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Japan Plant Starts Treating Radioactive Water

18 June 2011 02:07 (UTC +04:00)

Baku â€“ APA. A system for decontaminating highly radioactive water incorporating U.S. and French technology began full operations at Japan’s Fukushima Daiichi nuclear complex Friday, a development that will help reduce the vast amount of irradiated water that has become a major obstacle to bringing the plant to stability, APA reports quoting â€œThe Wall Street Journalâ€.
The water has flooded the reactor buildings and adjacent facilities, preventing workers from conducting necessary repairs, and has periodically contaminated the ocean through spillages.
"Stable operation of the decontamination system is a precondition for achieving a stable cooling of the reactors," said Sakae Muto, executive vice president of plant operator Tokyo Electric Power Co., or Tepco, in a news briefing Friday.
Tepco also said its roadmap for bringing the facility to a safe condition and stopping all radiation releases is proceeding as planned.
In releasing its latest update to the plan, Mr. Muto said the company was still confident it could meet its target of achieving a "cold shutdown" of the three most damaged reactors on schedule, which would mean by early 2012.
Mr. Muto also said Tepco hopes to achieve stable cooling of the spent fuel pools at all six reactors within the next month. The pools are where fuel is stored when it is removed from the main reactor units. The fuel must be covered with water and kept below boiling point.
Goshi Hosono, special advisor to Prime Minister Naoto Kan on nuclear issues, said of the new water-treatment system at the same news briefing: "This is a big step forward, as it significantly increases the chance of stabilizing the [damaged] reactors."
Officials also said that radiation levels at the plant, in northern Japan, are continuing to fall steadily after the March 11 earthquake and tsunami caused the worst nuclear accident ever in Japan and the second-worst globally, after the 1986 Chernobyl disaster.
The water-treatment system, which relies on technology from Kurion Inc. of the U.S. and Areva SA of France, is designed to cleanse water of radioactive materials, sea salt and oil, so that it can be recycled as reactor coolant.
Radioactive water has accumulated after Tepco kept injecting water into the reactors, even as much of it leaked out due to damage from the earthquake, tsunami and massive overheating of the units. More than 100,000 tons of contaminated water is now flooding the plant.
Tepco and government officials initially said that the system would come online by the end of May. But the construction was beset with glitches, pushing the launch date ever closer to the end of June, when contaminated water is expected to fill up all storages and start overflowing.
On Thursday, just before the system was about to start full operations, leaks were discovered in the Kurion equipment, prompting a shutdown of the whole system. Later, it was found that the leak was caused by a worker closing an outlet valve by mistake, not by defects with the system itself, allowing Tepco to proceed with the full operations.
Tepco also said Friday it is planning to construct a tightly sealed containment structure around the damaged reactor buildings of the plant to help avoid radiation leaks.
It said the planning is at an early stage and would be in addition to the polyester tents that are now being put up around the units, three of which were badly damaged from hydrogen explosions in the first week of the crisis.