Life,  Tech

Three Mile Island Accident: The Nuclear Meltdown That Changed the World

  Three Mile Island, located in Harrisburg, Pennsylvania, USA, is where the first furnace core meltdown occurred in the history of human nuclear energy development. Affected by this, the development of nuclear power in many countries once came to a standstill.
  Before the Three Mile Island accident, nuclear power had always been regarded as one of the safest energy sources. At 4 a.m. on March 28, 1979, Unit 2 of the Three Mile Island Nuclear Power Plant was operating at 97% power. A check valve jammed due to a malfunction, causing the condensate water to cut off, causing the condensate pump, condensate lift pump, and main feed water pump to fail. Abnormal operation will cause the turbine to shut down, which will then cause a chain-type abnormal reaction in the operating system.
  The operator panicked and took inappropriate measures. Two hours later, the top of the reactor was exposed, and the fuel rod cladding and pellets began to melt, releasing radioactive isotopes into the leaking coolant. A series of erroneous operations resulted in the gradual loss of cooling water in the reactor core. Part of the fuel rod zirconium cladding and uranium fuel melted. A large amount of radioactive materials, especially gases such as xenon and krypton, were released from the reactor together with iodine, and a small amount of radioactivity. The substance is released with the leakage of part of the cooling water.
  Sixteen hours after the turbine shut down, the reactor finally reached a stable state and the accident process was terminated. After the Three Mile Island accident, those who had pushed for nuclear energy fell silent, and the U.S. Nuclear Regulatory Commission hastily announced a moratorium on issuing licenses for the construction and operation of new nuclear power plants. The Three Mile Island accident shattered the myth of nuclear power safety. Later investigation reports showed that the accident was caused by a combination of factors such as design defects, equipment failure, and human error. The accident caused serious environmental pollution, and the successive clean-up costs were as high as 1 billion US dollars.
  After the accident, the United States was shocked and residents near the nuclear power plant were terrified. On the one hand, due to the partial meltdown of the reactor, a large amount of radioactive gas was released into the atmosphere, leading to the emergency evacuation of pregnant women and children within a 5-mile radius of the nuclear power plant, the closure of all schools within 10 miles, and an outbreak in New York involving 200,000 people. Protests against the construction of nuclear power plants. Public confidence in the development of nuclear energy was severely dampened, and the nuclear power industry was hit hard and unable to recover. In the following 30 years, the United States did not build or put into operation a single nuclear power unit.
  On the other hand, the accident promoted the pace of reform and healthy development of the nuclear power industry. The United States has strengthened nuclear power plant design and equipment requirements, and the Nuclear Regulatory Commission has also established a 24-hour on-duty operation center to respond to emergencies.

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