The “ice wall” that Tokyo Electric Power Co (Tepco) put in place a few years ago, with the intent of stopping water seepage into the basements of the Fukushima Dai-ichi nuclear plant, isn’t functioning as advertised (so to speak).
Going on an analysis performed by Reuters (using Tepco data), since the ice wall became “operational” — towards the end of August 2017 — an “average of 141 metric tonnes a day of water has seeped into the reactor and turbine areas.”
What that means is that after the ice wall was deemed to be fully operational that the flow of groundwater into the areas in question actually increased — as the previous 9 months (before August 2017) had seen an average of 132 metric tonnes a day of groundwater seepage.
Considering how expensive the ice wall was to put into place, and Tepco’s assurances to skeptics that the approach would be effective, this is very notable, to say the least.
As a result of this failure, large quantities of groundwater are continuing to flow into the basements of the Fukushima nuclear power plants, and there mingle with the extremely radioactive material present there.
Arguments are of course being made by Tepco officials, though, that since groundwater flows have lessened over the last few years that the ice wall is working (in conjunction with various pumps and drains), but considering the figures discussed above, effectiveness is certainly limited.
The company is claiming that, based on computer models, the ice wall is reducing groundwater flow into the reactors by around 95 tonnes a day, compared to 2 years ago.
Reuters provides more information:
“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 7 years ago this Sunday. Waves knocked out power and triggered meltdowns at 3 of the site’s 6 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 ($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 4 of the plant’s reactors. It then cools the brine to minus 30° 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.”
It should be realized that the more groundwater seepage there is into the areas in question, the more radioactive water there is to eventually deal with — or not deal with, as may be the case.
To date, the radioactive water at the Fukushima site has either been lost to the wider environment or is stored in large tanks at the facility. These storage tanks now total more than a thousand, and store over 1 million tonnes of radioactive water. Tepco has warned that it will run out of space at the site to store this water by as soon as early 2021. What happens then?
“I believe the ice wall was ‘oversold’ in that it would solve all the release and storage concerns,” commented Dale Klein, the former head of the US Nuclear Regulatory Commission, and the head of an external committee that’s advising Tepco on safety issues, to Reuters.
“The hydrology of the Fukushima site is very complicated and thus the exact water flow is hard to predict, especially during heavy rains.”
This reality was made especially clear last October when a typhoon affected the region, and 866 tonnes a day of groundwater flowed into the nuclear reactors for the duration.
The Reuters coverage provides a bit more:
“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…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.
“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.”
That’s not to say that such releases won’t be the eventual outcome, as they are one of the primary options now being considered by a government-commissioned task force working on the problem.
As far as whether the water in question actually does “only” contain radioactive tritium, that remains an open question as Tepco has yet to allow third-party testing of the store “purified” water in question. Without third-party testing, who actually knows what’s in it?
As a reminder here, the Fukushima nuclear disaster effectively began 7 years ago on Sunday and is quite obviously still ongoing. A vast amount of money has already been spent working to contain the nuclear material and contamination at the Fukushima site, but the reality remains that a vast amount more will have to be spent over the coming decades. The area itself will effectively remain unfit for human habitation indefinitely regardless of containment and remediation work.