Nucleus metropolis...!

           Nuclear weapons tests are experiments carried out to determine the effectiveness, yield and explosive capability of nuclear weapons. Throughout the twentieth century, most nations that have developed nuclear weapons have tested them. Testing nuclear weapons can yield information about how the weapons work, as well as how the weapons behave under various conditions and how structures behave when subjected to nuclear explosions. Additionally, nuclear testing has often been used as an indicator of scientific and military strength, and many tests have been overtly political in their intention; most nuclear weapons states publicly declared their nuclear status by means of a nuclear test.

           The first nuclear weapon was detonated as a test by the United States at the Trinity site on July 16, 1945, with a yield approximately equivalent to 20kilotons. The first hydrogen bomb, codenamed "Mike", was tested at the Enewetak atoll in the Marshall Islands on November 1 (local date) in 1952, also by the United States. The largest nuclear weapon ever tested was the "Tsar Bomba" of the Soviet Union at Novaya Zemlya on October 30, 1961, with an estimated yield of around 50 megatons.

Facts :

          By afternoon the wind had fallen silent over Pokhran. At 3:45 p.m., the timer detonated the three devices. Around 200 to 300 m deep in the earth, the heat generated was equivalent to a million degrees centigrade--as hot as temperatures on the sun. Instantly, rocks weighing around a thousand tonnes, a mini mountain underground, vapourised...shockwaves from the blasts began to lift a mound of earth the size of a football field by several metres. One scientist on seeing it said, "I can now believe stories of Lord Krishna lifting a hill." --India Today

           On 28 May 1998 Pakistan detonated five undergound nuclear tests. These followed five nuclear tests by India two weeks earlier. In response to the tests, novelist Arundhati Roy wrote that "This world of ours is four thousand, six hundred million years old. It could end in an afternoon."

           But these tests were merely the most recent in a long line of nuclear explosions beginning with the Trinity test on July 16, 1945. Over 2000 nuclear weapons have been detonated for testing purposes, over 500 in the atmosphere, under water or in space, and the rest underground. Of these about 1000 were conducted by the United States, 700 by the Soviet Union, 30 by the UK, 180 by France, 35 by China, 5 by India and 5 by Pakistan

           Some testing was also done with military personnel in the vicinity to determine military survivability and fighting capacity in a nuclear war. Research was also done on civilians exposed to radiation from nuclear testing to determine the effects of such exposure. Nuclear testing was also done in some cases for political purposes. India and Pakistan, for example, testing in 1998 in order to assert their status as nuclear weapon states.
 To get over these problems , few treaties were in action as follows . . .
1. Partial Test Ban Treaty 
In response to growing international awareness of the risks of radiation from nuclear tests, the Soviet Union, US and UK in 1963 negotiated an agreement to prohibit nuclear testing in the atmosphere, outer space and underwater .

2. Threshold Test Ban Treaty 
In 1974 the US and Soviet Union concluded the Threshold Test Ban Treaty under which they agreed not to conduct nuclear tests with an explosive yield over 150 kilotons (i.e. about 10 times the force of the Hiroshima bomb) .
3. Comprehensive Test Ban Treaty
In 1996, the United Nations adopted the Comprehensive Test Ban Treaty which had been negotiated in the Conference on Disarmament. The CTBT prohibits all nuclear test explosions, including explosions for peaceful purposes .

4. Comprehensive Test Ban Treaty Organisation (C.T.B.T.O)             
The CTBT establishes an agency for its implementation including an international monitoring system (IMS) to assist in verification. The IMS comprises facilities owned by the CTBTO, and those owned and operated by States parties .

 *     One of the reasons for these tests is to upgrade existing weapons designs and test new designs. Following such tests under the "Stockpile Stewardship Program" the US, for example, has introduced a new weapon into its stockpile - the B61-mod11.

        The US and France are known to be constructing new facilities capable of conducting nuclear experiments including the National Ignition Facility in California, the Dual-Axis Radiographic Hydrodynamic Testing Facility (DARHT) in Nevada and the Megajoule Facility in ? 

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