Thursday, February 20, 2014

New Leak of Radioactive Water at Fukushima Site

I have only sporadically kept an eye on events at Fukushima because frankly it depresses me each time. But, since this was shoved into my face I thought that I would mention it.

Tokyo Electric Power Co. (Tepco) has reported a new leak from one of the tanks holding contaminated water at the disaster site. According to the company, about 100 metric tons (26,400 gallons) of water may have escaped a concrete barrier, apparently because someone left a couple of valves open. The leak was located over 700 meters away from the ocean and officials say that they shut off the flow of water into the tank and are " in the process of recovering the leaked water and the earth it has contaminated" so this is different from the massive 300 ton (~72,000 gallon) leak of highly radioactive water that basically went from a holding tank into the ground and out into the ocean last summer.

Reuters reports Tepco officials as saying that ...
"Water is unlikely to have reached the ocean as there is no drainage in that tank area." Tepco said water overflowed from a large storage tank at the site late on Wednesday after a valve had remained open by mistake and sent too much contaminated water into a separate holding area.

The water leaked this time was still highly radioactive, with a beta radiation reading of 230 million becquerel per liter. A becquerel is a unit of radioactivity and international standards place a limit of 10 becquerels per liter in drinking water and 30 becquerels per liter in water released into the ocean.

In case you didn't know, ever since the earthquake, Tepco has been storing radioactive water in large storage tanks on the site. The fuel rods in the reactors still have to be kept cool, so a flow of water must be maintained, but the water comes out radioactive so it is placed in one of these large storage tanks. The site has become home to a collection of 1,000 odd tanks which were at 85% capacity back in August and they were adding around 400 tons of water each day. Goodness knows exactly what is going on now. These tanks are going to be horrible problem if another earthquake or tsunami hits the region.

Satellite images show how the number of water storage tanks has increased in the past two years. The tanks store contaminated water that has been used to cool the reactors. This image is from a BBC report done in August, 2013 - and things haven't been getting better either.

It became clear in the middle of last year that despite Tepco's claims, radioactive water had been leaking from the site into the ocean pretty much since the earthquake occurred. In addition to the storage tanks, the reactor buildings themselves are leaking, as are the spent fuel storage pools. The earthquake/tsunami did so much damage that all of the structures there are pervasively cracked. There is no easy way to either measure the full extent of these leaks, or to stop them.

The Japanese government now reports that approximately 300 tons of contaminated groundwater seeps into the ocean each day at the Fukushima-Daiichi station. 

To be clear - this is still a small amount of water that is getting into the ocean so the dilution effect is huge. That scary red and orange NOAA image that was circulating the web in August had nothing to do with radioactivity, it was a map of wave heights from the tsunami. And the reactor isn't going to 'meltdown soon' - it has already melted down - past tense - so those internet things are bogus too.

Now this doesn't mean that things are all rosy either. We have been polluting the ocean with radioactivity, chemicals and plastics for decades so we have done lots of damage and contaminated organisms living in the ocean.

Fukushima is still an ongoing disaster and it is going to be a long, long time before we have any good news about the site. 

This Tepco/Getty Images photo shows workers removing nuclear fuel rods from a pool at the Fukushima Daiichi Nuclear Power Plant on Nov. 18, 2013 in Okuma, Fukushima, Japan. (source)

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