TOKYO: Japan's nuclear safety agency raised the severity rating of the country's nuclear crisis Friday from Level 4 to Level 5 on a seven-level international scale, putting it on par with the Three Mile Island accident in Pennsylvania in 1979. Ryohei Shiomi, a spokesman for the nuclear safety agency, said Friday that the agency raised the rating of the Fukushima Dai-ichi nuclear crisis on the International Nuclear Event Scale. The scale defines a Level 4 incident as having local consequences and a Level 5 incident as having wider consequences. The hallmarks of a Level 5 emergency are severe damage to a reactor core, release of large quantities of radiation with a high probability of “significant” public exposure or several deaths from radiation. A partial meltdown at Three Mile Island also was ranked at Level 5. The Chernobyl accident of 1986, which killed at least 31 people with radiation sickness, raised long-term cancer rates, and spewed radiation for hundreds of miles (kilometers), was ranked Level 7. France's Nuclear Safety Authority has been saying since Tuesday that the crisis in northeastern Japan should be ranked Level 6 on the scale. Japan deployed a fleet of fire trucks to cool the quake-hit nuclear plant Friday to avert a catastrophe in what the head of the UN International Atomic Energy Agency called “a race against time”. Tons of water were used to douse overheating fuel rods at the Fukushima No.1 power station, which suffered critical damage in the massive earthquake and tsunami that rocked Japan a week ago. A “Chernobyl solution” may be the last resort for dealing with Japan's stricken nuclear plant, but burying it in sand and concrete is a messy fix that might leave part of the country as an off-limits radioactive sore for decades. Japanese authorities say it is still too early to talk about long-term measures while cooling the plant's six reactors and associated fuel-storage pools, comes first. “It's just not that easy,” Murray Jennex, a professor at San Diego State University in California, said when asked about the so-called Chernobyl option for dealing with damaged reactors, named after the Ukrainian nuclear plant that exploded in 1986. “They (reactors) are kind of like a coffee maker. If you leave it on the heat, they boil dry and then they crack,” he said. “Putting concrete on that wouldn't help keep your coffee maker safe. But eventually, yes, you could build a concrete shield and be done with it.” Experts say the cores at the six battered reactors at the Fukushima Daiichi power plant, 240 km (150 miles) north of Tokyo, are likely to be safely contained, but worry about the cooling pools for spent fuel, one of which contains plutonium. So far, authorities have failed to cool the pools, where normally water circulates continuously, keeping racks of spent nuclear fuel rods at a benign temperature. Helicopters and water cannon trucks have dumped tons of water on the reactors, but still the water in the pools is evaporating and the rods are heating up. It is also feared that the quake has smashed the rods into each other, which could cause a nuclear reaction. “It is not impossible to encase the reactors in concrete, but our priority right now is to try and cool them down first,” a Tokyo Electric Power official told a briefing on Friday.
