Original Date: 11/03/1996
Revision Date: 01/18/2007
Best Practice : Graphite and Carbon-Carbon Composite Research
The Carbon Materials Technology (CMT) Group of the Oak Ridge National Laboratory (ORNL) Metals and Ceramics Division is actively involved in the development of carbon-based materials for high-tech applications in the nuclear (both fission and fusion) and aerospace industries. In the process, this group is creating a database for the carbon materials (graphites and carbon-carbon composites) developed. Examples of some of these materials are GraphNOL N3M, a high-strength graphite developed for missile nose tips for the Navy, and Carbon-Bonded Carbon-Fiber, a light-weight thermal insulator developed for NASA.
The CMT Group is supporting U.S. deep space programs and has developed a carbon-carbon composite impact shell for use in the radioisotope thermal electric generator in spacecraft. The material has optimized energy-absorption characteristics to withstand the impact and reentry temperatures should the spacecraft accidentally return to earth.
The Group is developing a design database for the carbon-carbon composite control rods developed for the Modular High Temperature Gas Cooled Reactor. The effects of the reactor environment on the properties of the graphite will be monitored to support future design. The effects of temperature, pressure, Helium coolant chemistry and oxidation, and neutron irradiation will be monitored. The Group will be searching for indicators of strength and strain failures such as elastic constants, fatigue behavior, fracture mechanics data, thermal physical properties, and oxidation behavior and mechanisms. Testing for the effects of neutron irradiation is a unique capability of this group. It expects to apply the capability and the design database to develop a neutron irradiation tolerant carbon-carbon composite material to be used as the first wall armor in the Joint European Torus fusion reactor.
The CMT Group’s unique characterization facilities for carbon-based materials include high temperature thermal physical properties, thermal conductivity from -190° to 2,000°C, and thermal expansion and specific heat from room temperature to 1,400°C. It has created its own high-temperature heat-treatment and graphitization furnace capable of graphitizations at temperatures in excess of 3,000°C in a five-inch diameter by 30-inch long hot zone. A High Pressure Test Loop developed by the Group can test in an environment from room temperature to 1,000°C at 1,000 psi pressures and flow rates up to 37 SCF per minute.
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