axis is in the vertical direction. Inside the reactor pressure vessel 1 is a core 2 in which a plurality of fuel assemblies are arranged in a substantially cylindrical shape. A control rod that absorbs neutrons can be inserted into the core 2, and a part of an output control means (not shown) composed of the control rod and a device for driving the control rod is a nuclear reactor. It penetrates the lower part of the pressure vessel 1. The reactor pressure vessel 1 is provided with a supply pipe 4 for supplying the cooling water 3 and a discharge pipe 6 for taking out steam generated in the core 2.

  After the cooling water 3 is supplied from the supply pipe 4, the cooling water 3 flows downward in the annular portion inside the reactor pressure vessel 1 and outside the horizontal direction of the core 2. The cooling water 3 flowing into the lower part of the reactor pressure vessel 1 flows into the core 2 from the lower part of the core 2 and rises. The cooling water 3 heated in the reactor core 2 boils and is separated into steam and moisture by the steam separator 41. The saturated steam 5 dried by the steam dryer 42 is discharged from the reactor pressure vessel 1 through the discharge pipe 6 and drives a steam turbine (not shown) to contribute to power generation. The steam that has driven the steam turbine is returned to liquid by a condenser (not shown), and then supplied to the reactor pressure vessel 1 through the supply pipe 4 again. Further, the water separated by the steam separator 41 flows downward along the annular portion outside the core 2 together with the cooling water 3 supplied by the supply pipe 4.

  A detector assembly 8 is disposed in an annular portion between the inner surface of the reactor pressure vessel 1 and the core 2. The lower end of the cylindrical detector assembly 8 extending in the vertical direction is below the core lower end position 53, and the upper end of the detector assembly 8 is higher than the air / water interface position 51 generated inside the reactor pressure vessel 1. Above. As described above, the cooling water 3 is inside the reactor pressure vessel 1 and flows downward through the annular portion outside the core 2, and the lower part of the detector assembly 8 is located in this flow. . A plurality of detector assemblies 8 are arranged in the circumferential direction so as to surround the core 2. Note that the number of detector assemblies 8 may be set to an appropriate number according to the number of detectors incorporated in the detector assembly or the required detection accuracy.

  The detector assembly 8 is connected to the signal processing means 9 disposed outside the reactor pressure vessel 1 through the upper through hole 62 of the reactor pressure vessel 1. The signal processing means 9 is connected to the output distribution evaluation means 10, the flow rate evaluation means 11, the water level evaluation means 12 and the activation substance concentration distribution evaluation means 13. The cooling water temperature distribution evaluation means 14 is connected to the activation substance concentration distribution evaluation means 13.

  FIG. 2 is a cross-sectional view of the detector assembly 8 according to Embodiment 1 of the present invention. (A) shows a horizontal cross section of the detector assembly, (b) is a vertical cross-sectional view taken along line B-B in (a), and (c) is taken along line C-C in (a). A longitudinal sectional view, (d) shows a longitudinal sectional view taken along line D-D of (a).

  The detector assembly 8 has a cylindrical detector container 44 extending in the vertical direction. Inside the detector container 44, an output system output monitor 15, a water level gauge 17, an activation system output monitor 20, a side radiation distribution monitor 21, and a gamma ray detector 22 are arranged and stored in the horizontal direction. Further, a through hole 60 is provided at the lower end of the detector container 44, and a part of the thermocouple 23 protrudes downward from the through hole 60. The cables 61 connected to the respective detectors are collected on the upper part of the detector assembly 8, led out of the reactor pressure vessel 1 from the upper through hole 62 of the reactor pressure vessel 1, and sent to the signal processing device 9. It is connected. The cable 61 may include piping.

  The output system output monitor 15 has a structure in which a radiation detector 45 is housed inside a cylindrical container. Here, the radiation detector 45 includes a neutron detector. For example, three to nine radiation detectors 45 are arranged in different axial positions and in a range from the core lower end position 53 to the core upper end position 52.

  The activation system output monitor 20 has a structure in which a radiation detector 45 is housed in a cylindrical container. Again, the radiation detector 45 includes a neutron detector. Several radiation detectors 45 are arranged in different axial positions, and in a range from the core lower end position 53 to the core upper end position 52.

