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Petrie-Christian PhD Dissertation.pdf (6.87 MB)

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Characterization of the Performance of Sapphire Optical Fiber in Intense Radiation Fields, when Subjected to Very High Temperatures

Petrie, Christian Matthew
http://rave.ohiolink.edu/etdc/view?acc_num=osu1405011475

Abstract Details

2014, Doctor of Philosophy, Ohio State University, Nuclear Engineering.
The U.S. Department of Energy is interested in extending optically-based instrumentation from non-extreme environments to extremely high temperature radiation environments for the purposes of developing in-pile instrumentation. The development of in-pile instrumentation would help support the ultimate goal of understanding the behavior and predicting the performance of nuclear fuel systems at a microstructural level. Single crystal sapphire optical fibers are a promising candidate for in-pile instrumentation due to the high melting temperature and radiation hardness of sapphire. In order to extend sapphire fiber-based optical instrumentation to high temperature radiation environments, the ability of sapphire fibers to adequately transmit light in such an environment must first be demonstrated. Broadband optical transmission measurements of sapphire optical fibers were made in-situ as the sapphire fibers were heated and/or irradiated. The damage processes in sapphire fibers were also modeled from the primary knock-on event from energetic neutrons to the resulting damage cascade in order to predict the formation of stable defects that ultimately determine the resulting change in optical properties. Sapphire optical fibers were shown to withstand temperatures as high as 1300 °C with minimal increases in optical attenuation. A broad absorption band was observed to grow over time without reaching a dynamic equilibrium when the sapphire fiber was heated at temperatures of 1400 °C and above. The growth of this absorption band limits the use of sapphire optical fibers, at least in air, to temperatures of 1300 °C and below. Irradiation of sapphire fibers with gamma rays caused saturation of a defect center located below 500 nm, and extending as far as ~1000 nm, with little effect on the transmission at 1300 and 1550 nm. Increasing temperature during gamma irradiation generally reduced the added attenuation. Reactor irradiation of sapphire fibers caused an initial rapid increase in attenuation, followed by a linear increase with continued irradiation time at constant reactor power. The linear increases were a result of displacement damage, and the rate of increase was proportional to the neutron flux. The transmission of sapphire fibers at 1300 and 1550 nm in a reactor radiation environment would ultimately be limited by the growth of low wavelength defect centers, whose tails extend into the near infrared. A model was proposed for the reactor radiation-induced attenuation that involves three previously reported color centers. The model accounts for gamma radiation-induced ionization of pre-existing defects, generation of new defects via displacement damage, and conversion between defect centers via ionization and charge recombination. Heated reactor irradiation experiments showed that the rate of increase of the added attenuation during constant power reactor irradiation monotonically decreases with increasing temperature up to 1000 °C, with the most significant decrease occurring between 300 and 600 °C. Testing of sapphire fiber-based sensors under irradiation at high temperatures is recommended as future work, along with advanced life irradiation testing, for example in the Advanced Test Reactor or the High Flux Isotope Reactor.
Thomas Blue (Advisor)
Wolfgang Windl (Committee Member)
Lei Cao (Committee Member)
270 p.
Engineering; Experiments; Materials Science; Nuclear Engineering; Optics; Radiation
Sapphire; Fibers; Heated; Irradiation; Temperature; Reactor; Optical; Alumina; Al2O3; Radiation; Instrumentation; Defects; Absorption; Attenuation; Transmission; In-situ; Broadband; Nuclear; Single crystal; Corundum

Recommended Citations

Citations

  • Petrie, C. M. (2014). Characterization of the Performance of Sapphire Optical Fiber in Intense Radiation Fields, when Subjected to Very High Temperatures [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1405011475

    APA Style (7th edition)

  • Petrie, Christian. Characterization of the Performance of Sapphire Optical Fiber in Intense Radiation Fields, when Subjected to Very High Temperatures. 2014. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1405011475.

    MLA Style (8th edition)

  • Petrie, Christian. "Characterization of the Performance of Sapphire Optical Fiber in Intense Radiation Fields, when Subjected to Very High Temperatures." Doctoral dissertation, Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1405011475

    Chicago Manual of Style (17th edition)

osu1405011475
3,236
© 2014, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.