JP2008170223A - Measuring method of water level of nuclear reactor and its device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and device for measuring water level of a nuclear reactor having a simplified structure without requiring a complicated structure of the nuclear reactor. <P>SOLUTION: This method is provided with introducing a microwave generated by a microwave source 11, set outside of a pressure vessel 1 of a nuclear reactor, to inside of the pressure vessel 1, and projecting it to the water surface 16 of the water 1b stocked inside of the pressure vessel 1, and then the water level of the water 1b is obtained from the relationship between the intensity of the reflected microwave and time or from a resonant frequency. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a reactor water level measuring method and apparatus for measuring the liquid level height of a coolant in a boiling water reactor or a pressurized water reactor.

  Generally, a differential pressure type water level gauge is known as a water level gauge for a boiling water reactor (Patent Document 1). In the differential pressure type water level gauge, as shown in FIG. 9, instrumentation pipes 2, 3, and 4 are provided for the reactor pressure vessel 1 containing the core 1a and the coolant 1b, and the condensing tank 5 is attached. The upper instrumentation pipe 2 is connected to the lower instrumentation pipes 3 and 4 via differential pressure gauges 6 and 7, respectively. Since the differential pressure gauges 6 and 7 measure a pressure proportional to the reactor water level, the reactor water level can be obtained from the pressure. The reactor water level can be obtained by either of the differential pressure gauges 6 and 7, but the measurement range and accuracy are different. Reference numeral 8 denotes a differential pressure gauge for correction.

On the other hand, a thermocouple type water level gauge is known as a water level gauge for a pressurized water reactor. In the thermocouple type water level gauge, as shown in FIG. 10, a cladding tube 10 containing a thermocouple sensor 9 is attached to the reactor pressure vessel 1. The thermocouple sensor 9 has two temperature sensitive parts at the lower end, and one temperature sensitive part has a heat generating part. When the water level is present below the thermocouple sensor 9, since the temperature difference is generated in the temperature sensing part, the presence or absence of water is known, so that the water level can be obtained (Patent Document 2). Moreover, it can replace with the thermocouple type sensor 9, and can also use sensors, such as an ultrasonic wave, an electromagnetic, and a magnetism (patent document 3).
JP-A-5-302840 JP-A-8-220284 Japanese Patent Laid-Open No. 10-142028

  The conventional differential pressure type water level meter described above requires the instrumentation pipes 2, 3, 4 and the condensing tank 5 for measuring the reactor water level, and there is a problem that the structure of the reactor becomes complicated.

  On the other hand, in the above-described thermocouple type water level gauge, it is necessary to attach a plurality of thermocouple type sensors 9 or to attach a vertical drive mechanism to the thermocouple type sensor 9, and the structure of the nuclear reactor is similar to the differential pressure type water level gauge. There is a problem of becoming complicated.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a simple method and apparatus for measuring the reactor water level without complicating the structure of the reactor.

  The reactor water level measuring apparatus according to the present invention includes a microwave source that is installed outside a reactor pressure vessel and generates a microwave, a waveguide transmission unit that performs microwave transmission, and is connected to the waveguide transmission unit. Wireless transmission means for wirelessly transmitting microwaves to the outer wall of the pressure vessel, and cable transmission connected to the wireless transmission means on the outer wall of the pressure vessel, penetrating to the inside of the pressure vessel, and transmitting microwaves to the inside of the pressure vessel Means, antenna means connected to the cable transmission means, for projecting microwaves on the water surface inside the pressure vessel and receiving reflected microwaves, and received by the antenna means and external to the pressure vessel by the cable transmission means Waveguide branching means for branching and guiding after the reflected microwave transmitted to the wireless transmission by the wireless transmission means and transmitted to the waveguide transmission means, Detection means for detecting the reflected microwaves guided by the waveguide branching means, from the sensed reflected microwave configured to have a water level calculation means for calculating calculates the water level inside the pressure vessel.

  The method for measuring the reactor water level according to the present invention introduces a microwave generated by a microwave source provided outside the reactor pressure vessel into the pressure vessel and projects the microwave onto the surface of the water stored in the pressure vessel. The height of the surface of the water is obtained from the relationship between the intensity of reflected microwave and time or the resonance frequency.

