Thursday, August 29, 2013

Fukushima Update, August 2013

Water, water everywhere, and not a drop…

Two and a half years after the nuclear accidents at Fukushima, things are in worse shape than when the earthquake and tsunami hit.  Although it is difficult to really know what is going on there, we know the containment and cleanup is going rather poorly.

The six reactors there each suffered different kinds of accidents.  The two most serious ones were the damage to the core of the reactor in Unit 1, and the damage to the spent-fuel pool of Units 2&3.  In both cases, the immediate need has been, and continues to be cooling the fuel to keep it from melting.  Hence, large amounts of water continues to be pumped into these two facilities, resulting in the outflow of large amounts of radioactive contaminated water.  Under ideal conditions, this water would be captured, filtered, and then released.  A few glitches have come into play.

First of all, the buildings and structures are severely damaged, and the contaminated water is flooding the below-grade basements, and leaking into the groundwater below the plants.  Second, the earthquake altered some of the groundwater flows, so that it is now leaking in to some of the substructures of the plants, increasing the amount of water that has to be dealt with.  Third, the volume of radioactive water to be treated is far greater than the technical capacity available.  They have built over a thousand tanks to store the water for future treatment; and they will continue to add more tanks  for more water.  The problem is that some of the early tanks are already starting to leak.  “Tokyo Electric Power Co. says about 300 tons (300,000 liters, 80,000 gallons) of contaminated water leaked from one of the tanks, possibly through a seam (1),” and that highly radioactive water is getting into the groundwater, which will eventually reach the ocean.  The site of one of the leaks has soil contamination at such a high concentration, that a worker dealing with that leak would receive in one hour his maximum exposure dose allowable in five years.  “Masked workers found puddles with radiation readings of 100 millisieverts an hour near makeshift tanks that store contaminated water – enough to induce radiation sickness in less than 12 hours (2).” 

What to do?  Tepco has suggested building an ice dam all around the entire plant…they would put pipes down several hundred feet, and 24 inches apart, pump a refrigerant through it, and freeze the soil, blocking the flow of water.  Another option is to put a mechanical barrier down to divert the flow of water to somewhere…!  They are obviously going to have to repair the leaky tanks…maybe they should call on the folks who built the tanks at Hanford. 

The problem boils down to the fact that whatever is going to be done, it will be done in a dangerous, highly radioactive environment that will be technically challenging, very expensive, and putting thousands of workers at risk of the potential biological damages from radiation.  The Japanese government is willing to step in and take its budget surplus of several billion of dollars to help out.  However, this accident will run for decades, and will cost in the hundreds of billions of dollars…far more than the worth of the entire Japanese nuclear program.  Add to that the decommissioning cost of the 50 other idle reactors just in that country alone, and …well nuclear is cheap!

But, it’s only money.  Of greater concern is the potential long-term radioactive contamination of the Pacific Ocean, and the concentration of radioactivity in biological systems and fisheries that the world population is so highly dependent on.

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