About this Abstract |
| Meeting |
Materials in Nuclear Energy Systems (MiNES) 2025
|
| Symposium
|
Materials in Nuclear Energy Systems (MiNES) 2025
|
| Presentation Title |
Pyrolytic Decomposition of Optical Fiber Sensor Coatings and Implications for Radiation-Induced Sensor Drift |
| Author(s) |
Bryan M. Conry, James M. Kurley, Daniel C. Sweeney, Christian M. Petrie |
| On-Site Speaker (Planned) |
Bryan M. Conry |
| Abstract Scope |
Fiber optic sensors have been proposed for a wide range of nuclear reactor applications, including structural health monitoring, distributed temperature monitoring, and in-pile characterization of fuels and materials during irradiation in test reactors. A comprehensive understanding of how radiation affects the fiber optic signal quality and drift is essential for successful deployment in any nuclear reactor application. Previous work showed prohibitively large signal drift following exposure to high neutron fluence that could not be explained by radiation effects in the silica glass fiber. This work investigated the hypothesis that radiation effects in the polymer coatings that are applied to the fiber thermally or radiolytically transformed into glassy carbon and subsequently compacted under irradiation, transferring strain from the coating to the fiber and causing the observed sensor drift. The thermal degradation of acrylate and polyimide fiber coatings were evaluated following exposure to temperatures spanning 250 to 1300 °C, in both inert and oxidative atmospheres. The evolved structures were analyzed using thermogravimetric analysis, electron microscopy, and Raman spectroscopy. Findings indicate that under inert conditions both polymer types decompose into a glassy carbon-like residue that is well-bonded (i.e., strain-coupled) to the fiber. Furthermore, analytical modeling incorporating radiation-induced glassy carbon compaction data (from literature) predicts fiber strain and sensor drift that closely align with the prior experimental data. Thus, the results from this work provide a mechanistic explanation for the significant radiation-induced drift observed during neutron irradiation experiments and may be used to inform the design of future coatings for fiber-optic sensors for nuclear applications. |
| Proceedings Inclusion? |
Undecided |