  According to the present invention, it is possible to provide a simple method and apparatus for measuring a reactor water level without complicating the structure of the reactor.

  Hereinafter, first to fourth embodiments of a reactor water level measuring method and apparatus according to the present invention will be described with reference to the drawings.

(First embodiment)
(Constitution)
As shown in FIG. 1, the reactor water level measuring apparatus according to the present embodiment is installed outside the reactor pressure vessel 1 and generates a microwave 11 for measuring the water level inside the pressure vessel. And a waveguide transmission means 12 that guides and transmits microwaves to the vicinity of the reactor pressure vessel 1, and is attached to the waveguide transmission means 12 and the outer wall 13 of the reactor pressure vessel 1. Wireless transmission means 14a, 14b for wirelessly transmitting microwaves to the outer wall 13 of the pressure vessel 1, and wireless transmission means 14b on the outer wall 13 of the reactor pressure vessel 1, are attached to the inside of the reactor pressure vessel 1, A cable transmission means 15 for transmitting microwaves to the inside of the reactor pressure vessel 1 and an antenna that is attached to the cable transmission means 15 and that projects microwaves onto the water surface 16 inside the reactor pressure vessel 1. The reflected microwaves reflected by the tener means 17 and the water means 16 and received by the antenna means 17 and transmitted to the outside of the reactor pressure vessel 1 by the cable transmission means 15 are wirelessly transmitted and guided by the wireless transmission means 14a and 14b. After being transmitted to the transmission means 12, the branching waveguide means 18 branching, the detection means 19 for detecting the reflected microwave guided by the waveguide branching means 18, and the reactor pressure vessel 1 from the detected reflected microwave Some or all of the water level calculation means 20 for calculating and calculating the internal water level, the information wireless transmission means 21a and 21b for wirelessly transmitting the water level calculation results, the microwave source 11, the detection means 19 and the water level calculation means 20 Wireless operation means 22a, 22b for remotely operating the wireless communication and wireless transmission of information wireless transmission means 21a, 21b and wireless operation means 22a, 22b A radio relay unit 23 for relaying, and a.

  The microwave source 11 includes an electron tube such as a klystron, a magnetron, or a traveling wave tube, or a semiconductor element such as a Gunn diode. The frequency of the microwave is selected in consideration of the directivity and transmission loss of the microwave, and the dimensions of the wireless transmission means 14a and 14b and the cable transmission means 15.

  The waveguide transmission means 12 is formed of a hollow conductor and has no cross-sectional shape limitation, but the inner diameter is selected so as to match the frequency of the microwave.

Each of the wireless transmission units 14a and 14b is composed of a horn antenna, and the microwaves are highly linear, so the horn antennas are installed to face each other.
The cable transmission means 15 is comprised with the coaxial cable of the cross-sectional structure shown in FIG. 2, for example. FIG. 2 shows a coaxial cable having a double structure, which includes conductors 24 and 26, mineral insulators 25 and 27, and a stainless sheath 28. The cable transmission means 15 is attached to the outer wall 13 or the inner wall of the pressure vessel 1 by brazing, welding, or the like.

The antenna means 17 is composed of a horn antenna, like the radio transmission means 14a and 14b.
The waveguide branching means 18 is composed of a hollow conductor with a magnetic material installed therein, and, like the waveguide transmission means 12, there is no restriction on the cross-sectional shape, but the inner diameter dimension is adapted to the microwave frequency. Select. The waveguide branching means 18 is combined with the waveguide transmission means 12 to constitute a circulator, transmits the microwave generated by the microwave source 11 to the wireless transmission means 14a, and receives the reflected microwave received by the wireless transmission means 14a. The data is transmitted to the detection means 19.

The detection means 19 includes a bolometer, thermistor, diode, and the like.
As shown in FIG. 3, the water level calculation means 20 is composed of a signal processing device that obtains the relationship between the signal intensity of the detected reflected microwave and time. When steam and water form a two-phase state, since the dielectric constant differs between steam and water, a discontinuous point 29 where the signal intensity becomes discontinuous is formed.

