WO2019009462A1 - System for monitoring state of spent-nuclear-fuel cask - Google Patents

System for monitoring state of spent-nuclear-fuel cask Download PDF

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Publication number
WO2019009462A1
WO2019009462A1 PCT/KR2017/008770 KR2017008770W WO2019009462A1 WO 2019009462 A1 WO2019009462 A1 WO 2019009462A1 KR 2017008770 W KR2017008770 W KR 2017008770W WO 2019009462 A1 WO2019009462 A1 WO 2019009462A1
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temperature
communication module
canister
cask
spent
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PCT/KR2017/008770
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French (fr)
Korean (ko)
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김형철
채명은
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주식회사엔에스이
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    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21C—NUCLEAR REACTORS
    • G21C17/00—Monitoring; Testing ; Maintaining
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
    • G21F5/00—Transportable or portable shielded containers
    • G21F5/005—Containers for solid radioactive wastes, e.g. for ultimate disposal
    • G21F5/008—Containers for fuel elements
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E30/00—Energy generation of nuclear origin
    • Y02E30/30—Nuclear fission reactors

Definitions

  • the present invention relates to a spent fuel cask monitoring system, and more particularly, to a system for detecting and monitoring the occurrence of an abnormal state of spent fuel cask on the basis of temperature for long-term management of spent nuclear fuel cask .
  • the spent nuclear fuel after it has been burned for a certain period at a nuclear power plant is called spent nuclear fuel.
  • the spent fuel is subjected to a cooling process and is disposed of permanently in a reprocessing facility or a permanent storage. Since the spent fuel is a radioactive material that releases radiation and decay heat, it is necessary to safely store the spent fuel in order to transport and store the spent fuel before permanent disposal, And a storage cask having a structure capable of smoothly discharging decay heat is used.
  • the structure of these spent fuel cask is disclosed in Korean Patent No. 10-1333066, Korean Patent No. 10-1303085, and Korean Patent No. 10-0449792.
  • 1 shows the structure of a spent nuclear fuel storage cask including a concrete shielding structure.
  • the cask has a canister (14) for storing the spent nuclear fuel therein, and surrounds the canister with a concrete structure to shield the radiation.
  • the canister 14 is generally made of a cylindrical metal container and filled with a filling gas such as helium to allow the decay of spent fuel to be transferred to the outside of the canister by conduction, radiation, and convection.
  • Annular air cooling passages 22 and 24 are formed between the concrete structure and the canister so that the air introduced into the inlet 26 cools the outer wall of the canister and is discharged through the outlet 28.
  • the concrete structure is provided with a metal liner 30, a rib 31 for supporting the lower portion of the canister, and an upper lid 20.
  • the cask disclosed in Korean Patent No. 10-1303085 is a dual purpose storage cask, which is not provided with a concrete structure and an annular air cooling passage on the outside of the canister, An outer casing surrounding the outer casing and a neutron shielding material filled therein. In this case, a heat transfer fin made of a metal material having high thermal conductivity is connected between the canister and the outer casing.
  • Korean Patent Laid-Open Publication No. 10-2015-0076452 discloses a spent nuclear fuel cask in which a plurality of temperature sensors are horizontally arranged on a lid of a cask (storage container).
  • the lid of the cask normally has a cover on the upper part for shielding radiation, the heated fill gas flows into the upper space of the canister by the convection and diffuses. Therefore, by simply arranging a plurality of temperature sensors horizontally on the lid, It is difficult to grasp the internal state of the claw.
  • Spent fuel casking requires long-term management to ensure continuous cooling and radiation shielding over a period of several decades or longer, so that a more reliable state of continuous monitoring of the health of the cask, A surveillance system is needed.
  • the present invention aims to provide a system for monitoring the state of a spent nuclear fuel cask by calculating an internal variable of a canister based on the surface temperature of a canister for the purpose of monitoring the spent fuel cask for a long period of time.
  • the spent fuel cask condition monitoring system includes a plurality of temperature sensors for measuring a surface temperature of a canister of a cask, a transmitter communication module for collecting and transmitting temperature signals from the temperature sensor, And a monitoring server for receiving a temperature signal from the receiving end communication module and incorporating a correlation algorithm between the temperature and the monitoring target variable and calculating a monitoring target variable by using a correlation algorithm,
  • the communication module is composed of a plurality of units each corresponding to a plurality of spent nuclear fuel cask installed in the installation area, and is assigned a unique number. At least one or more of the receiver communication modules are installed in one installation area, Thereby identifying the transmitting-end communication module.
  • the transmitting terminal communication module of the spent fuel cask condition monitoring system uses battery power
  • the receiving terminal communication module uses power by direct wiring
  • the receiving terminal communication module and the transmitting terminal communication module perform wireless communication
  • the module and the monitoring server may be characterized in that they perform wired communication.
  • the monitoring server of the spent nuclear fuel cascade monitoring system compares the behavior of signals received from a plurality of transmitter communication modules installed in one installation area to determine an abnormal state of spent nuclear fuel cascade .
  • the plurality of temperature sensors measure the temperature at a predetermined position on the surface of the canister
  • the correlation algorithm embedded in the monitoring server is a pre-analysis result of the spent nuclear fuel cask And a neural network algorithm based on a database based on the neural network.
  • the correlation algorithm embedded in the monitoring server of the spent fuel cask condition monitoring system may be characterized in that a plurality of correlation algorithms are provided for each type of spent nuclear fuel cask.
  • the temperature sensor of the spent nuclear fuel cascade monitoring system may measure the temperature of the axial position of the canister on the surface of the canister so that the monitoring server acquires the axial surface temperature distribution information.
  • the spent nuclear fuel cascade monitoring system includes a temperature sensor for measuring the temperature of the ambient air supplied for cooling the cask and a temperature signal collected by the transmitter communication module includes ambient air temperature .
  • the plurality of temperature sensors of the spent fuel cask condition monitoring system measure the temperature of the axisymmetric position of the surface of the canister and the monitoring server compares the temperature signals of the symmetric positions to determine the soundness of the signal .
  • the spent fuel cask condition monitoring system has an effect of monitoring the internal variables such as the fuel temperature and the internal pressure by measuring the surface temperature without a measuring instrument passing through the pressure boundary of the canister.
  • the present invention has the effect of ensuring the stability of signal transmission in the surveillance system by securing multiple signal channels.
  • the present invention has a high degree of freedom in the remote location work of spent nuclear fuel cask in the installation area and has an effect of reducing the cost for installation or transfer work. Also, since the centralized monitoring server is used according to the unique number, the efficiency of the nationwide cask management and maintenance plan is increased.
  • the present invention has the effect of judging the abnormal state of the cascade by comparing the behaviors of the obtained signals and appropriately checking and taking measures.
  • the present invention it is possible to calculate more accurate monitoring variables by applying the optimal correlation algorithm for each cascade type, and it has a effect of widening the selection range of the cascade to the operator of the nuclear power plant.
  • the state monitoring system of the present invention has an effect of considering the influence of the monitoring target variable according to the temperature change of the ambient air.
  • the status monitoring system of the present invention has an effect of detecting the failure of the temperature sensor.
  • FIG. 1 is a schematic sectional view showing a spent fuel cask structure.
  • FIG. 2 is a configuration diagram of a spent fuel cask condition monitoring system according to the present invention.
  • FIG. 3 is a conceptual diagram of a correlation algorithm according to the present invention.
  • FIG. 4 is a top cross-sectional view showing a temperature sensor in an axisymmetric position of the canister according to the present invention.
  • the embodiment of the spent fuel cask condition monitoring system includes a plurality of temperature sensors 110 for measuring the surface temperature of the canister 100 of the spent nuclear fuel cask A communication terminal module 120 for collecting and transmitting temperature signals from the temperature sensor 110, a communication terminal module 130 for receiving a temperature signal from the terminal communication module 120, And a monitoring server 140 that receives a temperature signal from the receiving end communication module 140 and incorporates a correlation algorithm between the temperature and the monitoring target variables and calculates and displays monitored variables using a correlation algorithm .
  • the monitored variable applied to the cask condition monitoring system according to the present invention may be the internal pressure of the canister or the spent fuel cladding temperature.
