The Yomiuri Shimbun
The government will likely go ahead with a plan to spray resin inside the troubled Fukushima No. 1 nuclear power plant, which it hopes will contain the spread of radioactive substances, sources said Wednesday.
The government has begun full-fledged discussions on different plans to stop the spread of radioactive substances that have been leaking continuously from damaged reactors at the plant run by Tokyo Electric Power Co.
In addition to efforts to cool the reactors and spent nuclear fuel pools by TEPCO and the Self-Defense Forces, the government has asked for aid from private companies and other nations, including the United States, to deal with the accident.
It is believed spraying resin would minimize the spread of radioactive substances, which would allow repair work at the plant to proceed more smoothly, the sources said. Efforts to restore the reactors' cooling functions have seesawed repeatedly, with the detection Wednesday of radioactive iodine-131 at levels 3,355 times the legal limit in seawater near the plant being the latest wrench in the works.
Spraying resin on debris inside the plant could begin as early as Thursday, the government sources said. The operation would last for about two weeks, they said.
The plan involves using a remote-controlled robot to spray resin over about 80,000 square meters inside the 120,000-square-meter facility. The areas to be sprayed were contaminated by radiation from debris scattered by several hydrogen gas explosions in the days after the March 11 earthquake.
Synthetic resin would likely be used, possibly Kurita Water Industries Ltd.'s Kuricoat C-720 Green. The product is usually used to prevent dust and sand from being blown off reclaimed and developed land. Coating the debris with resin is expected to prevent the radioactive materials from spreading into the air.
The government had considered spraying resin from a helicopter, but about 3,000 flights would be necessary because only a limited amount could be sprayed each time. Since this method could also put helicopter crews in danger, the government rejected this option.
To address the about 25,000 square meters of buildings thought to be contaminated, such as those housing the reactors, some general contractors have proposed covering the structures with tents, covering the walls with sheets and other plans. But these plans could take months to complete, the sources said.
The government is also studying the possibility of using helicopters to spray other chemicals that could prevent the dispersal of radioactive substances.
Meanwhile, highly radioactive water in the basements of turbine buildings remains a big problem.
The Land, Infrastructure, Transport and Tourism Ministry said it had considered dispatching port-use tankers to collect the contaminated water and then shuttle it via Maritime Self-Defense Force vessels to tankers anchored offshore. But the Defense Ministry deemed the plan too risky.
"We don't have the ability to completely isolate the radiation-contaminated water, so that would've put SDF personnel at too much risk," a ministry official said.
The government is now considering building temporary facilities for storing the contaminated water inside the plant and other options.
These plans are being devised by a radiation control team comprised of senior officials from the Japanese and U.S. governments, nuclear experts, and personnel from the SDF and the U.S. military. The team is led by Sumio Mabuchi, a special adviser for the prime minister. The sources said the team decided to go ahead with the resin spraying at its meeting Tuesday.
The measures, however, are only stopgap, and the government said it would come up with more permanent solutions to contain the radioactive materials after temperatures in the nuclear fuel rod pools fall and the reactors stabilize.
"We have to end the crisis at the nuclear plant, minimize radioactive contamination of surrounding areas and prevent any health damage," Chief Cabinet Secretary Yukio Edano said at a press conference Wednesday. "To accomplish that, we have experts in various fields working on a variety of plans, including possibly covering [the buildings at the plant]."
(Mar. 31, 2011)
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