  The information wireless transmission means 21a and 21b are composed of wireless communication devices, and microwave communication, millimeter wave communication, and long wave to ultra short wave communication are applicable. The information to be transmitted is modulated and transmitted by the information wireless transmission means 21a, and received and demodulated by the information wireless transmission means 21b.

  Similarly to the information wireless transmission means 21a and 21b, the wireless operation means 22a and 22b are configured by wireless communication devices, and microwave communication, millimeter wave communication, and communication from long wave to ultrashort wave can be applied. The information to be transmitted is modulated and transmitted by the wireless operation means 22a, and received and demodulated by the wireless operation means 22b.

  A plurality of information wireless transmission means 21b and wireless operation means 22a can be installed in different places, but the carrier frequencies of the wireless operation means 22a and 22b and the information wireless transmission means 21a and 21b are set to be different.

  The wireless relay means 23 is an apparatus that amplifies and relays transmission signals of the information wireless transmission means 21a and 21b and the wireless operation means 22a and 22b when transmitting a long distance or a complicated route. For example, in the case of microwave communication, it is applied when the information wireless transmission means 21a and 21b cannot face each other. In addition, a plurality of wireless relay means 23 can be installed, and transmission paths can be multiplexed, multi-pathed, and distributed simultaneously to a plurality of locations.

(Function)
The microwave pulse-oscillated by the microwave source 11 is transmitted through the waveguide transmission means 12 to the wireless transmission means 14a, and is wirelessly transmitted from the wireless transmission means 14a. The wirelessly transmitted microwave is received by the wireless transmission means 14 b and transmitted from the outer wall 13 of the reactor pressure vessel 1 to the inside by the cable transmission means 15.

  In consideration of microwave transmission loss, a waveguide is suitable as a transmission means from the outer wall 13 of the reactor pressure vessel 1 to the inside. However, since the waveguide has a hollow structure, the airtightness in the reactor pressure vessel 1 is reduced. Sex cannot be maintained. On the other hand, a general coaxial cable cannot be applied because the reactor pressure vessel 1 is in a high temperature and high pressure and radiation environment. Therefore, by using the coaxial cable having the structure shown in FIG. 2, it can be applied to a high temperature and high pressure and radiation environment, and by attaching to the outer wall 13 or the inner wall of the reactor pressure vessel 1 by brazing or welding, the reactor pressure vessel 1 The inside airtightness can be secured.

  The pulsed microwave transmitted to the inside of the reactor pressure vessel 1 is projected from the antenna means 17 to the water surface 16 inside the reactor pressure vessel 1, and the microwave reflected by the water surface is received by the antenna means 17. . The reflected microwave returns from the antenna means 17 to the cable transmission means 15, is transmitted to the outside of the reactor pressure vessel 1, and is wirelessly transmitted from the wireless transmission means 14b. Then, the reflected microwave received by the wireless transmission means 14 a is guided by the waveguide branching means 18 and detected by the detection means 19. In addition, since the inside of the pressure vessel 1 is high temperature and high pressure, it will be in the mixed state of water and steam, and a detection signal may become small. In such a case, the microwave frequency is changed to reduce the transmission loss of the microwave so that the detection signal is increased.

  In the water level calculation means 20, the result as shown in FIG. 3 is obtained, and the discontinuous point 29 represents the water surface 16 which is a two-phase different dielectric constant, that is, the boundary surface between the vapor phase and the water phase. Here, when the discontinuous point 29 is unclear, the frequency of the microwave is changed as described above to make it clear. The water level is obtained from the propagation speed of the microwave and the time of the discontinuity point 29.

  The obtained water level is added with time, place, setting of the microwave source 11, and other necessary information, and is wirelessly transmitted from the information wireless transmission means 21a to the information wireless transmission means 21b via the wireless relay means 23. The information wireless transmission means 21b is installed in places such as the central operation room and outside the management area, and obtains the water level and other information efficiently and economically at those places.

