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Title: Composite materials for fusion applications

Ceramic matrix composites, CMCs, are being considered for advanced first-wall and blanket structural applications because of their high-temperature properties, low neutron activation, low density and low coefficient of expansion coupled with good thermal conductivity and corrosion behavior. This paper presents a review and analysis of the hermetic, thermal conductivity, corrosion, crack growth and radiation damage properties of CMCs. It was concluded that the leak rates of a gaseous coolant into the plasma chamber or tritium out of the blanket could exceed design criteria if matrix microcracking causes existing porosity to become interconnected. Thermal conductivities of unirradiated SiC/SiC and C/SiC materials are about 1/2 to 2/3 that of Type 316 SS whereas the thermal conductivity for C/C composites is seven times larger. The thermal stress figure-of-merit value for CMCs exceeds that of Type 316 SS for a single thermal cycle. SiC/SiC composites are very resistant to corrosion and are expected to be compatible with He or Li coolants if the O{sub 2} concentrations are maintained at the appropriate levels. CMCs exhibit subcritical crack growth at elevated temperatures and the crack velocity is a function of the corrosion conditions. The radiation stability of CMCs will depend on the stability of the fiber,more » microcracking of the matrix, and the effects of gaseous transmutation products on properties. 23 refs., 14 figs., 1 tab.« less
Authors:
; ;
Publication Date:
OSTI Identifier:
6129347
Report Number(s):
PNL-SA-19391; CONF-911111--7
ON: DE92003001; TRN: 91-033346
DOE Contract Number:
AC06-76RL01830
Resource Type:
Conference
Resource Relation:
Conference: International conference on fusion reactor materials, Clearwater, FL (United States), 17-22 Nov 1991
Research Org:
Pacific Northwest Lab., Richland, WA (United States)
Sponsoring Org:
DOE; USDOE, Washington, DC (United States)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; Ma; 36 MATERIALS SCIENCE; CERAMICS; CORROSION; CRACK PROPAGATION; PHYSICAL RADIATION EFFECTS; THERMAL CONDUCTIVITY; THERMONUCLEAR REACTOR MATERIALS; BREEDING BLANKETS; DAMAGING NEUTRON FLUENCE; FEASIBILITY STUDIES; FIRST WALL; SILICON CARBIDES; CARBIDES; CARBON COMPOUNDS; CHEMICAL REACTIONS; MATERIALS; NEUTRON FLUENCE; PHYSICAL PROPERTIES; RADIATION EFFECTS; REACTOR COMPONENTS; SILICON COMPOUNDS; THERMODYNAMIC PROPERTIES; THERMONUCLEAR REACTOR WALLS 700480* -- Fusion Technology-- Component Development; Materials Studies-- (1992-); 700420 -- Fusion Technology-- Plasma-Facing Components-- (1992-); 360204 -- Ceramics, Cermets, & Refractories-- Physical Properties; 360206 -- Ceramics, Cermets, & Refractories-- Radiation Effects; 360203 -- Ceramics, Cermets, & Refractories-- Mechanical Properties; 360205 -- Ceramics, Cermets, & Refractories-- Corrosion & Erosion