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*STTR Project:
Life Prediction of SiC/SiC Composites in
Advanced Nuclear Reactors—Hyper-Therm High-Temperature Composites, Inc., 18411 Gothard Street, Unit B, Huntington Beach, CA 92648; 714-375-4085; www.htcomposites.com
Dr. Robert J. Shinawski, Principal Investigator, Robert.shinawski@htcomposites.com
Mr. Wayne S.
Steffier, Business Official, wayne.steffier@htcomposites.com
DOE Grant No.
DE-FG02-06ER86276
Amount: $749,998
Research Institution
Some Generation IV nuclear reactor designs call for high reactor core temperatures to improve thermodynamic efficiency and produce process heat. Materials for this application must be capable of sustaining temperatures approaching 1000ºC and be stable under neutron irradiation for the life of the reactor. The material used to contain the control rod is one such application, where, in addition to the high-temperature high-radiative flux, the sheath material is subjected to large thermal gradients and thermal cycling. Silicon-carbide-fiber-reinforced silicon carbide matrix composites, which are stable under these high neutron fluxes, have been identified as a candidate material for these applications, and a preliminary database of mechanical and thermal properties is being generated. However, because the intended lifecycle of the control rod sheath is thirty years, accelerated test methods are required. This project will develop a means of life prediction for nuclear grade SiC/SiC. In Phase I, accelerated stress rupture testing was used to evaluate the composite material. The test data and associated calculations identified three aging regimes: passive oxidation, active oxidation, and creep related strain. The bases for an empirical and a micromechanical reliability model were established for predictive capabilities. In Phase II, the validity of the accelerated aging system will be demonstrated through a significant set of stress rupture data, in order to examine the effect of temperature and oxygen partial pressure. A reliability model will be completed to offer probabilistic failure estimates.
Commercial Applications and Other Benefits as described by the awardee: The validated composite material would benefit the DOE development efforts for Generation IV fission reactors, and also would benefit the longer range development of fusion power. Both of these energy generation approaches would substantially reduce dependence on foreign sources of fossil fuels as well as reduce greenhouse gas emissions.