  On the other hand, the operation, stop, emergency stop, and other necessary operation and operation conditions related to the microwave source 11, the detection unit 19, and the water level calculation unit 20 are set by the wireless operation unit 22a, and the wireless operation unit is connected via the wireless relay unit 23. 22b is wirelessly transmitted. Then, the microwave source 11, the detection unit 19, and the water level calculation unit 20 are operated by the wireless operation unit 22b. Similarly to the information wireless transmission means 21b, the wireless operation means 22a is installed in a place such as a central operation room or outside the management area, and is operated efficiently and economically.

(effect)
According to the present embodiment, the microwave is used to measure the water level inside the reactor pressure vessel 1, the microwave is transmitted to the inside of the pressure vessel using the antenna and the coaxial cable, and the reactor pressure vessel 1 By measuring the water level from the microwave reflected by the water surface 16 inside, the instrumentation piping is unnecessary, and the drive mechanism and multiple sensors are unnecessary, which may complicate the structure of the reactor. A simple reactor water level measuring device can be provided. In addition, it is possible to grasp the water level and other information from a remote location such as outside the central control room or management area by wireless operation, and it is also possible to simultaneously grasp the water level and other information at each remote location. it can.

(Second Embodiment)
(Constitution)
Next, a reactor water level measuring apparatus according to a second embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the same structure as 1st Embodiment, and the overlapping description is abbreviate | omitted.

  The reactor water level measuring apparatus according to the present embodiment is installed outside the reactor pressure vessel 1 and generates a microwave source 11 for measuring the water level inside the reactor pressure vessel 1. A waveguide transmission means 30 for waveguide-transmitting microwaves to the outer wall 13 of the pressure vessel 1 and a waveguide transmission means 30 connected to the outer wall 13 of the reactor pressure vessel 1 and penetrating to the inside of the reactor pressure vessel 1. The cable transmission means 15 for transmitting the microwave to the inside of the reactor pressure vessel 1 and the microwave that is attached to the structure in the reactor pressure vessel 1 and transmits the microwave to the water surface 16 inside the reactor pressure vessel 1. The antenna means 31 for projecting to the reflection, the reflection reflected by the water surface 16 and received by the antenna means 31, and transmitted by the cable transmission means 15 to the waveguide transmission means 30 outside the reactor pressure vessel 1 Waveguide branching means 18 for branching the microwave, detection means 19 for detecting the reflected microwave guided by the waveguide branching means 18, and calculating the water level inside the reactor pressure vessel 1 from the detected reflected microwave Water level calculation means 20, information wireless transmission means 21a, 21b for wirelessly transmitting the water level calculation result, and wired relay means 32 for transmitting a part or all of the wireless transmission by wire. Yes.

  Like the waveguide transmission means 12, the waveguide transmission means 30 is composed of a conductor having a hollow structure, and there is no restriction on the cross-sectional shape, but the inner diameter dimension is selected so as to match the microwave frequency.

  The antenna means 31 is constituted by a parabolic antenna and is attached to a structure in the reactor pressure vessel 1 such as a steam separator or a steam generator, an inner wall of the reactor pressure vessel 1 or the like. The antenna means 31 projects the microwave on the water surface 16 inside the reactor pressure vessel 1, and the shape and direction of the parabolic antenna are set so that the reflected wave can be received. Since the antenna means 31 is separated from the cable transmission means 15, the structure is simple and the maintenance during the periodic inspection is easy.

  The wired relay means 32 is an apparatus that amplifies and transmits the transmission signals of the information wireless transmission means 21a and 21b and the wireless operation means 22a and 22b when transmitting a complicated route. The wired relay unit 32 includes a wireless transmission / reception device and a signal transmission cable, and performs wired communication between the wireless reception device and the wireless transmission device using the signal transmission cable. The signal transmission cable can be laid in the same manner as other instrumentation wirings, or can be converted into an optical signal and transmitted through an optical fiber cable. Similarly to the wireless relay unit 23, a plurality of wired relay units 32 can be installed, and transmission paths can be multiplexed, multi-pathed, and simultaneously distributed to a plurality of locations.

