Underground nuclear tests

Testing has been a fundamental factor in the design of nuclear weapons. Therefore, up to now, six countries have performed about 1900 tests, of 

In 1963, the first international treaty against testing nuclear weapons was signed and after that, only France (atmospheric and underwater tests until 1974) and China (until 1980) continued. After 1980, all the tests have been underground. One of the positive results of the G7 Group, enlarged to include 

Underground nuclear explosions are usually performed at a depth of hundreds of metres in order to 

The known effects of an underground explosion are the melting of rocks near the bomb and their fracturing for an extended surrounding volume. Certain events are seismic waves produced by the explosion and the ensuing surface disturbances in lakes and lagoons. 

The radioactive products (with a long half life and at a few hours from the time of the blast) released in the rock cavities have the following order of magnitude  

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Keller, C.E., Utility of Shock Models for Underground Nuclear Tests, in Shock Waves in Condensed Matter—1983 (edited by Asay, J.R., Graham, R.A., and Straub, G.K.), North-Holland Physics, Amsterdam, 1984, pp. 485-487. 

The advent of the space age, the testing of intercontinental ballistic missiles, the use of space probes, the existence of radiation belts in outer space, and the increasing utilization of military and civilian satellites have triggered further studies on the effects of nuclear radiation on all types of materials, including expls, propints, pyrots and related materials. Nuclear radiation effects studies range from steady-state to transient environments, from ground zero to upper atmosphere levels and from underground nuclear tests to simulation techniques in the laboratory which in turn cover all phases of vulnerability and survivability... 

A total of 41 atmospheric nuclear tests were conducted in the open air between July 1966 and September 1974, 37 at Mururoa Atoll and four at Fangataufa Atoll, and 137 underground nuclear tests took place deep below the surface of the atolls between June 1975 and January 1996, 127 at Mururoa Atoll and ten at Fangataufa Atoll. 

Safety trials were conducted to investigate the behaviour of the core of a nuclear device under simulated faulty detonation conditions. The core is destroyed by the conventional explosive detonation of such a device, with the production of finely divided plutonium and plutonium oxide which are widely dispersed if the test is not confined. Usually no fission takes place, though there was a very small fission energy release in three of the French underground safety trials. (Since there was some explosive yield, these three trials are sometimes counted as nuclear tests which would put the total number of underground nuclear tests at Mururoa and Fangataufa atolls at 140 rather than 137.) All of the 15 safety trials were carried out at Mururoa. 

French underground nuclear tests and safety trials at Mururoa and Fangataufa Atolls (after IAEA, 1998, and references therein)... 

In August 1995, following the announcement in June 1995 of a final series of eight underground nuclear tests at the South Pacific site, the French Government submitted a written request to the IAEA to assess independently the radiological consequences of the nuclear tests at Mururoa and Fangataufa atolls, and undertook to provide information needed for the assessment. 

The concentration of tritium in each lagoon was found to be higher than in the open ocean, as the result of leakages from a number of the cavity-chimneys created by underground nuclear tests. 

Carrigan, C.R., Heinle, R.A., Hudson, G.B., Nitao, J.J. and Zucca, J.J., Trace gas emissions on geological faults as indicators of underground nuclear testing. Nature, 382 (1996) 528. 

Seabed Treaty 1972 94 countries prohibits emplacing nuclear weapons or weapons of mass destruction on the sea bed and the ocean floor beyond the 12- mile coastal zone. Threshold Test Ban Treaty (TTBT) 1974 United States, USSR prohibits underground nuclear tests having a yield exceeding 150 kilotons. South Pacific Nuclear Free-Zone Treaty (Treaty of Rarotonga) 1985 15 countries prohibits testing, deployment, or acquisition of nuclear weapons in the South Pacific. 

In contrast, the five remote sensor technologies for detecting and identifying underwater or underground nuclear tests (radionuclide, seismic, infrasound, hydroacoustic, and... 

Such ideas spurred the quest to produce still heavier elements in subsequent thermonuclear tests. Indeed, the rather long-lived nuclide Fm (half-life Tin = 100 days) was detected in later nuclear tests, indicating capture of at least 19 neutrons in uranium. However, attempts to produce and detect still heavier elements in underground nuclear tests conducted at the Nevada Test Site all failed, thus dashing hopes that heavier long-lived elements could be produced via this multiple neutron-capture process that, as it had been postulated, might... 

Underground testing The underground tests of nuclear weapons were begun in 1951 by the USA and in 1961 by the USSR. Until 1998,1,876 underground nuclear tests were carried out in seven countries (O Table 55.27). 

The release of into the atmosphere at the Nevada underground site was estimated to be 5,000 TBq. If other tests release similar amounts of assuming similar magnitudes of explosions, the total release by underground nuclear tests is estimated to be 15,000 TBq of The estimated released was about 0.004% of the estimated total production of If the same rate can be applied to other gaseous radionuclides, 50 PBq of Xe and 0.1 TBq of were released by the underground tests. 

You asked me to write to you about certain plans under examination for carrying out underground nuclear test explosions. 

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