Deep beneath Fukushima’s crippled nuclear power station a massive underground reservoir of contaminated water that began spilling from the plant’s reactors after the 2011 earthquake and tsunami has been creeping slowly toward the sea.
Now, 2 1/2 years later, experts fear it is about to reach the Pacific and greatly worsen what is fast becoming a new crisis at Fukushima: the inability to contain vast quantities of radioactive water.
The looming crisis is potentially far greater than the discovery earlier this week of a leak from a tank used to store contaminated water used to cool the reactor cores. That 300-ton (80,000 gallon) leak is the fifth and most serious since the disaster of March 2011, when three of the plant’s reactors melted down after a huge earthquake and tsunami knocked out the plant’s power and cooling functions.
But experts believe the underground seepage from the reactor and turbine building area is much bigger and possibly more radioactive, confronting the plant’s operator, Tokyo Electric Power Co., with an invisible, chronic problem and few viable solutions. Many also believe it is another example of how TEPCO has repeatedly failed to acknowledge problems that it could almost certainly have foreseen — and taken action to mitigate before they got out of control.
“This is a race against the clock,” said Toyoshi Fuketa, a commissioner on the Nuclear Regulation Authority.
Compounding TEPCO’s problems is the new leak discovered this week. Most of the 300 tons is believed to have seeped into the ground, but some may have escaped into the sea through a rainwater gutter, said Zengo Aizawa, the company’s executive vice president.
That, too, may be a harbinger of more problems ahead.
Some 1,000 steel tanks built across the plant complex contain nearly 300,000 tons (300 million liters, 80 million gallons) of partially treated contaminated water. About 350 of them have rubber seams intended to last for only five years. Company spokesman Masayuki Ono said it plans to build additional tanks with welded seams that are more watertight, but will have to rely on rubber seams in the meantime.
Shinji Kinjo, a regulatory official in charge of the Fukushima disaster, said the rubber-seam tanks are mostly built in a rush when the contaminated water problem started, and often lacked adequate quality tests and require close attention.
Workers have already spotted two more questionable tanks during inspection Thursday.
“It’s like a haunted house, one thing happening after another,” said Nuclear Regulation Authority Chairman Shunichi Tanaka, referring to the spate of problems at the plant. “But we must take any steps that would reduce risks to avoid a fatal accident.”
Leaks of highly contaminated water from the aboveground tanks aggravate the groundwater problem.
“Any contamination in the groundwater would eventually flow into the ocean. That is very difficult to stop even with barriers,” said Ken Buesseler, a marine chemist at the Woods Hole Oceanographic Institution in Massachusetts. He found that radioactive cesium levels in most fish caught off the Fukushima coast hadn’t declined in the year following the March 2011 disaster, suggesting that the contaminated water from the reactor-turbine areas is already leaking into the sea.