简体中文
Japan's nuclear regulator on Monday provisionally approved a plan to construct an underground frozen wall at the crippled Fukushima Daiichi nuclear power plant to help deal with the rapid buildup of contaminated water at the site.
The Nuclear Regulation Authority (NRA) green lit Tokyo Electric Power Co.'s. (TEPCO) plans to begin the construction of the wall in June, which will involve driving steel pipes 30 meters into the soil around a 1.5 kilometer perimeter surrounding the No. 1 to 4 reactors damaged in the 2011 earthquake-triggered tsunami.
Officials from TEPCO said that liquid calcium chloride at minus 40 degrees Celsius will be injected into the pipes to freeze the surrounding soil, which, in theory, will prevent groundwater from mixing with coolant water that is becoming contaminated when it comes into contact with melted nuclear fuel.
Initially there had been concerns that the construction of the ice wall would cause the ground around the reactor buildings to sink, which could compromise the effectiveness of the containment process, but NRA Commissioner Toyoshi Fuketa said Monday that such concerns had been allayed by TEPCO.
"I think we have been able to confirm today the scale of ground sinking, which is what we have most feared as side effects of building the wall," Fuketa was quoted as saying.
Fuketa added however that the project was not straightforward and that concerns remain about taking accurate radiation readings inside the reactor buildings once the ice wall is in place.
The government has earmarked around 32 billion yen to build the ice wall, including 14 billion yen coming from reserve funds under the fiscal 2013 budget, with the project planned to be fully operational by the end of March 2015.
The plan for the ice wall, the technique of which has been used previously in engineering projects, but not on a scale of Fukushima or for the expected duration, has been met with some criticism by experts on the matter who believe capping the reactors in concrete, as was the case following the 1986 Chernobyl disaster, would be a more effective means of dealing with the ongoing crisis.
Harutoshi Funabashi, a Hosei University professor and expert on the matter who led an academic review of the post-disaster Fukushima recovery efforts, said Japan's plan is "just a tactic to avoid taking responsibility and facing an angry public."
He and other critics of the ice wall move have urged the government to take lessons form the Chernobyl incident and consider alternative options.
"Admitting that no one can live near the plant for a generation would open the way for all sorts of probing questions and doubts," Funabashi said previously, adding that the government opposes the idea as images of a wide area of Fukushima Prefecture being designated a no-go zone, would further turn the Japanese population against nuclear technology.
But Shunsuke Kondo, chairman of the government's Atomic Energy Commission has said that if the reactors were just buried then "no one would want to see the face of another nuclear power plant for years."
Japan's Prime Minister Shinzo Abe, also a proponent of bringing Japan's idled nuclear reactors back online, has said the ice wall project is a means of finding a "fundamental solution" to the problem of containing the radioactive water, rather than reacting to each new problem as it arises, as has been the case on numerous occasions since the multiple meltdowns first started in March 2011.
The overall decommissioning of the plant is expected to take around 40 years, with the removal of all nuclear fuel from the No. 4 reactor building being completed by the end of this year, TEPCO has said.
