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Several hundred engineers continue struggle to prevent meltdown at nuclear plant but the risks are still immense Radiation, aftershocks, fire, a tsunami evacuation, and hours and hours of difficult, dangerous labour trying to do what nobody in history has done before: prevent four doomed nuclear reactors from a catastrophic meltdown. Today was a typically extraordinary day at work for the several hundred engineers, contract employees and emergency personnel at Tokyo Electric’s Daiichi power plant, where standards of normality have shifted along with tectonic plates since a magnitude nine earthquake struck offshore just over a month ago. Just how far those standards have shifted was apparent when, during the day, Japan’s Nuclear and Industrial Safety Agency upgraded the disaster from five to seven on the INES scale. This is the highest level, a “major accident”, putting Fukushima on a par with the explosion at Chernobyl in 1986. It is unclear whether the workers at the plant were made aware of the reassessment, but they are likely to have more urgent tasks on their minds. Employees whose responsibilities formerly involved the dull tasks of watching monitors, examining pipes and driving pick-up trucks now find themselves in an emergency operation to douse exposed fuel rods, plug leaks of radiation millions of times above normal, and pump nitrogen into reactor buildings to prevent explosions. Their work has been complicated by aftershocks that continue to ripple through the region and cause renewed damage and delays. In the past week there have been two tremors in excess of magnitude seven and many more fives and sixes. One of the latest yesterday morning set off a blaze outside the No 4 reactor building and prompted a tsunami warning and the evacuation of workers to higher ground. Even without these extra hazards, the risks are immense. Along with the reactors, pools of spent fuel bring the amount of radioactive material at the Fukushima plant to a considerably higher level than that at Chernobyl, though less has been released. It is less combustible and stored in stronger containment vessels, but leaks have been a constant concern. Several buildings were ripped apart by explosions in the early days of the disaster. The generators powering the cooling systems were knocked out by the tsunami flood waters. Reactors 1,2 and 3 have all experienced at least partial fuel melting, which releases radionuclides such as iodine-131 and caesium-137. Reactor 4 is also badly damaged. To cope, the plant’s operator, Tokyo Electric, has downgraded safety baselines both for the workers and the surrounding environment. With the approval of the Japanese government, it has increased the permissible radiation exposure level for the Fukushima workers from 50 millisieverts a year to 250. This raises the risk of cancer by about 1.25 percentage points above the population average. Yet even working in short shifts at this increased level, the radioactivity is so high in some areas, such as the No 3 reactor, that plant managers say humans may never enter again. Elsewhere, the workers are kitted out in protective suits, masks and breathing apparatus, but there have been accidents. Two workers had to be hospitalised for radiation burns after stepping in highly contaminated water without boots. For more than a week after the accident, most did not have dosimeters for measuring background radiation. The government has provided more and the US has donated devices, but conditions remain tough. Isao Sasakawa, a former employee, wrote on his blog earlier in the crisis: “It makes my heart ache when I imagine my former colleagues, boss and cousin working in that cramped space, wearing protective clothing and masks, unable to move freely and suffocating in order to prevent the damage from getting worse. I hope for a miracle so they all come back safely.” Most workers are company employees or emergency personnel. But there are also contract workers, who are being offered danger bonuses that would take their earnings to $1,000 a day. US nuclear experts have been highly critical of Tepco’s strategy for regaining control at Fukushima. They say that some of the low-wage labourers have been exposed to radiation levels far in excess of what would be legal in America. Robert Alvarez, who worked on nuclear policy in the Clinton administration, said: “This is what we call in the US ‘body banking’ – just using bodies to absorb radiation and spread the risk around. Most of these workers are ill-informed and probably not being measured for risk.” The workers’ tasks have evolved with the crisis. In the early days, the priority was to douse overheating reactors and spent fuel with water from fire trucks and helicopters. When the fresh water ran out, they used water from the Pacific. This appears to have prevented a complete meltdown of the three reactors, but it has left a series of new problems, including deposits of salt that are blocking pipes, and pools of contaminated water. Still more alarming was the leak of highly radioactive water from a concrete pit near reactor No 2. This persisted for days, resulting in saltwater with radioactive iodine that was 7.5m times the legal limit at one point. The flow was eventually staunched by injecting “water glass” or sodium silicate into the floor of the cracked pit. Workers had previously tried using cement, rags, absorbent polymers found in nappies and coloured bath salts to trace the path of contamination. Other mitigation plans include putting in silt barriers near discharge pipes, and covering the plant with sheets on a steel frame. Giant concrete pumps are being sent to the area from overseas and Japan has also reportedly asked Russia for its floating radioactive waste treatment facility, the Landysh. The operation is likely to take months. Japan’s industry minister, Banri Kaieda, said the basements of reactor buildings and underground trenches have been flooded with 60,000 tonnes of radioactive water that will have to be pumped into alternative vessels, including waste tanks, an artificial floating island and US navy barges. To make space for the most contaminated water Tokyo Electric has broken its own regulations and dumped 11,500 tons of relatively low-level contaminated water into the sea. The prognosis remains uncertain. A confidential assessment by the Nuclear Regulatory Commission, leaked to the New York Times, suggested the situation could yet spiral out of control because of pressure on containment structures and the vulnerabilities of the emergency cooling system. But Japan’s prime minister, Naoto Kan, insisted yesterday that things were moving in the right direction. “Compared with before, today’s situation is improving step by step, or as I have just said, the release of radioactive particles is declining,” Kan said. “But it has not yet reached the point where we can predict what will happen.” Despite yesterday’s upgrade of the disaster, authorities insisted the total amount of radiation leaked from Fukushima is still only a tenth that of Chernobyl. Haruki Madarame, chairman of the Nuclear Safety Commission, estimates that 10,000 terabecquerels of radioactive materials per hour were released for several hours in the early stages of the disaster. According to Kyodo news, it has since dropped to under one terabecquerel per hour. But Tokyo Electric Power has warned the radiation total could still exceed the 1986 disaster if leaks are not fixed. Advocacy groups concur. Michael Mariotte, who heads the US-based Nuclear Information Research Service, said: “There is potential, ultimately, for higher radiation releases than Chernobyl, depending on how this plays out, because you have got four reactors and the spent fuel pools, and it is playing out over a far longer time.” Plans are now underway to find a long-term solution. Four of the General Electric-made reactors have been condemned, but they need to cool before they can be made safe. This is likely to take months. Engineers from Toshiba, Westinghouse and Babcock & Wilcox have reportedly begun looking at the options to remove the spent fuel and seal the plant. At Fukushima there have been no deaths so far due to radiation. Japan has done more than the Soviet Union to contain its nuclear disaster, but whether it is enough will be clearer through studies of the health of the frontline workers and local residents in the months ahead. Research proposals are already being submitted. The workers of Fukushima, who have been lauded in the past month as heroes or Kamikaze suicide warriors, may yet be most famous as nuclear guinea pigs. Japan Japan disaster Natural disasters and extreme weather Nuclear power Suzanne Goldenberg Jonathan Watts guardian.co.uk