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Jung-Ryul Lee 1, a See Yenn Chong 1, b , Chang Yong Y u n 1 ,c , Hoon Sohn 2 , d 1 Dept. of Aerospace Engineering, Chonbuk National University, 664-14 Duckjin-dong, Duckjin-gu, Jeonju, Chonbuk, 561-756, Republic of Korea 2 Dept. of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, 335 Gwahangno, Yuseong-gu, Daejon, Korea a leejrr@jbnu.ac.kr, b chongandy@live.com , c ch yun0207 @ nate .com , d hoonsohn@kaist.ac.kr Keywords: Structural health monitoring, Nuclear power plant, Metal-coated optical fiber, Fiber Bragg grating acoustic sensor Abstract. Nuclear power plant (NPP) is commonly categorized as a harsh environment that gives rise age-related degradation on the structures of plant and eventually leads to radiation leakage that threatens to human. Integrated structural health monitoring (ISHM) technology is a strong candidate for NPP accidents. The emergence of optical fiber technology into SHM system for NPP was greatly interes...

Jung-Ryul Lee a , , , See Yenn Chong a , Chang-Yong Yun a and Dong-Jin Yoon b a Department of Aerospace Engineering, Chonbuk National University, 664-14 Duckjin-dong, Duckjin-gu, Jeonju, Chonbuk 561-756, Republic of Korea b Safety Measurement Center, Korea Research Institute of Standards and Science, 209 Gajeong-ro Yuseong-gu, Daejeon, Republic of Korea Received 5 June 2010; revised 17 July 2010; accepted 15 August 2010. Available online 30 August 2010. Abstract A fiber Bragg grating (FBG) sensor head, using a pressure coupling mechanism, was designed for broadband frequency response and structural strain-free characteristic. The pressure-coupled sensor heads were connected to a simultaneous multipoint acoustic sensing system based on a tunable laser. An intelligent lasing wavelength stabilization algorithm capable of identifying the direction of spectrum movement, the wavelength shifting speed, and a fiber bending event was developed so that the simultaneou...