The international community is constantly on the lookout for signs of nuclear weapons detonations. To this end, an international monitoring system (IMS) has been established to detect any potential nuclear explosions. This system relies on radionuclide technologies to detect ultratrace levels of radioactive noble gas xenon, a by-product of nuclear detonations. In 1955, the United States conducted Operation Wigwam, an underwater nuclear test at a depth of 600 m, to assess the vulnerability of submarines to nuclear explosions.
This was followed by the first underwater nuclear test, 'Baker', in 1946 at the Pacific Proving Grounds in the Marshall Islands. The Comprehensive Nuclear-Test-Ban Treaty (CTBT) of 1996 bans all nuclear explosions anywhere and by anyone. Despite this, some countries may still attempt to conduct nuclear tests to develop or improve their nuclear weapons capabilities. To prevent this, it is important to monitor the world for any signs of such explosions. There are several ways to detect a nuclear detonation, including seismic, hydroacoustic and infrasound detection, air sampling, and satellites.
The Low-Performance Nuclear Monitoring Program is a research enterprise designed to improve the ability to monitor potential evidence of evasive nuclear explosives. However, there is a limit to the sensitivity of underground and submarine systems. Very small nuclear explosions at a great distance from receiving sites may go undetected or misidentified as a small earthquake. Studies and evaluations have estimated that cancer deaths due to global radiation doses from nuclear test programmes in the atmosphere of the five nuclear-weapon States amount to hundreds of thousands.