The Japanese government is investigating how radioactive concrete ended up in an apartment complex built to house Fukushima residents evacuated from homes near the stricken Fukushima Daiichi Nuclear Power Plant.
The contamination was discovered after a high-school student in the city of Nihonmatsu was found to have been exposed to 60 percent more radiation in three months than the government rates as safe for an entire year.
Schools in Nihonmatsu, about 40 miles from the Fukushima Daiichi nuclear plant that was eventually destroyed by damage done during a March, 2010 Tsunami, is temporary home to many residents evacuated from the vicinity of the plant.
Investigators traced the source of the high-schooler's exposure to radioactive cesium in the concrete structure of the six-month-old apartment building in which the student and a dozen families lived.
The building was erected hurriedly, using gravel from a quarry in the town of Namie, less than a dozen miles from the Fukushima plant.
That puts the quarry well within the 12-mile "no-go" zone declared by the Japanese government that forbids any material from areas heavily irradiated by the plants from being used outside it.
Japanese officials were criticized for having sketchy and inadequate plans for dealing with natural disasters serious enough to affect the two Fukushima power plants.
One weakness in that lack of preparation was overoptimistic estimations of how well the plants would contain radiation and how far any contamination might reach.
Though the Tsunami struck March 11, it wasn’t until the last week in April that the 12-mile no-go zone was firmly established and enforced.
Due to that delay, the gravel found in the three-story Nihonmatsu apartment building was on the ground, exposed to both radiation and radioactive fallout for six weeks before being shipped out to be used in nearby construction projects.
The quarry owner told the Japanese Nuclear Emergency Response agency the quarry shipped 5,200 tons of gravel to 19 construction and cement companies between March 14 and April 22, when the 12-mile no-go zone was closed.
The agency is tracing other shipments to identify other potential risks.
Despite the extra radiation, the Nuclear Emergency Response agency does not plan to tear down the building or order residents to leave.
Even in the most intensely irradiated areas within the building, annual exposure would equal about 10.86 millisieverts, not the 20 millisieverts required before the agency requires a building be evacuated, according to the WSJ.
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