Japan's nuclear agency wants to raise the severity level of the new radioactive water leak at the Fukushima. The problem is more serious than initially expected.
The incident — newly discovered leaks of radioactive water — was first classified as a level one incident on the International Nuclear and Radiological Event Scale (INES), which refers to an "anomaly". Now, reports the BBC, that's set to be upgraded to level three — which makes it count as a "serious incident". That might not sound a huge jump, until you realise that the severity of an event is about 10 times greater for each increase in level. So, just 100 times worse than expected then.
In fact, on the seven-point scale, a three counts as the most serious incident. The rest of the scale, four to seven, is reserved for accidents, with only two events ever scoring a seven: the initial meltdowns at Chernobyl and Fukushima.
The current problems at Fukushima is a result of radiation levels detected in puddles surrounding the site. Over 300 tonnes of radioactive water surround the abandoned plant, and one puddle of contaminated water was found to be emitting 100 millisieverts an hour of radiation. That's serious, as Masayuki Ono explained to Reuters:
One hundred millisieverts per hour is equivalent to the limit for accumulated exposure over five years for nuclear workers; so it can be said that we found a radiation level strong enough to give someone a five-year dose of radiation within one hour.
Ground crews are now attempting to stem flows from leaking tanks with sandbags, and suck up the puddles that have been forming. It's slow work though, with workers being rotated regularly to avoid overexposure to radiation — which means plenty of the water has already disappeared into the ground. [BBC]