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Water, Rats, Outages: Japan Nuke Plant Precarious

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The cause of the outage wasn’t clear at the time, but TEPCO later released a photo of the electrocuted rat, which had fallen on the bottom of the switchboard outhouse. The most extensive outage since the crisis started after the March 2011 disasters caused some Fukushima residents to even consider evacuation.

Two weeks later, a new water processing machine designed to remove most radioactive elements temporarily stopped after a worker pushed a wrong button. The next day, one of the fuel storage pools lost power again for several hours when part of a wire short-circuited a switchboard while an operator installed anti-rat nets. TEPCO reported three other minor glitches on the same day, including overheating of equipment related to boron injection to the melted reactors.

Regulatory officials acknowledge that rats and snakes are abundant at the plant, and TEPCO has started to take steps to protect pipes and cables from rat gnawing. Replacement of parts and equipment to those of higher quality and long-term use is in progress.

In the latest development, three of the plant’s seven underground tanks are leaking. TEPCO reported the first leak early, hours after the plant’s second power outage. Within days, the damage spread to three tanks, paralyzing the plant’s storage plans for contaminated water.

TEPCO says none of the about 120 tons of radioactive water that leaked was believed to have reached the nearby Pacific Ocean. Experts suspect the radioactive water has been leaking since early in the crisis, citing high contamination in fish caught in waters just off the plant.

The contaminated water is by far the most serious of the recent problems because of its potential impact on water management and the environment.

The tanks are crucial to the management of contaminated water used to cool melted fuel rods at the plant’s wrecked reactors. The reactors are stable, but the melted fuel they contain must be kept cool with water, which leaks out of the reactors’ holes and ruptures and flows into basement areas.

“The contaminated water situation is on the verge of collapse,” Tanaka said. But he said there was no choice but to keep adding water, while trying to seek ways to minimize the leaks and their risks.

To address local outrage over the recent problems and TEPCO’s failure to detect problems earlier, company president Naomi Hirose traveled to Fukushima and apologized for the problems.

He promised to expedite the construction of steel containers and move all the water there from the underground tanks, at the request of Industry Minister Toshimitsu Motegi.

The underground tanks, all built by Maeda Corp., come in different sizes, including one the size of an Olympic-size swimming pool and similar to an industrial waste dump. They are dug into the ground and protected by two layers of polyethylene linings inside the outermost clay-based lining, with a felt padding in between each layer.

Regulators suspect a design problem with the underground tanks, which TEPCO allegedly chose over steel tanks as a cheaper option.

“The nuclear crisis is far from over,” the nationwide Mainichi newspaper said in a recent editorial.

“There is a limit to what the patchwork operation can do on a jury-rigged system.”

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Posted by FanningCommunications on May 1st, 2013 and filed under News. You can follow any responses to this entry through the RSS 2.0. You can leave a response by filling following comment form or trackback to this entry from your site

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