Long-term radiation effects on fibre Bragg grating temperature sensors in a low flux nuclear reactor

Fibre Bragg grating (FBG) temperature sensors have already shown short-term radiation tolerance in nuclear environments. However, the effect of long-term irradiation needed to be investigated. We therefore characterized multiplexed FBG temperature sensors inserted early 2000 in an irradiation channel of a low flux nuclear reactor. After 50 months, we show that the sensors still operate satisfactorily and that the measured drift is lower than 3 °C. © 2004 IOP Publishing Ltd.