The Krell Institute manages Ph.D. fellowships. The DOE NNSA SSGF supports students researching properties of materials under extreme conditions and hydrodynamics, nuclear science, or high energy density physics. The DOE NNSA LRGF facilitates extended national laboratory experience while supporting the doctoral studies in engineering/applied sciences, physics, materials, or mathematics/computational science.
https://www.krellinst.org/program-management