Japan's nuclear watchdog has upgraded its alert level for radiation leaks at the Fukushima Daiichi nuclear plant, underlying the deepening crisis at the crippled facility.
The decision to raise the severity level of the leaks from one to three on the international nuclear and radiological event scale is seen as another sign that the engineers are losing control over the leaks.
A spokesman for the Nuclear Regulation Authority (NRA) said the move meant changing the status of the crisis from "anomaly" to "serious incident" on the scale, for the first time since the plant suffered a triple meltdown in March 2011. The decision has to be confirmed by the IAEA, the UN agency that monitors nuclear energy around the world.
"We are in a situation where there is no time to lose," said NRA chairman Shunichi Tanaka.
Operator Tokyo Electric Power Co (Tepco) said this week that one of about 1,060 giant storage tanks at the plant had leaked 300 tonnes of radioactive water. The company said caesium 134, caesium 137, iodine 131 and manganese 54 form part of the cocktail of toxins in the water, which is sufficiently radioactive to deliver a five-year dose of radiation to bystanders in a short time. The company has yet to identify the precise source of the leak.
Engineers have been struggling to keep melted uranium rods cool since the plant’s cooling system was knocked out by the earthquake and tsunami on March 11th, 2011. They have rigged up a makeshift cooling system that feeds highly contaminated water back to the temporary tanks via a jerry-rigged warren of pipes.
Critics fear the leak could be a harbinger of worse to come. The joints in about a third of the tanks are sealed with plastic packing that may have been damaged by radiation.
“Our concern is that the problem is not just with this one tank, it may be generic problem with many of the tanks,” said Aileen Mioko Smith, an antinuclear activist with the Japan-based environmentalist group Green Action.
“Sealant expands in the summer and contracts in winter. We don’t know what the cold weather will do to the tanks.”
Tepco spokesman Yoshikazu Nagai said workers at the plant are "trying hard to ensure that does not happen". "We're strengthening our system for containing and measuring contaminated water," he said.
Tepco has denied that any of the contaminated water has reached the ocean, about 500m away.
Engineers rely on visual checks of the tanks, which hold a total of about 400,000 tonnes of water, to determine water levels. Some observers have criticised the utility for not installing measuring equipment that could have enabled it to spot the latest leak quicker.
Workers at the plant are also struggling to control huge quantities of contaminated groundwater. The utility said this month 300 tonnes of the water is running into the sea every day, though it said this has since been cut to less than 30 tonnes. Earlier this month prime minister Shinzo Abe described the situation at the plant as "urgent" and pledged to increase government involvement in decommissioning its reactors.
