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.”
A fire caused by a burst gas pipe yesterday spread to several homes and sent a fireball soaring into the sky outside Malaysia’s largest city, injuring more than 100 people. The towering inferno near a gas station in Putra Heights outside Kuala Lumpur was visible for kilometers and lasted for several hours. It happened during a public holiday as Muslims, who are the majority in Malaysia, celebrate the second day of Eid al-Fitr. National oil company Petronas said the fire started at one of its gas pipelines at 8:10am and the affected pipeline was later isolated. Disaster management officials said shutting the
DITCH TACTICS: Kenyan officers were on their way to rescue Haitian police stuck in a ditch suspected to have been deliberately dug by Haitian gang members A Kenyan policeman deployed in Haiti has gone missing after violent gangs attacked a group of officers on a rescue mission, a UN-backed multinational security mission said in a statement yesterday. The Kenyan officers on Tuesday were on their way to rescue Haitian police stuck in a ditch “suspected to have been deliberately dug by gangs,” the statement said, adding that “specialized teams have been deployed” to search for the missing officer. Local media outlets in Haiti reported that the officer had been killed and videos of a lifeless man clothed in Kenyan uniform were shared on social media. Gang violence has left
US Vice President J.D. Vance on Friday accused Denmark of not having done enough to protect Greenland, when he visited the strategically placed and resource-rich Danish territory coveted by US President Donald Trump. Vance made his comment during a trip to the Pituffik Space Base in northwestern Greenland, a visit viewed by Copenhagen and Nuuk as a provocation. “Our message to Denmark is very simple: You have not done a good job by the people of Greenland,” Vance told a news conference. “You have under-invested in the people of Greenland, and you have under-invested in the security architecture of this
Japan unveiled a plan on Thursday to evacuate around 120,000 residents and tourists from its southern islets near Taiwan within six days in the event of an “emergency”. The plan was put together as “the security situation surrounding our nation grows severe” and with an “emergency” in mind, the government’s crisis management office said. Exactly what that emergency might be was left unspecified in the plan but it envisages the evacuation of around 120,000 people in five Japanese islets close to Taiwan. China claims Taiwan as part of its territory and has stepped up military pressure in recent years, including
RSS