The radiation leak in Japan immediately recalls memories of accidents at the Chernobyl, Ukraine, and Three Mile Island, US, power stations, and how it unfolds will be a critical test for international acceptance of nuclear energy.
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.
There are direct comparisons with the 1979 disaster at Three Mile Island in the US — in both cases a cooling fault led to a buildup of pressure in the radioactive core and resulted in a relatively small radiation leak.
Both 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 stricken Japanese reactor north of Tokyo has little parallel, however, with the Soviet plant at Chernobyl, where fundamental design faults led to a deadly series of explosions in 1986, causing hundreds of deaths among emergency workers and contamination across Ukraine and beyond throughout Europe.
Japan’s nuclear agency said the problem at Fukushima rated a four 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.
In Japan, the earthquake and possibly the following tsunami overwhelmed mains and back-up power to the coolant pumps.
At 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. However, unlike in Chernobyl, there was no breach of a pressure vessel, the shell which insulates the heart of a reactor, nor any major radiation leak.
Comparing the problems at Fukushima with Three Mile Island, Robin Grimes, director of the Centre 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 addition, he said, there was no evidence that the core at Fukushima had melted, as happened at Three Mile Island.
That would, if it happened, lead to a greater buildup of radiation within the pressure vessel. Nor was there any sign yet that inner protective shields were damaged, Grimes said.
He said an increase in radiation in the surrounding area of eight times the normal, natural level was an indication that damage to the reactor was limited so far.
The plants at Fukushima and Three Mile Island use water cooling technology in common with most nuclear reactors. Their use of water is slightly different, however.
The Japanese reactor applies heat from the nuclear reactions in the fuel rods directly to water, creating steam which drives an electricity-generating turbine. At Three Mile Island, water under pressure transfers heat to a separate system in a less direct process for producing steam.
In Chernobyl, in a safety check gone wrong, the operators deliberately prevented a shutdown of the reactor in a rapidly escalating fiasco. Runaway nuclear fission reactions created a buildup of pressure and a massive and deadly radiation leakage as explosions ripped through a too-feeble reactor shell.
Three Mile Island did not result in a serious leak, but was still damaging at the time for the reputation of nuclear power.
The Fukushima reactor dates to the early 1970s, older than many still in use, and the industry has since developed “even safer” reactors better equipped to cool naturally, Grimes said.
Opponents of nuclear power have been swift to use the problems at Fukushima to reinforce arguments that the hazards of atomic energy outweigh the benefits.
Supporters say that the ability of Japan’s dozens of reactors to survive frequent earthquakes shows their worth, particularly to countries like Japan, which lack their own reserves of oil, gas and coal.
“We must remember that there are 55 reactors in Japan and this was a huge earthquake,” said Paddy Regan, professor of Nuclear Physics at the University of Surrey near London. “As a test of the resilience and robustness of nuclear plants, it seems they have withstood the effects very well.”
‘CROSSING THE LINE’: China’s embassy in Seoul criticized US Forces Korea Commander General Xavier Brunson, asking if his ‘hostile’ remarks were authorized by Washington South Korea and the US are in talks over recent public remarks by the commander of US Forces Korea, Seoul’s presidential office said yesterday, after the comments drew sharp criticism from China. In a recent podcast interview, US Forces Korea Commander General Xavier Brunson described South Korea as “the dagger in the heart of Asia” from China’s east coast, prompting the Chinese embassy in Seoul to say that he had “truly crossed the line.” The interview came amid growing speculation that Washington might seek to expand the role of US Forces Korea in countering the growing regional influence of China, a key
Through the noise of rushing papers and whirring belts at a print factory in Kyoto, two creators watch their photo essay come to life in broadsheet form — part of an effort to win new audiences in the age of artificial intelligence (AI). Despite the decline of the publishing industry, self-publication and handmade “zine” magazines are growing in popularity in Japan, reflecting the nation’s enduring love of paper in the digital era. While speaking to Agence France-Presse at the plant, his hands black with ink, one of the creators, Kazuma Obara, said: “I think [paper] is a medium that engages all five
Australian researchers have trained lab-grown brain cells on a silicon computer chip to play the 1990s shooter game Doom and said they are just scratching the surface of what the neurons could be capable of doing. It is the science-fiction work of biotech boffins at Cortical Labs, who researched and developed the technology that harnesses the workings of the brain’s networking system. Each so-called “biological computer” contains about 200,000 living human brain cells, grown from stem cells that were harvested from blood donations. Having mastered the simple computer game Pong, where a paddle is moved up and down to send a ball
France experienced its hottest spring on record, the French weather service said on Tuesday, after an exceptional early heat wave that also broke highs for the season in England and Wales. Meteo-France said the average nationwide temperature over March to May was 13.8°C — about 1.7°C above the norm, and surpassing records set in 2011 and 2020. “The warmest spring since records began in 1900,” it said in a bulletin. All three months were warmer than average, but the onset of an “unprecedented heatwave” late last month pushed the mercury to highs typically seen at the height of the summer. “Our country had never
RSS