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Thorium Energy Alliance (TEA) is a non-governmental, non-profit 501(c)3, educational organization based in the United States, that seeks to promote energy security of the world through use of thorium as a fuel source. The potential for use of thorium was studied extensively during the 1950s and 60s, and now worldwide interest is being revived due to limitations and issues concerning safety, economics, use and issues in availability of other energy sources. TEA advocates thorium based nuclear power in present reactors and primarily in next generation reactors. TEA promotes a number of initiatives to educate scientists, engineers, government officials, policy makers and the general public. ==Energy crisis and the role of thorium== TEA promotes the use of thorium using a diverse rationale. Increasing world population, depleting resources and global warming have put severe constraints on the choices of power generation available today. Traditional fossil fuel based energy generation faces two-fold challenges in terms of depleting resources and need to keep greenhouse gas emissions in control. While interim measures like natural gas and unconventional oil are proposed, these still have a carbon footprint and are not universally available. Hydropower use has reached a natural limit in many parts of the world, and the existing capacity is under stress due to climate change.〔Urban, Frauke and Mitchell, Tom (2011). (Climate change, disasters and electricity generation ). London: Overseas Development Institute and Institute of Development Studies〕 Renewable energy is seen as an important component of future energy generation, but being essentially intermittent, can not be effectively managed by the current power distribution technologies. Hence, nuclear energy is seen as an important option for power generation in many countries. Most of the energy made is from fossil fuels and as it is common knowledge fossil fuels create a very large carbon footprint, which leads us to getting energy from nuclear power and reactors. But the most common nuclear reactor is uranium which causes a lot of global warming and as you can imagine carbon dioxide which doesn't help the reduction of carbon footprint; but thorium is a way safer and cleaner way to use nuclear power. Thorium is a safer, cleaner and more abundant alternative fuel; it produces about a thousand times less waste throughout the supply chain than uranium. So as you can imagine thorium had a considerably smaller carbon footprint that uranium.〔Siegel, RP (2011) "Are Thorium Reactors the Carbon-free Answer?"〕 Present generation nuclear reactors are all uranium based, fueled with either fresh mined uranium or recycled plutonium and uranium as the fissile material. There are concerns about a continued supply of uranium, due to resource depletion, as well as various obstacles to mining uranium deposits. Moreover, the currently widely deployed nuclear reactors harness less than 3% of the energy content of uranium fuel. This in turn leaves large quantities of radioactive wastes to be disposed of safely. The issue of disposal of these wastes has not been addressed convincingly anywhere in the world. Moreover, a vast majority of the present generation reactors are based on the original design of reactors meant to power submarines, and whose safety is ensured by several active features and standard operating practices. Under various circumstances, these features and procedures were seen to fail, bringing about catastrophic consequences. Highly enriched uranium and separated plutonium are also the feed-stock for nuclear weapons. Thorium has been proposed as a clean, safe, proliferation resistant and sustainable source of energy which additionally is free from most of the issues associated with uranium. The average crustal abundance of thorium is four times more than that of uranium. Thorium is invariably associated with rare earth elements or rare metals like niobium, tantalum and zirconium. Hence, it can be recovered as a by-product of other mining activities. Already, large quantities of thorium recovered from rare earth element operations have been stockpiled in many countries. Thorium is fertile material, and essentially all thorium can be used in a nuclear reactor. Thorium is not fissile in itself, absorbs a neutron to transmute into uranium-233, which can fission to produce energy. Therefore, a thorium based fuel cycle produces very little, easily manageable waste compared to uranium. Thorium based fuel cycle options can be used to 'burn' all the presently accumulated nuclear waste. Various thorium based reactor designs are inherently more safe than uranium based reactors. However nuclear proliferation could be a serious problem which has to be addressed. Despite all the favorable factors, and utilization in commercial reactors in the past, interest in thorium diminished in the late 1980s due to various reasons. Critics of thorium claim that the advantages are over stated and it is unlikely to be a useful source of energy. Experts point the adverse economics and the availability of plentiful sources of energy that will deter full commercialization of thorium based energy. These and other issues regarding the use of thorium have been debated. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Thorium Energy Alliance」の詳細全文を読む スポンサード リンク
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