It has been just over four months since an earthquake and tsunami caused a triple meltdown at the Fukushima Daiichi nuclear power station in Japan. Today, the Tokyo Electric Power Company, which runs the plant, released an update of its efforts to bring the troubled reactors under control.
The news was largely good. Temperatures at the three damaged reactors have remained relatively low since the first days after the accident, and the spent fuel pools, which some feared were heavily damaged, appear stable. A system to recirculate cooling water has been installed to reduce the build-up of radioactive water at the site, and it appears to be running, after a few initial glitches.
At the same time, problems continue to plague the region as a result of the accident. Thousands of Fukushima residents remain unable to return to their homes, and contamination continues to show up in the food supply. Today, Japan was forced to ban beef shipments from the prefecture after some samples were found to have caesium-137 contamination levels as high as 2,300 becquerels per kilogram. The government limit for contamination is just 500 becquerels per kilogram.
To put this into context, the contamination limit on food in Europe has long been set at 1250 becquerels per kilogram, although there have been moves to reduce this to 500 becquerels per kilogram.
At the plant, the next step will involve installing a temporary cover on reactor unit 1 to reduce the spread of radioactive material. Construction of the lightweight cover could begin later this month. With a little luck, the reactor’s cores will drop below 100 degrees Celsius sometime over winter, allowing TEPCO to declare a successful cold shutdown. That will be good news for the company and Japan, but it’s only the start of the cleanup operation. Eventually the fuel from Fukushima will have to be removed and put into deep storage. That operation is likely to stretch for decades.
For full coverage of the Fukushima disaster, go to Nature’s news special.
For a selection of our coverage in Japanese, see Nature Asia Pacific.