ENGINEERS IN Japan’s ruined Fukushima nuclear plant have revealed it suffered a triple meltdown in the four days after being battered by a huge earthquake and tsunami on March 11th.
The news confirms fears that reactor three, which contains controversial mixed uranium-plutonium fuel, known as Mox, was among the casualties of the world’s worst nuclear disaster since Chernobyl. Mox is considered thousands of times more toxic than uranium nuclear fuel.
Plant operator Tokyo Electric Power Co (Tepco) said yesterday that most of the nuclear rods inside reactors two and three had melted and fallen to the bottom of their containment vessels. Last week the company admitted that most of the fuel rods in reactor one had melted after the plant’s cooling systems were knocked out.
“The situation inside two and three is almost the same,” said Tepco spokesman Yoshimi Hitosugi last night. The company said the fuel in reactor three took about 60 hours to melt. The reactor melted down 100 hours after the magnitude nine quake struck.
Critics suspect Japan’s largest utility concealed the extent of the damage to the five-reactor complex in the immediate aftermath of the disaster to avoid causing panic, a charge Tepco denies. “Of course we assumed that there had been a meltdown inside the reactors but until we could confirm the data we were unable to release this information,” said Mr Hitosugi.
About 100,000 people have been forced to evacuate the area around the complex. Acting under advice from Tepco, the Japanese authorities only slowly expanded the evacuation area in March, from an initial 3km radius to 20km.
Villages outside the zone are this month being emptied of their populations to escape radiation.
Thousands of Fukushima residents confronted government officials in Tokyo this week to demand they reverse a decision to raise by 20 times radiation limits for schools in the area. The decision, which raises radiation exposure on children from 1 to 20 millisieverts per year – the maximum permitted dose for German nuclear workers – has caused bitter controversy.
“It’s already two months since the accident and our children have been exposed to so much radiation,” said housewife Mika Okano.
“It’s the government’s job to protect young people. Instead, they’re putting them in danger to defend nuclear power.”
Japan’s ministry of education has promised to review the decision in the summer holidays, but many parents said that would be too late. “Would they send their own children to live in Fukushima?” asked Sumie Kojima? “It’s shameful that they would do this. They should evacuate everyone from the prefecture.”
Officials from the International Atomic Energy Agency arrived in Japan yesterday on a fact-finding tour . Among the issues they will be examining is the huge and growing stockpile of radioactive water – about 80,000 tons – pumped from the reactors, which Tepco engineers are struggling to reprocess or dump.