Safer Storage for Spent Nuclear Fuel Rods

First of all, what are "spent" fuel rods? "Spent" just means that the fuel rod as reached the end of its life, or is no longer usable and is removed from the nuclear reactor core. Once they're removed, they're replaced by new fuel rods, but where do they end up? The spent rods are still extremely hot, not to mention highly radioactive.

As of current, most spent fuel rods are kept on site in cooling pools. The fuel rods are submerged onto racks in pools of circulating water that draws away the heat from the rods, maintaining stability. But just how safe is this method of containment? Turns out, not very. Should something go wrong, such as a malfunction or natural disaster that causes the water to either leak out of the pool or the circulation to cease, the spent fuel rods would heat the water to the point of boiling and evaporation. If water cannot be replenished efficiently, the rods may become exposed as the water level drops. Increasing temperatures can cause the metal cladding encasing the uranium fuel could rupture and catch fire releasing great amounts of radioactive substances into the environment. The spent fuel rods are held in less adequate containment, so any release of radioactive materials would more than likely reach the outside atmosphere.

What can we do to avoid such a disaster? Well, with more and more spent fuel rods being added to such cooling pools, the risk for overheating is escalating. But, there may be a solution in a safer storage method: Dry cask storage. Spent fuel rods that have been chilling in the cooling pool for more than five years are considered cool and safe enough to move to dry cask storage. A dry cask is made of steel and concrete, with the concrete acting as a radiation buffer, and further cooling of the fuel rod can be accomplished by air flow driven by the heat of the spent fuel.

Dry casks also have their share of security and safety concerns, but with less spent fuel being kept in cooling pools, workers may have more time to compensate for a loss of water in the pool. There would also be more space in the pool, allowing for greater cooling of the spent fuel rods. Finally, if an accident should occur in a cooling pool to which point workers could not reverse the damage, less radioactive material would be emitted from the pool than if the pool was full.

Citation — Literary Source: http://www.ucsusa.org/nuclear-power/nuclear-waste/safer-storage-of-spent-fuel#.VwbRYKQrLIU