JP2018205040A - Nuclear reactor facility and method of measuring oxygen in nuclear reactor containment vessel - Google Patents

Abstract

To measure an oxygen concentration or an oxygen partial pressure inside a nuclear reactor containment vessel even when a loss of the AC power supply occurs.SOLUTION: According to one embodiment, a nuclear reactor facility includes: an air feed pipe 41 for taking out a sample gas inside a nuclear reactor containment vessel 12; an instrument 33 for measuring oxygen outside the containment vessel arranged outside the nuclear reactor containment vessel 12 and measuring an oxygen partial pressure of the sample gas fed out by the air feed pipe 41; a recycling pipe 43 for returning the sample gas discharged from the instrument 33 to the inside of the nuclear reactor containment vessel 12; a blower 31 for driving the sample gas inside the air feed pipe 41 and the recycling pipe 43; and an instrument 15a for measuring oxygen inside the containment vessel arranged inside the nuclear reactor containment vessel 12 for measuring the oxygen partial pressure of the gas inside the nuclear reactor containment vessel 12.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to a nuclear reactor facility and a method for measuring oxygen in a containment vessel.

  The nuclear power generation facility has equipment for ensuring the safety of the nuclear reactor and related facilities in the event of a severe accident, and has a mechanism that can grasp the situation of the accident and take measures for convergence.

  In particular, the gas phase state in the reactor containment vessel is important information for sensing abnormalities during normal operation and grasping the situation during severe accidents, and is constantly required to be monitored.

  In a conventional nuclear reactor facility, hydrogen and oxygen concentrations in the gas phase are measured by a containment vessel atmosphere monitor. The equipment is installed outside the containment vessel, the gas phase inside the containment vessel is transferred to the equipment by a blower, and humidity, temperature, pressure, etc. are adjusted and measured using a cooler. ing.

Japanese Patent Laying-Open No. 2006-532079 JP2015-125138A Japanese Patent Application Laid-Open No. 60-042690

  However, it has been clarified that the existing facilities alone cannot take sufficient measures to deal with severe accidents, as severe accidents at the Fukushima Daiichi Nuclear Power Station associated with the Great East Japan Earthquake occurred. In a conventional nuclear reactor facility, when AC power is lost when a severe accident occurs, the containment vessel atmosphere monitor cannot be operated, and at present, constant monitoring cannot be achieved. In particular, in severe accidents at the Fukushima Daiichi Nuclear Power Station, an event that damages the reactor facility due to a hydrogen explosion caused by the reaction of hydrogen and oxygen has occurred, and it is important to monitor the gas phase concentration to prevent hydrogen explosions.

  Therefore, there is a need for a system that measures the gas phase composition at the time of a severe accident without adjusting gas transfer, dehumidification, cooling, pressure reduction, etc. that require an AC power supply.

  In particular, oxygen coexists with hydrogen, causing combustion and explosion, and its concentration measurement is important for accident management.

  As a prior art for dealing with such a situation, a method for measuring an oxygen concentration by a combustion reaction of hydrogen and oxygen has been proposed. When such a technique is used, the oxygen concentration can be measured in the presence of hydrogen, but cannot be measured in an environment where hydrogen does not coexist.

  In addition, it is desirable to calibrate the oxygen sensor periodically. However, when installed in a reactor containment vessel with a complicated shape, it is difficult from the viewpoint of installation space to route the piping for supplying calibration gas to the oxygen sensor. is there.

  The problem to be solved by the embodiment of the present invention is to make it possible to measure the oxygen concentration or oxygen partial pressure in the reactor containment vessel when the AC power supply is lost.

  According to one aspect of the present invention, a nuclear reactor facility includes a nuclear reactor containment vessel, and an air supply pipe that is connected to a sample gas extraction unit of the nuclear reactor containment vessel and extracts a sample gas in the nuclear reactor containment vessel; An oxygen measuring device outside the containment vessel that is arranged outside the reactor containment vessel and measures an oxygen partial pressure of the sample gas delivered by the air supply pipe, a sample gas return unit of the reactor containment vessel, and Connected to the oxygen measuring device outside the containment vessel and arranged in a return pipe for returning the sample gas discharged from the oxygen measuring device outside the containment vessel into the reactor containment vessel, and the air supply pipe or the return pipe. A blower for driving the sample gas inside the air supply pipe and the return pipe, and an oxygen partial pressure of the gas in the nuclear reactor containment vessel arranged in the nuclear reactor containment vessel And having a paid container oximeter, a.

