DoD Directive 5210.63: Security of Nuclear Reactors and Special Nuclear Materials [open pdf - 129KB]
"It is DoD policy to ensure that nuclear reactors and Special Nuclear Materials (SNM) receive special protection because of their operational importance and the serious consequences of unauthorized possession or use of nuclear materials. The conservation of SNM; the safety of the public, operating personnel, and property; and the protection of SNM from sabotage, theft, loss, or diversion are of paramount importance during all phases of operations. This directive re-affirms DoD policy regarding responsibilities, procedures, and minimum standards for safeguarding DoD nuclear reactors and special nuclear materials (SNM)."
DoD Directive 5210.63; DoDD 5210.63