Experts question efficacy of Japan's 'Great Ice Wall'

Ring of frozen water-filled cylinders buried underground latest attempt to contain contamination from Fukushima Daiichi nuclear plant

Experts question efficacy of Japan's 'Great Ice Wall'

World Bulletin/News Desk

Work is scheduled to begin next month on an underground frozen wall surrounding the damaged Fukushima Daiichi nuclear power plant -- a "Great Ice Wall" designed to keep radioactive groundwater from reaching the ocean.

It's been more than three years since the plant went into failure, a 15-metre tsunami triggered by the Tohoku earthquake disabling the power supply and cooling of three of its six reactors. According to the World Nuclear Association, all three cores largely melted in the first few days, Japan -- struggling to cope with the death of over 19,000 people in the tsunami -- is endeavoring to prevent any release of radioactive materials, particularly in contaminated water leaking from the units. 

The Ice wall is the latest attempt to contain the contamination -- that is of course, if the Yen 32 billion ($315 million) state-funded project is not delayed or possibly scratched entirely as being both unproven and too expensive.

Already experts both inside and outside of Japan are questioning the value of the project and suggesting alternative means to solve the groundwater contamination problems. Toyoshi Fuketa, a member of the new, independent Nuclear Regulation Authority, is among them:

"We need to know if the frozen wall is truly effective," Fuketa told the Japan Times. "More importantly, will it cause unforeseen problems?"

Such thoughts have been echoed by Dale Klein, a former chairman of the U.S. nuclear industry safety body Nuclear Regulatory Commission, who now works as a consultant in Japan. He instead suggests digging wells and pumping the water into the ocean, thereby bypassing the plant.

The "Great Ice Wall" is a ring of water-filled cylinders buried about 30 meters in the ground and then frozen solid. It is meant to prevent groundwater from entering the basements of the damaged nuclear plants, mingling with the highly contaminated water used to keep the melted cores cool.

The project was proposed by the Kajima Corp., one of Japan’s largest construction companies, which claimed to have experience using such technology to shore up walls in tunnel projects. But no one has ever before tried to freeze soil on such a large scale for an indefinite period.

That the utility and government of Japan would take such an unproven project seriously is a testament to the scope of the problem. With around 400 tons of groundwater seeping downhill into the reactor bowls daily, where they pick up dozens of highly radioactive nuclides, one could say that they were eager to try anything.

Rather than simply dump such highly contaminated water into the Pacific, the owner of Fukushima, the Tokyo Electric Power Co (Tepco), has constructed more than 1,000 makeshift tanks that currently store about 450,000 tons of radioactive water.

Last summer, however, the utility and government were embarrassed by stories of tanks leaking small amounts of radioactive water near the plants. Media reported that the tanks were jerry-built, erected as fast as possible just to keep ahead of groundwater seepage -- seams bolted not welded, for example.

Prime Minister Shinzo Abe was concerned that scary headlines about leaking radioactive water would seriously compromise Tokyo’s bid to host the 2020 Olympics, so the government quickly endorsed the ice wall project and dug into its budget to come up with the Yen 47 billion of public money to pay for it along with other technology to deal with the crisis.

It allowed Abe to controversially declare everything "under control," during a Tokyo presentation that celebrated Japan getting the games over Istanbul and Madrid.

Beleaguered Tepco is already a ward of the state, with the government owning just over 50 percent of the company's shares -- its price to inject some Yen 10 trillion in public money to help the utility meet its huge compensation liabilities.

The crisis would ease considerably if Tepco could get another piece of decontamination technology working properly. The Advanced Liquid Processing System (ALPS) has the capability of removing some 62 different radionuclides (atoms with unstable nuclei), everything except tritium, a radioactive isotope of hydrogen.

The ALPS decontamination technology was developed by an American company called Energy Solutions and is administered at the Fukushima site by the Toshiba Corp. If it were working as advertised, the treated water would probably be safe enough to dump into the ocean.

That would be a boon to fishermen in the region who have suffered from being so close to the disaster site. South Korea, for example, still bans importation of fish caught from eight northeast Japan prefectures -- including two that don't even have a coastline.

Unfortunately, Toshiba has had a difficult time getting the system working properly. Problems concerning corrosion have delayed full employment of the technology. Japan's new Nuclear Regulation Authority, created as an independent watchdog in the wake of the disaster, has repeatedly warned Tepco to get its decontamination act together.

The nuclear regulator has a strong hold over Tepco, in that the utility is very anxious to get one or more of its seven huge but undamaged nuclear power plants located on the Sea of Japan back in operation. Its plan to return to profitability depends on it.

Like every other one of Japan’s 48 nuclear reactors, Tepco’s non-damaged nuclear plants have been offline for two years while the new nuclear safety watchdog determines whether they meet new and stricter safety standards that would allow some of them to restart.

One of the 17 plants with pending restart applications is one of the Sea of Japan plants, but the chairman of the nuclear regulator, Shunichi Tanaka, has threatened to return the application if Tepco doesn't get the groundwater situation in hand.

That is one reason why, despite the reservations, the ice wall will likely get built.

Güncelleme Tarihi: 17 Mayıs 2014, 12:05