  According to another aspect of the present invention, there is provided a method for measuring oxygen in a reactor containment vessel by using a blower through an air supply pipe connected to a sample gas extraction portion of the reactor containment vessel. The sample gas is taken out, passed through an oxygen storage device outside the containment vessel arranged outside the reactor containment vessel, and the sample gas after passing through the oxygen storage device outside the containment vessel is passed through the reactor containment vessel A sample gas circulation step for returning the sample gas to the reactor containment vessel through the sample gas return unit, and a sample gas oxygen for measuring an oxygen partial pressure of the sample gas taken out through the gas supply pipe by the oxygen measuring device outside the containment vessel A partial pressure measurement step, and an oxygen content in the containment vessel for measuring an oxygen partial pressure in the containment vessel by an oxygen measuring device in the containment vessel disposed in the containment vessel. Based on the oxygen partial pressure of the sample gas obtained from the measurement step and the sample gas oxygen partial pressure measurement step, the oxygen partial pressure in the reactor containment vessel obtained from the oxygen partial pressure measurement step in the containment vessel And a correction step for correcting.

  According to another aspect of the present invention, a method for measuring oxygen in a reactor containment vessel includes a measuring device carrying-in step of carrying a portable oxygen measuring device into the reactor containment vessel, and the portable oxygen measuring device. Based on the portable oxygen partial pressure measurement step for measuring the oxygen partial pressure in the reactor containment vessel and the output of the oxygen measuring device in the containment vessel fixed in the reactor containment vessel, From the fixed oxygen partial pressure measurement step based on the oxygen partial pressure in the reactor containment vessel obtained from the fixed oxygen partial pressure measurement step for measuring the oxygen partial pressure and the portable oxygen partial pressure measurement step, A correction step of correcting the partial pressure of oxygen in the obtained reactor containment vessel.

  According to the embodiment of the present invention, the oxygen concentration or oxygen partial pressure in the reactor containment vessel can be measured at the time of loss of the AC power supply without significant modification to the existing nuclear reactor facility.

1 is a schematic sectional elevation view showing an embodiment of a nuclear reactor facility according to the present invention. It is a graph which shows an example of the characteristic of the limiting current type oxygen sensor which can be utilized by one Embodiment of the nuclear reactor facility which concerns on this invention, Comprising: It is a graph which shows the relationship between oxygen partial pressure and an output voltage. It is a flowchart which shows the procedure of 1st Embodiment of the oxygen measuring method in a reactor containment vessel which concerns on this invention. It is a flowchart which shows the procedure of 2nd Embodiment of the oxygen measuring method in a reactor containment vessel which concerns on this invention.

  Hereinafter, embodiments will be described with reference to the drawings. Here, the same or similar parts are denoted by common reference numerals, and redundant description is omitted.

[First Embodiment]
FIG. 1 is a schematic sectional elevation view showing an embodiment of a nuclear reactor facility according to the present invention. Here, a boiling water nuclear power plant is shown as an example of a nuclear reactor facility. A reactor containment vessel 12 is housed inside the reactor building 11, and a reactor pressure vessel 13 containing nuclear fuel is installed in the reactor containment vessel 12. The reactor containment vessel 12 is divided into a dry well 21 and a wet well 22, and the reactor pressure vessel 13 is disposed in the dry well 21.

  In order to constantly analyze and monitor the atmospheric composition of the dry well 21 and the wet well 22, a containment vessel atmosphere monitor 14 is installed outside the reactor containment vessel 12. A dry well gas phase gas supply pipe (air supply pipe) 41 for sending gas in the gas phase portion from the dry well 21 to the containment vessel atmosphere monitor 14 is connected, and the gas phase portion of the gas phase portion is connected from the wet well 22 to the containment vessel atmosphere monitor 14. A wet well gas phase gas supply pipe (air supply pipe) 42 for sending gas is connected. A return pipe 43 for returning the gas measured by the containment atmosphere monitor 14 to the dry well 21 is connected.

  The containment vessel atmosphere monitor 14 includes a blower 31, a cooler (heat exchanger) 32, and an oxygen concentration detector (outside containment oxygen measuring device) 33. The gas sent from the dry well gas phase gas supply pipe 41 and the wet well gas phase gas supply pipe 42 is pressurized by the blower 31, cooled by the cooler 32, and then sent to the oxygen concentration detector 33. The gas discharged from the oxygen concentration detector 33 is returned to the dry well 21 (reactor containment vessel 12) through the return pipe 43.

