As part of a self-imposed moratorium on testing, the United States has not conducted an
explosive nuclear test since 1992. Since that time, the Department of Energy's (Department)
National Nuclear Security Administration (NNSA) has used the Stockpile Stewardship
Program, an effort that includes analytical simulation, laboratory experiments, and weapons
refurbishments, to maintain the stockpile without nuclear testing. Under current national
policy, however, the Department may be called upon, within a three-year timeframe, to
resume underground nuclear testing at the Nevada Test Site (Nevada) under certain
circumstances. These situations include the identification of a new type of weapon problem
or an accumulation of uncertainties about the reliability of the nuclear stockpile. Prior to
performing any test, the Department is required by Title 10 of the Code of Federal
Regulations (CFR) Part 830, Nuclear Safety Management, to complete various safety
analyses. In addition, Department Orders 452.1C, Nuclear Explosive and Weapon Surety
Program, and 452.2C, Nuclear Explosive Safety, require a nuclear explosive safety study,
which is a formal evaluation of the controls to meet nuclear explosive safety standards.