  • the monitored variable may be a processed parameter from the measured variable rather than the physical variable. Therefore, the spent fuel cask condition monitoring system according to the present invention has an effect of monitoring the internal variables such as the fuel temperature and the internal pressure by measuring the surface temperature without using a measuring instrument passing through the pressure boundary of the canister.
  • the cask includes a cylindrical metallic canister in which the spent nuclear fuel is normally received, and a cask for storing only an annular gap space with the concrete structure Or may be a storage and transportation container having an outer casing enclosing the outside of the canister with a neutron shielding material.
  • the temperature sensor 110 is preferably attached to the surface of the canister in a gap space in the case of a storage-only container to measure the surface temperature of the canister.
  • the surface temperature of the canister may be a secondary surface temperature that is attached to the outer casing and appears through heat conduction.
  • the temperature sensor 110 measures the surface temperature and sends it to the transmitter communication module 120.
  • a thermocouple or a resistance temperature detector (RTD) may be used as the temperature sensor.
  • the transmitting-end communication module 120 is configured to correspond to a plurality of spent nuclear fuel cask installed in a predetermined installation site, and collects the canister surface temperature information of each cask.
  • the transmitting-end communication module 120 is preferably installed adjacent to the cascade.
  • the receiving end communication module 130 is installed to cover one installation area, and collects the canister surface temperature information of all the cascades installed in the installation area.
  • One receiving end communication module 130 may be installed for one installation area, but a plurality of receiving end communication modules 130 may be provided to secure multiple signal channels, thereby ensuring stability of signal transmission of the monitoring system.
  • the surveillance server 140 can collect the surface temperature information of the canisters of all the cascades transmitted from the plurality of installation sites operated by the nuclear power plant through the receiver communication module 130.
  • Each transmitting-end communication module 120 is assigned a unique number, and the monitoring server 140 can identify the transmitting-end communication module 120 assigned to each cascade by its unique number.
  • the transmitting-end communication module 120 uses battery power
  • the receiving-end communication module 130 uses an alternating current or direct-current power by direct wiring. It is preferable that the receiving end communication module 130 and the transmitting end communication module 120 are in wireless communication and the receiving end communication module 130 and the monitoring server 140 are in wired communication.
  • the restoration communication includes communication via the Internet as illustrated in FIG.
  • the transmitting end communication module 120 includes an analog-to-digital converter (ADC), a microcomputer, a wireless module for transmission, a power supply circuit, and a battery. (Access Point) board and controller, an LTE modem, a storage device, a 220V power supply circuit, and the like.
  • ADC analog-to-digital converter
  • the installation area can be operated by designating and operating a specific area within the site of a nuclear power plant or by designating a private building.
  • the spent nuclear fuel is withdrawn from the storage tank of the power plant and is stored in the cask, and the temperature sensor 110 and the transmitting terminal communication module 120 allocated with the unique number are installed and installed in the designated installation area. Register the unique number and monitor the status of the corresponding cascade by its unique number.
  • the present invention uses a battery power source for the transmitting terminal communication module 120, wirelessly communicates with the receiving terminal communication module 130, and manages the cascade according to the unique number, thereby providing a degree of freedom in remote placement of spent fuel cask And the cost required for installation or transfer work is reduced. Also, since the centralized monitoring server is used according to the unique number, the efficiency of the nationwide cask management and maintenance plan is increased.
  • Spent fuel stored in a spent nuclear fuel cask emits decay heat almost constantly over a period of decades. Therefore, if the spent nuclear fuel is stored in the specified conditions, the cask is thermally designed do. Therefore, when the design conditions of the spent fuel cask are satisfied, the monitored variables produced by the monitoring system represent steady-state values for constant ambient air conditions.
  • the main purpose of the state monitoring system of the present invention is to detect whether the monitored variable indicates an abnormal behavior and to monitor an abnormal state, not to obtain an accurate value of the monitored variable.
  • the cascades installed in the same installation area are placed under the same ambient air cooling conditions and the behavior of the processed signal from the surface temperature of the cask canister in the installation area, depending on the daily and seasonal changes in air conditions, such as temperature and humidity,
  • the cascade indicating the difference in the set range from the average behavior can be determined as an abnormal state. Therefore, the monitoring server 140 can compare the behaviors of the signals received from the plurality of transmitting-end communication modules 120 installed in one installation area to determine an abnormal state of the spent nuclear fuel cask and take appropriate measures and measures .
  • the spent fuel cascade monitoring system calculates a monitoring target variable such as the internal fuel temperature or pressure using a correlation algorithm built in the monitoring server 140.
  • a correlation algorithm built in the monitoring server 140.
  • the results of the analysis on the cascade are made into a database and the correlation between the surface temperature and the monitored variables is derived based on the database.
  • the temperature sensor measures the temperature at a predetermined position with respect to the canister, and a preliminary analysis is performed on this position.
  • the algorithm can use either a function form of the response surface model or a neural network model between the surface temperature of a plurality of fixed positions and the monitored variable.
  • General well-known methods can be used for constructing reaction surface model functions and neural network models, and there is no particular limitation. For the construction of neural network model, Y.-H.
  • Figure 3 is a correlation algorithm for calculating a maximum fuel cladding temperature (T-PCT) and the pressure (Press) by function (f T, f P) of the three sensors the temperature is attached to the surface of the canister 310 as an input ( 320). Also shown in FIG. 3 is the thermal analysis database 330 used to derive the correlation, which is not directly used in peak fuel cladding temperature and pressure calculations and is therefore indicated by the dashed line.
  • FIG. 3 exemplarily shows three surface temperatures, but it is not limited thereto, and a correlation algorithm can be constructed including additional measurement signals.
  • the spent nuclear fuel cascade monitored by the monitoring server 140 may have a plurality of different forms with different designs.
  • the monitoring server 140 separately forms and builds a correlation algorithm for each type of cascade, and when the cascade is additionally registered in the monitoring server 140, the monitoring server 140 generates a cascade corresponding to the unique number of the transmitter communication module 120 The corresponding cascade type is input.
  • the optimal correlation algorithm for each type of cascade it is possible to calculate more accurate monitoring variables, and it is possible to broaden the selection range of cascade to the operator of the nuclear power plant.
  • the monitoring target variable may be the internal pressure of the canister and the maximum temperature of the spent fuel cladding pipe.
  • the filling gas inside the canister may be helium, nitrogen, or the like, but helium with high thermal conductivity is preferable. Since the shaft of the cask canister is normally operated in the direction of gravity, the maximum temperature position of the fuel cladding tube tends to be deflected upward in the axial direction as the influence of the convection portion in the heat transfer mechanism in the canister such as conduction, convection and radiation is great. Therefore, when the pressure is lowered due to leakage of the filling gas, the convection mechanism is weakened, and the maximum temperature position of the fuel cladding gradually decreases to the central portion, and the maximum temperature value tends to increase as the heat transfer decreases. This phenomenon means that there is a correlation that can predict the pressure or temperature from the change of the axial temperature distribution, and the correlation algorithm can be constructed through the pre-analysis as described above.
  • the positions arranged in the axial direction may be one or two or more positions evaluated as having a high temperature sensitivity by the pre-analysis.
  • the canister of the cask If the canister of the cask is damaged due to defects or corrosion, the filling gas leaks and the pressure inside the canister is reduced. Such pressure reduction can be detected by the correlation algorithm of the condition monitoring system according to the present invention. Also, when the cooling function is deteriorated due to clogging of the air inlet and the temperature of the fuel cladding tube is increased, the detection by the state monitoring system of the present invention is also possible.
  • the correlation algorithm can be reinforced by adding the cooling air temperature to the temperature variables included in the correlation algorithm built in the monitoring server 140 in addition to the canister surface temperature. And a temperature sensor for measuring the temperature of the inlet air or the ambient air supplied for cooling the spent nuclear fuel cask.
  • the temperature signal collected by the transmitter communication module may include ambient air temperature.
  • the spent nuclear fuel bundles 410 stored in the canister 400 generally have an axisymmetric arrangement. Therefore, when the temperature sensors 431, 432, 433, 434 measure the temperature at the axially symmetric position of the surface of the canister, the surface temperatures at the symmetric positions have values close to each other.