(Function)
The microwave pulsated by the microwave source 11 is efficiently transmitted to the outer wall 13 of the reactor pressure vessel 1 by the waveguide transmission means 30 and is transmitted to the inside of the reactor pressure vessel 1 by the cable transmission means 15. Inside the reactor pressure vessel 1, the cable transmission means 15 serves as a primary radiator to radiate microwaves, which are reflected by the antenna means 31 and projected to the water surface 16 inside the reactor pressure vessel 1. Is done. The microwave reflected by the water surface is reflected by the antenna means 31, received by the cable transmission means 15 of the primary radiator, and transmitted to the outside of the reactor pressure vessel 1. Then, the reflected microwave transmitted to the outside of the reactor pressure vessel 1 is detected by the detection means 19 through the waveguide branching means 18 after being guided through the waveguide transmission means 30. When the detection signal is small, as in the first embodiment, the microwave frequency is changed to reduce the transmission loss of the microwave so that the detection signal becomes large. Since the water level calculation means 20 obtains the result as shown in FIG. 3, the water level is obtained from the time of the discontinuous point 29 and the propagation speed of the microwave. Here, when the discontinuous point 29 is unclear, the frequency of the microwave is changed as described above to make it clear.

  The obtained water level is added with time, place, setting of the microwave source 11, and other necessary information, and is wirelessly transmitted from the information wireless transmission means 21a to the information wireless transmission means 21b via the wired relay means 32, and is operated centrally. Obtain water level and other information efficiently and economically in places such as rooms and out of control areas. In addition, since the part of the wire relay means 32 is a signal transmission cable, transmission is easy even if it is a complicated path | route, and the utilization of the existing instrumentation wiring is also possible.

(effect)
According to the present embodiment, the microwave is used to measure the water level inside the reactor pressure vessel 1, and the microwave is transmitted to the inside of the reactor pressure vessel 1 using the waveguide and the coaxial cable. By measuring the water level from the microwave reflected by the water surface 16 in the reactor pressure vessel 1, the number of instrumentation pipes can be reduced, and a drive mechanism and a plurality of sensors are not required. It is possible to provide a simple reactor water level measuring device that does not become complicated.

  Further, the antenna means 31 in the reactor pressure vessel 1 is attached to a structure in the reactor pressure vessel 1 or an inner wall of the reactor pressure vessel 1 and transmits a microwave to the inside of the reactor pressure vessel 1. Since it is separated from the transmission means 15, the structure is simple and the maintenance during the periodic inspection is easy.

  Furthermore, even when the central control room or outside the control area is at the end of complicated routes, the water level and other information can be grasped at these locations, and a simple reactor water level measurement device should be provided. Can do. In addition, the water level and other information can be grasped simultaneously at each remote location.

(Third embodiment)
(Constitution)
Next, a reactor water level measuring apparatus according to a third embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the same structure as 1st, 2nd embodiment, and the overlapping description is abbreviate | omitted.

  The reactor water level measuring apparatus according to the present embodiment is installed outside the reactor pressure vessel 1 and generates a microwave source 11 for measuring the water level inside the reactor pressure vessel 1. A waveguide transmission means 30 for waveguide-transmitting microwaves to the outer wall 13 of the pressure vessel 1 and a waveguide transmission means 30 connected to the outer wall 13 of the reactor pressure vessel 1 and penetrating to the inside of the reactor pressure vessel 1. In the same manner as the cable transmission means 15 for transmitting the microwave to the inside of the reactor pressure vessel 1 and the antenna means 31 attached to the structure in the reactor pressure vessel 1 for wirelessly transmitting and receiving the microwave transmitted by the cable. Reflecting means 33a and 33b which are attached to the structure in the pressure vessel, reflect the microwave projected from the antenna means 31 and project it to the water surface 16, and float on the water surface 16 to transmit the microwave. Reflected by the floating reflecting means 33c and the floating reflecting means 33c, further reflected by the reflecting means 33a and 33b and received by the antenna means 31, and by the cable transmission means 15 outside the reactor pressure vessel 1 Waveguide branching means 18 for branching and guiding the reflected microwave from the water surface 16 transmitted to the waveguide transmission means 30, and detection for detecting the reflected microwave from the water surface 16 guided by the waveguide branching means 18. Means 19; water level calculation means 20 for calculating the water level inside the reactor pressure vessel 1 from the detected reflected microwave; and information wireless transmission means 21a, 21b for wirelessly transmitting the water level calculation results; Wire relaying means 32 for transmitting a part or all of the wireless transmission by wire.

