Due to rising concern about radioactive fallout from increasingly big nuclear tests underwater, in space, in the atmosphere and underground, as well as concern over the burgeoning arms race between NATO and Warsaw Pact countries, the US, UK, and USSR decided to negotiate a test-ban treaty. These concerns became more pronounced after the United States successfully tested a hydrogen bomb and a thermonuclear device with the power of eight megatons of TNT in November 1952, and 15 megatons later on, and when the U.S.S.R. detonated a 50-megaton nuclear warhead, deliverable by a bomber, in October 1961.
Diplomatic exchanges went through 1959 and 1960, and in-person negotiations continued until 1963, when five Warsaw Pact countries, five NATO countries, and eight non-aligned countries met in Geneva to hammer out the details of what would become the Limited (or Partial) Test Ban Treaty). Initially, the Soviet Union proposed a testing ban along with a disarmament agreement dealing with both conventional and nuclear weapon systems. It was only later during 1959 and into the early 1960s that the United States, the United Kingdom, and the Soviet Union agreed to detach a general agreement on nuclear disarmament from a ban on nuclear weapons testing.
The Soviet Union agreed only to a testing ban with no verification regime or protocols. The United States and United Kingdom insisted on intrusive, inspection-based control systems as a means to verify compliance. On the other hand, the U.S.S.R. held the position that surveillance and seismic detection equipment operated from outside the boundaries of any signatory was adequate to verify compliance. The Western Powers thought that any agreement not subject to a control system rigorous enough to verify compliance would set a bad precedent in nuclear arms control for future agreements. Read more