  • temperature sensors 431 and 433, 432 and 434 respectively show temperature sensor pairs in symmetrical positions. Therefore, the temperature of the position where the plurality of temperature sensors are arranged axially symmetrically with respect to the surface of the canister can be measured, and the monitoring server can judge the soundness of the signal by mutually comparing the signals at the symmetric positions. That is, when the temperature measurement value of the symmetric position is out of the setting range, it is possible to detect the failure of the temperature sensor.
  • the present invention provides a system for monitoring the state of a spent nuclear fuel cask by calculating an internal variable of a canister on the basis of the surface temperature of the canister for the purpose of monitoring the cascade of cask storing spent fuel generated in a nuclear power plant . Therefore, the present invention is applicable to industries related to nuclear power generation.

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  • General Engineering & Computer Science (AREA)
  • High Energy & Nuclear Physics (AREA)
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  • Monitoring And Testing Of Nuclear Reactors (AREA)

Abstract

A system for monitoring a state of a spent-nuclear-fuel cask, according to the present invention, comprises: a plurality of temperature sensors for measuring a surface temperature of a canister of a cask; a transmitting end communication module for collecting a temperature signal from the temperature sensor and transmitting the same; a receiving end communication module for receiving the temperature signal from the transmitting end communication module; and a monitoring server for receiving the temperature signal from the receiving end communication module and including a correlation algorithm between the temperature and a variable to be monitored, and calculating, by using the correlation algorithm, the variable to be monitored. The system for monitoring the state of the spent-nuclear-fuel cask, of the present invention, includes an effect of capable of monitoring internal variables such as a nuclear fuel temperature and an internal pressure by measuring the surface temperature without a measurement instrument penetrating a pressure boundary of the canister.

Description

사용후핵연료 캐스크 상태 감시 시스템Spent fuel cask condition monitoring system
본 발명은 사용후핵연료 캐스크 상태 감시 시스템에 관한 것으로서, 구체적으로는 사용후핵연료 캐스크의 장기적 관리를 위하여 온도 기반으로 사용후핵연료 캐스크의 이상 상태 발생을 탐지 및 감시하기 위한 시스템에 관한 것이다.The present invention relates to a spent fuel cask monitoring system, and more particularly, to a system for detecting and monitoring the occurrence of an abnormal state of spent fuel cask on the basis of temperature for long-term management of spent nuclear fuel cask .
원자력 발전소에서 소정 기간 연소된 후 배출되는 핵연료를 사용후핵연료(spent nuclear fuel)라 한다. 사용후핵연료는 냉각 과정을 거쳐 재처리 시설이나 영구저장소에서 영구처분 되는데, 사용후핵연료는 방사선과 붕괴열을 방출하는 방사성 물질이므로, 이를 영구처분 전에 운반 및 중간 저장하기 위해서는 사용후핵연료를 안전하게 격납하여 방사선을 차폐하고 붕괴열을 원활히 방출할 수 있는 구조로 이루어진 사용후핵연료 캐스크(보관용기; storage cask)를 사용한다. The spent nuclear fuel after it has been burned for a certain period at a nuclear power plant is called spent nuclear fuel. The spent fuel is subjected to a cooling process and is disposed of permanently in a reprocessing facility or a permanent storage. Since the spent fuel is a radioactive material that releases radiation and decay heat, it is necessary to safely store the spent fuel in order to transport and store the spent fuel before permanent disposal, And a storage cask having a structure capable of smoothly discharging decay heat is used.
이들 사용후핵연료 캐스크의 구조는 한국 등록특허 10-1333066호, 한국 등록특허 10-1303085호, 한국 등록특허 10-0449792호 등에 개시되어 있다. 도1은 콘크리트 차폐구조물을 포함하는 사용후핵연료 보관 전용 캐스크의 구조를 도시한다. 캐스크는 내부에 사용후 핵연료를 격납하는 캐니스터(canister; 14)를 구비하고 그 외부를 콘크리트 구조체로 둘러싸 방사선 차폐를 한다. 캐니스터(14)는 통상 원통형상의 금속제 용기로 제작되며, 내부에 헬륨 등의 충진 가스를 채워 전도, 복사, 대류에 의하여 사용후핵연료의 붕괴열이 캐니스터 외부로 전달되도록 한다. 콘크리트 구조체와 캐니스터 사이에는 환상(annular)의 공기 냉각 유로(22,24)가 형성되어, 입구(26)로 유입된 공기가 캐니스터 외벽을 냉각하고 출구(28)를 통하여 배출되는 구조를 갖는다. 통상 콘크리트 구조체에는 금속 라이너(30), 캐니스터 하부를 지지하는 리브(31) 및 상부 덮개(20)가 구비된다. 한편, 한국 등록특허 10-1303085호에 개시된 캐스크는 보관(storage) 및 운반(transport) 겸용 용기(dual purpose storage cask)로서 캐니스터 외측에 콘크리트 구조체 및 환상의 공기 냉각 유로가 형성되어 있지 않고, 캐니스터의 외부를 감싸는 외부케이싱과 그 내부에 충전된 중성자차폐재를 포함하는 구조를 예시한다. 이런 경우에는 통상 캐니스터와 외부케이싱의 사이에는 열전도성이 높은 금속 소재로 이루어진 열전달부재(heat transfer fin)가 연결 설치된다.The structure of these spent fuel cask is disclosed in Korean Patent No. 10-1333066, Korean Patent No. 10-1303085, and Korean Patent No. 10-0449792. 1 shows the structure of a spent nuclear fuel storage cask including a concrete shielding structure. The cask has a canister (14) for storing the spent nuclear fuel therein, and surrounds the canister with a concrete structure to shield the radiation. The canister 14 is generally made of a cylindrical metal container and filled with a filling gas such as helium to allow the decay of spent fuel to be transferred to the outside of the canister by conduction, radiation, and convection. Annular air cooling passages 22 and 24 are formed between the concrete structure and the canister so that the air introduced into the inlet 26 cools the outer wall of the canister and is discharged through the outlet 28. Typically, the concrete structure is provided with a metal liner 30, a rib 31 for supporting the lower portion of the canister, and an upper lid 20. [ Meanwhile, the cask disclosed in Korean Patent No. 10-1303085 is a dual purpose storage cask, which is not provided with a concrete structure and an annular air cooling passage on the outside of the canister, An outer casing surrounding the outer casing and a neutron shielding material filled therein. In this case, a heat transfer fin made of a metal material having high thermal conductivity is connected between the canister and the outer casing.
한국 공개특허 10-2015-0076452호에서는 캐스크(보관용기)의 뚜껑(lid)에 온도 센서를 수평 방향으로 다수 배치하는 사용후핵연료 캐스크를 공개하고 있다. 그러나 통상 캐스크의 뚜껑에는 방사선 차폐를 위하여 상부에 덮개가 존재할 뿐 아니라 가열된 충진 가스가 대류에 의하여 캐니스터 상부 공간으로 유동되어 확산하므로 단순히 뚜껑에 다수의 온도 센서를 수평 방향으로 배치하는 것만으로 캐스크의 내부 상태를 파악하기는 곤란하다. Korean Patent Laid-Open Publication No. 10-2015-0076452 discloses a spent nuclear fuel cask in which a plurality of temperature sensors are horizontally arranged on a lid of a cask (storage container). However, since the lid of the cask normally has a cover on the upper part for shielding radiation, the heated fill gas flows into the upper space of the canister by the convection and diffuses. Therefore, by simply arranging a plurality of temperature sensors horizontally on the lid, It is difficult to grasp the internal state of the claw.
사용후핵연료 캐스크는 수십년 이상 장기간에 걸쳐서 지속적인 냉각과 방사선 차폐를 보장하기 위한 장기적인 관리가 요구되므로, 캐스크의 건전성 상태를 지속적으로 감시하고 이상이 감지되면 필요한 조치를 취할 수 있도록 보다 신뢰성 있는 상태 감시 시스템이 필요하다.Spent fuel casking requires long-term management to ensure continuous cooling and radiation shielding over a period of several decades or longer, so that a more reliable state of continuous monitoring of the health of the cask, A surveillance system is needed.