  In the case of the present embodiment, the shape and orientation of the parabolic antenna are set so that the antenna means 31 can perform wireless transmission and reception using multiple reflections by the reflecting means 33a and 33b and the floating reflecting means 33c.

  The reflecting means 33a and 33b are made of a flat or parabolic conductor, and are attached to a structure 34 in the reactor pressure vessel 1 such as a steam separator or a steam generator, an inner wall of the reactor pressure vessel 1 or the like. . Further, depending on the situation, the surface of the structure 34 in the reactor pressure vessel 1 or the inner wall surface of the reactor pressure vessel 1 can be used as the reflection means.

  The floating reflecting means 33 c is configured by attaching a float to a flat plate-shaped or parabolic conductor, and floats on the water surface 16.

(Function)
The microwave pulsated by the microwave source 11 is efficiently transmitted to the outer wall 13 of the reactor pressure vessel 1 by the waveguide transmission means 30 and is transmitted to the inside of the reactor pressure vessel 1 by the cable transmission means 15. Inside the reactor pressure vessel 1, the microwave radiated from the tip of the cable transmission means 15 is reflected by the antenna means 31, and then repeatedly reflected between the reflecting means 33 a and 33 b and projected onto the water surface 16. The The microwave projected on the water surface 16 is reflected by the floating reflecting means 33 c on the water surface 16, is further subjected to multiple reflection between the reflecting means 33 a and 33 b, is incident on the antenna means 31, and is received by the cable transmission means 15. Is done. The received microwave reflected from the water surface is detected by the detection means 19 by the same action as in the second embodiment.

  In the present embodiment, since the microwaves are efficiently reflected by the reflecting means 33a and 33b and the floating reflecting means 33c, the detecting means 19 can obtain a detection signal with a high S / N ratio. The water level is obtained from the discontinuous point 29 shown in FIG. Here, when the discontinuity 29 is unclear, the microwave frequency is changed to be clear as in the first and second embodiments.

  Then, by using the information wireless transmission means 21a, 21b and the wired relay means 32 to transmit information wirelessly and by wire, the water level and other information are acquired in places such as the central operation room and outside the management area.

(effect)
According to the present embodiment, the microwave is used to measure the water level inside the reactor pressure vessel 1, and the microwave is transmitted to the inside of the reactor pressure vessel 1 using the waveguide and the coaxial cable. The number of instrumentation pipes can be reduced by efficiently reflecting the microwaves by the reflecting means 33a, 33b, 33c provided on the reactor internal structure and the water surface, and measuring the water level from the microwaves reflected by the water surface. Simple measurement of the reactor water level without the need for a drive mechanism and multiple sensors, and the ability to measure a high signal-to-noise ratio without increasing the size of the microwave source and complicating the reactor structure An apparatus can be provided.

(Fourth embodiment)
(Constitution)
Next, a reactor water level measuring apparatus according to a fourth embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the same structure as 1st-3rd embodiment, and the overlapping description is abbreviate | omitted.

  The reactor water level measuring apparatus according to the present embodiment is installed outside the reactor pressure vessel 1 and generates a microwave source 11 for measuring the water level inside the reactor pressure vessel 1. A waveguide transmission means 30 for waveguide-transmitting microwaves to the outer wall 13 of the pressure vessel 1 and a waveguide transmission means 30 connected to the outer wall 13 of the reactor pressure vessel 1 and penetrating to the inside of the reactor pressure vessel 1. The cable transmission means 15 for transmitting the microwave to the inside of the reactor pressure vessel 1 and the microwave transmitted through the cable are installed in the reactor pressure vessel 1, and are submerged in accordance with the water level of the water surface 16. Waveguide transmission / reception means 35 of varying length, and microwaves resonated according to the submerged length of the waveguide transmission / reception means 35 and transmitted to the waveguide transmission means 30 outside the pressure vessel 1 by the cable transmission means 15 The A waveguide branching means 18 for branching and guiding, a detection means 19 for detecting a microwave guided by the waveguide branching means 18, and a water level inside the reactor pressure vessel 1 from the detected resonance frequency of the microwave A water level calculation means 20 that calculates the water level, information wireless transmission means 21a and 21b that wirelessly transmit the water level calculation results, and a wired relay means 32 that transmits part or all of the wireless transmission by wire. Has been.

