The Case for Moving U.S. Nuclear Fuel to Dry Storage

One of the lesser-noted facts of the Fukushima nuclear disaster—where loss of coolant in spent-fuel pools has resulted in massive radiation releases—is that some fuel at the plant was stored in so-called dry casks, and these casks survived the March 11 earthquake and tsunami intact.

This fact is likely to result in new calls to move some spent fuel out of water pools at reactor sites in the United States—where it is packed more densely than the fuel in the stricken Japanese pools—and into outdoor dry casks, experts say.

"What will likely happen very quickly is that the [Nuclear Regulatory Commission] and utilities will arrive at a consensus that moving fuel to dry storage needs to be accelerated to get as much spent fuel out of the pools as fast as possible," says Ron Ballinger, an MIT nuclear engineer. In Japan, he says, "the dry storage casks weathered the earthquake and tsunami with zero problems."

The U.S. is home to at least 65,000 tons of nuclear reactor waste, more than in any other nation, and this figure grows by about 2,200 tons each year. "In general, U.S. reactors have a great deal more fuel in their spent-fuel-pools than the reactors at Fukushima

In a pool, by contrast, the proximity of fuel rods to one another causes heat buildup that requires water to be circulated continually. As Fukushima has demonstrated, pumps and their backup systems can fail, and water in spent fuel pools can leak out or boil away.

Over the past three decades, delays in opening a permanent repository for spent nuclear fuel in the United States has led the U.S. Nuclear Regulatory Commission to allow existing spent fuel pools to be "reracked" to increase the density of rods inside them.

Vitrification

A vitrification experiment for the study of nuclear waste disposal

Long-term storage of radioactive waste requires the stabilization of the waste into a form which will neither react nor degrade for extended periods of time. One way to do this is through vitrification.^[23] Currently at Sellafield the high-level waste (PUREX first cycle raffinate) is mixed with sugar and then calcined. Calcination involves passing the waste through a heated, rotating tube. The purposes of calcination are to evaporate the water from the waste, and de-nitrate the fission products to assist the stability of the glass produced.^[24]

The 'calcine' generated is fed continuously into an induction heated furnace with fragmented glass.^[25] The resulting glass is a new substance in which the waste products are bonded into the glass matrix when it solidifies. This product, as a melt, is poured into stainless steel cylindrical containers ("cylinders") in a batch process. When cooled, the fluid solidifies ("vitrifies") into the glass. Such glass, after being formed, is highly resistant to water.^[26]

After filling a cylinder, a seal is welded onto the cylinder. The cylinder is then washed. After being inspected for external contamination, the steel cylinder is stored, usually in an underground repository. In this form, the waste products are expected to be immobilized for a long period of time (many thousands of years).^[27]

The glass inside a cylinder is usually a black glossy substance. All this work (in the United Kingdom) is done using hot cell systems. The sugar is added to control the ruthenium chemistry and to stop the formation of the volatile RuO₄ containing radioactive ruthenium isotopes. In the west, the glass is normally a borosilicate glass (similar to Pyrex), while in the former Soviet bloc it is normal to use a phosphate glass. The amount of fission products in the glass must be limited because some (palladium, the other Pt group metals, and tellurium) tend to form metallic phases which separate from the glass. Bulk vitrification uses electrodes to melt soil and wastes, which are then buried underground.^[28] In Germany a vitrification plant is in use; this is treating the waste from a small demonstration reprocessing plant which has since been closed down.^[24]^[29]

Isn’t Yucca Mountain dry storage?

Didn’t the weenie in the WH recently cave into pressure from Harry Reid (or pay him back for 2008 election help: take your pick) by ruling out a Yucca Mountain nuclear repository?
http://www.lvrj.com/news/nuclear-waste-blue-ribbon-panel-to-start-work-86253967.html

In short, by unilaterally taking off the table the safest location for spent nuclear fuel, didn’t POTUS jeopardize the health and safety of all Americans for short-term political gain?

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