August 2007

Press Release:

Long-term temperature monitoring in a low flux nuclear reactor using a Micron Optics interrogator

Nuclear industry shows a growing interest for the possibilities offered by the fibre optic technology for both data communication and sensing applications. Researchers of Belgian Nuclear Research Centre extensively evaluated the Fibre Bragg Grating (FBG) sensors in various nuclear environments, both gamma and mixed gamma-neutron fields. The results evidenced the radiation hardness of commercial off-the-shelve temperature sensors FBGs written in naturally photosensitive optical fibers during accelerated irradiation tests. However, predicting the response of components or systems exposed to low dose rate ionising radiation based on accelerated tests is often very difficult. The researchers present temperature measurements with FBG sensors, in operation since January 2000. These sensors were therefore exposed to low dose rate mixed gamma-neutron radiation during more than three years.

The sensors were measured in reflection using a FBG-IS system (Micron-Optics, USA). It consists of a broadband LED and a Fiber Fabry-Perot Tunable Filter with an internal reference. It achieves a10pm wavelength accuracy. (FBG-IS system is the first generation of product provided by Micron Optics. Now Micron Optics sm125 optical sensing interrogator which achieves 1pm wavelength accuracy is an ideal interrogator used for temperature measurement in hazard environment.)

FBG sensors have shown a very promising radiation tolerance under accelerated gamma radiation. The long term reliability under low mixed gamma neutron fields needed to be assessed to complete our previous irradiation tests. The spectral characteristics of the FBGs written in naturally photosensitive fiber have reached a long term stability. The temperature sensitivity was found to remain unaffected by the long term irradiation allowing to perform a temperature measurement change with an accuracy better than 3?, which is acceptable for many temperature measurement applications in nuclear installation monitoring.

For full article, you can download from: https://www.sckcen.be/sckcen_en/activities/research/reactorsafety/fusion/annualreport2004/

Contributions/Publications/25_11_Long_term_temperature_monitoring.pdf

About Micron Optics, Inc.

Micron Optics, a leading provider of tunable optical technologies, offers a comprehensive portfolio of components and instruments for Optical Sensing, Biotech and Telecom markets. Built upon its solid technology foundation, Micron Optics' products span from simple tunable components to fast swept laser modules to fast and accurate optical instrumentation. Since 1990, Micron Optics has been a privately held company based in Atlanta.