  In the case of the present embodiment, the water level calculation means 20 is constituted by a signal processing device that obtains the relationship between the frequency of the microwave and the signal intensity as shown in FIG. In the waveguide transmission / reception means 35, the resonance of the microwave occurs because the resonance of the microwave occurs with the water surface 16 as the reflection end.

  As shown in FIG. 8, the waveguide transmission / reception means 35 is configured by a hollow conductor having an end opening 37 at the lower end and an upper opening 38 at the upper end, and is installed in the reactor pressure vessel 1 to be placed on the water surface 16. The submerged length changes according to the water level, water enters the same height as the water level from the opening 37 at the lower end, and high-temperature and high-pressure steam escapes from the upper opening 38. It resonates at a frequency that depends on the water level. The relationship between the resonance frequency 36 and the water level is measured in advance.

(Function)
The microwave continuously oscillated by the microwave source 11 is transmitted to the outer wall 13 of the reactor pressure vessel 1 by the waveguide transmission means 30 and is transmitted to the waveguide transmission / reception means 35 inside the reactor pressure vessel 1 by the cable transmission means 15. Is done. In the waveguide transmitting / receiving means 35, resonance occurs at a frequency corresponding to the water level of the water surface 16.

  Here, while scanning the frequency of the microwave, it is transmitted from the cable transmission means 15 to the outside of the reactor pressure vessel 1, guided through the waveguide transmission means 30, and then detected by the waveguide branching means 18. Detect with. The waveguide transmission / reception means 35 can efficiently transmit microwaves, and the detection means 19 can obtain a detection signal with a high S / N ratio.

  In the water level calculation means 20, the result as shown in FIG. 7 is obtained, and the resonance frequency 36 indicates the resonance frequency of the waveguide transmission / reception means 35. Therefore, the actual water level is obtained from the relationship between the resonance frequency measured in advance and the water level. .

  The obtained water level is added with time, place, setting of the microwave source 11, and other necessary information, and is wirelessly transmitted from the information wireless transmission means 21a to the information wireless transmission means 21b via the wired relay means 32, and is operated centrally. Obtain water level and other information in places such as rooms and out of control areas.

(effect)
According to the present embodiment, the microwave is used to measure the water level inside the reactor pressure vessel 1, and the microwave is transmitted to the inside of the reactor pressure vessel 1 using the waveguide and the coaxial cable. Since the water level is measured from the resonance frequency of the microwave that resonates on the water surface in the waveguide transmission / reception means 35 that efficiently transmits the microwave, the number of instrumentation pipes can be reduced, and a drive mechanism and a plurality of sensors are unnecessary. Become. In addition, because it is possible to detect microwaves with a high signal-to-noise ratio, high-precision water level measurement is possible without increasing the size of the microwave source, and simple measurement of the reactor water level without complicating the reactor structure. An apparatus can be provided.

