Safety & Security of Commercial Spent Nuclear Fuel Storage
Spent nuclear fuel rods contain the highly radioactive waste by-product from
the uranium pellets in the rods, which have fissioned as result of a controlled,
sustained nuclear reaction in around 100 commercial nuclear reactors around
the United States.
The used fuel is no longer considered efficient in creating electricity, because
its fission process has slowed, but is still thermally hot. Until these isotopes,
which include plutonium, decay, they are harmful and require careful
handling and monitoring. They are put into long-term storage, not disposal..
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Water-Pool Storage
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Steam is released from the heat of a nuclear reaction. Currently, most spent fuel rods are stored under at least 20 feet of water at
the nuclear reactor. According to the Nuclear Regulatory Commission (NRC), the water-pool option provides "adequate" shielding from the radiation for
anyone near the pool.
Current regulations permit the NRC to review and approve increases in the
amount of spent fuel that can be stored in the pool, by reracking of the spent
fuel pool grid for fuel rod consolidation.
Many of these reactor sites are located on or near bodies of water but are
required to have community alert systems in place and be able to withstand
hurricane-force winds. These potential targets are supposed to also be able to
withstand a plane attack.
On-Site Dry Storage
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Fuel rods have to cool more than 12 months before being moved to dry storage. As the cooling ponds fill and fuel rods have cooled at least 1 year, they are placed into special steel canisters, which are filled with inert gas, sealed and tested for leaks. They are then placed in concrete vaults, each the size of a one-car garage to await transportation to long-term storage.
There are no current licensed permanent disposal repositories for this
high-level radioactive waste. Fuel rods are spent and removed from the
reactor about every 12 to 18 months and replaced with fresh fuel. Spent fuel
rods continue to stockpile on-site at the reactors.
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Transportation
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Nuclear waste is transported in canisters across the country. High-level radioactive waste is transported in the special canisters across
country on barges, trains and trucks. Questions remain whether the casks can
withstand a diesel fire or a drop from an overpass, for example. Critics against
the continued creation of nuclear waste argue that the transportation of the
radioactive "dirty bomb" material threatens national security.
Long-Term Storage
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Determining a long-term storage solution for nuclear waste is complicated. The NRC regulates the storage of radioactive waste, but the Department of
Energy is responsible for building the long-term repository. The DOE has met
with setbacks in finding a geologically stable location for the site that will be
safe during the radioactive life of the nuclear waste given the history of leaks
at national radioactive waste repositories. The radioactive isotopes take as
long as hundreds of thousands of years to decay.
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References
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