“For half a century, ACA has been providing the world … with advocacy, analysis, and awareness on some of the most critical topics of international peace and security, including on how to achieve our common, shared goal of a world free of nuclear weapons.”

– Izumi Nakamitsu
UN High Representative for Disarmament Affairs
June 2, 2022
Threshold Test Ban Treaty (TTBT)

The Threshold Test Ban Treaty (TTBT) between the United States and the Soviet Union establishes a nuclear threshold through the prohibition of nuclear tests that exceed 150 kilotons. The threshold prevents the testing of new or existing nuclear weapons that exceed the fractional-megaton range. The United States and Soviet Union are subject to verification provisions. These are conducted through hydrodynamic yield measurements, seismic monitoring, and on-site inspections.

Opened for Signature: 3 July 1974

Entry into force: 11 December 1990

Official Text: http://www.state.gov/t/isn/5204.htm#treaty

Status and Signatories: http://www.state.gov/t/isn/5204.htm#narrative

ACA Backgrounder: https://www.armscontrol.org/factsheets/Nuclear-Testing-and-Comprehensive-Test-Ban-Treaty-CTBT-Timeline