Active Irradiation Testing of Temperature Sensing Capability of Clad Sapphire Optical Fibers with Type 2 Bragg Gratings using Optical Backscatter Reflectometry

Technical Report · Thu Mar 26 04:00:00 EDT 2020

DOI:https://doi.org/10.2172/1700531· OSTI ID:1700531

Petrie, Christian ^[1]; Blue, Thomas ^[2]; Calderoni, Pattrick ^[3]; McCary, Kelly M. ^[3]; Wilson, Brandon ^[2]; Adams, Tiffany M. ^[3]

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1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
2. The Ohio State Univ., Columbus, OH (United States)
3. Idaho National Lab. (INL), Idaho Falls, ID (United States)

This work investigated the temperature-sensing capabilities of Type II fiber Bragg gratings (FBGs) inscribed in sapphire optical fiber in the Ohio State University Research Reactor (OSURR). A Luna Innovations 4600 optical backscatter reflectometer (OBR) was used to interrogate FBGs in three sapphire optical fibers with an internal cladding that was developed by Ohio State. The sapphire fibers were fusion-spliced to silica lead fibers. In addition to the sapphire fibers, two silica fibers with the same Type II FBGs were included in the experiment as a reference. The fiber-based sensors were irradiated in the Central Irradiation Facility (CIF) of the OSURR for a total of 40 hours over 5 days at a reactor power of 450 kW, resulting in a total neutron fluence of approximately 2.5 × 10¹⁸ n/cm² and a gamma dose of approximately 3.48 Grad. Two K-type thermocouples were included within the rig: one at the core centerline and the other 12 inches above the top of the core. The temperature was not actively controlled, but the thermocouples were used to provide a reference to which the fiber-based temperature measurements could be compared.

• Research Organization: Idaho National Laboratory (INL), Idaho Falls, ID (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE)
• DOE Contract Number: AC07-05ID14517
• OSTI ID: 1700531
• Report Number(s): INL/EXT--20-57797-Rev000
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
optical fiber
sapphire fibers