본 발명은 사용후핵연료 캐스크의 장기적 상태 감시를 목적으로 하며, 캐니스터 표면 온도에 근거하여 캐니스터 내부 변수를 산출하여 사용후핵연료 캐스크의 상태를 감시하는 시스템을 제공하기 위한 것이다.The present invention aims to provide a system for monitoring the state of a spent nuclear fuel cask by calculating an internal variable of a canister based on the surface temperature of a canister for the purpose of monitoring the spent fuel cask for a long period of time.
본 발명에 따른 사용후핵연료 캐스크 상태 감시 시스템은 캐스크의 캐니스터 표면온도를 측정하는 복수개의 온도 센서, 상기 온도 센서로부터 온도 신호를 수집하여 송신하는 송신단 통신모듈, 상기 송신단 통신모듈로부터 온도 신호를 수신하는 수신단 통신모듈, 및 상기 수신단 통신모듈로부터 온도 신호를 수신하며, 온도와 감시대상변수 간의 상관관계 알고리즘을 내장하며, 상관관계 알고리즘을 사용하여 감시대상변수를 산출하는 감시서버를 포함하며, 송신단 통신모듈은 설치구역에 설치된 복수의 사용후핵연료 캐스크에 각각 대응되도록 복수개로 구성되어 고유번호가 할당되며, 수신단 통신모듈은 하나의 설치구역에 대하여 적어도 하나 이상 설치되며, 감시서버는 고유번호에 의하여 송신단 통신모듈을 식별하는 것을 특징으로 한다. The spent fuel cask condition monitoring system according to the present invention includes a plurality of temperature sensors for measuring a surface temperature of a canister of a cask, a transmitter communication module for collecting and transmitting temperature signals from the temperature sensor, And a monitoring server for receiving a temperature signal from the receiving end communication module and incorporating a correlation algorithm between the temperature and the monitoring target variable and calculating a monitoring target variable by using a correlation algorithm, The communication module is composed of a plurality of units each corresponding to a plurality of spent nuclear fuel cask installed in the installation area, and is assigned a unique number. At least one or more of the receiver communication modules are installed in one installation area, Thereby identifying the transmitting-end communication module.
본 발명에 따른 사용후핵연료 캐스크 상태 감시 시스템의 송신단 통신모듈은 배터리 전원을 사용하며, 수신단 통신모듈은 직접배선에 의한 전원을 사용하며, 수신단 통신모듈과 송신단 통신모듈은 무선통신하며, 수신단 통신모듈과 감시서버는 유선통신 하는 것을 특징으로 할 수 있다. The transmitting terminal communication module of the spent fuel cask condition monitoring system according to the present invention uses battery power, the receiving terminal communication module uses power by direct wiring, the receiving terminal communication module and the transmitting terminal communication module perform wireless communication, The module and the monitoring server may be characterized in that they perform wired communication.
본 발명에 따른 사용후핵연료 캐스크 상태 감시 시스템의 감시 서버는 하나의 설치구역에 설치된 복수의 송신단 통신모듈로부터 수신된 신호의 거동을 상호 비교하여 사용후핵연료 캐스크의 이상 상태를 판정하는 것을 특징으로 할 수 있다. The monitoring server of the spent nuclear fuel cascade monitoring system according to the present invention compares the behavior of signals received from a plurality of transmitter communication modules installed in one installation area to determine an abnormal state of spent nuclear fuel cascade .
본 발명에 따른 사용후핵연료 캐스크 상태 감시 시스템에서 복수개의 온도 센서는 캐니스터 표면의 사전에 정해진 위치의 온도를 측정하며, 감시서버에 내장된 상관관계 알고리즘은 사용후핵연료 캐스크에 대한 사전분석결과에 근거한 데이터베이스를 기반으로 구축된 신경회로망 알고리즘인 것을 특징으로 할 수 있다. In the spent fuel cascade monitoring system according to the present invention, the plurality of temperature sensors measure the temperature at a predetermined position on the surface of the canister, and the correlation algorithm embedded in the monitoring server is a pre-analysis result of the spent nuclear fuel cask And a neural network algorithm based on a database based on the neural network.
본 발명에 따른 사용후핵연료 캐스크 상태 감시 시스템의 감시서버에 내장된 상관관계 알고리즘은 사용후핵연료 캐스크의 형태별로 복수개 구비되는 것을 특징으로 할 수 있다. The correlation algorithm embedded in the monitoring server of the spent fuel cask condition monitoring system according to the present invention may be characterized in that a plurality of correlation algorithms are provided for each type of spent nuclear fuel cask.
본 발명에 따른 사용후핵연료 캐스크 상태 감시 시스템의 온도 센서는 캐니스터의 표면에 축 방향으로 배열된 위치의 온도를 측정하여 감시서버가 축방향 표면온도 분포 정보를 취득하는 것을 특징으로 할 수 있다. The temperature sensor of the spent nuclear fuel cascade monitoring system according to the present invention may measure the temperature of the axial position of the canister on the surface of the canister so that the monitoring server acquires the axial surface temperature distribution information.
본 발명에 따른 사용후핵연료 캐스크 상태 감시 시스템은 캐스크 냉각을 위하여 공급되는 주변 공기의 온도를 측정하는 온도 센서를 포함하며, 송신단 통신모듈이 수집하는 온도 신호에 주변 공기 온도가 포함되는 것을 특징으로 할 수 있다. The spent nuclear fuel cascade monitoring system according to the present invention includes a temperature sensor for measuring the temperature of the ambient air supplied for cooling the cask and a temperature signal collected by the transmitter communication module includes ambient air temperature .
본 발명에 따른 사용후핵연료 캐스크 상태 감시 시스템의 복수개의 온도 센서는 캐니스터 표면의 축 대칭 위치의 온도를 측정하고, 감시서버는 대칭 위치의 온도 신호를 상호 비교함으로써 신호의 건전성을 판단하는 것을 특징으로 할 수 있다.The plurality of temperature sensors of the spent fuel cask condition monitoring system according to the present invention measure the temperature of the axisymmetric position of the surface of the canister and the monitoring server compares the temperature signals of the symmetric positions to determine the soundness of the signal .
본 발명에 따른 사용후핵연료 캐스크 상태 감시 시스템은 캐니스터의 압력경계를 관통하는 측정계기가 없이 표면온도를 측정하여 핵연료 온도 및 내부 압력 등의 내부 변수를 감시할 수 있는 효과를 갖는다.The spent fuel cask condition monitoring system according to the present invention has an effect of monitoring the internal variables such as the fuel temperature and the internal pressure by measuring the surface temperature without a measuring instrument passing through the pressure boundary of the canister.
본 발명은 다중의 신호 채널을 확보함으로써 감시 시스템의 신호 전송의 안정성을 도모하는 효과를 갖는다. The present invention has the effect of ensuring the stability of signal transmission in the surveillance system by securing multiple signal channels.
본 발명은 설치구역에서 사용후핵연료 캐스크의 원격지 배치 작업에 자유도가 높고, 설치 또는 이전 작업에 소요되는 비용이 저감되는 효과가 있다. 또한 고유번호에 의하여 중앙 관제방식의 감시서버를 사용하므로 전국적인 캐스크 관리 및 보수 계획의 효율성이 증대되는 효과가 있다.The present invention has a high degree of freedom in the remote location work of spent nuclear fuel cask in the installation area and has an effect of reducing the cost for installation or transfer work. Also, since the centralized monitoring server is used according to the unique number, the efficiency of the nationwide cask management and maintenance plan is increased.
본 발명은 취득된 신호의 거동을 상호 비교하여 캐스크의 이상 상태를 판정하고 적절한 확인 및 조치를 취할 수 있는 효과가 있다. The present invention has the effect of judging the abnormal state of the cascade by comparing the behaviors of the obtained signals and appropriately checking and taking measures.
본 발명은 캐스크 형태 별로 최적의 상관관계 알고리즘을 적용함으로써 더욱 정확한 감시변수 산출이 가능하며, 원전 운영자에게 캐스크의 선택 폭을 넓게 해 주는 효과가 있다.According to the present invention, it is possible to calculate more accurate monitoring variables by applying the optimal correlation algorithm for each cascade type, and it has a effect of widening the selection range of the cascade to the operator of the nuclear power plant.
