TY - GEN
T1 - Suitability of type-II fiber Bragg gratings in sapphire optical fiber for temperature sensing in treat
AU - Wilson, Brandon
AU - McCary, Kelly
AU - Blue, Thomas
N1 - Publisher Copyright:
© 2018 Westinghouse Electric Company LLC All Rights Reserved
PY - 2019
Y1 - 2019
N2 - Sapphire optical fiber, with an internal cladding and an array of type-II Bragg gratings inscribed in it, was tested in-situ in the Ohio State Research Reactor (OSURR) to determine the viability of using sapphire as a sensor in an ionizing radiation environment. The sapphire fiber was attached to an optical frequency domain reflectometer (OFDR), which recorded the temperature of the fiber, at the locations of the gratings along the fiber, during the irradiations in the OSURR. The sapphire Bragg gratings survived the irradiations in the OSURR and produced reasonable temperature measurements for ~2.1 Equivalent Full Power Hours (EFPHs) of irradiation, corresponding to a neutron fluence of ~1.7 x 1017 n/cm2. The lead-in silica fiber, and perhaps the sapphire fiber itself, exhibited darkening, which affected sensing during the third day of irradiation; but adjusting the sensitivity of the OFDR corrected for this. During the reactor irradiations on the following day, the fiber produced reasonable temperature measurements to a four day total irradiation of ~8.8 EFPH, corresponding to a neutron fluence of ~7.3 x 1017 n/cm2. In summary, the sapphire sensors survived to fluences that are larger than those that they must withstand for testing in TREAT (~1 x 1017 n/cm2). The accuracy and precision of these sensors still needs to be determined. Also, it is must be acknowledge that fiber darkening in silica and sapphire may be flux dependent.
AB - Sapphire optical fiber, with an internal cladding and an array of type-II Bragg gratings inscribed in it, was tested in-situ in the Ohio State Research Reactor (OSURR) to determine the viability of using sapphire as a sensor in an ionizing radiation environment. The sapphire fiber was attached to an optical frequency domain reflectometer (OFDR), which recorded the temperature of the fiber, at the locations of the gratings along the fiber, during the irradiations in the OSURR. The sapphire Bragg gratings survived the irradiations in the OSURR and produced reasonable temperature measurements for ~2.1 Equivalent Full Power Hours (EFPHs) of irradiation, corresponding to a neutron fluence of ~1.7 x 1017 n/cm2. The lead-in silica fiber, and perhaps the sapphire fiber itself, exhibited darkening, which affected sensing during the third day of irradiation; but adjusting the sensitivity of the OFDR corrected for this. During the reactor irradiations on the following day, the fiber produced reasonable temperature measurements to a four day total irradiation of ~8.8 EFPH, corresponding to a neutron fluence of ~7.3 x 1017 n/cm2. In summary, the sapphire sensors survived to fluences that are larger than those that they must withstand for testing in TREAT (~1 x 1017 n/cm2). The accuracy and precision of these sensors still needs to be determined. Also, it is must be acknowledge that fiber darkening in silica and sapphire may be flux dependent.
KW - Fiber Bragg Gratings
KW - Nuclear Reactor
KW - Optical Frequency Domain Reflectometry
KW - Radiation effects
KW - Sapphire Optical Fiber
UR - http://www.scopus.com/inward/record.url?scp=85070983061&partnerID=8YFLogxK
M3 - Conference contribution
AN - SCOPUS:85070983061
T3 - 11th Nuclear Plant Instrumentation, Control, and Human-Machine Interface Technologies, NPIC and HMIT 2019
SP - 478
EP - 487
BT - 11th Nuclear Plant Instrumentation, Control, and Human-Machine Interface Technologies, NPIC and HMIT 2019
PB - American Nuclear Society
T2 - 11th Nuclear Plant Instrumentation, Control, and Human-Machine Interface Technologies, NPIC and HMIT 2019
Y2 - 9 February 2019 through 14 February 2019
ER -