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WASH-1400, 'The Reactor Safety Study', was a report produced in 1975 for the Nuclear Regulatory Commission by a committee of specialists under Professor Norman Rasmussen. It "generated a storm of criticism in the years following its release".〔 In the years immediately after its release, WASH-1400 was followed by a number of reports that either peer reviewed its methodology or offered their own judgments about probabilities and consequences of various events at commercial reactors. In at least a few instances, some offered critiques of the study's assumptions, methodology, calculations, peer review procedures, and objectivity.〔John Byrne and Steven M. Hoffman (1996). ''Governing the Atom: The Politics of Risk'', Transaction Publishers, p. 147.〕 A succession of reports, including NUREG-1150, the State-of-the-Art Reactor Consequence Analyses and others, have carried-on the tradition of PRA and its application to commercial power plants. The report correctly foresaw the impact a tidal wave could have on a nuclear power station. It concluded that "Some plants are located on the sea shore where the possibility of tidal waves, and waves and high water levels due to hurricanes exist. The plant design in these cases must accommodate the largest waves and water levels that can be expected. Such events were assessed to represent negligible risks." (Section 5.4.6 "Other external causes") ==Overview== WASH-1400 considered the course of events that might arise during a serious accident at a (then) large modern Light water reactor. It estimated the radiological consequences of these events, and the probability of their occurrence, using a fault tree/event tree approach. This technique is called Probabilistic Risk Assessment (PRA). The report concluded that the risks to the individual posed by nuclear power stations were acceptably small, compared with other tolerable risks. Specifically, the report concluded, using the methods and resources and knowledge available at the time, that the probability of a complete core meltdown is about 1 in 20,000 per reactor per year. The study was peer-reviewed by the 'Lewis Committee' in 1977, which broadly endorsed the methodology as the best available, but cautioned that the risk figures were subject to large uncertainty. The methods used were comparatively simple by today's standards and based on early understanding of key phenomenology. Amidst a period of intensive (and expensive) research and discussion, inspired in part by the Three Mile Island accident, work continued on PRA including NUREG-1150 and an ongoing study being performed by the Nuclear Regulatory Commission called the State-of-the-Art Reactor Consequence Analyses (SOARCA)(). Specific Studies were also made of two plants at Zion and Indian Point—the so-called Z/IP Study. The PRA methodology became generally followed as part of the safety-assessment of all modern nuclear power plants. In the 1990s, all U.S. nuclear power plants submitted PRAs to the NRC under the Individual Plant Examination program (), and five of these were the basis for the 1991 NUREG-1150. According to Table 6-3 on pg. 112 of WASH-1400, individual persons have a less than 1 in 5,000,000,000 (Tbl 6-3, pg. 112) chance of dying on a yearly basis from the operation of 100 nuclear power plants in the United States. This is less than yearly risk of being struck by lightning and being killed (1 in 20,000,000, Tbl 6-3, pg. 112), being in a fatal auto collision (1 in 3,000 chance of dying, Tbl 6-3, pg. 112), or any other accident risk mentioned in WASH-1400. WASH-1400 is now NUREG-75/014. 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「WASH-1400」の詳細全文を読む スポンサード リンク
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