본 발명의 상태 감시 시스템은 주변 공기의 온도 변화에 따른 감시대상변수의 영향을 고려하는 효과를 갖는다.The state monitoring system of the present invention has an effect of considering the influence of the monitoring target variable according to the temperature change of the ambient air.
본 발명의 상태 감시 시스템은 온도센서의 고장 여부를 감지하는 효과를 갖는다.The status monitoring system of the present invention has an effect of detecting the failure of the temperature sensor.
도1은 사용후핵연료 캐스크 구조를 나타내는 간략 단면도이다.1 is a schematic sectional view showing a spent fuel cask structure.
도2는 본 발명에 따른 사용후핵연료 캐스크 상태 감시 시스템의 구성 개념도이다.2 is a configuration diagram of a spent fuel cask condition monitoring system according to the present invention.
도3은 본 발명에 따른 상관관계 알고리즘의 개념도이다.3 is a conceptual diagram of a correlation algorithm according to the present invention.
도4는 본 발명에 따른 캐니스터 축대칭 위치의 온도센서를 나타내는 평단면도이다.4 is a top cross-sectional view showing a temperature sensor in an axisymmetric position of the canister according to the present invention.
이하에서는 본 발명에 따른 구체적인 실시예가 설명된다. 그러나 본 발명은 여러 가지 다양한 형태로 변형하여 구현될 수 있으며 여기에서 설명하는 실시예에 한정되지는 않는다. 본 발명에 첨부된 도면은 설명의 편의를 위하여 간략화 되었으며, 본 발명을 명확하게 설명하기 위해서 설명과 관계없는 부분은 생략되었다. Hereinafter, specific embodiments according to the present invention will be described. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
본 발명에 따른 사용후핵연료 캐스크 상태 감시 시스템의 실시예는 도2에 개념적으로 도시된 바와 같이, 사용후핵연료 캐스크의 캐니스터(100) 표면 온도를 측정하는 복수개의 온도 센서(Temperature Sensor; 110), 온도 센서(110)로부터 온도 신호를 수집하여 송신하는 송신단 통신모듈(Communication Transmitter Module; 120), 송신단 통신모듈(120)로부터 온도 신호를 수신하는 수신단 통신모듈(Communication Receiver Module; 130), 그리고 수신단 통신모듈(140)로부터 온도 신호를 수신하며, 온도와 감시대상변수 간의 상관관계 알고리즘을 내장하며, 상관관계 알고리즘을 사용하여 감시대상변수를 산출하여 표출하는 감시서버(140)를 포함하여 구성된다. As shown in FIG. 2, the embodiment of the spent fuel cask condition monitoring system according to the present invention includes a plurality of temperature sensors 110 for measuring the surface temperature of the canister 100 of the spent nuclear fuel cask A communication terminal module 120 for collecting and transmitting temperature signals from the temperature sensor 110, a communication terminal module 130 for receiving a temperature signal from the terminal communication module 120, And a monitoring server 140 that receives a temperature signal from the receiving end communication module 140 and incorporates a correlation algorithm between the temperature and the monitoring target variables and calculates and displays monitored variables using a correlation algorithm .
본 발명에 따른 캐스크 상태 감시 시스템에 적용되는 감시대상변수는 캐니스터의 내부 변수인 압력 또는 사용후핵연료 피복관 온도일 수 있다. 감시대상변수는 물리적 변수가 아닌 측정 변수로부터 가공된 처리 변수(processed parameter)일 수도 있다. 따라서 본 발명에 따른 사용후핵연료 캐스크 상태 감시 시스템은 캐니스터의 압력경계를 관통하는 측정계기가 없이도 표면온도를 측정하여 핵연료 온도 및 내부 압력 등의 내부 변수를 감시할 수 있는 효과를 갖는다. The monitored variable applied to the cask condition monitoring system according to the present invention may be the internal pressure of the canister or the spent fuel cladding temperature. The monitored variable may be a processed parameter from the measured variable rather than the physical variable. Therefore, the spent fuel cask condition monitoring system according to the present invention has an effect of monitoring the internal variables such as the fuel temperature and the internal pressure by measuring the surface temperature without using a measuring instrument passing through the pressure boundary of the canister.
도2에서 사용후핵연료 캐스크의 상세 구조는 도시되지 않았으나, 캐스크는 통상 사용후핵연료가 수납되는 원통 형상의 금속제 캐니스터를 포함하며, 콘크리트 구조체와의 사이에 환형의 갭 공간을 구비하는 보관 전용 캐스크이거나 또는 캐니스터 외부를 중성자차폐재로 둘러싸고 외부케이싱이 구비된 보관 및 운송 겸용 용기 일 수 있다.The detailed structure of the spent nuclear fuel cask is not shown in FIG. 2, but the cask includes a cylindrical metallic canister in which the spent nuclear fuel is normally received, and a cask for storing only an annular gap space with the concrete structure Or may be a storage and transportation container having an outer casing enclosing the outside of the canister with a neutron shielding material.
온도 센서(110)는 보관 전용 용기의 경우 갭 공간 내에서 캐니스터의 표면에 부착되어 캐니스터의 표면온도를 측정하는 것이 바람직하다. 보관 및 운송 겸용 용기인 경우에는 외부케이싱에 부착되어 캐니스터의 표면온도가 열전도를 통해서 나타나는 2차적인 표면온도일 수 있다. The temperature sensor 110 is preferably attached to the surface of the canister in a gap space in the case of a storage-only container to measure the surface temperature of the canister. In the case of a container for both storage and transportation, the surface temperature of the canister may be a secondary surface temperature that is attached to the outer casing and appears through heat conduction.
온도 센서(110)는 표면온도를 측정하여 송신단 통신모듈(120)로 보낸다. 온도센서로는 통상 열전대(Thermocouple)나 측온저항계(RTD, Resistance Temperature Detector) 등이 사용될 수 있다.  The temperature sensor 110 measures the surface temperature and sends it to the transmitter communication module 120. As the temperature sensor, a thermocouple or a resistance temperature detector (RTD) may be used.
송신단 통신모듈(120)은 정해진 설치구역(Site)에 설치된 복수의 사용후핵연료 캐스크에 각각 대응되도록 복수개로 구성되어 각 캐스크의 캐니스터 표면온도 정보를 수집한다. 송신단 통신모듈(120)은 캐스크에 인접하여 설치되는 것이 바람직하다. 수신단 통신모듈(130)은 하나의 설치구역을 커버하도록 설치하여 그 설치구역에 설치된 모든 캐스크의 캐니스터 표면온도 정보를 수집한다. 통상 하나의 설치구역에 대하여 수신단 통신모듈(130)을 한 개 설치할 수 있지만 복수의 수신단 통신모듈(130)을 설치하여 다중의 신호 채널을 확보함으로써 감시 시스템의 신호 전송의 안정성을 도모할 수 있다. The transmitting-end communication module 120 is configured to correspond to a plurality of spent nuclear fuel cask installed in a predetermined installation site, and collects the canister surface temperature information of each cask. The transmitting-end communication module 120 is preferably installed adjacent to the cascade. The receiving end communication module 130 is installed to cover one installation area, and collects the canister surface temperature information of all the cascades installed in the installation area. One receiving end communication module 130 may be installed for one installation area, but a plurality of receiving end communication modules 130 may be provided to secure multiple signal channels, thereby ensuring stability of signal transmission of the monitoring system.
도2는 이해를 돕기 위하여 두 개의 설치구역(Site-A, Site-B)을 예시하여 도시 하고 있으며, 설치구역 A에 n개의 캐스크가 도시되고 이에 대응되는 n개의 송신단 통신모듈(120)이 도시되어 있다. 감시서버(140)는 원자력발전소에 운영되는 다수의 설치구역으로부터 수신단 통신모듈(130)을 통하여 전송되는 모든 캐스크의 캐니스터 표면온도 정보를 수집할 수 있다. 2 shows an example of two installation areas (Site-A and Site-B) for understanding, where n cascades are shown in the installation area A, and n transmitting-end communication modules 120 corresponding thereto Respectively. The surveillance server 140 can collect the surface temperature information of the canisters of all the cascades transmitted from the plurality of installation sites operated by the nuclear power plant through the receiver communication module 130.
