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Gee, Nobody Could Have Foreseen a Problem With the Spent Fuel Rods

Fnord12 tells me it's too late to invest in iodine tablets.

Some countries have tried to limit the number of spent fuel rods that accumulate at nuclear power plants -- Germany stores them in costly casks, for example, while Chinese nuclear reactors send them to a desert storage compound in western China's Gansu province. But Japan, like the United States, has kept ever larger numbers of spent fuel rods in temporary storage pools at the power plants, where they can be guarded with the same security provided for the power plant.

Figures provided by Tokyo Electric Power on Thursday show that most of the dangerous uranium at the power plant is actually in the spent fuel rods, not the reactor cores themselves. The electric utility said that a total of 11,195 spent fuel rod assemblies were stored at the site.


While spent fuel rods generate significantly less heat than newer ones, there are strong indications that the fuel rods have begun to melt and release extremely high levels of radiation.

Tokyo Electric said this week that there was a chance of "recriticality" in the storage ponds -- that is to say, the uranium in the fuel rods could become critical in nuclear terms and resume the fission that previously took place inside the reactor, spewing out radioactive byproducts.

If recriticality takes place, the uranium starts to warm. If a lot of fission occurs, which may only happen in an extreme case, the uranium would melt through anything underneath it. If it encounters water as it descends, a steam explosion may then scatter the molten uranium.

One big worry for Japanese officials is that reactor No. 3, the main target of the helicopters and water cannons on Thursday, uses a new and different fuel. It uses mixed oxides, or mox, which contains a mixture of uranium and plutonium, and can produce a more dangerous radioactive plume if scattered by fire or explosions.


Tell me again why nuclear power's better.

By min | March 17, 2011, 3:36 PM | Liberal Outrage & Science | Comments (1)| Link

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