JAEA-Technology JAEA-Technology 2008-087 Development of Surface Temperature Measurement for Simulated Fuel Rod Heater - Noise Reduction Temperature Signal of Thin-Thermocouple - 模擬燃料棒ヒーターにおける表面温度計測の技術開発 佐川 淳 柴本 泰照 東海研究開発センター 原子力科学研究所 工務技術部 Engineering Services Department Nuclear Science Research Institute Tokai Research and Development Center March 2009 Japan Atomic Energy Agency 日本原子力研究開発機構 Jun SAGAWA and Yasuteru SIBAMOTO ― 細径熱電対温度信号のノイズ対策 ─
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JAEA-Technology...JAEA-Technology JAEA-Technology 2008-087 Development of Surface Temperature Measurement for Simulated Fuel Rod Heater - Noise Reduction Temperature Signal of Thin-Thermocouple
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JAEA
-TechnologyJAEA-Technology
2008-087
Development of Surface Temperature Measurement for Simulated Fuel Rod Heater
- Noise Reduction Temperature Signal of Thin-Thermocouple -
模擬燃料棒ヒーターにおける表面温度計測の技術開発
佐川 淳 柴本 泰照
東海研究開発センター 原子力科学研究所
工務技術部
Engineering Services DepartmentNuclear Science Research Institute
Tokai Research and Development Center
March 2009
Japan Atomic Energy Agency 日本原子力研究開発機構
JAEA
-Technology 2008-087 模擬燃料棒ヒーターにおける表面温度計測の技術開発
―
細径熱電対温度信号のノイズ対策 ―
日本原子力研究開発機構
Jun SAGAWA and Yasuteru SIBAMOTO
― 細径熱電対温度信号のノイズ対策 ─
i
JAEA-Technology 2008-087
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2008 12 17
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319-1195 2-4
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JAEA-Technology 2008-087
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JAEA-Technology 2008-087
Development of Surface Temperature Measurement for Simulated Fuel Rod Heater
- Noise Reduction Temperature Signal of Thin-Thermocouple -
Jun SAGAWA and Yasuteru SIBAMOTO+
Engineering Services Department, Nuclear Science Research Institute, Tokai Research and Development Center, Japan Atomic Energy Agency
Tokai-mura, Naka-gun, Ibaraki-ken
(Received December 17, 2008)
In experimental facilities to investigate a system integral-response and/or to verify fuel rod integrity of nuclear reactors, the electrical heater specially manufactured to simulate the real nuclear fuel rod with the same scale have been used in the core of the experimental facility. This type of the electrical heater, so-called “simulated fuel rod”, is a kind of a sheath heater which involves Nichrome coiled wire as a heat generation element in the metal cladding tube. An alternating current power is supplied for heat generation source in this heater and thin thermocouples were embedded on the cladding surface to measure the fuel surface temperature. It means that a switching regulator by silicon-controlled rectifier is used to control the AC electrical power and undesirable electrical noises are superimposed on the thermocouples' signals by the time variation of the heater current. Although a low-pass-filter with a low cut-off frequency was commonly applied to remove the noises in the previous steady-state experiment, the problem have arisen that a fast temperature transient could not be followed due to a time-delay accompanied by the filter in the transient experiment.
In the present study, we reveal the noise characteristics and designed / manufactured the new noise reduction filter with to reduce the time delay one-tenth less than that in the previous simple filter. The time constant of this filter is less than 10 ms which is smaller than that of thin thermocouples determined by its heat capacity. It can be regarded as the response speed enough to the practical application.
Keywords: Simulated Fuel Rod Heater, Thermocouples, Electrical Noise, Capacitive Coupling, Electromagnetic Induction, Alternative Current, Low-Pass-Filter, Band-Elimination-Filter
Collaborating Engineer Reactor Safety Research Unit, Nuclear Safety Research Center
1.1 Background and Purpose............................................................................................. 1 1.2 Major cause and Characteristics of Noise................................................................... 4
1.2.1 Noise due to Capacitive Coupling .......................................................................... 4 1.2.2 Noise due to Electromagnetic Induction................................................................ 8
1.3 Identification of Noise Source and its Countermeasures......................................... 11
2 Design and Fabrication of Filter Circuit.......................................................................... 15
Fig. 1.1 Cross sectional view of simulated fuel rod.................................................................. 3 Fig. 1.2 Schematic view temperature measurement by thermocouple ................................... 7 Fig. 1.3 Details of electrical equivalent circuit for noise ......................................................... 7 Fig. 1.4 Generation of electromagnetic induction noise......................................................... 10 Fig. 1.5 Variation of noise by heater power supply ................................................................ 13 Fig. 1.6 Frequency characteristics of noise data .................................................................... 14 Fig. 2.1 Signal processing form thermocouple to data acquisition system ........................... 17 Fig. 2.2 Macrograph of noise data........................................................................................... 18 Fig. 2.3 Characteristics of thermocouple response ................................................................ 18 Fig. 2.4 Frequency characteristics of 2nd order LPF and BEF filter (Bode diagram) ......... 19 Fig. 2.5 Electrical circuit diagram of 2nd order LPF and BEF ............................................. 21Fig. 2.6 On-board device implementation .............................................................................. 26 Fig. 2.7 Practical wiring ........................................................................................................ 26 Fig. 2.8 Trimmer to adjust the filter circuit ........................................................................... 27 Fig. 3.1 Comparison of gain characteristics ........................................................................... 30 Fig. 3.2 Comparison of the present filter with LPF in frequency characteristics ................ 31 Fig. 3.3 Transient characteristics of the present filter .......................................................... 32
(3) Maruyama, Y., Asaka, H., Satou, A., Nakamura, H..: “Single rod experiments on transient void behavior during low-pressure reactivity-initiated accidents in light water reactors”, Nucl. Eng. Des., 236, 1693-1700 (2006).
(4) ” ”2 pp.510-516 (2003)
(5) Richard P. Feynman Robert B. Leighton Matthew L. Sands
(6) SPECIAL No.44 CQ(7)(8) OP 100 CQ(9) TL071_072_074 Data Sheet Texas Instruments, Incorporated (10) EROS Panasonic(11) RJ-5(12) MMT
(13) RPE(14) TSL Series TSL0709 TDK(15) TXL Series TRACO POWER (16) PSpice CQ(17) SPICE CQ