각 송신단 통신모듈(120)은 고유번호가 할당되며, 감시서버(140)는 고유번호에 의하여 각 캐스크에 할당된 송신단 통신모듈(120)을 식별할 수 있다.Each transmitting-end communication module 120 is assigned a unique number, and the monitoring server 140 can identify the transmitting-end communication module 120 assigned to each cascade by its unique number.
송신단 통신모듈(120)은 배터리 전원을 사용하고, 수신단 통신모듈(130)은 직접배선에 의한 교류 또는 직류 전원을 사용하는 것이 바람직하다. 수신단 통신모듈(130)과 송신단 통신모듈(120)은 무선통신하며, 수신단 통신모듈(130)과 감시서버(140)는 유선통신(wired communication) 하는 것이 바람직하다. 여기서 유신통신은 도2에 예시된 바와 같이 인터넷을 통한 통신을 포함한다. Preferably, the transmitting-end communication module 120 uses battery power, and the receiving-end communication module 130 uses an alternating current or direct-current power by direct wiring. It is preferable that the receiving end communication module 130 and the transmitting end communication module 120 are in wireless communication and the receiving end communication module 130 and the monitoring server 140 are in wired communication. Herein, the restoration communication includes communication via the Internet as illustrated in FIG.
통상적으로 송신단 통신모듈(120)은 아날로그-디지털 변화기(ADC), 마이컴, 송신용 무선 모듈, 전원회로, 배터리를 포함하여 구성되며, 수신단 통신모듈(130)은 예를 들어 수신용 무선모듈, AP(Access Point) 보드 및 제어기, LTE 모뎀, 저장장치, 220V 전원회로 등을 포함하여 구성될 수 있다.The transmitting end communication module 120 includes an analog-to-digital converter (ADC), a microcomputer, a wireless module for transmission, a power supply circuit, and a battery. (Access Point) board and controller, an LTE modem, a storage device, a 220V power supply circuit, and the like.
설치구역은 통상 원자력발전소의 부지내 특정 구역을 지정하여 운영하거나 전용 건물을 지정하여 운영될 수 있다. 사용후핵연료를 발전소 저장조로부터 인출하여 캐스크에 격납 밀봉하고 온도 센서(110)와 고유번호가 할당된 송신단 통신모듈(120)을 장착하고 지정된 설치구역에 설치하는 작업을 수행하고, 감시서버를 통하여 고유번호를 등록하고 고유번호에 의하여 해당 캐스크의 상태를 감시한다. The installation area can be operated by designating and operating a specific area within the site of a nuclear power plant or by designating a private building. The spent nuclear fuel is withdrawn from the storage tank of the power plant and is stored in the cask, and the temperature sensor 110 and the transmitting terminal communication module 120 allocated with the unique number are installed and installed in the designated installation area. Register the unique number and monitor the status of the corresponding cascade by its unique number.
본 발명은 송신단 통신모듈(120)에 배터리 전원을 사용하고, 수신단 통신모듈(130)과 무선통신 하고 고유번호에 의하여 캐스크를 관리함으로써 설치구역에서 사용후핵연료 캐스크의 원격지 배치 작업에 자유도가 높고, 설치 또는 이전 작업에 소요되는 비용이 저감되는 효과가 있다. 또한, 고유번호에 의하여 중앙 관제방식의 감시서버를 사용하므로 전국적인 캐스크 관리 및 보수 계획의 효율성이 증대되는 효과가 있다.The present invention uses a battery power source for the transmitting terminal communication module 120, wirelessly communicates with the receiving terminal communication module 130, and manages the cascade according to the unique number, thereby providing a degree of freedom in remote placement of spent fuel cask And the cost required for installation or transfer work is reduced. Also, since the centralized monitoring server is used according to the unique number, the efficiency of the nationwide cask management and maintenance plan is increased.
사용후핵연료 캐스크에 보관된 사용후핵연료는 수십 년간의 기간 내에서는 거의 일정하게 붕괴열을 방출하므로 캐스크는 규정 조건내의 사용후핵연료가 보관될 경우 무동력의 자연 냉각에 의하여 허가조건이 유지되도록 열설계 된다. 그러므로 사용후핵연료 캐스크의 설계조건이 충족되는 건전한 상태일 경우, 감시 시스템이 산출하는 감시대상변수는 일정한 주변 공기 조건에 대하여 정상 상태(steady-state) 값을 나타낸다. Spent fuel stored in a spent nuclear fuel cask emits decay heat almost constantly over a period of decades. Therefore, if the spent nuclear fuel is stored in the specified conditions, the cask is thermally designed do. Therefore, when the design conditions of the spent fuel cask are satisfied, the monitored variables produced by the monitoring system represent steady-state values for constant ambient air conditions.
본 발명의 상태 감시 시스템은 감시대상변수의 정확한 값을 취득하는 것이 주목적이 아니라, 감시대상변수가 이상(abnormal) 거동을 나타내는지 여부를 탐지하여 이상 상태를 감시하는 것이 주목적이다. 동일한 설치구역에 설치된 캐스크들은 동일한 주변 공기 냉각 조건에 놓여지고, 온도 및 습도 등 공기 조건의 일간(daily) 및 계절적 변화에 따라 해당 설치구역의 캐스크 캐니스터 표면온도로부터 처리된 신호의 거동은 평균적 추세(trend)를 나타낼 것이므로, 평균적 거동으로부터 설정 범위 이상 차이를 나타내는 캐스크는 비정상 상태로 판정할 수 있다. 따라서 감시 서버(140)는 하나의 설치구역에 설치된 복수의 송신단 통신모듈(120)로부터 수신된 신호의 거동을 상호 비교하여 사용후핵연료 캐스크의 이상 상태를 판정하고 적절한 확인 및 조치를 취할 수 있다. The main purpose of the state monitoring system of the present invention is to detect whether the monitored variable indicates an abnormal behavior and to monitor an abnormal state, not to obtain an accurate value of the monitored variable. The cascades installed in the same installation area are placed under the same ambient air cooling conditions and the behavior of the processed signal from the surface temperature of the cask canister in the installation area, depending on the daily and seasonal changes in air conditions, such as temperature and humidity, The cascade indicating the difference in the set range from the average behavior can be determined as an abnormal state. Therefore, the monitoring server 140 can compare the behaviors of the signals received from the plurality of transmitting-end communication modules 120 installed in one installation area to determine an abnormal state of the spent nuclear fuel cask and take appropriate measures and measures .
