6 Juin 2013
TOKYO — The operator of the stricken Fukushima nuclear plant said Wednesday that it had found a leak in one of the hundreds of steel tanks used to store radioactive water at the plant, raising renewed questions about the company’s ability to handle the plant’s cleanup.
The discovery comes a day after the operator, the Tokyo Electric Power Company, or Tepco, admitted that it had found cesium particles in groundwater flowing into the Fukushima Daiichi plant, reversing its earlier assertion that the water was uncontaminated.
The company stressed that the size of the tank leak was small — the equivalent of about a quart had dripped out so far, it said — and that the level of radioactivity in groundwater was within safe levels. However, the problems are the latest in a string of mistakes and mishaps that have added to mounting criticism of the government’s decision to leave the tricky cleanup in the hands of Tepco, the company that many say allowed the triple meltdown two years ago to happen in the first place.
Recently, Tepco has struggled to deal with tens of millions of gallons of contaminated, toxic water at the plant, which must be stored in the large steel tanks that now occupy virtually every available bit of space there. The amount of radioactive water has continued to grow as groundwater has flowed at a rate of 100,000 gallons per day into the basements of the damaged reactor buildings. This contaminated water must be drawn off every day to prevent it from overwhelming makeshift systems that cool the melted reactors.
The company has installed a new filtering system that it says removes every type of radioactive particle but one, tritium. Still, that leaves it no choice but to keep storing the water rather than dumping it.
Wednesday’s leak underscored the risks of doing so at the plant, where a larger spill might potentially reach the nearby Pacific Ocean. The leaking tank had just been installed to store toxic water from an underground storage pond that needed to be emptied after it, too, sprang a leak.
Faced with growing public alarm over the water crisis, the government last week ordered Tepco to stop the influx of groundwater by freezing soil around the reactor buildings, a novel plan that calls for creating a wall of underground ice. The company has also planned to reduce the influx by pumping some of the groundwater into the sea before it reaches the buildings and becomes contaminated.
However, the pumping plan needs the approval of residents and commercial fishermen in areas outside the evacuation zone immediately around the plant, who have been slowly regaining their livelihoods since the meltdowns spewed radiation over northeastern Japan. The company had been offering them reassurances that the water to be dumped contained no radioactive particles that could further contaminate the ocean.
Those plans could now be jeopardized by Tuesday’s admission that the groundwater in fact does contain cesium, a byproduct of the meltdowns. The company, which conceded that it had erred in previous tests, said it had found up to 0.39 becquerels of radioactive cesium 137 per liter of water, an amount that is far below Japan’s safety level for drinking water of 10 becquerels per liter.
Still, it may be enough to scuttle or at least put on hold the company’s plan to pump groundwater into the sea. Just last week, the company sought to persuade local fishing cooperatives by telling them that levels of cesium in the groundwater were so low that they could not be detected. Those reassurances were met with intense skepticism by fishermen who, even before Tuesday’s admissions, said they no longer trusted any assertions made by Tepco.