Currently, the most common reactors in the United States are the Boiling Water Reactors and Pressurized Water Reactors, both variants of the Light Water Reactor (LWR). These reactors utilize water as both a coolant to control the fission reaction as well as to generate steam to turn turbines, generating electricity. In a Boiling Water Reactor, the water evaporates in the same vessel it comes in contact with the nuclear fuel. In a Pressurized Water Reactor, the superheated water is kept under high pressure until it reaches a secondary chamber, where it then evaporates. [1]
Used uranium fuel can be recycled to create more useable fuel. Recycling nuclear fuel would create a closed fuel cycle, which would reduce the need for uranium mining and enrichment, reduce the volume of waste in geological repositories, mitigate the risk of proliferation by avoiding the production of separated plutonium, and create a waste byproduct less toxic than single use uranium. Though recycling technology exists today, the majority of countries using nuclear power do not recycle their uranium fuel. This is because the supplies of uranium are high and the prices are low, thus making it uneconomical to recycle. Experts predict that recycling uranium fuel will become more prominent as the price of maintaining an open fuel cycle rises.[2]
Used nuclear fuel is a toxic, long-lived byproduct of nuclear power generation – some components of this spent fuel can be radioactive for millions of years. Over time, several methods of disposing of spent nuclear fuel have been proposed, including sealing it in canisters on the bottom of the ocean and sending it to a toxic waste repository on the moon. Many of these alternatives were either non-environmentally-friendly or cost prohibitive. Experts decided that the best storage method would be a deep geologic repository, in which the nuclear waste is placed in shielded containers underneath bedrock in order to prevent any radiation from leaking into the surrounding environment. The isolated waste would slowly decay and become less radioactive after time, until it may ultimately be disposed.
Unfortunately, the United States has not yet built the planned Yucca Mountain geologic repository. In the interim, nuclear waste is stored on-site at nuclear power plants around the country. It is first placed in a concrete-lined pool of water to cool the spent fuel and shield workers from radiation. After this, it is placed in dry steel and concrete storage containers in a concrete bunker.
Research by Margaret Rich