본 발명에 따른 사용후핵연료 캐스크 상태 감시 시스템은 감시서버(140)에 내장된 상관관계 알고리즘을 사용하여 내부의 핵연료 온도나 압력 등의 감시대상변수를 산출한다. 이 알고리즘 구축을 위하여 캐스크에 대하여 사전에 분석한 결과를 데이터베이스화 하고 이 데이터베이스에 근거하여 표면온도와 감시대상변수 간의 상관관계를 도출한다. 온도 센서는 캐니스터에 대하여 사전에 정해진 위치의 온도를 측정하며, 사전 분석은 이 위치에 대하여 수행한다. 알고리즘은 복수의 정해진 위치의 표면 온도와 감시대상변수 간의 반응표면 모델(response surface model)의 함수 형태 또는 신경회로망(neural network) 모델을 사용할 수 있다. 반응표면 모델 함수 및 신경회로망 모델 구축을 위하여 잘 알려진 일반적 방법들을 사용할 수 있으며 특별한 제한은 없다. 신경회로망 모델 구축에 대하여는 Y.-H. Pao, Adaptive Pattern Recognition and Neural Networks. Reading, MA: Addison-Wesley, 1989 등을 참고할 수 있다. 도3은 캐니스터(310) 표면에 부착된 3개의 센서 온도를 입력으로 하는 함수(fT, fP)에 의하여 최고 핵연료 피복관 온도(T-PCT) 및 압력(Press)을 산출하는 상관관계 알고리즘(320)을 개념적으로 나타낸다. 또한 도3에는 상관관계를 도출하기 위하여 사용된 열분석 데이터베이스(330)를 나타내었으며, 이 데이터베이스는 최고 핵연료 피복관 온도 및 압력 산출 시에는 직접 사용되는 것은 아니므로 점선의 연결선으로 표시되었다. 도3은 3개소의 표면온도를 예시적으로 나타내었으나, 이에 한정되는 것은 아니며 추가적인 측정신호를 포함하여 상관관계 알고리즘을 구성할 수 있다.The spent fuel cascade monitoring system according to the present invention calculates a monitoring target variable such as the internal fuel temperature or pressure using a correlation algorithm built in the monitoring server 140. In order to construct this algorithm, the results of the analysis on the cascade are made into a database and the correlation between the surface temperature and the monitored variables is derived based on the database. The temperature sensor measures the temperature at a predetermined position with respect to the canister, and a preliminary analysis is performed on this position. The algorithm can use either a function form of the response surface model or a neural network model between the surface temperature of a plurality of fixed positions and the monitored variable. General well-known methods can be used for constructing reaction surface model functions and neural network models, and there is no particular limitation. For the construction of neural network model, Y.-H. Pao, Adaptive Pattern Recognition and Neural Networks. Reading, MA: Addison-Wesley, 1989. Figure 3 is a correlation algorithm for calculating a maximum fuel cladding temperature (T-PCT) and the pressure (Press) by function (f T, f P) of the three sensors the temperature is attached to the surface of the canister 310 as an input ( 320). Also shown in FIG. 3 is the thermal analysis database 330 used to derive the correlation, which is not directly used in peak fuel cladding temperature and pressure calculations and is therefore indicated by the dashed line. FIG. 3 exemplarily shows three surface temperatures, but it is not limited thereto, and a correlation algorithm can be constructed including additional measurement signals.
감시서버(140)가 감시하는 사용후핵연료 캐스크는 설계가 다른 복수개의 다양한 형태가 있을 수 있다. 이 경우 감시서버(140)는 각 캐스크의 형태별로 상관관계 알고리즘을 별도로 형성하여 내장하고, 감시서버(140)에 캐스크를 추가 등록할 때 송신단 통신모듈(120) 고유번호에 대응되는 캐스크에 대하여 해당되는 캐스크 형태를 입력한다. 이와 같이 캐스크 형태 별로 최적의 상관관계 알고리즘을 적용함으로써 더욱 정확한 감시변수 산출이 가능하며, 원전 운영자에게 캐스크의 선택 폭을 넓게 해 주는 효과가 있다.The spent nuclear fuel cascade monitored by the monitoring server 140 may have a plurality of different forms with different designs. In this case, the monitoring server 140 separately forms and builds a correlation algorithm for each type of cascade, and when the cascade is additionally registered in the monitoring server 140, the monitoring server 140 generates a cascade corresponding to the unique number of the transmitter communication module 120 The corresponding cascade type is input. By applying the optimal correlation algorithm for each type of cascade, it is possible to calculate more accurate monitoring variables, and it is possible to broaden the selection range of cascade to the operator of the nuclear power plant.
본 발명에 따른 캐스크 상태 감시 시스템에서 감시대상변수는 캐니스터의 내부 압력 및 사용후핵연료 피복관 최고온도일 수 있다. In the cascade monitoring system according to the present invention, the monitoring target variable may be the internal pressure of the canister and the maximum temperature of the spent fuel cladding pipe.
캐니스터 내부의 충진 가스는 헬륨, 질소 등이 사용될 수 있으나 열전도도가 높은 헬륨이 바람직하다. 통상 캐스크 캐니스터의 축은 중력방향으로 세워서 동작되므로, 전도, 대류, 복사 등의 캐니스터 내 열전달 메커니즘 중에서 대류 부분의 영향이 클수록 핵연료 피복관 최대온도 위치는 축방향 상부로 편향되는 경향을 갖게 된다. 따라서 충진 가스가 누설되어 압력이 낮아지면 대류 메커니즘이 약화되어 핵연료 피복관 최대온도 위치는 점차 중앙부로 내려오며 열전달 저하에 따라 최고 온도 값은 증가하는 경향을 나타낸다. 이러한 현상은 축방향 온도 분포 변화로부터 압력이나 온도를 예측할 수 있는 상관관계(correlation)가 존재함을 의미하며, 앞서 기술된 바와 같은 사전 분석을 통하여 상관관계 알고리즘을 구축할 수 있다.The filling gas inside the canister may be helium, nitrogen, or the like, but helium with high thermal conductivity is preferable. Since the shaft of the cask canister is normally operated in the direction of gravity, the maximum temperature position of the fuel cladding tube tends to be deflected upward in the axial direction as the influence of the convection portion in the heat transfer mechanism in the canister such as conduction, convection and radiation is great. Therefore, when the pressure is lowered due to leakage of the filling gas, the convection mechanism is weakened, and the maximum temperature position of the fuel cladding gradually decreases to the central portion, and the maximum temperature value tends to increase as the heat transfer decreases. This phenomenon means that there is a correlation that can predict the pressure or temperature from the change of the axial temperature distribution, and the correlation algorithm can be constructed through the pre-analysis as described above.
그러므로 온도 센서를 캐니스터의 표면에 축 방향으로 배열되는 위치의 온도를 측정하여 감시서버가 축방향 표면온도 분포 정보를 취득하면 이를 입력으로 하여 사전에 구축된 상관관계 알고리즘을 적용하여 캐니스터의 내부 압력이나 핵연료 피복관 최고온도를 산출할 수 있다. 여기서 축 방향으로 배열되는 위치는 사전 분석에 의하여 온도 민감도가 크다고 평가되는 1 또는 2 이상의 위치일 수 있다.Therefore, by measuring the temperature of the position where the temperature sensor is arranged in the axial direction on the surface of the canister, and when the monitoring server obtains the axial surface temperature distribution information, it inputs the correlation information, The fuel cladding tube temperature can be calculated. Here, the positions arranged in the axial direction may be one or two or more positions evaluated as having a high temperature sensitivity by the pre-analysis.
캐스크의 캐니스터가 결함이나 부식 등으로 인하여 건전성이 훼손되면 충진 가스가 누출되어 캐니스터 내부 압력이 감소하게 되며, 이러한 압력 감소는 본 발명에 따른 상태 감시 시스템의 상관관계 알고리즘에 의하여 탐지가 가능하다. 또한, 공기 입구 막힘 등의 이유로 냉각 기능이 저하되어 핵연료 피복관 온도가 증가되는 경우도 본 발명의 상태 감시 시스템 의하여 탐지가 가능하다. If the canister of the cask is damaged due to defects or corrosion, the filling gas leaks and the pressure inside the canister is reduced. Such pressure reduction can be detected by the correlation algorithm of the condition monitoring system according to the present invention. Also, when the cooling function is deteriorated due to clogging of the air inlet and the temperature of the fuel cladding tube is increased, the detection by the state monitoring system of the present invention is also possible.
감시서버(140)에 내장된 상관관계 알고리즘에 포함되는 온도 변수에 캐니스터 표면온도 외에 냉각 공기 온도를 추가하여 상관관계 알고리즘을 보강할 수 있다. 이를 위하여 사용후핵연료 캐스크 냉각을 위하여 공급되는 입구 공기 또는 주변 공기의 온도를 측정하는 온도 센서를 포함하며, 송신단 통신모듈이 수집하는 온도 신호에 주변 공기 온도가 포함되도록 할 수 있다. 이에 의하여 주변 공기의 온도 변화에 따른 감시대상변수의 영향을 반영하여 상관관계 알고리즘의 정확도를 향상시킬 수 있다.The correlation algorithm can be reinforced by adding the cooling air temperature to the temperature variables included in the correlation algorithm built in the monitoring server 140 in addition to the canister surface temperature. And a temperature sensor for measuring the temperature of the inlet air or the ambient air supplied for cooling the spent nuclear fuel cask. The temperature signal collected by the transmitter communication module may include ambient air temperature. Thus, the accuracy of the correlation algorithm can be improved by reflecting the influence of the monitoring target variable according to the temperature change of the ambient air.
