Overview of the U.S. Fusion Materials Sciences Program

Highlights of recent U.S. fusion materials research activities are summarized, including multiscale materials modeling and experimental results. Recent first principles atomistic calculations on vanadium and iron-helium have found that previous interatomic potentials incorrectly predict several important point defect properties. Molecular dynamics simulations of displacement cascades are now approaching energies equivalent to 14 MeV fusion neutrons. Considerable effort is being devoted to understanding the fundamental mechanisms of low temperature radiation hardening and embrittlement. Work is also in progress to determine the allowable temperature and dose operating regimes for candidate reduced activation structural materials (including transmutant helium effects). New compositions of reduced activation steels and vanadium alloys with potential for significantly improved properties are being investigated. Due to recent improvements in SiC/SiC ceramic composites, engineering-relevant mechanical property tests are being introduced to replace historical qualitative screening tests. Materials research in support of the ITER burning plasma physics machine is briefly described.