Comprehensive Nuclear-Test-Ban Treaty: Background and Current Developments [Updated March 4, 2008] [open pdf - 266KB]
"A comprehensive nuclear-test-ban treaty (CTBT) is the oldest item on the nuclear arms control agenda. Three treaties currently bar all but underground tests with a maximum force equal to 150,000 tons of TNT. The Natural Resources Defense Council states the United States conducted 1,030 nuclear tests, the Soviet Union 715, the United Kingdom 45, France 210, and China 45. The last U.S. test was held in 1992; Russia claims it has not tested since 1990. In 1998, India and Pakistan announced several nuclear tests. Each declared a test moratorium; neither has signed the CTBT. North Korea conducted a nuclear test in 2006. Since 1997, the United States has held 23 'subcritical experiments' at the Nevada Test Site, most recently on August 30, 2006, to study how plutonium behaves under pressures generated by explosives. […]. Russia has reportedly held some since 1998, including several in 2000. The U.N. General Assembly adopted the CTBT in 1996. As of March 4, 2008, 178 states had signed it; 144, including Russia, had ratified; and of the 44 that must ratify the treaty for it to enter into force, 41 had signed and 35 had ratified. […]. The Bush Administration opposes the CTBT, adheres to the test moratorium, has not ruled out resumed testing, and has no plans to test. It has reduced the time needed to conduct a nuclear test. Critics raised concerns about the implications of these policies for testing and new weapons."
CRS Report for Congress, RL33548