  The side radiation monitor 21 has a structure in which a radiation detector 46 is housed inside a cylindrical container. A plurality of radiation detectors 46 are arranged at different axial positions in the range from the core lower end position 53 to the air-water interface position 51.

  The gamma ray detector set 22 has a structure in which three gamma ray detectors 47 are housed in a cylindrical container. The gamma ray detector 47 is disposed in the vicinity of the air / water interface position 51, between the core upper end position 52 and the air / water interface position 51, and below the core lower end position 53. Note that the number of gamma ray detectors 22 is not limited to three, and two or more appropriate numbers of gamma ray detectors 22 may be provided depending on the required measurement accuracy.

  The detector assembly 8 may be disposed so that the output system output monitor 15 and the activation system output monitor 20 that detect neutrons having a relatively short range face the core 2 to increase the detection efficiency.

  A coolant through hole 18 is provided below the detector assembly 8 at a position lower than the core lower end position 53, and the steam penetration portion is located at a position facing the saturated steam 5 during normal operation of the reactor. 19 is provided. Due to the pressure difference between the coolant through-hole 18 and the steam through-hole 19, a coolant level is generated inside the detector assembly 8. A water level gauge 17 for measuring the position of the liquid level is installed. As the water level gauge 17, for example, pressure gauges arranged at different axial positions can be used.

  Next, the operation of the reactor state monitoring apparatus according to the first embodiment will be described.

  Knowing any two quantities of reactor thermal power, coolant temperature and coolant flow rate, the remaining quantity can be determined from the thermal balance of the reactor.

  The outputs of the output system output monitor 15 and the activation system output monitor 20 are processed by the signal processing means 9 to obtain the neutron flux distribution. The power distribution evaluation means 10 obtains the neutron flux distribution in the core from the neutron flux distribution at the position of the detector assembly 8, and calculates the thermal output of the reactor. The startup system output monitor 20 is installed for the purpose of monitoring the thermal output at the time of startup of the nuclear reactor.

  The output of the thermocouple 23 is converted by the signal processing means 9 into the temperature of the cooling water 3 at the lower end position of the detector assembly 8, that is, the temperature of the cooling water 3 at the core inlet.

  The coolant flow rate can be obtained from the thermal output of the reactor and the coolant temperature at the core inlet obtained here.

The cooling water 3 includes a nitrogen isotope ( ¹⁶ N) having a mass number of 16 generated by activation of water. FIG. 3A is a diagram schematically showing the distribution of ¹⁶ N inside the reactor pressure vessel 1, and a part of the detector assembly 8 is omitted. FIG. 3B is a diagram showing the concentration distribution of ¹⁶ N at the position of the detector assembly 8. Here, reference numeral 16 indicates a ¹⁶ N. 3 (a) is not shows the atomic itself ^{16 N,} in which the concentration of ^{16 N} at each position shown schematically.

¹⁶ N generated in the core 2 flows upward from the core 2 together with the cooling water 3, and partly flows along with the saturated steam 5. Further, a part of ¹⁶ N flows to the lower part of the reactor pressure vessel 1 between the core 2 and the inner surface of the reactor pressure vessel 1 in the same manner as the cooling water 3 supplied from the water supply pipe 4.

¹⁶ N emits gamma rays of 6 MeV or higher. The energy of gamma rays generated from other activations detected inside the reactor pressure vessel 1 is about 2 MeV or less. In addition, although a maximum of 10 MeV gamma rays are generated inside the core 2, the gamma rays are attenuated at positions sufficiently away from the core 2, so that the gamma rays of 2 MeV or more are only the gamma rays emitted from ¹⁶ N. Therefore, the concentration of ¹⁶ N can be calculated by measuring the intensity of gamma rays of 2 MeV or more. That is, the radioactive substance concentration distribution evaluating means 13 can calculate the ¹⁶ N concentration at the detection position from the output of the gamma ray detector 22 received via the signal processing means 9.

^{Since 16} N decays at a constant rate with time, the concentration of ¹⁶ N contained in the cooling water 3 decreases with time. Therefore, calculated from the output of the gas-liquid interface and ^{16 N} concentrations calculated from the output of the arranged gamma ray detector 22 in the vicinity, disposed between the core upper and gas-water interfacial gamma ray detectors 22 ¹⁶ Based on the N concentration and the distance between the two gamma ray detectors 22, the moving speed of ¹⁶ N between the two gamma ray detectors 22, that is, the flow rate of the cooling water 3 can be calculated.

