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ALPS? Oops, another snag

August 2, 2014
Plan to complete radioactive water purification at Fukushima plant hits snag


Tokyo Electric Power Co. (TEPCO) is unlikely to reach its target of completing purification of radiation-contaminated water stored at the crippled Fukushima No. 1 Nuclear Power Plant by the end of fiscal 2014, it has been learned.

The anticipated failure is attributed to the malfunction of ALPS, the multi-nuclide removal equipment installed at the plant. While the apparatus is supposed to remove radioactive materials from contaminated water, the device has not worked properly as planned. TEPCO has admitted to the dim prospects of not reaching the target deadline at this rate.

With the utility's work to build ice walls to prevent an influx of groundwater into reactor buildings at the plant also hitting a snag, the latest development once again underscores the difficulties in reducing the amount of contaminated water.

Then TEPCO Vice President Zengo Aizawa had earlier told a September 2013 press conference, "We'd like to purify the full amount (of contaminated water) by the end of fiscal 2014." His statement came in response to Prime Minister Shinzo Abe's assertion during Tokyo's bid presentation for the 2020 Olympics that "the situation (at the Fukushima nuclear plant) is under control."

The utility had planned to reduce the amount of 62 types of radioactive substances in contaminated water to levels that meet standards, aside from tritium that cannot be removed by ALPS.

A trial operation of ALPS commenced in March last year. However, the device has often been suspended following various incidents of trouble. While roughly 470,000 metric tons of contaminated water is currently stored on the plant's premises, only about 110,000 tons -- or slightly over 20 percent -- has so far been treated for purification. What's more, even the processed water still contains cobalt-60 and three other types of radioactive substances above acceptable levels, on top of tritium.

TEPCO plans to start installing additional ALPS devices sometime after September and bolster its ability to process contaminated water to 2,000 tons a day starting in October. However, even if all these devices go into full operation, only up to around 400,000 tons of tainted water would be processed by the end of March next year at best. This means the utility may be able to treat some 360,000 tons of highly concentrated radioactive water remaining in storage tanks but will not be able to finish reprocessing the 110,000 tons that have already undergone treatment but still contain four types of radioactive materials.

"Our goal is to reduce the risks of contaminated water. We can say we have lowered the risks once we have had the entire amount of contaminated water go through the ALPS system once by the end of March next year," said a TEPCO public relations official.

An official at the Agency for Natural Resources and Energy said, "It will be fine if the risks of storing contaminated water are reduced, even if the four types of radioactive substances remain."

The Nuclear Regulation Authority (NRA), however, offered a skeptical view. "Even if additional ALPS devices are installed, we can't tell if they will be activated properly. Under such circumstances, it is impossible to predict how much contaminated water will be treated," said an NRA official.

If highly concentrated radioactive water remains in storage at the plant, there will be a constant risk of leakage of such water. Moreover, since radiation levels near the storage tanks holding highly contaminated water are very high, workers would be exposed to greater doses of radiation during decommissioning work.

Contaminated water at the plant has been accumulating because a daily amount of 400 tons of groundwater flow into reactor buildings where melted nuclear fuel has yet to be removed. While TEPCO has been taking measures such as pumping up groundwater, the effects remains unclear.

August 02, 2014(Mainichi Japan)

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