Operation JULIN

Beginning in 1963, the number of nuclear weapon tests conducted by the United States continually declined until 1992, when all testing ceased. In 1992, the last eight nuclear tests were conducted at the Nevada Test Site. Four of these tests were conducted by Los Alamos and four by Lawrence Livermore National Laboratory. The Department of Defense participated in two of these tests and the United Kingdom one.

All nuclear tests and test series have been given names since the first test, Trinity, which was detonated in July 1945. Since 1961, nuclear tests have been scheduled and conducted by fiscal year. The name for the Fiscal Year 1992 series was Julin.

The Los Alamos Tests

The first Operation Julin test, codenamed, Lubbock, took place on October 18, 1991, with an announced yield between 20 and 150 kilotons. The second Los Alamos test, Junction was detonated on March 26, 1992, again with an announced yield between 20 and 150 kilotons. Unlike Lubbock, Junction was a treaty verification test. On April 30, 1992 Los Alamos, in partnership with the Department of Defense, detonated Diamond Fortune, a weapons effect test of less than 20 kilotons yield. The last Los Alamos test, and the last test conducted by the United States, Divider, took place on September 23, 1992. Divider, as test to ensure the safety of U.S. deterrent forces, had an announced yield of less than 20 kilotons. Since Divider, no tests of nuclear weapons have been conducted by the United States.