Japan nuclear regulator says Fukushima radioactive water leaks now an "emergency"
06 August 2013
Highly radioactive water leaking into the ocean from Japan's crippled Fukushima nuclear plant is creating an "emergency" that the operator is struggling to contain, according to the country's nuclear watchdog, and countermeasures planned by plant operator Tokyo Electric Power Co (Tepco) were only a temporary solution.
Fukushima contaminated water tanks - Photo: IAEA
The contaminated groundwater has breached an underground barrier, is rising towards the surface and has exceeded legal limits of radioactive discharge, said Shinji Kinjo, head of a Nuclear Regulatory Authority (NRA) taskforce.
Tepco's "sense of crisis is weak", Kinjo said. "Right now, we have an emergency."
There has been spate of water leaks and power failures at the plant, devastated by the 2011 earthquake and tsunami. Its operator, Tokyo Electric Power Company (Tepco), has been criticised heavily for its lack of transparency over the leaks.
Tepco has been widely castigated for its failure to prepare for the 2011 tsunami and earthquake that devastated its Fukushima plant, as well as being lambasted for its inept response to the reactor meltdowns. It has also been accused of covering up shortcomings.
It was not immediately clear how much of a threat the contaminated groundwater could pose. In the early weeks of the disaster the Japanese government allowed Tepco to dump tens of thousands of tonnes of contaminated water into the Pacific as an emergency measure.
Tepco said it was taking measures to prevent contaminated water from leaking into the bay near the plant. In an emailed statement to Reuters a company spokesman said Tepco deeply apologised to residents in Fukushima prefecture, the surrounding region and the larger public for causing more inconvenience, worry and trouble.
The utility pumps out 400 tonnes a day of groundwater flowing from the hills above the Fukushima Daiichi nuclear plant into the basements of the destroyed buildings. There it mixes with highly irradiated water that is used to cool the reactors and maintain a stable state below 100C (32F).
Tepco is trying to prevent groundwater from reaching the plant by building a bypass but recent spikes of radioactive elements in seawater have prompted the utility to reverse months of denials and finally admit that tainted water is reaching the sea.
In an effort to prevent more leaks into the bay of the Pacific Ocean plant workers created the underground barrier by injecting chemicals to harden the ground along the shoreline of the No 1 reactor building. But that barrier is only effective in solidifying the ground at least 1.8 metres below the surface.
By breaching the barrier the water can seep through the shallow areas of earth into the nearby sea. More seriously, it is rising towards the surface – a break of which would accelerate the outflow.
It has been clear for months now that the operators of the Fukushima plant are in deep trouble, according to the BBC.
The only course of action is to pump water out. But this has to be stored, and more than 1,000 giant holding tanks surrounding the plant are nearly all full.
Tepco said on August 5 it plans to start pumping out a further 100 tonnes of groundwater a day.
The regulatory taskforce overseeing accident measures of the Fukushima Daiichi nuclear power station, which met on Friday, concluded that new measures are needed to stop the water from flowing into the sea that way, Kinjo said.
Tepco said on August 2 that a cumulative 20tn to 40tn becquerels of radioactive tritium had probably leaked into the sea since the disaster. The company said this was within legal limits. A becquerel is a measure of the release of radioactive energy.
Tritium is far less harmful than caesium and strontium, which have also been released from the plant. Tepco is scheduled to test strontium levels next.
Tepco said on August 5 that caesium levels at an observation post 53 metres from the sea had jumped in the past week. Readings for caesium-134 were almost 15 times higher at 310 becquerels a litre.
Caesium-137, with a half-life of 30 years, was also 15 times higher than it had been five days ago at 650 becquerels a litre. A much larger spike in radioactive caesium in July in a different well led to Tepco overturning months of denials and admitting that radioactive water had been leaking into the sea.
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