New dose estimates for the surrounding population lead the news from Fukushima this week, and a government official said the country’s retreat from nuclear power may not mean the closure of all reactors in the medium term.
Recent developments related to the Tokyo Electric Power Co. reactors severely damaged following last year’s earthquake and tsunami include:
New Radiation Estimates
The World Health Organization released a preliminary study that projected radiation doses near the plant and beyond. As summarized by World Nuclear News, the report estimated that most Fukushima prefecture residents received doses between 1 and 10 millisieverts in the year following the accident, with the exception of two areas where doses ranged from 10 to 50 mSv. For context, the study noted 10 mSv is the reference level for yearly public exposure to radiation from radon. Estimated doses for people living in prefectures contiguous to Fukushima Prefecture ranged from 0.1 to 10 mSv.
The study did not estimate doses for the area within 20 kilometers of the plant where the first evacuation took place and that remains uninhabited. It also assumed high levels of consumption of food produced in Fukushima prefecture.
The study placed thyroid doses of iodine-131 at 1 to 10 mSv for adults and at 10 to 100 mSv for children in much of Fukushima prefecture, with the worst-hit areas expected to see adult doses of 10 to 100 mSv. In one location, the study estimated infant doses at 100 to 200 mSv.
Separately, TEPCO on Thursday updated its estimate of radiation released into the atmosphere during March 2011. Kyodo News reported the utility now estimates 900,000 terabecquerels of radioactive contaminants were released, which is nearly twice an earlier estimate made by a government nuclear agency.
Edano: Some Plants May Remain Online
While a government committee examines Japan’s long-term energy policy, Industry Minister Yukio Edano told a Japanese newspaper that the country’s phase-out of nuclear power might not mean permanent closure for reactors before the end of their design lives. Edano told the Asahi Shimbun that the government will reduce the country’s nuclear generation by decommissioning reactors after 40 years in service and not replacing them, which would leave many reactors in operation for decades to come. The government is considering five scenarios for nuclear power’s share of generation in 2030, ranging from none to 35 percent.