DoDM 5210.42: Nuclear Weapons Personnel Reliability Program, January 13, 2015, Incorporating Change 2, Effective March 23, 2017 [open pdf - 373KB]
"This manual reissues DoD 5210.42-R (Reference (a)) as a DoD manual in accordance with the authority in DoD Directive 5134.08 (Reference (b)). It implements the policy in DoD Instruction 5210.42 (Reference (c)), assigns responsibilities, and prescribes mandatory procedures for the DoD Nuclear Weapons Personnel Reliability Program (PRP) to ensure the safety and security of the U.S. nuclear deterrent mission."
Department of Defense Instruction 5210.42; DoDI 5210.42
Defense Technical Information Center: http://www.dtic.mil/