Tepco’s ‘ice wall’ fails to freeze Fukushima’s toxic water buildup

By Aaron Sheldrick and Malcolm Foster

OKUMA, Japan (Reuters) – A costly “ice wall” is failing to keep groundwater from seeping into the stricken Fukushima Dai-ichi nuclear plant, data from operator Tokyo Electric Power Co shows, preventing it from removing radioactive melted fuel at the site seven years after the disaster.

When the ice wall was announced in 2013, Tepco assured skeptics that it would limit the flow of groundwater into the plant’s basements, where it mixes with highly radioactive debris from the site’s reactors, to “nearly nothing.”

However, since the ice wall became fully operational at the end of August, an average of 141 metric tonnes a day of water has seeped into the reactor and turbine areas, more than the average of 132 metric tonnes a day during the prior nine months, a Reuters analysis of the Tepco data showed.

The groundwater seepage has delayed Tepco’s clean-up at the site and may undermine the entire decommissioning process for the plant, which was battered by a tsunami seven years ago this Sunday. Waves knocked out power and triggered meltdowns at three of the site’s six reactors that spewed radiation, forcing 160,000 residents to flee, many of whom have not returned to this once-fertile coast.

Though called an ice wall, Tepco has attempted to create something more like a frozen soil barrier.

Using 34.5 billion yen ($324 million) in public funds, Tepco sunk about 1,500 tubes filled with brine to a depth of 30 meters (100 feet) in a 1.5-kilometre (1-mile) perimeter around four of the plant’s reactors. It then cools the brine to minus 30 degrees Celsius (minus 22 Fahrenheit).

The aim is to freeze the soil into a solid mass that blocks groundwater flowing from the hills west of the plant to the coast.

However, the continuing seepage has created vast amounts of toxic water that Tepco must pump out, decontaminate and store in tanks at Fukushima that now number 1,000, holding 1 million tonnes. It says it will run out of space by early 2021.

“I believe the ice wall was ‘oversold’ in that it would solve all the release and storage concerns,” said Dale Klein, the former chairman of the U.S. Nuclear Regulatory Commission and the head of an external committee advising Tepco on safety issues.

“The hydrology of the Fukushima site is very complicated and thus the exact water flow is hard to predict,” he said, “especially during heavy rains.”

TYPHOON

The water inflows often fluctuate with rainfall. The dry month of January averaged 83 tons a day, Tepco data showed.

But when a typhoon struck during the last week of October, 866 tons a day poured into the reactors.

Overall, Tepco says a combination of drains, pumps and the ice wall has cut water flows by three-quarters, from 490 tons a day during the December 2015 to February 2016 period to an average of 110 tons a day for December 2017 to February 2018.

It is hard to measure exactly how much the ice wall is contributing, Tepco officials say, but based on computer analysis the utility estimates the barrier is reducing water flows by about 95 tonnes a day compared to two years ago, before the barrier was operating.

“Our assessment is that the ice wall has been effective,” said Naohiro Masuda, Tepco’s chief decommissioning officer, adding that rain falling within the ice wall perimeter contributed to surging volumes. “We now believe we have a system in place to manage the water level.”

However, a government-commissioned panel on Wednesday offered a mixed assessment of the ice wall, saying it was partially effective but more steps were needed.

Controlling the groundwater seepage using the ice wall has been central to Japan’s program to show it had the Fukushima decommissioning in hand.

The barrier was announced just days before Tokyo won the bid to host the 2020 Summer Olympics and Prime Minister Shinzo Abe declared that Fukushima was “under control” in his final pitch to the International Olympic Committee.

In addition to the building costs, the ice wall needs an estimated 44 million kilowatt hours of electricity a year to run, enough to power about 15,000 typical Japanese homes.

NO MORE SPACE

Meanwhile, Tepco must decide how to cope with the growing volume of water stored on site.

The purification process removes 62 radioactive elements from the contaminated water but it leaves tritium, a mildly radioactive element that is difficult to separate from water. Not considered harmful in low doses, tritium is released into oceans and rivers by nuclear plants around the world at various national standard levels.

But local residents, particularly fishermen, oppose ocean releases because they fear it will keep consumers from buying Fukushima products. Many countries, including South Korea and China, still have restrictions on produce from Fukushima and neighboring areas.

A government-commissioned task force is examining five options for disposing of the tritium-laced water, including ocean releases, though no decision has been made.

Ken Buesseler, a radiochemist at the Woods Hole Oceanographic Institution in the United States, suggests that Tepco should open the tanks to external inspections to see if the water is safe.

“From the public’s viewpoint, I think they’d want a bit of independent confirmation,” Buesseler said. “It’s no harder and a lot cheaper than building an ice wall.”

(Reporting by Malcolm Foster and Aaron Sheldrick; Editing by Christian Schmollinger)

Workers at Washington nuclear waste plant take cover after tunnel collapse

The Purex (Plutonium Uranium Extraction Plant) separations facility at the Hanford Works is seen in an undated aerial photo. The building has been vacant for nearly twenty years but remains highly contaminated, according to the Department of Energy. DOE/Handout via REUTERS

By Tom James

SEATTLE (Reuters) – A tunnel partly collapsed on Tuesday at a plutonium handling facility at the Hanford Nuclear Reservation in Washington state, leading authorities to evacuate some workers and instruct others to take cover, federal officials said.

Workers took cover and turned off ventilation systems after minor damage was discovered in the wall of a transport tunnel, a spokeswoman for the Department of Energy said by telephone from the Hanford Joint Information Center.

The damage was more serious than initially reported, and the take-cover order was expanded to cover the entire facility after response crews found a 400-square-foot section of the decommissioned rail tunnel had collapsed, she said.

“The tunnel itself was breached. There was a 20-foot wide hole,” the spokeswoman said.

No spent nuclear fuel is stored in the tunnel, and no further evacuations have been ordered for workers, nor have any warnings for civilians around the site been issued, she said.

She declined to identify herself, citing agency policy.

The site is in southeastern Washington on the Columbia River, about 170 miles (270 km) east of Seattle. Operated by the federal government, it was established in the 1940s and manufactured plutonium that was used in the first nuclear bomb as well as other nuclear weapons. It is now being dismantled and cleaned up by the Energy Department.

“This is a potentially serious event,” said Edwin Lyman, a senior scientist at the Union of Concerned Scientists. “I can see why the site ordered emergency measures. Collapse of the earth covering the tunnels could lead to a considerable radiological release.”

Lyman pointed to a description of the storage tunnels from a report from the Consortium For Risk Evaluation with Stakeholder Participation in 2015 about the Hanford site, saying there is quite a lot of cesium-137 and plutonium in those tunnels. Those are radioactive materials that can cause radiation sickness and death depending on the amount and length of exposure.

Mostly decommissioned, Hanford has been a subject of controversy and conflict between state and local authorities, including a lawsuit over worker safety and ongoing cleanup delays. The site has been described in media reports as the most contaminated nuclear site in the United States.

The evacuation did not affect the nearby nuclear power plant operated by Energy Northwest, company spokesman John Dobken said. The Columbia nuclear plant was located about 12 miles southeast of where the incident at Hanford occurred, he said.

(Reporting by Tom James in Seattle; Additional reporting by Scott DiSavino in New York; Editing by Cynthia Osterman and Lisa Shumaker)