Thus, from the coolant flow rate obtained by measuring the gamma rays emitted from ¹⁶ N, the thermal output of the reactor and the thermal balance of the reactor obtained from the outputs of the output system output monitor 15 and the startup system output monitor 20 The cooling water temperature can also be obtained. Further, it is obtained from the coolant flow rate obtained by measuring gamma rays emitted from ¹⁶ N, the thermal output of the reactor obtained from the outputs of the output system output monitor 15 and the startup system output monitor 20, and the output of the thermocouple 23. The cooling water temperature may be corrected in consideration of the thermal balance of the reactor.

  The output system output monitor 15 and the start system output monitor 20 have a plurality of detectors in the axial direction, and can calculate the axial output distribution of the core. Furthermore, if a plurality of detector assemblies 8 are provided, the power distribution in the horizontal plane of the core can be calculated. By the three-dimensional nuclear thermo-hydraulic coupling calculation using the distribution of fissile material concentration in the fuel assembly at the time of production, the concentration distribution of the flammable poison, the history of fuel assembly arrangement and control rod insertion ratio, etc. The thermal output of the core and its distribution may be corrected based on the obtained concentration distribution of the fissile material in the core.

Since the cooling water 3 supplied from the supply pipe 4 has sufficiently passed through the core 2, it hardly contains ¹⁶ N. On the other hand, after passing through the core 2, the cooling water 3 flowing again to the lower part of the reactor pressure vessel 1 without being discharged from the discharge pipe 6 to the outside of the reactor pressure vessel 1 contains a relatively large amount of ¹⁶ N. It is. Further, the cooling water 3 flowing again to the lower part of the reactor pressure vessel 1 without being discharged outside the reactor pressure vessel 1 has a slightly higher temperature than the cooling water 3 supplied from the supply pipe 4. If these cooling waters 3 are not sufficiently mixed, the temperature of the cooling water 3 varies depending on the location. If a plurality of detector assemblies 8 are provided, the temperature difference of the cooling water 3 can also be calculated from the concentration of ¹⁶ N contained in the cooling water 3.

  Similarly, if a plurality of detector assemblies 8 are provided, a temperature difference depending on the location of the cooling water 3 can be measured by a plurality of thermocouples 23.

The distribution of the concentration of ¹⁶ N contained in the cooling water 3 is calculated by the activation substance concentration distribution evaluation means 13. Based on the distribution of the concentration of ¹⁶ N contained in the cooling water 3 output from the activation substance concentration distribution evaluation means 13, the measurement result of the thermocouple 23, the cooling water temperature distribution evaluation means 14 is provided at the inlet of the core 2. Evaluate the coolant temperature distribution.

  As described above, a liquid level is generated inside the detector assembly 8 corresponding to the water level of the reactor. This liquid level position is measured by a water level gauge 17, and the water level evaluation means 12 calculates a mass converted water level inside the reactor pressure vessel 1. In calculating the mass-converted water level, the calculation accuracy can be improved by correcting the power distribution calculated by the power distribution evaluation unit 10 and the core flow rate calculated by the flow rate evaluation unit 11.

  The output of the side radiation distribution monitor 21 is converted into a radiation intensity distribution by the signal processing means 9. The power distribution evaluation means 10 can improve the calculation accuracy of the heat power distribution in the furnace by correcting with the radiation intensity distribution. The output of the side radiation distribution monitor 21 can also be used for sensitivity correction of the output system output monitor 15 and the activation system output monitor 20. Further, since the output of the side radiation distribution monitor 21 is measured at various axial positions above and below the air-water interface position 51, the intensity of the radiation generated by nuclear fission and the intensity of the radiation by the radioactive material are respectively measured. The density distribution of the cooling water in the reactor vessel 1 can be estimated by measuring. The estimation result of the density distribution of the cooling water can be used for correcting the mass-converted water level calculated by the water level evaluation unit 12.

  As described above, the first embodiment according to the present invention eliminates the need for a through portion through which various detectors pass below the core of the reactor pressure vessel. Further, by arranging the detector outside the core, the amount of radiation applied to the detector is reduced, so that the frequency of replacement of the detector can be reduced. Furthermore, instrumentation piping for water level measurement and flow rate measurement can be reduced, and a method for calculating the temperature distribution at the core inlet can be obtained.

