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The Energy Multiplier Module (EM2 or EM squared) is a nuclear fission power reactor under development by General Atomics. It is a modified version of the Gas Turbine Modular Helium Reactor (GT-MHR) and is capable of converting spent nuclear fuel into electricity and industrial process heat, without separative or conventional nuclear reprocessing. ==Design specifications== The EM2 is an advanced modular reactor expected to produce 265 MWe (500 MWth) of power at and be fully enclosed in an underground containment structure for 30 years without requiring refueling. The EM2 differs from current reactors because it doesn't use water coolant but is instead a gas-cooled fast reactor, which uses helium as a coolant for an additional level of safety. The reactor uses a composite of silicon carbide as cladding material and beryllium oxide as neutron reflector material, another level of safety because the ceramics can handle higher temperatures. The reactor unit is coupled to a high-efficiency direct-drive helium gas turbine which in turn drives a generator for the production of electricity. Use of a gas turbine allows a heat conversion efficiency much greater than conventional steam turbines currently in use. The nuclear core design is based upon a new conversion technique in which an initial “starter” section of the core provides the neutrons required to convert used nuclear fuel, thorium or depleted uranium (DU) into burnable fissile fuel.〔“With Disposal Uncertain, Waste Burning Reactors Gain Traction – EM2 to Burn LWR Fuel,” Nuclear New Build Monitor, March 15, 2010〕 First generation EM2 units use uranium starters (approximately 15 percent U235) to initiate the conversion process. The starter U235 is consumed as the used nuclear fuel/DU or used nuclear fuel/thorium is converted to fissile fuel. The core life expectancy is approximately 30 years (using used nuclear fuel and DU) without refueling. Substantial amounts of valuable fissile material remain in the EM2 core at the end of life. This material is reused as the starter for a second generation of EM2s, without conventional reprocessing. There is no separation of individual heavy metals required and no enriched uranium needed. Only unusable fission products would be removed and stored. All EM2 heavy metal discharges could be recycled into new EM2 units, effectively closing the nuclear fuel cycle, which minimizes nuclear proliferation risks and the need for long-term repositories to secure nuclear materials. 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「Energy Multiplier Module」の詳細全文を読む スポンサード リンク
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