Comprehensive Nuclear-Test-Ban Treaty: Background and Current Developments

Jonathan Medalia
Specialist in Nuclear Weapons Policy

A ban on all nuclear tests is the oldest item on the nuclear arms control agenda. Three treaties that entered into force between 1963 and 1990 limit but do not ban such tests. In 1996, the U.N. General Assembly adopted the Comprehensive Nuclear-Test-Ban Treaty (CTBT), which would ban all nuclear explosions. In 1997, President Clinton sent the CTBT to the Senate, which rejected it in October 1999. In a speech in Prague in April 2009, President Obama said, “My administration will immediately and aggressively pursue U.S. ratification of the Comprehensive Test Ban Treaty.” However, the Administration focused its efforts in 2010 on securing Senate advice and consent to ratification of the New Strategic Arms Reduction Treaty (New START). The Administration has indicated it wants to begin a CTBT “education” campaign with a goal of securing Senate advice and consent to ratification, but there have been no hearings on the treaty in the 111th or 112th Congresses. As of December 2011, 182 states had signed the CTBT and 156, including Russia, had ratified it. However, entry into force requires ratification by 44 states specified in the treaty, of which 41 had signed the treaty and 36 had ratified. Seven conferences have been held to facilitate entry into force, most recently on September 23, 2011.

Nuclear testing has a long history, beginning in 1945. The Natural Resources Defense Council states that the United States conducted 1,030 nuclear tests, the Soviet Union 715, the United Kingdom 45, France 210, and China 45. (Of the U.K. tests, 24 were held jointly with the United States and are not included in the foregoing U.S. total.) 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 announced that it conducted nuclear tests in 2006 and 2009. Since 1997, the United States has held 26 “subcritical experiments” at the Nevada National Security Site, most recently in February 2011, to study how plutonium behaves under pressures generated by explosives. It asserts these experiments do not violate the CTBT because they cannot produce a self-sustaining chain reaction. Russia reportedly held some since 1998.

Congress addresses nuclear weapon issues in the annual National Defense Authorization Act and the Energy and Water Development Appropriations Act. It considers the Stockpile Stewardship Program (listed as Weapons Activities), which seeks to maintain nuclear weapons without testing; the FY2011 appropriation was $6.896 billion, and the FY2012 request is $7.630 billion. Congress considers a U.S. contribution to a global system to monitor possible nuclear tests. The FY2012 request is $33.0 million, with another $7.5 million requested for projects to improve the CTBT verification regime.

This report will be updated occasionally. This version reflects Indonesia’s ratification of the treaty on December 6, 2011, and makes other updates throughout. CRS Report RL34394, Comprehensive Nuclear-Test-Ban Treaty: Issues and Arguments, by Jonathan Medalia, presents CTBT pros and cons in detail. CRS Report R40612, Comprehensive Nuclear-Test-Ban Treaty: Updated “Safeguards” and Net Assessments, by Jonathan Medalia, discusses safeguards— unilateral steps to maintain U.S. nuclear security consistent with nuclear testing treaties—and their relationship to the CTBT. CRS Report R41908, Energy and Water Development: FY2012 Appropriations, coordinated by Carl E. Behrens, provides details on stockpile stewardship.


Date of Report: December 7, 2011
Number of Pages: 55
Order Number: RL33548
Price: $29.95

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