TheThreeMileIslandAccident美国三里岛事故

1、 Introduction Main reason Process Emergency measures Aftermath Influence Lessons learnedThe Three Mile Island accident was a partial nuclear meltdown which occurred in one of the two United States Three Mile Island nuclear reactors in Dauphin County, Pennsylvania, on March 28, 1979. It was the worst

2、 accident in U.S. commercial nuclear power plant history. The partial meltdown resulted in the release of small amounts of radioactive gases and radioactive iodine into the environment.Unit 2(二号反应堆二号反应堆)The power plant was owned and operated by General Public Utilities and Metropolitan Edison (Met E

3、d). The reactor involved in the accident, Unit 2, was a pressurized water reactor manufactured by Babcock & Wilcox.u Consequences of stuck valve u Human factors confusion over valve statuslThe design of the PORV(减压阀) indicator light was fundamentally flawed .And the operators had not been trained to

4、 use it. lThe operators did not correctly diagnose the probleml Nuclear leak alarm did not attract the attention of operators主水泵停转辅助回路中隔离阀门未打开辅助水泵未正常开启二号回路冷却水蒸汽发生器反应堆热量聚集堆芯压力上升稳压器减压阀开启一号回路冷却水流出放射性物质泄漏 Schools were closed and residents were urged to stay indoors. pregnant women and pre-school age chi

5、ldren were emergency evacuation. Farmers were told to keep their animals under cover and on stored feed Cleanup started in August 1979 and officially ended in December 1993, with a total cleanup cost of about $1 billion lIn total approximately 2.5 million curies of radioactive gases, and approximate

6、ly 15 curies of iodine-131 was released into the environment lThe average radiation dose to people living within ten miles of the plant was eight millirem(毫雷姆） Eight millirem is about equal to a chest X-ray.lDisease rates in areas further than 10 miles from the plant were never examined .l the accid

7、ent has had no observable long term health effects According to the IAEA(国际原子能机构) the Three Mile Island accident was a significant turning point in the global development of nuclear power Many similar Babcock and Wilcox reactors on order were canceled; in total, 51 U.S. nuclear reactors were canceled from 19801984 To avoid causing enormous economic losses ,increasing the cost of the building of nuclear power plant safety facilities To strengthen the training of opera