[Embodiment 2]
FIG. 4 is a configuration diagram of the reactor state monitoring apparatus according to the second embodiment of the present invention.

  In the second embodiment, a gas sealing tube 28 is installed inside the reactor pressure vessel 1. The type of gas sealed in the gas sealing tube 28 is not limited. For example, an inert gas such as argon may be sealed, or a vacuum may be used. Further, a detector assembly 8 and a lower detector assembly 68 are installed in the vicinity of the gas sealing tube 28 and outside the reactor pressure vessel 1. The detector assembly 8 installed in the vicinity of the side surface of the reactor pressure vessel 1 includes an output system output monitor 15, an activation system output monitor 20, and a side radiation monitor, similarly to the detector assembly 8 in the first embodiment. 21 and a gamma ray detector set 22 are included. The lower detector assembly 68 facing the lower portion of the reactor pressure vessel 1 includes an output system output monitor 15, an activation system output monitor 20, and a gamma ray detector set 22. Since the detector assembly 8 and the lower detector assembly 68 are located outside the reactor pressure vessel 1 and the water level meter does not make sense, the detector assembly 8 and the lower detector assembly 68 have a water level meter and a coolant through hole. Absent. Moreover, each detection apparatus does not need to be stored in an integral container, and may be disposed separately.

  Usually, most of the radiation (including neutron rays) inside the reactor pressure vessel 1 is shielded by the cooling water 3. Since the gas sealed tube 28 guides the radiation inside the reactor to the outside of the reactor pressure vessel 1, the intensity of the radiation at the position of the detector 31 installed outside the reactor pressure vessel increases. Therefore, even inside the reactor pressure vessel 1, the state inside the reactor pressure vessel 1 can be accurately measured. In particular, when the gas-filled tube 28 is inserted into the core 2, it becomes possible to directly measure the radiation inside the core 2, and it is also possible to measure local output changes inside the core 2.

  Further, since the radiation with higher intensity is guided to the outside of the reactor pressure vessel 1 by the gas sealing tube 28, the detector assembly 8 shields other than the surface facing the gas sealing tube 28, and the influence of radiation is small. It may be made to become.

  As described above, by using the gas sealing tube 28, even if the detector assembly 8 is installed outside the reactor pressure vessel 1, information inside the reactor pressure vessel 1 can be accurately grasped. Thereby, it becomes possible to reduce the penetration part of the lower part of the reactor pressure vessel 1. FIG. Moreover, the amount of radiation irradiation can be reduced by installing a detector outside the core 2, and the replacement of the detector can be reduced.

  The above description is merely an example, and the present invention is not limited to the above-described embodiments, and can be implemented in various forms. For example, when applied to a sodium-cooled fast breeder reactor, the cooling water 3 may be replaced with sodium. In addition, when applied to a nuclear reactor having no air-water interface such as a pressurized water reactor, a water level gauge, a coolant through hole, and the like may be deleted from the detector assembly.

The system block diagram of the in-furnace state monitoring apparatus of Embodiment 1 of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram of the detector assembly of Embodiment 1 of this invention, Comprising: (a) is a horizontal sectional view, (b) is a BB sectional view taken on the line of (a), (c) is (a). CC sectional view taken on line CC, (d) is a sectional view taken on line DD of (a). It is a schematic diagram of distribution of the nitrogen isotope of mass number 16 of Embodiment 1 of this invention, Comprising: (a) is a longitudinal cross-sectional view of a reactor vessel, (b) is an axial direction of the nitrogen isotope concentration of mass number 16 distribution. The system block diagram of the in-furnace state monitoring apparatus of Embodiment 2 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Reactor pressure vessel, 2 ... Core, 3 ... Cooling water, 4 ... Supply piping, 5 ... Saturated steam, 6 ... Discharge piping, 8 ... Detector assembly, 9 ... Signal processing means, 10 ... Output distribution evaluation means 11 ... Flow rate evaluation means, 12 ... Water level evaluation means, 13 ... Activated substance concentration distribution evaluation means, 14 ... Cooling water temperature distribution evaluation means, 15 ... Output system output monitor, 16 ... Nitrogen isotope having a mass number of 16, 17 DESCRIPTION OF SYMBOLS ... Water level meter, 18 ... Cooling water penetration part, 19 ... Steam penetration part, 20 ... Activation system output monitor, 21 ... Side radiation distribution monitor, 22 ... Gamma ray detector set, 23 ... Thermocouple, 28 ... Gas enclosure tube, DESCRIPTION OF SYMBOLS 41 ... Air-water separator, 42 ... Steam dryer, 44 ... Detector container, 45 ... Radiation detector, 46 ... Radiation detector, 47 ... Gamma ray detector, 51 ... Air-water interface position, 52 ... Core upper end position, 53 ... Core lower end position, 60 ... Through hole, 61 ... K Le, 62 ... upper through hole, 68 ... lower detector assembly

