How polluted is the ocean near Daiichi Japan? — rogerwhart
Timely of you to ask.
From today’s New York Times.
Two years after a triple meltdown that grew into the world’s second worst nuclear disaster, the Fukushima Daiichi nuclear power plant is faced with a new crisis: a flood of highly radioactive wastewater that workers are struggling to contain.
Groundwater is pouring into the plant’s ravaged reactor buildings at a rate of almost 75 gallons a minute. It becomes highly contaminated there, before being pumped out to keep from swamping a critical cooling system. A small army of workers has struggled to contain the continuous flow of radioactive wastewater, relying on hulking gray and silver storage tanks sprawling over 42 acres of parking lots and lawns. The tanks hold the equivalent of 112 Olympic-size pools.
Earlier this month, Bloomberg reported:
Tokyo Electric Power Co. (9501)’s discovery of leaks in water storage pits at the wrecked Fukushima atomic station raises the risk the utility will be forced to dump radioactive water in the Pacific Ocean…
…While the company has since built a makeshift sealed cooling system, underground water is breaching basement walls at a rate of about 400 tons a day and becoming contaminated, according to Tepco’s estimate.
The company has two options, reports Bloomberg. One is to build above ground storage facilities but with 400 tons of contaminated water pouring in a day, it can only build so much. The second option, which Bloomberg says the company is hesitant to do but isn’t ruling out, is to dump the water into the ocean.
Back in November, Nature had this to say:
The Fukushima disaster caused by far the largest discharge of radioactivity into the ocean ever seen. A new model presented by scientists from Woods Hole Oceanographic Institution in Massachusetts estimates that 16.2 petabecquerels (1015 becquerels) of radioactive caesium leaked from the plant — roughly the same amount that went into the atmosphere.
Most of that radioactivity dispersed across the Pacific Ocean, where it became diluted to extremely low levels. But in the region of the ocean near the plant, levels of caesium-137 have remained fixed at around 1,000 becquerels, a relatively high level compared to the natural background. Similarly, levels of radioactive caesium in bottom-dwelling fish remain pretty much unchanged more than 18 months after the accident…
…a fresh analysis by oceanographer Jota Kanda at the Tokyo University of Marine Science and Technology suggests that not one source, but three, are responsible. First, radioactivity from the land is being washed by rainfall into rivers, which carry it to the sea. Second, the plant itself is leaking around 0.3 terabecquerels (1012 becquerels) per month, he estimates.
But Kanda thinks that the third source, marine sediment, is the main cause of the contamination. Around 95 terabecquerels of radioactive caesium has found its way to the sandy ocean floor near the plant.
Becquerels? That would be a unit of radioactivity. To get at the science of all this, we suggest you ask this guy. — Michael
Have a question? Ask away.
Image: Satellite view of Daiichi, Japan (indicated by the red pin), via Google Maps.