  Since the oxygen concentration detector 33 included in the containment vessel atmosphere monitor 14 is installed outside the reactor containment vessel 12, it can be appropriately calibrated during periodic inspection of the reactor or during normal operation.

  A pressure gauge 35 is installed in the reactor containment vessel 12. Although FIG. 1 shows an example in which the pressure gauge 35 is installed in the dry well 21, the pressure gauge may be installed in both the dry well 21 and the wet well 22. Further, a pressure gauge may be installed in the containment vessel atmosphere monitor 14.

  The dry well gas phase gas supply pipe 41 and the wet well gas phase gas supply pipe 42 are respectively connected to the reactor containment vessel 12, that is, in the reactor containment vessel 12 in the vicinity of the sample gas extraction portions 36 and 37. In-container oxygen sensors (in-container oxygen measuring devices) 15a and 15b are arranged. Further, in the location where the return pipe 43 is connected to the reactor containment vessel 12, that is, in the reactor containment vessel 12 in the vicinity of the sample gas return section 38, the in-container oxygen sensor 15c (oxygen measuring device in the containment vessel). Is arranged.

  In addition, instruments such as pipes and pressure gauges, electric wires (not shown) for extracting their signals, and equipment (not shown) for responding to severe accidents are arranged.

  The in-container oxygen sensors 15a, 15b, and 15c are, for example, a limiting current type using a solid oxide ion conductor.

  The atmosphere in the reactor containment vessel 12 at the time of a severe accident can be a temperature of about 300 ° C., a pressure of 1 MPa or less, a high-dose atmosphere, and a steam atmosphere equivalent to a saturated vapor pressure due to the damage of the reactor pressure vessel 13 or the like. Also, depending on the severity and progress of severe accidents, incidental facilities may not function due to loss of AC power.

  By the way, the limiting current type oxygen sensor selectively transmits oxygen ions by applying a voltage to a solid oxide oxygen ion conductor such as yttria stabilized zirconia using an electrode made of metal or metal oxide. The oxygen partial pressure is measured by measuring the current value accompanying ion permeation. In order to make the solid oxide oxygen ion conductor function, the solid oxide oxygen ion conductor portion is heated to about 300 to 800 ° C. for use. Therefore, the function can be maintained even when a gas phase having a temperature assumed in a severe accident flows into the limiting current type oxygen sensor.

  Further, the structure of the limiting current type oxygen sensor has a structure without a sealed portion that causes a pressure difference with the external pressure, and the structure is destroyed even when the pressure in the reactor containment vessel 12 rises. There is nothing.

  In addition, the limiting current type oxygen sensor can be composed of an inorganic substance, and can maintain its function even in a high-dose atmosphere at the time of a severe accident.

  Since the limit current type oxygen sensor generates water electrolysis depending on the applied voltage, it is desirable to use the oxygen sensor below the potential at which water electrolysis occurs when used in the reactor containment vessel 12. Since the electrolysis temperature of water depends on the solid oxide oxygen ion conductor and the electrode temperature, the recommended operating potential cannot be defined in general, but it is 2.0 V or less with respect to the standard hydrogen electrode potential. It is desirable to operate at a potential. The limiting current type oxygen sensor is operated only with a DC power supply in principle, and is installed directly inside the reactor containment vessel, and does not perform pretreatment of the gas phase that requires AC power supply such as cooling and dehumidification. It is possible to operate even in an environment where power is lost.

  As described above, the limiting current type oxygen sensor can cope with the atmosphere in the containment vessel 12 at the time of a severe accident by operating within predetermined operating conditions, and the in-container oxygen sensors 15a and 15b. , 15c.

  The characteristics of the limiting current type oxygen sensor using the solid oxide oxygen ion conductor will be described with reference to FIG. FIG. 2 is a graph showing an example of the characteristics of a limiting current oxygen sensor that can be used in an embodiment of a nuclear reactor facility according to the present invention, and is a graph showing the relationship between oxygen partial pressure and output voltage. As shown in FIG. 2, the limiting current type oxygen sensor shows a behavior in which the response current increases linearly according to the partial pressure of oxygen. By acquiring a response straight line corresponding to the oxygen partial pressure in advance, one-point calibration or two-point calibration in an atmosphere with a known oxygen concentration is possible.