Claims (15)

In the reactor condition monitoring device that monitors the condition of the reactor,
A transmission means for transmitting a signal through the penetration of the reactor vessel;
A radiation detector disposed inside the reactor vessel;
Output evaluation means for calculating a thermal output of the reactor based on a signal output from the radiation detector and transmitted by the transmission means;
Coolant temperature measuring means for measuring the temperature of the coolant disposed inside the reactor vessel;
The flow rate of the coolant flowing through the core based on the coolant temperature measured by the coolant temperature measuring unit and transmitted by the transmitting unit, the thermal power calculated by the output evaluating unit, and the thermal balance of the reactor A flow rate estimating means for estimating
A reactor state monitoring device characterized by comprising: In the reactor condition monitoring device that monitors the condition of the reactor,
A transmission means for transmitting a signal through the penetration of the reactor vessel;
A radiation detector disposed inside the reactor vessel;
Output evaluation means for calculating a thermal output of the reactor based on a signal output from the radiation detector and transmitted by the transmission means;
A gamma ray detector set that is disposed in at least two locations and detects gamma rays generated from radioactive material in which a part of the coolant is activated;
A flow rate evaluation means for calculating a flow rate of coolant flowing through the core based on a ratio of gamma ray intensities detected by the gamma ray detector set, a distance between the gamma ray detectors, and a half-life of the radioactive material;
A coolant temperature estimating means for estimating a coolant temperature based on the heat output calculated by the output evaluating means, the coolant flow rate calculated by the flow rate evaluating means and the thermal balance of the reactor;
A reactor state monitoring device characterized by comprising: In the reactor condition monitoring device that monitors the condition of the reactor,
A transmission means for transmitting a signal through the penetration of the reactor vessel;
A radiation detector disposed inside the reactor vessel;
Output evaluation means for calculating a thermal output of the reactor based on a signal output from the radiation detector and transmitted by the transmission means;
Coolant temperature measuring means for measuring the temperature of the coolant disposed inside the reactor vessel;
A gamma ray detector set that is disposed in at least two locations and detects gamma rays generated from radioactive material in which a part of the coolant is activated;
A flow rate evaluation means for calculating a flow rate of coolant flowing through the core based on a ratio of gamma ray intensities detected by the gamma ray detector set, a distance between the gamma ray detectors, and a half-life of the radioactive material;
Based on the heat output calculated by the output evaluation means, the coolant temperature measured by the coolant temperature measurement means, and the coolant flow rate calculated by the flow rate evaluation means, the heat output, the coolant temperature, and the coolant temperature Correction means for correcting at least one of the flow rates;
A reactor state monitoring device characterized by comprising:   4. The power output evaluation unit includes a plurality of radiation detectors having different vertical positions, and has a function of calculating a thermal power distribution in the vertical direction of the nuclear reactor. The reactor state monitoring device described.   The said power evaluation means is provided with the several radiation detector from which a horizontal direction position differs, and has the function to calculate the thermal power distribution of the horizontal surface of the said reactor, The one of the Claims 1 thru | or 4 characterized by the above-mentioned. Reactor condition monitoring equipment.   The power output evaluation unit has a function of correcting the thermal power distribution of the nuclear reactor based on the arrangement and irradiation history of the nuclear fuel constituting the core. The reactor state monitoring device described.   The said power evaluation means has a function which correct | amends the thermal power distribution of the said reactor based on the information regarding the operating condition of the control means of the said core, The Claim 1 thru | or 6 characterized by the above-mentioned. Reactor condition monitoring device. The nuclear reactor is a nuclear reactor in which a coolant level is formed inside the nuclear reactor vessel,
A detector vessel disposed outside the reactor core in the horizontal direction and inside the reactor vessel, and having openings above and below the liquid level;
A liquid level detecting means for detecting a liquid level of the coolant formed in the detector container by a pressure difference in the opening of the detector container;