도4에 도시된 바와 같이 캐니스터(400) 내부에 격납되는 사용후핵연료 다발(410)들은 통상 축대칭의 배열구조를 갖는다. 따라서 온도 센서(431,432,433,434)가 캐니스터 표면의 축대칭 위치의 온도를 측정하면, 대칭위치의 표면온도는 서로 근사한 값을 갖게 된다. 도4에서 온도센서 431과 433, 432와 434는 각각 대칭위치의 온도센서 쌍을 도시한다. 따라서 복수개의 온도 센서가 캐니스터의 표면의 축 대칭으로 배열되는 위치의 온도를 측정하고, 감시서버가 대칭 위치의 신호를 상호 비교함으로써 신호의 건전성을 판단할 수 있다. 즉, 대칭 위치의 온도 측정값이 설정 범위를 벗어날 경우 온도센서의 고장 여부를 감지할 수 있다.As shown in FIG. 4, the spent nuclear fuel bundles 410 stored in the canister 400 generally have an axisymmetric arrangement. Therefore, when the temperature sensors 431, 432, 433, 434 measure the temperature at the axially symmetric position of the surface of the canister, the surface temperatures at the symmetric positions have values close to each other. In Fig. 4, temperature sensors 431 and 433, 432 and 434 respectively show temperature sensor pairs in symmetrical positions. Therefore, the temperature of the position where the plurality of temperature sensors are arranged axially symmetrically with respect to the surface of the canister can be measured, and the monitoring server can judge the soundness of the signal by mutually comparing the signals at the symmetric positions. That is, when the temperature measurement value of the symmetric position is out of the setting range, it is possible to detect the failure of the temperature sensor.
본 발명은 원자력 발전소에서 생성되는 사용후핵연료를 보관하는 캐스크의 장기적 상태 감시를 목적으로 하며, 캐니스터 표면 온도에 근거하여 캐니스터 내부 변수를 산출하여 사용후핵연료 캐스크의 상태를 감시하는 시스템을 제공하기 위한 것이다. 그러므로 본 발명은 원자력 발전과 관련된 산업에 이용 가능하다.The present invention provides a system for monitoring the state of a spent nuclear fuel cask by calculating an internal variable of a canister on the basis of the surface temperature of the canister for the purpose of monitoring the cascade of cask storing spent fuel generated in a nuclear power plant . Therefore, the present invention is applicable to industries related to nuclear power generation.

Claims (8)

  1. 사용후핵연료가 수납되는 금속제 캐니스터를 포함하는 사용후핵연료 캐스크의 캐니스터 표면온도를 측정하는 복수개의 온도 센서; A plurality of temperature sensors for measuring a surface temperature of a canister of a spent fuel cask including a metal canister containing spent fuel;
    상기 온도 센서로부터 온도 신호를 수집하여 송신하는 송신단 통신모듈; A transmitting terminal communication module for collecting and transmitting a temperature signal from the temperature sensor;
    상기 송신단 통신모듈로부터 온도 신호를 수신하는 수신단 통신모듈; 및A receiving terminal communication module for receiving a temperature signal from the transmitting terminal communication module; And
    상기 수신단 통신모듈로부터 온도 신호를 수신하며, 온도와 감시대상변수 간의 상관관계 알고리즘을 내장하며, 상관관계 알고리즘을 사용하여 감시대상변수를 산출하는 감시서버;를 포함하며,And a monitoring server receiving the temperature signal from the receiving end communication module and incorporating a correlation algorithm between the temperature and the monitoring target variable and calculating a monitoring target variable using the correlation algorithm,
    상기 송신단 통신모듈은 설치구역에 설치된 복수의 사용후핵연료 캐스크에 각각 대응되도록 복수개로 구성되어, 고유번호가 할당되며, The transmitting-end communication module is configured to have a plurality of units each corresponding to a plurality of spent nuclear fuel cascades installed in an installation area,
    상기 수신단 통신모듈은 하나의 설치구역에 대하여 적어도 하나 이상 설치되며,At least one or more receiving module may be installed in one installation area,
    상기 감시서버는 고유번호에 의하여 송신단 통신모듈을 식별하는 것을 특징으로 하는 사용후핵연료 캐스크 상태 감시 시스템.Wherein the monitoring server identifies the transmitting end communication module by a unique number.
  2. 제1항에 있어서, The method according to claim 1,
    상기 송신단 통신모듈은 배터리 전원을 사용하며, The transmitter communication module uses battery power,
    상기 수신단 통신모듈은 직접배선에 의한 전원을 사용하며,The receiving end communication module uses power by direct wiring,
    수신단 통신모듈과 송신단 통신모듈은 무선통신하며, The receiving end communication module and the transmitting end communication module are in wireless communication,
    수신단 통신모듈과 감시서버는 유선통신 하는 것을 특징으로 하는 사용후핵연료 캐스크 상태 감시 시스템.Wherein the receiving terminal communication module and the monitoring server communicate with each other by wire communication.
  3. 제1항에 있어서, The method according to claim 1,
    상기 감시 서버는 하나의 설치구역에 설치된 복수의 송신단 통신모듈로부터 수신된 신호의 거동을 상호 비교하여 사용후핵연료 캐스크의 이상 상태를 판정하는 것을 특징으로 하는 사용후핵연료 캐스크 상태 감시 시스템.Wherein the monitoring server compares the behavior of signals received from a plurality of transmitting-end communication modules installed in one installation area to determine an abnormal state of the spent nuclear fuel cask.
  4. 제1항에 있어서, The method according to claim 1,
    복수개의 온도 센서는 캐니스터 표면의 사전에 정해진 위치의 온도를 측정하며,The plurality of temperature sensors measure the temperature of the predetermined position of the canister surface,
    상기 감시서버에 내장된 상관관계 알고리즘은 사용후핵연료 캐스크에 대한 사전분석결과에 근거한 데이터베이스를 기반으로 구축된 신경회로망 알고리즘인 것을 특징으로 하는 사용후핵연료 캐스크 상태 감시 시스템.Wherein the correlation algorithm embedded in the monitoring server is a neural network algorithm built on a database based on a pre-analysis result of spent fuel cask.
  5. 제1항에 있어서, The method according to claim 1,
    상기 감시서버에 내장된 상관관계 알고리즘은 사용후핵연료 캐스크의 형태별로 복수개 구비되는 것을 특징으로 하는 사용후핵연료 캐스크 상태 감시 시스템.Wherein a plurality of correlation algorithms built in the monitoring server are provided for each type of spent nuclear fuel cask.
  6. 제1항에 있어서, The method according to claim 1,
    상기 복수개의 온도 센서는 캐니스터의 표면에 축 방향으로 배열된 위치의 온도를 측정하여 상기 감시서버가 축방향 표면온도 분포 정보를 취득하는 것을 특징으로 하는 사용후핵연료 캐스크 상태 감시 시스템.Wherein the plurality of temperature sensors measure temperature at a position axially arranged on a surface of the canister, and the monitoring server acquires axial surface temperature distribution information.
  7. 제1항에 있어서, The method according to claim 1,
    사용후핵연료 캐스크 냉각을 위하여 공급되는 주변 공기의 온도를 측정하는 온도 센서를 포함하며, 송신단 통신모듈이 수집하는 온도 신호에 주변 공기 온도가 포함되는 것을 특징으로 하는 사용후핵연료 캐스크 상태 감시 시스템.And a temperature sensor for measuring a temperature of ambient air supplied for cooling the spent nuclear fuel cask, wherein ambient temperature is included in the temperature signal collected by the transmitter communication module, .
  8. 제1항에 있어서, The method according to claim 1,
    상기 복수개의 온도 센서는 캐니스터 표면의 축 대칭 위치의 온도를 측정하고, 감시서버는 대칭 위치의 온도 신호를 상호 비교함으로써 신호의 건전성을 판단하는 것을 특징으로 하는 사용후핵연료 캐스크 상태 감시 시스템.Wherein the plurality of temperature sensors measure the temperature of the axisymmetric position of the surface of the canister and the monitoring server judges the soundness of the signal by comparing the temperature signals at the symmetric positions with each other.
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