  Since the characteristics of the oxygen sensors 15a, 15b, and 15c in the storage container may change due to radiation irradiation or the passage of time, it is necessary to calibrate appropriately after installation. However, since these sensors are installed in the reactor containment vessel 12, it is difficult to perform calibration work by taking the sensors out of the reactor containment vessel 12. Therefore, in this embodiment, measurement is performed using the containment vessel atmosphere monitor 14 with a gas that is substantially the same as the measurement target of the in-container oxygen sensors 15a, 15b, and 15c, and the in-container oxygen sensors 15a, 15b, Calibrate 15c. Since the containment vessel atmosphere monitor 14 is disposed outside the reactor containment vessel 12, detailed description is omitted, but calibration can be performed as appropriate.

  According to this embodiment, the oxygen concentration or oxygen content of the gas in the reactor containment vessel 12 is measured by the containment vessel atmosphere monitor 14 and the containment vessel oxygen sensors 15a, 15b, and 15c during the normal operation and periodic inspection of the reactor. The pressure can be measured. Further, since the containment vessel atmosphere monitor 14 and the oxygen sensors 15a, 15b, and 15c in the containment vessel are intended to measure gases in the reactor containment vessel 12 at positions corresponding to each other, the oxygen sensors 15a, 15b, and 15c in the containment vessel are measured. Can be calibrated by the output of the containment vessel atmosphere monitor 14. Furthermore, even when the gas in the reactor containment vessel 12 cannot be measured by the containment vessel atmosphere monitor 14 at the time of the power loss accident, the gas in the reactor containment vessel 12 by the containment vessel oxygen sensors 15a, 15b, 15c Measurement of oxygen partial pressure can be performed.

  In addition, by using the existing containment vessel atmosphere monitor 14, the dry well gas phase gas supply pipe 41, the wet well gas phase gas supply pipe 42 and the return pipe 43, oxygen sensors 15a, 15b and 15c in the containment vessel are newly provided. This can be achieved simply by installing a new one.

  FIG. 3 is a flowchart showing the procedure of the first embodiment of the method for measuring oxygen in a reactor containment according to the present invention.

  In the configuration shown in FIG. 1, first, the blower 31 is driven to circulate the gas (sample gas) in the reactor containment vessel 12 (step S11). That is, the gas in the reactor containment vessel 12 is sent to the containment vessel atmosphere monitor 14 through the dry well gas phase gas supply pipe 41 and the wet well gas phase gas supply pipe 42. The sample gas exiting the blower 31 in the containment vessel atmosphere monitor 14 is cooled by the cooler 32 and then sent to the oxygen concentration detector 33. The sample gas that has passed through the oxygen concentration detector 33 is returned into the reactor containment vessel 12 through the return pipe 43.

  Next, the oxygen concentration detector 33 in the containment vessel atmosphere monitor 14 detects the oxygen concentration of the sample gas (step S12). At the same time, the pressure in the reactor containment vessel 12 is measured by the pressure gauge 35 (step S13). This pressure may be measured by a pressure gauge (not shown) in the containment vessel atmosphere monitor 14.

  Next, the oxygen partial pressure in the reactor containment vessel 12 is calculated based on the oxygen concentration instruction value obtained from the containment vessel atmosphere monitor 14 and the pressure measurement result obtained from the pressure gauge in the reactor containment vessel 12. (First oxygen partial pressure calculation step S14).

  On the other hand, output currents from the in-container oxygen sensors 15a, 15b, and 15c are detected (step S15). Next, the oxygen partial pressure in the nuclear reactor containment vessel 12 is calculated based on the output currents of the containment vessel oxygen sensors 15a, 15b, and 15c (second oxygen partial pressure calculation step S16).

  Next, the result of the first oxygen partial pressure calculation step S14 and the result of the second oxygen partial pressure calculation step S16 are compared (step S17). If these results do not match within a predetermined range (in step S17). In the case of No), the current values of the in-container oxygen sensors 15a, 15b, and 15c are calibrated (step S18). That is, the conversion equation for calculating the oxygen partial pressure from the output currents of the in-container oxygen sensors 15a, 15b, and 15c is adjusted.

  In step S17, when the result of the first oxygen partial pressure calculation step S14 and the result of the second oxygen partial pressure calculation step S16 match within a predetermined range (Yes in step S17), the calibration is completed.

  By adopting this embodiment, the inside of the containment vessel 12 can be kept in the containment vessel even during normal operation of the reactor without newly installing piping and equipment for calibrating the in-container oxygen sensors 15a, 15b, 15c inside the containment vessel 12. It is possible to check and calibrate the health of the oxygen sensor.

[Second Embodiment]
FIG. 4 is a flowchart showing the procedure of the second embodiment of the method for measuring oxygen in a reactor containment vessel according to the present invention.

