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 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

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.

According to a report this week by the International Energy Agency, which isn't an especially alarmist body, the chances grow every day that the world will warm by more than 2C (4F), which scientists estimate is the limit beyond which change becomes chaotic and unknowable, and much more dangerous. To stay within that limit, the proportion of carbon dioxide in the atmosphere mustn't exceed 450ppm (parts per million). Its present level is 390ppm and last year, despite recession, more carbon dioxide from fossil fuels poured into the atmosphere than ever before. The world goes on gobbling up oil, coal and gas in increasing amounts and will continue to build power stations and steel mills that depend on their energy. "Fossil fuel lock-in" is the term, meaning an ongoing commitment to coal and oil that will be impossible to undo until long after 2020, which, according to climate science, is when carbon emissions need to start their decline.

Is it time to consider shifting efforts away from saving some of the world's most famous species?

It is a controversial proposition and the implications of it are both moral and environmental, but in a recent survey of nearly 600 scientists involved in wildlife protection, around 60 per cent agreed with the idea of shifting efforts away from species that are too difficult or too costly to preserve in the wild.

Many experts have rejected that, saying we have no business making judgements over one species at the expense of another.

Authorities trying to decontaminate radioactive soil in the aftermath of the accident at the Fukushima No. 1 nuclear power plant have found that sunflowers, despite their reputation for absorbing radioactive cesium, have little effect, an experiment has shown. [...] The experiment on removing radioactive cesium started in May in farmland totaling 7,000 square meters in Iitatemura and other locations in Fukushima Prefecture. In the experiment, the effects of the following four methods were examined: scraping away surface soil; washing contaminated soil with water and removing the water; burying topsoil and replacing it with subsoil; and using sunflowers and other plants to absorb radioactive cesium in soil. The results showed the least effective of the four methods was the use of plants.

Japan's nuclear safety agency today rejected a claim in British newspaper The Independent that the earthquake itself, not the subsequent tsunami, destroyed cooling systems leading to meltdowns at the Fukushima Daiichi nuclear plant. [...] An IAEA spokesman said that a report from the mission – led by Mike Weightman the UK's chief inspector of nuclear installations – contains detailed accounts of the failure of cooling systems in the early hours of the disaster which challenge the idea that the quake caused the damage, as claimed in The Independent. Meanwhile, TEPCO said on Wednesday that overall radiation released from the three damaged Fukushima reactors is now a 10-millionth of peak levels recorded on 15 March, just after the accident.

What really happened at the Fukushima Daiichi Nuclear Power Plant to cause a meltdown? TEPCO and the government of Japan have provided many explanations. They don't make sense. The one thing they haven't provided is the truth. It's time that they did.

Tests conducted by Minamisoma on about 900 residents showed low levels of internal radiation exposure and no one required immediate treatment, despite the city's proximity to the leaking Fukushima No. 1 nuclear plant, municipal officials said Saturday.

When converted to exposure over the next 50 years, one resident measured just above 1 millisievert of radioactive cesium, while tests on most of the other residents revealed exposure of 0.1 millisievert or less, they said. The maximum radiation exposure limit for a person not involved in nuclear-related work is 1 millisievert per year.