Seismic risk at the Fukushima nuclear plant increased after the magnitude 9 earthquake that hit Japan last March, scientists report. The new study, which uses data from over 6,000 earthquakes, shows the 11 March tremor caused a seismic fault close to the nuclear plant to reactivate. The results are now published in Solid Earth, an open-access journal of the European Geosciences Union (EGU).

The research suggests authorities should strengthen the security of the Fukushima Daiichi nuclear power plant to withstand large earthquakes that are likely to directly disturb the region. The power plant witnessed one of the worst nuclear disasters in history after it was damaged by the 11 March 2011 magnitude 9 earthquake and tsunami. But this tremor occurred about 160 km from the site, and a much closer one could occur in the future at Fukushima.

The village of Kawauchi near the crippled Fukushima No. 1 nuclear power plant declared an end to evacuation on Tuesday and called on residents to return.

Kawauchi is the first among municipalities located in evacuation zones designated after the nuclear accident to take such a step.

The village will restart administrative services and reopen schools, nurseries and clinics in April, Kawauchi Mayor Yuko Endo said at a press conference.

Last year, the Japanese government ordered the nuclear authorities to conduct tests on all Japan's reactors after the 11 March meltdown at Fukushima Daiichi raised questions about the safety of nuclear power, particularly in a country prone to earthquakes and tsunami.

Earlier this week, a team of experts from the International Atomic Energy Agency [IAEA] began a review of the safety tests but said it was up to the Japanese government whether or not to approve the restart of idle reactors.

Currently only three of Japan's 54 reactors – just over 6% of its total nuclear capacity – are in operation after the Fukushima accident forced the closure of active reactors for safety checks.

The Ministry of the Environment on Jan. 26 announced a schedule for decontamination work covering 26,700 hectares of "special decontamination areas" tainted with radioactive materials from the damaged Fukushima No. 1 nuclear plant.

The schedule eyes completion of decontamination work in areas where the yearly radiation dosage is below 50 millisieverts per year by the end of March 2014. However, the effectiveness of decontamination efforts is still unclear and there are a host of issues to deal with after the decontamination work is finished, including the building of infrastructure for each community. It remains unknown whether residents will be able to return to their homes.

The government's schedule does not clarify the targets for reducing radiation levels. The results of model decontamination work that the Cabinet Office is handling are expected to be released in February or March, and the Ministry of the Environment plans to wait for those results before deciding on targets.

The Japanese government is launching a large-scale cleanup of the fields, forests, and villages contaminated by the Fukushima nuclear disaster. But some experts caution that an overly aggressive remediation program could create a host of other environmental problems.

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Ten months after the nuclear disaster, trust in the authorities is nearly nonexistent. Without it, Japan’s government risks the biggest cleanup fiasco of all: a decontamination effort that carries huge financial and environmental costs but still fails to convince Fukushima residents that their homes, farms, and forests are safe once again

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Japan may announce on December 16 that tsunami-damaged nuclear reactors in Fukushima are in a cold shutdown, the Yomiuri newspaper reported on Friday, an important milestone in its plan to bring under control the worst nuclear accident in 25 years.

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Declaring a cold shutdown will have repercussions well beyond the plant as it is one of the criteria the government has said must be met before it begins allowing 80,000 residents evacuated from within a 20 km (12 mile) radius of the plant to return home.

A considerable amount of the melted fuel is thought to have penetrated the reactor's pressure vessel and fallen to the bottom of the containment vessel, which includes the pressure vessel, TEPCO said.

If it is assumed that all of the fuel at the No. 1 reactor fell to the containment vessel, this could have eroded the vessel's 100-centimeter-thick concrete bottom by 65 centimeters, it said. But the fuel would not penetrate the containment vessel, it added.

At the No. 2 and No. 3 reactors where cooling continued for a certain period of time, about 60 pct of fuel is estimated to have melted. If all of the melted fuel is assumed to have fallen to the reactors' containment vessels, their bottoms could have been eroded by at the most 12 centimeters and 20 centimeters, respectively.

More than six months after the March 11 Great East Japan Earthquake only 43 percent of the evacuees said they definitely want to return to where they used to live, compared with 62 percent in the first survey in June.

Tepco said that the Daiichi reactors were emitting about 200 million becquerels of radiation per hour as of mid-September, about one four-millionths of the amount seen in the days after the March 11 disaster. It said this translates to about 0.4 millisievert per year of radiation measured at the fringes of the plant, below the 1 millisievert legal limit. [...] Temperatures at all four of its spent fuel pools had fallen to levels considered stable by August. As of Tuesday temperatures at all the spent fuel pools were below 40 degrees.