Gov't estimates everything will be fine by 2021

Please note that the Japanese Government is still only aiming at reducing the yearly admissible exposure to 20 millisieverts

June 24, 2014

Government estimates all Fukushima areas safe for living by 2021

http://ajw.asahi.com/article/0311disaster/fukushima/AJ201406240055

THE ASAHI SHIMBUN

FUKUSHIMA--Evacuees can return home in the hardest-hit areas around the stricken Fukushima No. 1 nuclear plant by 2021, after decontamination work sufficiently reduces radiation levels there, according to government estimates released on June 23.

The Cabinet Office’s working team in charge of assisting the lives of nuclear disaster victims estimated that cleanup efforts and “natural decontamination effects” will cut annual radiation doses by 54 to 76 percent in the “difficult-to-return” zones around the plant.

The numbers were presented to local government leaders at a meeting in the prefectural capital of Fukushima. The meeting was held by the industry ministry’s panel that is promoting reconstruction of coastal areas in Fukushima Prefecture.

The government intends to use the latest estimates to reassure evacuees so that it can lift evacuation orders as early as possible.

But Jin Kowata, director of the Nogami No. 1 administrative district of Okuma town, raised doubts about the Cabinet Office’s estimates.

“The results are too optimistic,” he said. “I want (the central government) to release more accurate estimates for the nearer future instead of the ones for 10 years after the disaster.”

All residents of Okuma were forced to evacuate after the Great East Japan Earthquake and tsunami caused the triple meltdown at the plant in March 2011.

The Cabinet Office’s team took into account the results of the Environment Ministry’s model decontamination program in the zones last fiscal year. It also factored in natural decontamination effects based on the half-lives of radioactive substances and the impact of rain, wind and other natural elements.

The estimates are also based on the premise that personal exposure to radiation remains around 70 percent of the air dose rates.

The central government currently plans to allow evacuees to return to their homes when annual radiation doses in each region decline to 20 millisieverts or less.

According to the team’s estimate for areas where 100 millisieverts per year were detected in November, adults who live in wooden houses and stay outside for 6.5 hours a day will be exposed to 6 to 12 millisieverts in 2021 if decontamination work is conducted.

Even without cleanup work, the radiation dose readings for those people are estimated to drop to 24 millisieverts by 2021.

The team has not estimated the radioactive doses for children.

However, it is unclear if the decontamination efforts will continue producing the significant results that they are currently achieving, and geographic features could also negatively affect the results of the cleanup programs

.

(This article was written by Senior Staff Writer Noriyoshi Otsuki and Yuri Oiwa.)

Estimates of 2021 radiation doses predict drop-off in Fukushima

http://www.japantimes.co.jp/news/2014/06/24/national/estimates-of-2021-radiation-doses-predict-drop-off-in-fukushima/#.U6ke3bHi91s

JIJI

FUKUSHIMA – Radiation doses in parts of Fukushima Prefecture now deemed uninhabitable because of contamination will fall by over half by 2021, government estimates released Monday show.

Annual doses per person would fall below 20 millisieverts if decontamination work is done, according to the estimates by the Cabinet Office.

It is the first time that radiation exposure estimates have been compiled for the areas where annual doses stand above 50 millisieverts. An annual reading of 20 millisieverts or less is one of the conditions for the evacuation advisory to be lifted.

The estimates were presented at a meeting Monday in the city of Fukushima of a private panel that advises Kazuyoshi Akaba, the minister of economy, trade and industry, on measures to help reconstruct municipalities around Tokyo Electric Power Co.’s Fukushima No. 1 nuclear plant.

According to the Cabinet Office, atmospheric radiation levels in the most contaminated areas are expected to decrease by half or more within 10 years of the accident, due to the natural decay of the radioactive substances as well as rain and wind sweeping some of the substances away. With decontamination work, the levels would drop further, it said. As of last November, atmospheric radiation levels in the areas stood at 3.8-19 microsieverts per hour.

Annual radiation doses for residents who spend eight hours outdoors a day would reach up to 37 millisieverts if cleanup measures are not taken. Decontamination efforts would see the annual exposure level fall to 3-19 millisieverts, the Cabinet Office said.

Decontamination work was done in parts of the highly polluted areas on a trial basis between last October and January. But no full-fledged decontamination program has been drawn up for the areas.

Radiation near nuke plant could be reduced below 20 millisieverts in 2021: gov't

http://mainichi.jp/english/english/newsselect/news/20140624p2a00m0na005000c.html

The government has estimated that decontamination work could cut the annual radiation dose in specified areas near the crippled Fukushima No. 1 Nuclear Power Plant from around 100 millisieverts to less than 20 millisieverts in 2021.

The Cabinet Office announced the estimated yearly radiation exposure in designated evacuation zones, or areas where the yearly radiation dose totals more than 50 millisieverts, on June 23. It based the estimates on Environment Ministry data, including the outcome of model decontamination projects.

Based on calculations from November last year, an adult male who spent eight hours outside and 16 hours inside each day near the plant would be exposed to 100 millisieverts of radiation per year. By March 2021, 10 years after the nuclear disaster, however, the Cabinet Office calculated that that figure would drop to 37 millisieverts -- even if no decontamination work was carried out.

If decontamination work were successfully completed in March 2015, the figure would drop to 9-10 millisieverts in 2021, and if the effects of decontamination were low, it would still fall to 17-19 millisieverts, the Cabinet Office calculated.

A yearly radiation dose of 20 millisieverts is a yardstick for lifting evacuation orders.

Meanwhile, in areas where the yearly radiation dosage totaled 50 millisieverts, the figure would drop to 19 millisieverts in March 2021 without decontamination work. If the cleansing work was carried out with success, the dosage would drop to 6-7 millisieverts, and it would drop to 10-11 millisieverts if the work was not as effective as hoped.

"The figures are estimates, based on various hypotheses, and we need to interpret them while allowing for a margin of error," a Cabinet Office official commented. "We will offer the information to local residents in plain language and use the data for disaster recovery."

Some Fukushima evacuees and municipal governments, however, are requesting that the national government work on reducing the yearly permissible exposure dose to one millisievert.