Sunday, March 27, 2011

Radiation Leakage from Fukujima

Here are some interesting bits from an article in the magazine New Scientist talking about the nuclear radiation released by the meltdown at Fukujima:
Japan's damaged nuclear plant in Fukushima has been emitting radioactive iodine and caesium at levels approaching those seen in the aftermath of the Chernobyl accident in 1986. Austrian researchers have used a worldwide network of radiation detectors – designed to spot clandestine nuclear bomb tests – to show that iodine-131 is being released at daily levels 73 per cent of those seen after the 1986 disaster. The daily amount of caesium-137 released from Fukushima Daiichi is around 60 per cent of the amount released from Chernobyl.

The difference between this accident and Chernobyl, they say, is that at Chernobyl a huge fire released large amounts of many radioactive materials, including fuel particles, in smoke. At Fukushima Daiichi, only the volatile elements, such as iodine and caesium, are bubbling off the damaged fuel. But these substances could nevertheless pose a significant health risk outside the plant.

...

In the 10 days it burned, Chernobyl put out 1.76 × 1018 becquerels of iodine-131, which amounts to only 50 per cent more per day than has been calculated for Fukushima Daiichi. It is not yet clear how long emissions from the Japanese plant will continue.

Similarly, says Wotawa, caesium-137 emissions are on the same order of magnitude as at Chernobyl. The Sacramento readings suggest it has emitted 5 × 1015 becquerels of caesium-137 per day; Chernobyl put out 8.5 × 1016 in total – around 70 per cent more per day.

"This is not surprising," says Wotawa. "When the fuel is damaged there is no reason for the volatile elements not to escape," and the measured caesium and iodine are in the right ratios for the fuel used by the Fukushima Daiichi reactors. Also, the Fukushima plant has around 1760 tonnes of fresh and used nuclear fuel on site, and an unknown amount has been damaged. The Chernobyl reactor had only 180 tonnes.

The amounts being released, he says, are "entirely consistent" with the relatively low amounts of caesium and iodine being measured in soil, plants and water in Japan, because so much has blown out to sea. The amounts crossing the Pacific to places like Sacramento are vanishingly small – they were detected there because the CTBT network is designed to sniff out the tiniest traces.

...

The Chernobyl accident emitted much more radioactivity and a wider diversity of radioactive elements than Fukushima Daiichi has so far, but it was iodine and caesium that caused most of the health risk – especially outside the immediate area of the Chernobyl plant, says Malcolm Crick, secretary of a United Nations body that has just reviewed the health effects of Chernobyl. Unlike other elements, he says, they were carried far and wide by the wind.
I'm losing confidence in Japan as well as the US since this disaster hasn't been brought under control and the information we are getting is through third parties and not official government sources. The promise to bring power to the plant dragged on for over a week and when power arrived suddenly we were told that you couldn't just start up the cooling system. There is no information about the scope & scale of the disaster and now authoritative statement of what has to be done and the expected time it will take. Worst of all, there is no guidance on the radioactive release stating what has been released, when it is expected to be under control, and what we can expect over the coming weeks and months.

I'm starting to get very cynical about this situation and the competence of the authorities. I'm now wondering why they didn't just bury the site under a hundred feet of water impervious concrete to prevent these weeks and weeks of radiation leakage. It is obvious that Tepco is incompetent and has lied about safety in the past, so why are these clowns still "in charge" of the cleanup?

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