1/7/2023 0 Comments Radiation island steamCHERNOBYLĪt Chernobyl, in a safety check gone wrong, the operators deliberately prevented a shutdown of the reactor in a rapidly escalating fiasco. At Three Mile Island, water under pressure transfers heat to a separate system in a less direct process for producing steam. The Japanese reactor applies heat from the nuclear reactions in the fuel rods directly to water, creating steam which drives an electricity-generating turbine. Their use of water is slightly different, however. The plants at Fukushima and Three Mile Island used water cooling technology in common with most nuclear reactors. “That you’re only getting eight times background radiation outside the exploded structure suggests to me the containment vessel and the nuclear reactor pressure vessel both remain intact,” he said. He said that an increase in radiation in the surrounding area of eight times the normal, natural level was an indication that damage to the reactor was so far limited: We don’t know yet,” he said, referring to the uranium fuel rods which lie at the heart of nuclear power generation. “It could be that we’ve had a breach of a fuel pin, a core melt. Nor was there any sign yet that inner protective shields were damaged, Grimes said. That would, if it happened, lead to a greater build-up of radiation within the pressure vessel. In addition, he said, there was no evidence that the core at Fukushima had melted, as happened at Three Mile Island. But, unlike at Chernobyl, there was no breach of a pressure vessel, the shell which insulates the heart of a reactor, nor any major radiation leak.Ĭomparing the problems at Fukushima with Three Mile Island, Robin Grimes, director of the Center of Nuclear Engineering at Imperial College London, said: “There are parallel situations in terms of some of the processes that have occurred, but not parallel because in one case it was due to the safety processes in place and in this case it was natural disaster.” In Japan, the earthquake and possibly the following tsunami overwhelmed mains and back-up power to the coolant pumps.Īt Three Mile Island in Pennsylvania human and technical error caused a confused response to a similar failure, leading to over-heating, a meltdown of the nuclear core and a write-off of the reactor. Japan’s nuclear agency said the problem at Fukushima rated a 4 on a seven-point scale of gravity, less severe than Three Mile Island, which was a 5, and well short of Chernobyl, a full 7. The stricken Japanese reactor north of Tokyo has little parallel, however, with the Soviet plant at Chernobyl, where fundamental design faults led to a deadly serious of explosions in 1986, causing hundreds of deaths among emergency workers and contamination across Ukraine and beyond throughout Europe. There are direct comparisons with the 1979 disaster at Three Mile Island in the United States - in both cases a cooling fault led to a build up of pressure in the radioactive core and resulted in a relatively small radiation leak.īoth use water to control the temperature as uranium degrades in a nuclear chain reaction at the reactors’ core, creating steam which drives a turbine to generate electricity. The Fukushima incident, brought on by the biggest earthquake ever recorded in Japan, took a turn for the worse on Saturday after a blast blew the roof off the facility. A view of the Three Mile Island nuclear power plant from Goldsboro, Pennsylvania, March 22, 1999.
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