  In the second embodiment, the in-container oxygen sensors 15a, 15b, and 15c are installed in the reactor containment vessel 12 as in the first embodiment described above. The in-container oxygen sensors 15a, 15b, and 15c are, for example, a limiting current type using a solid oxide ion conductor. Thereby, the oxygen concentration in the reactor containment vessel 12 can be measured even at the time of a power loss accident.

  In the first embodiment, data of the containment vessel atmosphere monitor 14 is used for calibration of the oxygen sensors 15a, 15b, 15c in the containment vessel. In the second embodiment, for calibration of the oxygen sensor 15 in the containment vessel. The difference is that data of a portable oxygen sensor (not shown) is used.

  Assume that in-container oxygen sensors 15a, 15b, and 15c are fixedly installed in the reactor containment vessel 12 in advance. The calibration of the in-container oxygen sensors 15a, 15b, and 15c is performed, for example, at a periodic inspection when the nuclear reactor is stopped. As shown in FIG. 4, the portable oxygen sensor is carried in the vicinity of the in-container oxygen sensors 15a, 15b, 15c in the reactor containment vessel 12 during the periodic inspection and temporarily installed (step S21). At this time, a portable pressure gauge (not shown) may be carried and temporarily installed in the vicinity of the portable oxygen sensor together with the portable oxygen sensor.

  Next, the oxygen concentration at that position is detected by the portable oxygen sensor carried into the reactor containment vessel 12 (step S22). At this time, the pressure in the reactor containment vessel 12 is measured by an existing pressure gauge or a portable pressure gauge carried in at this time (step S23).

  Next, based on the oxygen concentration obtained in step S22 and the pressure obtained in step S23, the oxygen partial pressure at that position is calculated (first oxygen partial pressure calculating step S24).

  On the other hand, as in step S15 of the first embodiment, output currents from the in-container oxygen sensors 15a, 15b, and 15c are detected (step S25). Next, as in step S16 of the first embodiment, the oxygen partial pressure in the reactor containment vessel 12 is calculated based on the output currents of the containment vessel oxygen sensors 15a, 15b, 15c (second oxygen Partial pressure calculation step S26).

  Next, the result of the first oxygen partial pressure calculation step S24 and the result of the second oxygen partial pressure calculation step S26 are compared (step S27). If these results do not match within a predetermined range (in step S27). In the case of No), the current values of the in-container oxygen sensors 15a, 15b, and 15c are calibrated (step S28). That is, the conversion equation for calculating the oxygen partial pressure from the output currents of the in-container oxygen sensors 15a, 15b, and 15c is adjusted.

  In step S27, if the result of the first oxygen partial pressure calculation step S24 and the result of the second oxygen partial pressure calculation step S26 match within a predetermined range (Yes in step S27), the calibration is completed.

  By adopting this second embodiment, the containment oxygen sensor 15 can be soundly operated without newly installing piping or equipment for calibrating the in-container oxygen sensors 15a, 15b, 15c inside the reactor containment vessel 12. Confirmation and calibration are possible.

[Other Embodiments]
The above embodiments are presented as examples, and are not intended to limit the scope of the invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. This embodiment and its modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 11 ... Reactor building, 12 ... Reactor containment vessel, 13 ... Reactor pressure vessel, 14 ... Containment vessel atmosphere monitor, 15a, 15b, 15c ... Containment vessel oxygen sensor (oxygen measuring device in containment vessel), 21 ... Dry Well, 22 ... Wet well, 31 ... Blower, 32 ... Cooler (heat exchanger), 33 ... Oxygen concentration detector (oxygen measuring device outside containment vessel), 35 ... Pressure gauge, 36, 37 ... Sample gas extraction part, 38 ... Sample gas return section, 41 ... Dry well gas phase air supply pipe (air supply pipe), 42 ... Wet well gas phase air supply pipe (air supply pipe), 43 ... Return pipe

Claims (8)