The figure which shows the structure of the measuring apparatus of the reactor water level of the 1st Embodiment of this invention. Sectional drawing which shows the structure of the cable transmission means with which the reactor water level measuring apparatus of the 1st Embodiment of this invention is equipped. The graph explaining operation | movement of the water level calculating means with which the reactor water level measuring apparatus of the 1st Embodiment of this invention is equipped. The figure which shows the structure of the measuring apparatus of the reactor water level of the 2nd Embodiment of this invention. The figure which shows the structure of the measuring apparatus of the reactor water level of the 3rd Embodiment of this invention. The figure which shows the structure of the measuring apparatus of the reactor water level of the 4th Embodiment of this invention. The graph explaining operation | movement of the water level calculating means with which the reactor water level measuring apparatus of the 4th Embodiment of this invention is equipped. The figure which shows the structure of the waveguide transmission / reception means with which the reactor water level measuring apparatus of the 4th Embodiment of this invention is equipped. The figure which shows the structure of the conventional reactor water level measuring apparatus. The figure which shows the structure of the conventional reactor water level measuring apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Reactor pressure vessel, 1a ... Core, 1b ... Coolant, 2, 3, 4 ... Instrument piping, 5 ... Condensing tank, 6, 7, 8 ... Differential pressure gauge, 9 ... Thermocouple sensor, 10 ... Coating Tube 11, microwave source 12, waveguide transmission means 13, outer wall of pressure vessel 14 a, 14 b wireless transmission means 15 cable transmission means 16 water surface 17 antenna means 18 waveguide branching means , 19 ... detection means, 20 ... water level calculation means, 21a, 21b ... information wireless transmission means, 22a, 22b ... wireless operation means, 23 ... wireless relay means, 24,26 ... conductor, 25,27 ... mineral insulator, 28 ... Stainless steel sheath, 29 ... Discontinuous point, 30 ... Waveguide transmission means, 31 ... Antenna means, 32 ... Wire relay means, 33a, 33b, 33c ... Reflection means, 34 ... In-furnace structure, 35 ... Waveguide transmission / reception Means 36 ... resonance frequency 37 ... end Mouth, 38 ... upper opening.

Claims (11)

  A microwave source installed outside the pressure vessel of the nuclear reactor to generate microwaves, waveguide transmission means for guiding and transmitting microwaves, and microwave transmission to the outer wall of the pressure vessel connected to the waveguide transmission means Wireless transmission means connected to the wireless transmission means at the outer wall of the pressure vessel, penetrating to the inside of the pressure vessel, and transmitting to the inside of the pressure vessel, microwave transmission to the inside of the pressure vessel, connected to the cable transmission means, Antenna means for projecting microwaves onto the water surface inside the pressure vessel and receiving reflected microwaves; and wirelessly transmitting reflected microwaves received by the antenna means and transmitted to the outside of the pressure vessel by the cable transmission means After being transmitted wirelessly by the means and transmitted to the waveguide transmission means, the waveguide branching means for branching and guiding and guided by the waveguide branching means Detection means for detecting the elevation microwave, sensed reflected microwave reactor water level measuring device, characterized in that it comprises a water level calculation means for calculating calculates the water level inside the pressure vessel from.   The reactor water level measuring device according to claim 1, further comprising a waveguide transmission unit instead of the wireless transmission unit.   The reactor water level measuring device according to claim 1 or 2, wherein the water level calculating means calculates the water level inside the pressure vessel from the relationship between the intensity of the detected reflected microwave and time.   The reactor water level measuring device according to any one of claims 1 to 3, further comprising reflecting means that floats on a water surface in the nuclear reactor and reflects microwaves.   The reactor water level measuring device according to any one of claims 1 to 4, further comprising reflection means attached to a part or a plurality of parts of the structure in the nuclear reactor to reflect microwaves. .   The atom according to any one of claims 1 to 3, further comprising: a waveguide transmission / reception unit that transmits and receives a microwave by being partially immersed in water inside the pressure vessel, instead of the antenna unit. Reactor water level measuring device.   7. The reactor water level measuring device according to claim 1, further comprising information wireless transmission means for wirelessly transmitting information on a water level calculation result by the water level calculation means.   The reactor water level according to any one of claims 1 to 7, further comprising wireless operation means for remotely operating at least one of the microwave source, the detection means, and the water level calculation means wirelessly. Measuring device.   The reactor water level measuring device according to claim 7 or 8, further comprising: a wireless relay unit that relays wireless transmission by at least one of the information wireless transmission unit and the wireless operation unit.   The reactor water level measuring device according to claim 7 or 8, further comprising a wired relay unit that transmits part or all of the wireless transmission by the information wireless transmission unit and the wireless operation unit by wire.   The microwave generated by the microwave source provided outside the reactor pressure vessel is introduced into the pressure vessel and projected onto the water surface stored in the pressure vessel, and the relationship between the intensity of reflected microwave and time or A method for measuring a reactor water level, wherein the water level is determined from a resonance frequency.

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