Dr. Lance L. Snead, Associate Division Director
Materials Under Extremes Section
Program Manager, Fusion Reactor Materials Program
Materials Science & Technology Division
Oak Ridge National Laboratory
P.O. Box 2008
Oak Ridge, TN 37831-6140
Phone: (865) 574-9942
Field of Specialization:
Dr. Snead's research is primarily on radiation damage to structural materials with emphasis on high temperature structural materials and fuels. A brief outline of his research activities are as follows:
- Dr. Snead has lead efforts towards the development of ceramic composites for nuclear power applications. Over the past ten years substantial improvement have been made in both base properties and the radiation stability of these materials due in large part to a fundamental understanding of the mechanisms governing their behavior under irradiation. Based on this work SiC composites now exist which are essentially irradiation stable allowing the material to transition from the development into the deployment stage in nuclear systems. Currently, these materials are being developed for both long-range fusion reactor application and near-term gas-cooled reactor application.
- The second general topic of Dr. Snead’s research deals with the fundamental irradiation effects in ceramic materials including graphite, carbon fiber composites, silicon carbide, zirconium carbide, and other ceramics. Research ranges from the fundamentals of amorphization in SiC, which was first demonstrated by Dr. Snead for neutron irradiation, to the study of dimensional stability and thermal conductivity degradation following irradiation.
- In addition to structural ceramics such as SiC/SiC composites, ceramics are also being used for electrically insulating components. Dr. Snead and coworkers have been involved in the electrical properties of insulating materials under irradiation and have studied the so-called radiation induced electrical degradation (RIED) phenomenon, which raised serious questions to the use of insulators such as alumina for fusion systems. The results of this series of experiments led to the assertion that RIED will not be an issue for fusion systems. Dr. Snead is currently increasing the effort into the thermal properties of insulating ceramics such as alumina, aluminum nitride as well as silicon carbide.
- More recently, Dr. Snead has been involved in the characterization and property evaluation for high-temperature gas-cooled reactor fuels. Emphasis has been on the TRISO fuels overcoated with SiC or ZrC including mechanical testing of these materials and fundamental description of important parameters such as thermal transport.