Switzerland and weapons of mass destruction

Swiss Confederation
Nuclear program start date1945 (ended in 1988)
First nuclear weapon testNone
First thermonuclear weapon testNone
Last nuclear testNone
Largest yield testNone
Total testsNone
Peak stockpileNone
Current stockpileNone
Current strategic arsenalNone
Cumulative strategic arsenal in megatonnageNone
Maximum missile rangeNone
NPT partyYes

Switzerland made detailed plans to acquire and test nuclear weapons during the Cold War. Less than two weeks after the nuclear bombings of Hiroshima and Nagasaki, the Swiss government started studying the possibility of building nuclear weapons, and continued its military nuclear program for 43 years until 1988. However, it ratified the Treaty on the Non-Proliferation of Nuclear Weapons in 1977.

Switzerland operated the DIORIT heavy water reactor from 1960 and the Lucens heavy water reactor from 1966, and carried out nuclear reprocessing, producing small quantities of plutonium, although it was not weapons-grade.

The Swiss Dassault Mirage IIIS interceptor was envisioned as a nuclear weapons delivery system capable of reaching Moscow, to deter the Soviet Union. Switzerland also considered the possibility of defensive nuclear attacks on Swiss territory.

Switzerland never possessed biological weapons, but did have a program to develop and test chemical weapons.