Administration

2003 · 88243 — Washington DC: National Nuclear Security Administration Office of Defense Programs 2003. Presumed a unique copy. Unknown if other copies were made. CD is in a paper envelope with a clear plastic face. Good. This disc is marked UNCLASSIFIED and there are no dissemination limitation markings on the three text files contained therein. These files are Implementation Plan FY 2004 Rev. 1 9 pages Management Plan Rev 9 pages and Program Plan Version 4 37 pages includes some strike-out passages. Underground tests conducted by the Soviet Union continued until 1990 the United Kingdom until 1991 the United States until 1992 and both China and France until 1996. In signing the Comprehensive Nuclear-Test-Ban Treaty in 1996 these countries pledged to discontinue all nuclear testing; the treaty has not yet entered into force because of its failure to be ratified by eight countries. Non-signatories India and Pakistan last tested nuclear weapons in 1998. North Korea conducted nuclear tests in 2006 2009 2013 2016 and 2017. The most recent confirmed nuclear test occurred in September 2017 in North Korea. The 2022 NPR says that the United States continues to observe a moratorium on nuclear explosive testing. NNSA conducts subcritical i.e. those that do not produce a nuclear yield experiments and uses other tools to maintain stockpile reliability. The 2018 NPR stated that "the United States will not resume nuclear explosive testing unless necessary to ensure the safety and effectiveness of the U.S. nuclear arsenal." The 2022 NPR notes that the United States "maintains a nuclear explosive test readiness program in the event it is required to resolve technical uncertainties" but "does not envision or desire a return to nuclear testing." Underground nuclear testing is the test detonation of nuclear weapons that is performed underground. When the device being tested is buried at sufficient depth the nuclear explosion may be contained with no release of radioactive materials to the atmosphere. <br /> The extreme heat and pressure of an underground nuclear explosion causes changes in the surrounding rock. The rock closest to the location of the test is vaporized forming a cavity. Farther away there are zones of crushed cracked and irreversibly strained rock. Following the explosion the rock above the cavity may collapse forming a rubble chimney. If this chimney reaches the surface a bowl-shaped subsidence crater may form. The first underground test took place in 1951. Further tests soon led scientists to conclude that even notwithstanding environmental and diplomatic considerations underground testing was of far greater scientific value than all other forms of testing. This understanding strongly influenced the governments of the first three nuclear powers to sign of the Limited Test Ban Treaty in 1963 which banned all nuclear tests except for those performed underground. From then until the signing of the Comprehensive Nuclear-Test-Ban Treaty in 1996 most nuclear tests were performed underground which prevented additional nuclear fallout from entering into the atmosphere. National Nuclear Security Administration, Office of Defense Programs unknown