A containment vessel,
An air supply pipe connected to the sample gas extraction portion of the reactor containment vessel to take out the sample gas in the reactor containment vessel; and
An oxygen measuring device outside the containment vessel that is arranged outside the reactor containment vessel and measures an oxygen partial pressure of the sample gas delivered by the air feeding pipe;
A return pipe connected to the sample gas return section of the nuclear reactor containment vessel and the oxygen measuring device outside the containment vessel and returning the sample gas discharged from the oxygen measuring device outside the containment vessel into the reactor containment vessel;
A blower that is arranged in the air supply pipe or the return pipe and drives the sample gas inside the air supply pipe and the return pipe;
An oxygen measuring instrument in the containment vessel that is arranged in the reactor containment vessel and measures the oxygen partial pressure of the gas in the reactor containment vessel;
A nuclear reactor facility characterized by comprising:   2. The nuclear reactor facility according to claim 1, wherein the in-container oxygen measuring device is disposed in the sample gas extraction unit or the sample gas return unit.   The nuclear reactor facility according to claim 1 or 2, wherein the oxygen measuring device in the reactor containment vessel includes a limiting current type oxygen sensor using a solid oxide oxygen ion conductor. A sample gas in the reactor containment vessel is taken out using a blower through an air supply pipe connected to a sample gas take-out portion of the reactor containment vessel, and the outside of the containment vessel arranged outside the reactor containment vessel A sample gas circulation step for passing the oxygen measuring device and returning the sample gas after passing through the oxygen measuring device outside the containment vessel into the reactor containment vessel through a sample gas return part of the reactor containment vessel;
A sample gas oxygen partial pressure measuring step for measuring an oxygen partial pressure of the sample gas taken out through the air supply pipe by the oxygen measuring device outside the containment vessel;
A step of measuring oxygen partial pressure in the containment vessel, wherein the oxygen partial pressure in the reactor containment vessel is measured by an oxygen measuring device in the containment vessel disposed in the reactor containment vessel;
Correction for correcting the oxygen partial pressure in the reactor containment obtained from the containment oxygen partial pressure measurement step based on the oxygen partial pressure of the sample gas obtained from the sample gas oxygen partial pressure measurement step Steps,
A method for measuring oxygen in a containment vessel, comprising: The outside-container oxygen measuring device includes an oxygen concentration measuring device
The sample gas oxygen partial pressure measuring step includes:
An oxygen concentration measuring step of measuring the oxygen concentration of the sample gas by the oxygen measuring device outside the containment vessel;
A pressure measuring step for measuring the pressure in the reactor containment vessel;
A first oxygen partial pressure calculating step for calculating an oxygen partial pressure based on the oxygen concentration obtained from the oxygen concentration measuring step and the pressure in the reactor containment vessel obtained from the pressure measuring step;
Including
The containment vessel oxygen measuring device includes an oxygen sensor that outputs an output current corresponding to an oxygen partial pressure in the reactor containment vessel,
The step of measuring oxygen partial pressure in the containment vessel
Including a second oxygen partial pressure calculating step of calculating an oxygen partial pressure in the reactor containment vessel based on an output current of the oxygen sensor;
The method for measuring oxygen in a reactor containment vessel according to claim 4. A measuring instrument loading step for loading a portable oxygen measuring instrument into the reactor containment vessel;
A portable oxygen partial pressure measuring step of measuring an oxygen partial pressure in the reactor containment vessel by the portable oxygen measuring device;
A fixed oxygen partial pressure measuring step for measuring an oxygen partial pressure in the reactor containment vessel based on an output of an oxygen measuring device in the containment vessel fixed in the reactor containment vessel;
Based on the oxygen partial pressure in the reactor containment vessel obtained from the portable oxygen partial pressure measurement step, the oxygen partial pressure in the reactor containment vessel obtained from the fixed oxygen partial pressure measurement step is corrected. Correction steps to
A method for measuring oxygen in a containment vessel, comprising: The portable oxygen measuring device includes an oxygen concentration measuring device,
The portable oxygen partial pressure measurement step includes:
An oxygen concentration measurement step of measuring the oxygen concentration in the reactor containment vessel by the portable oxygen measuring device;
A pressure measuring step for measuring the pressure in the reactor containment vessel;
A first oxygen partial pressure calculating step for calculating an oxygen partial pressure based on the oxygen concentration obtained from the oxygen concentration measuring step and the pressure in the reactor containment vessel obtained from the pressure measuring step;
Including
The containment vessel oxygen measuring device includes an oxygen sensor that outputs an output current corresponding to an oxygen partial pressure in the reactor containment vessel,
The fixed oxygen partial pressure measurement step includes:
Including a second oxygen partial pressure calculating step of calculating an oxygen partial pressure in the reactor containment vessel based on an output current of the oxygen sensor;
The method for measuring oxygen in a reactor containment vessel according to claim 6.   8. The reactor containment vessel oxygen measuring device includes a limiting current type oxygen sensor using a solid oxide oxygen ion conductor, according to any one of claims 4 to 7. Method for measuring oxygen in the containment vessel.

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