Fukushima return: at nuclear site, how safe is “safe?” — National Geographic Daily News

” For the first time since Japan’s Fukushima Daiichi nuclear power disaster three years ago, residents of a small portion of the surrounding restricted area are being allowed to return home, even though radiation levels remain elevated.

At midnight on March 31, the Japanese government officially lifted an evacuation order for a portion of the Miyakoji district of Tamura, a city about 12 miles (20 kilometers) inland from the nuclear plant. Some 360 residents are now free to return to their homes, according to the Japanese newspaper Asahi Shimbun. They were among 80,000 people from the surrounding communities who were forced to flee after the earthquake-triggered tsunami of March 11, 2011, inundated Fukushima, knocked out its crucial backup power, and set off a catastrophic accident and release of radiation. The vast majority of the evacuees remain barred from returning.

While precise measurements for Miyakoji weren’t available, other locations in the vicinity had radiation exposure levels as high as 80 to 170 microsieverts per hour about one week after the Fukushima accident, according to the Harvard Health Blog. (A single chest x-ray is about 100 microsieverts.)

Tons of Soil Removed

Before the residents were allowed to return this week, an extensive cleanup was undertaken in the Miyakoji district.

Kathryn Higley, a professor of nuclear engineering and radiation health physics at Oregon State University, said that workers removed tons of surface soil, grasses, and plants that had been contaminated with airborne radioactivity released by the nuclear plant during the partial meltdowns and explosions. That material was packed in plastic sacks and sent to storage facilities for containment while its radioactivity decays. Additionally, the crews hosed down the exteriors of buildings and other areas where people might have contact with such contamination. Typically, such operations could reduce radiation exposure levels by 10 to 100 times, she said.

Even so, the radiation that remains at Miyakoji is still probably much higher than what it was before the accident, according to Kelly Classic, a health physicist for the Mayo Clinic in Rochester, Minnesota, and an expert on radiation exposure.  She said that the most recent testing at Miyakoji showed a range between 0.1 and 0.5 microsieverts per hour. On an annual basis, that means that residents are exposed to as much as 4,380 microsieverts per year, which Classic said is about ten times the normal background radiation level for the area.

These levels are far below what it would take to cause immediate illness, but the risk of long-term exposure to low-level radiation is unclear. Studies of radiotherapy patients and others indicate that there is a significant increase in cancer risk if lifetime exposure exceeds 100,000 microsieverts, according to the World Health Organization. A person exposed daily to radiation at the high end of the levels now seen at Miyakoji would reach that lifetime exposure level in fewer than 23 years.

Bid to Avoid Payments?

Classic and other experts said they were concerned that returning residents might be exposed to levels of radioactivity higher than 0.5 microsieverts per hour if they drank water from local aquifers or ate vegetables and meat grown in the area. Surface measurements by government inspectors, who walked around with hand-held radiation meters, might not have detected contamination from such sources, Classic said.

Residents have expressed mixed feelings about the lift of the evacuation order, according to published reports.

Edwin Lyman, a physicist and a senior scientist for the Union of Concerned Scientists, said he was concerned that the Japanese government was reopening Miyakoji and other restricted areas before they were fully cleaned up, out of a desire to stop paying compensation to evacuees. According to Asahi Shimbun, the government’s Nuclear Damage Liability Facilitation Fund has lent Tokyo Electric Power Company (TEPCO), the utility that operated the stricken plant, 1.5 trillion yen ($14.63 billion) so far to pay compensation to people in restricted areas. Lifting the evacuation orders would hasten the end of those payments.

“People should not be forced to make a choice between losing their homes and not being compensated, and moving back to a region that’s still more radioactive than it was before the accident,” Lyman said.

Asahi Shimbun also reported that the government plans to lift the evacuation order for a portion of the village of Kawauchi inhabited by 276 people in late July. Other communities with evacuation orders that may soon be lifted include Katsurao, Nahara, Iitate, Minami-Soma, and Kawamata.

Other communities, such as Okuma and Tutaba, closer to where the plant is located, are unlikely to see their restrictions lifted anytime soon, because the radiation levels still remain too high, the Japanese paper reported. ”

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One thought on “Fukushima return: at nuclear site, how safe is “safe?” — National Geographic Daily News

  1. Pingback: Fukushima, Japan disaster news update | Dear Kitty. Some blog

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