Know facts about top 10 nuclear powers of the world

New Delhi: There are eight nations in the world which have conducted nuclear tests openly, but there are several other countries, which are nuclear powers, but have not conducted any nuclear test so far. There are several other countries which are clandestinely pursuing the manufacture of nuclear weapons.The above assessment is based on the combined findings of the Federation of American Scientists, CIA World Factbook, Nuclear Threat Initiative and the US Census Bureau.Here are the top 10 nuclear powers of the world: 1. USA Estimated Warheads: 7,650Operational: 2,150Reserve: 2,500Retired, awaiting dismantlement: 3,000First Test: 1945Most Recent Test: 1992It is estimated that about 500 warheads are assigned to land-based missiles, 1,150 are assigned to nuclear submarines and 300 are ready to be deployed on aircraft.Also, as part of NATO's nuclear sharing program, an additional 200 B61 gravity bombs are deployed in five NATO countries: Belgium, Germany, Italy, the Netherlands and Turkey, the report notes. 2. Russia Estimated Warheads: 8,420Operational: 1,720In Reserve: 2,700Retired, awaiting dismantlement: 4,000First Test: 1949Most Recent Test: 1990Of those, it is estimated that about 1,070 warheads are assigned to land-based missiles, 350 are assigned to nuclear submarines and 300 are ready to be deployed on aircraft, according to the report.3. United Kingdom Estimated Warheads: 225 Operational: Fewer than 160 In Reserve: 65 First Test: 1952 Most Recent Test: 1991 Total Tests: 45All are assigned to nuclear submarines, the country's only launch mechanism. In 1998, it retired all air-delivered nuclear weapons, the report notes.4. France Estimated Warheads: 300 Operational: 290 In Maintenance or awaiting dismantlement: 10 First Test: 1960 Most Recent Test: 1996 Of those, about 240 are thought to be assigned to nuclear submarines, while the other 50 are ready to be deployed on aircraft. France dismantled its land-based nuclear weapons in 1996, according to the report.5. China Estimated Warheads: 240 Operational: Unknown First Test: 1964 Most Recent Test: 1996 Total Tests: 45 Of China's 240 estimated warheads, about 180 can be carried via aircraft or land-based missiles. The rest are either awaiting dismantlement or meant for nuclear submarines that are not yet available, the report states.6. India Estimated Warheads: 80-100 Operational: 0 First Test: 1974 Most Recent Test: 1998 Total Tests: 6 The warheads in storage can be carried via aircraft or land-based missiles. India is looking to add a sea-based launch mechanism, report notes. 7. Pakistan Estimated Warheads: 90-110 Operational: 0 First Test: 1998 Most Recent Test: 1998 Total Tests: 6 The warheads in storage can be carried via aircraft or land-based missiles, report states. 8. North Korea Estimated Warheads: Fewer than 10 First Test: 2006 Most Recent Test: 2013 Total Tests: 3 Experts say the country has plutonium for about 10 warheads, but it is not thought to have the technology to deliver the weapons, the report states. North Korea has conducted three underground nuclear tests, with the most recent coming in February. It has also carried out ballistic missile tests. But it is not thought to have brought the two technologies together yet, the report adds.9. Israel Estimated Warheads: 80 First Test: No confirmed test Most Recent Test: No confirmed test Total Tests: No confirmed test Israel refuses to confirm or deny the widespread belief that it has the bomb, but it is believed to have about 80 atomic weapons and enough plutonium for as many as 200, according to the Federation of American Scientists. 10. Iran Estimated Warheads: 0 First Test: No confirmed test Most Recent Test: No confirmed test Total Tests: No confirmed test A number of Western nations have placed economic and arms-related sanctions on Iran since 2010, when the International Atomic Energy Agency said Tehran was pursuing technology that could be used to build nuclear weapons.Last year, the IAEA confirmed that Iran had begun enriching uranium at its Fordo nuclear facility, the report stated.Iran maintains its nuclear program is for civilian energy purposes only. But the IAEA has said it cannot verify whether the intent of the program is for peaceful means.