Helium Cooled CMC First Wall Structure

50567-98-I Helium Cooled CMC First Wall Structure--Refractory Composites, Inc., 107 North Langley Road, Glen Burnie, MD 21060-6538; (410) 768-2490 Mr. Edward L. Paquette, Principal Investigator Mr. Edward L. Paquette, Business Official DOE Grant No. DE-FG02-98ER82718 Amount: $74,744 Fusion reactor first walls must withstand high radiation and heat fluxes. SiC composites are potentially desirable materials due to low neutron activation, low afterheat characteristics, and excellent high temperature structural properties. However, SiC composites must be cooled to survive the first wall environment. Helium would be the preferred gas coolant if helium leakage into the reactor plasma region could be avoided. Unfortunately, helium leak-tight SiC composites have not been demonstrated and may not be feasible. This project will develop alternative technology which builds on experience with metal lined or metal embedded ceramic matrix composite (CMC) cooled structures developed for high heat flux applications in rocket engines (in which the thermal loads are very similar to those in fusion reactors). A helium cooled CMC system with radiation tolerant metallic sealants and interface coating systems will be developed and demonstrated. SiC/SiC composite tubular structures with internal metal liner and interface coating systems will also be developed. These liner/coating candidates will be subjected to thermal stresses associated with high heat flux conditions and evaluated for thermostructural and thermal conduction performance. Candidate composite/metal liner interface coating systems will also be subjected to high radiation fluxes followed by microstructural and elemental analyses. In Phase II, CMC panel assemblies with coolant manifolds will be developed for use in high heat flux and irradiating environments. Commercial Applications and Other Benefits as described by the awardee: Cooled CMC structures are heat transfer structures which can be extended to other power conversion applications such as indirect fired gas turbine topping cycles and hot gas control valve applications for gas turbine topping cycles involving fluidized bed combustors or gasifiers. _