Fukushima nuclear plant ice wall little more than costly experiment

Graphic shows the ice wall surrounding the four reactors. Courtesy of ANN News.

It measures 1.5 km in length and 30 meters in height, taking 260,000 people to construct at a cost of ¥34.5 billion — so far. 

The subterranean ice wall that surrounds the four stricken reactors at Fukushima No. 1 Nuclear Power Plant, where multiple explosions and meltdowns occurred in March 2011, is nearing completion, but the efficacy of its proposed function is coming under increased scrutiny.  

When construction of the wall was announced in mid 2013, it was proposed that over 1,500 pipes would be inserted into the ground around the reactors and then filled with coolant frozen to a temperature of minus 30 C to freeze the earth and form a barrier of permafrost extending 30 meters underground that would prevent groundwater from flowing into the reactor buildings and keep radioactively contaminated water from leaking out into the Pacific Ocean.

As mentioned in “Yoshida’s Dilemma,” the project was unprecedented and unproven in the nuclear industry, and its rationale and efficacy were questioned even by the most staunchly nuclear of experts. Former US Nuclear Regulatory Commission chairman Dale Klein, said during a tour of the nuclear plant in 2014 he was “not convinced the freeze wall was the best option.”

There was, from the outset, a sense of the “experimental” about the project, with even Prime Minister Shinzo Abe admitting that funding for such a wall could pass smoothly through legislative channels due to its unprecedented nature. Although smaller scale ice walls had been built in the past, they were nothing on the scale of the 1.5 km monster being proposed for Fukushima.  Either way, a tried and tested measure would be far more difficult to sell.

This was highlighted by another wall project presented in 2012 by former Land, Infrastructure, Transport and Tourism Minister Sumio Mabuchi, who was drafted in by one of Abe's predecessors, Naoto Kan, during the disasters to serve as a special advisor in charge of handling the Fukushima accident. 

Mabuchi’s research had shown that groundwater had been entering the plant’s reactors since 1971 – a natural consequence of the plant being built on land that had been made lower than the water table by cutting down the 35-meter cliff that had previously stood there.

TEPCO subsequently had sunk wells to mitigate the problem, but computer simulations, Mabuchi claimed, had shown this to be ineffective and that some contaminated water had been flowing into the ocean.

Determined to prevent another environmental catastrophe, Mabuchi suggested the construction of a four-sided, 30-meter-deep Bentonite slurry wall, “like a square bathtub” around the four reactors to prevent the groundwater water entering the site and mingling with radioactive contaminants.

Initially, Fukushima No. 1 plant operator TEPCO balked at the estimated $1 billion plan, telling Mabuchi it would bankrupt them, but he eventually managed to persuade then TEPCO vice-president Sakae Muto by highlighting the wide-reaching implications should no action be taken.

Yet, a day before making the project public,  Muto requested the announcement be delayed until after a shareholders’ meeting two weeks later. The reason was included in a memo to the government, when TEPCO said such an announcement could cause the market to conclude that TEPCO was “moving a step closer toward insolvency.”

In the end, the announcement was never made and two years later, Abe took the plaudits when he announced the start of the publicly funded ice wall project.

Three years on, the frequently troubled and delayed project is approaching completion, with a 7-meter section all that remains to join the four-sides of the rectangular wall together. If the “Mabuchi Plan” had gone ahead, the slurry wall would have been up and running four years ago. Once again the tax payer was being asked to shoulder the burden for plant operator TEPCO, while the globe’s waters were contaminated further as the new plan crawled into motion.

Now, some experts are not only expressing doubts about the ice wall’s efficacy, but its necessity, also. At the very least, there is a  sense of it being too little, too late.

Japan's Nuclear Regulation Authority has commented that the wall's effectiveness was difficult to gauge until independent analysis had been carried out. However, there were still doubts.

“We doubt the ice wall is going to be as effective as TEPCO claims it will be,” an NRA official told AFP on condition of anonymity. Moreover, in June NRA acting chief Toyoshi Fuketa publicly accused TEPCO of lying about the wall’s effectiveness.

Even those managing the wall's construction seem unsure. In a news conference at the end of July, the president of Fukushima Daiichi Decontamination & Decommissioning Engineering Co., Naohiro Masuda, described the ice wall as “becoming quite effective,” but was unable to give concrete details why, saying, "I can't say how effective." 

Perhaps one reason is that other countermeasures have been introduced in the interim. In the aftermath of the nuclear disaster, about 400 tons of contaminated ground water was being produced each day, most of it stored in giant containers on the grounds of the stricken Fukushima plant. That figure has reportedly now fallen to roughly 130 tons per day, largely due to a subdrain system that draws water from about 40 wells sunk around the reactor buildings. 

According to an article in the Mainichi Shinbun, an official of the secretariat of Japan's Nuclear Regulation Authority commented that the subdrain system “performs the primary role” in solving the groundwater problem, while the ice wall “will probably be effective enough to supplement that." 

The inference is clear: the ice wall is no longer viewed, even by those who planned and created it, as an effective, or imperative/leading, means of battling the contaminated water issue. 

Some have argued that the wall was in fact nothing more than a show right from outset.

First, the timing of TEPCO's announcement of the ice wall, in May 2013, is of note: It fell just a few months before Tokyo made its bid to host the 2020 Olympics. Many felt that the wall was simply a front to quash global fears and convince the international community that -- as PM Abe put it -- Fukushima was "under control" (a claim that was subsequently labeled "a lie" by former PM Junichiro Koizumi). 

Mabuchi, meanwhile, suggested that other forces were at play. “I am filled with tremendous regret” that the slurry wall plan was rejected, Mabuchi said, adding that politicians and industry alike are well aware of utilities companies’ leverage when it comes to garnering votes.

What’s more,  Mabuchi says that not even the government was convinced the wall could succeed. In the fine print of Abe’s Liberal Democratic Party’s plan for the wall there is a caveat stating that should the ice wall plan fail, a clay wall would be built in its place, he says. 

Interestingly, there was virtually no public outcry at the announcement of the ice wall. Not even when it was revealed that the cost of maintaining it will exceed 1 billion yen a year, and that those involved with undertaking that maintenance would be in danger of being exposed to high levels of radiation.

Furthermore, a TEPCO spokesperson told me that the wall would require 45 million kWh of electricity per year to run – that’s roughly the equivalent energy used by 5,000 households over 12 months.

Nagoya University professor emeritus Akira Asaoka commented in the Mainichi that "The way things stand, we'll have to keep maintaining an ice wall that isn't very effective," and adding "We should consider a different type of wall." 

​Another expert told me in an off-the-record interview that one reason the "ice wall experiment" had been pushed through was to gain kudos among the globe's nuclear fraternity, while its success, though not guaranteed, might prove handy in exporting the technology in the event of other nuclear emergencies and recouping some of the extraordinary cost of building yet another of what writer Alex Kerr has termed Japan's "useless monuments."