When TEPCO first announced they were building an underground ice-wall in 2013, skeptics were assured it would limit the amount of groundwater seeping into the stricken plant’s basements where it mixes with highly radioactive debris from the site’s reactors, to “nearly nothing.”
The nearly mile-long ice-wall was completed in March 2016, nearly a year behind schedule at a cost of $312 million. Once the ice-wall was fully turned on, which occurred in August 2017, it was supposed to become a massive ice barrier surrounding the four reactors.
In a statement released by Tokyo Electric Power Company (TEPCO) in 2016, officials said: “We will create an impermeable barrier by freezing the soil itself all the way down to the bedrock that exists below the plant. When groundwater flowing downhill reaches this frozen barrier, it will flow around the reactor buildings, reaching the sea just as it always has, but without contacting the contaminated water within the reactor buildings.”
TEPCO’s announcement on the ice-wall
Groundwater has been seeping into the Fukushima Daiichi facility daily since that March day in 2011 when disaster struck the nuclear power plant, causing radiation-contaminated water to seep from the reactors, despite attempts to stop the flow.
On March 1, 2018, TEPCO announced the fully-operational ice-wall “has cut back on the amount of radiation-tainted water that is generated by an estimated 95 metric tons a day,” according to The Mainichi.
In the announcement, TEPCO explained they had used computers to estimate the flow of groundwater, thereby reaching the conclusion the wall was reducing the flow by at least half of what would be produced if the wall did not exist.
Additionally, the utility said that polluted groundwater was reduced by about 400 tons a day now due to combined measures, such as the wall and wells pumping up water, compared with before such measures were taken.
“It has become clear that the ice wall, on its own, has the effect of reducing contaminated water,” a TEPCO representative said. A government panel of experts will deliberate the validity of the power company’s estimate.
However, The Asahi Shimbun points out that experts are saying the utility’s assessment on how well the wall is working is based on figures from periods when there was little rain. The assessment left out figures that showed the water volume rose to 1,000 tons or so a day in late October when two typhoons struck the area.
How effective is the ice-wall?
A Reuters analysis of the TEPCO data showed some striking differences in what TEPCO announced on March 1 and what Reuters came up with. Remember that TEPCO said the amount of groundwater had been reduced to 95 metric tons a day.
According to Reuters, “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.”
What this all amounts to is that TEPCO is still struggling to pump out the contaminated water from the reactor basements, decontaminate and then store the water in large tanks on the grounds of the facility. There are now over 1,000 tanks, holding 1 million tonnes, and TEPCO 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.”
