A Fabry-Perot fiber optic sensor utilizes a unique interferometric mechanism and signal processing technique. It employs a Fizeau interferometer and a Charge-Coupled Device to locate the position of the maximum interference fringe intensity rather than absolute light intensity, which is most likely affected by external stressors such as irradiation and high pressure/temperature. A Fabry-Perot fiber optic temperature sensor was investigated for potential application in harsh environments expected in nuclear power plants. The sensor design and simulation of its signal processing are fully described in this paper. A methodology was developed based on IEEE-323 and ISA-dS67.06 to evaluate the sensors in normal and abnormal design basis accident environments. The experimental results of radiation and environmental qualification tests are summarized. Two sensors exhibited no failure and acceptable performance when exposed to gamma radiation to doses of 15 kGy and 1.33 MGy, respectively. Three sensors were irradiated to a total neutron fluence of 2.6x10¹⁶ neutrons/cm² and a total gamma dose of 1.09MGy. These demonstrated a temperature shift of about 34°F but responded linearly to temperature, and the offset was reduced by approximately 63% through annealing the sensors.

Date Published: 25 October 2002
PDF: 11 pages
Proc. SPIE 4772, Electro-Optical System Design, Simulation, Testing, and Training, (25 October 2002); doi: 10.1117/12.451824

Published in SPIE Proceedings Vol. 4772:
Electro-Optical System Design, Simulation, Testing, and Training
Richard M. Wasserman; Scott L. DeVore, Editor(s)