Liquid level position estimating means for estimating the position of the coolant level inside the reactor vessel from the output of the liquid level detecting means transmitted by the transmitting means passing through the through-hole. The reactor state monitoring apparatus according to any one of claims 1 to 7, characterized in that   9. The reactor state monitoring apparatus according to claim 1, further comprising a detector assembly in which a plurality of means for detecting the state of the reactor is stored.   Coolant density estimation means for estimating the density of the coolant inside the reactor vessel based on the gamma ray intensity detected by the gamma ray detector disposed outside the reactor core in the horizontal direction and the thermal output of the reactor The reactor state monitoring apparatus according to any one of claims 1 to 9, wherein In the reactor condition monitoring device that monitors the condition of the reactor,
A gas-filled tube disposed inside the reactor vessel;
A radiation detector that detects radiation that reaches the outside of the reactor vessel through the gas enclosure tube;
Based on the signal output from the radiation detector, the power evaluation means for calculating the thermal power of the reactor,
A reactor state monitoring device characterized by comprising: In the reactor condition monitoring device that monitors the condition of the reactor,
A gas-filled tube disposed inside the reactor vessel;
A gamma ray detector set for detecting gamma rays generated from the activated material that reaches the outside of the reactor vessel through the gas enclosure tube;
A flow rate evaluation means for calculating a flow rate of coolant flowing through the core based on a ratio of gamma ray intensities detected by the gamma ray detector set, a distance between the gamma ray detectors, and a half-life of the radioactive material;
A reactor state monitoring device characterized by comprising: In the reactor state monitoring method for monitoring the state of the reactor,
An output evaluation step of detecting the intensity of radiation in the reactor vessel and calculating a thermal output of the reactor based on a signal transmitted through a penetration portion of the reactor vessel;
A coolant temperature measuring step for measuring the temperature of the coolant inside the reactor vessel;
Based on the heat output calculated in the output evaluation step, the coolant temperature measured in the coolant temperature measurement step, and the thermal balance of the reactor, the flow rate estimation step for estimating the flow rate of the coolant flowing through the core,
A reactor state monitoring method characterized by comprising: In the reactor state monitoring method for monitoring the state of the reactor,
An output evaluation step of detecting the intensity of radiation in the reactor vessel and calculating a thermal output of the reactor based on a signal transmitted through a penetration portion of the reactor vessel;
Detect gamma rays generated from the radioactive material that has been activated at least in two places by the coolant, the ratio of the intensity of these gamma rays, the distance between the locations where the gamma rays are detected, and the half-life of the radioactive material On the basis of the flow rate evaluation step of calculating the flow rate of the coolant flowing through the core,
A coolant temperature estimation step for estimating a coolant temperature based on the heat output calculated in the power evaluation step, the coolant flow rate calculated in the flow rate evaluation step, and the thermal balance of the reactor,
A reactor state monitoring method characterized by comprising: In the reactor state monitoring method for monitoring the state of the reactor,
An output evaluation step of detecting the intensity of radiation in the reactor vessel and calculating a thermal output of the reactor based on a signal transmitted through a penetration portion of the reactor vessel;
A coolant temperature measuring step for measuring the temperature of the coolant inside the reactor vessel;
Detect gamma rays generated from the radioactive material that has been activated at least in two places by the coolant, the ratio of the intensity of these gamma rays, the distance between the locations where the gamma rays are detected, and the half-life of the radioactive material On the basis of the flow rate evaluation step of calculating the flow rate of the coolant flowing through the core,
Based on the heat output calculated in the output evaluation step, the coolant temperature measured in the coolant temperature measurement step, and the coolant flow rate calculated in the flow rate evaluation step, the heat output, the coolant temperature, and the coolant temperature A correction step for correcting at least one of the flow rates;
A reactor state monitoring method characterized by comprising:

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