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How is waste disposed of? | Why fission and not fusion? | What happens if a reactor malfunctions? | Links to Additional Information
How is nuclear reactor waste disposed of?
Currently, most spent nuclear fuel rods are stored on-site at the power plant in giant cooling pools. The fuel rods continue to generate heat even after their uranium has finished its fission process. This, however, is only a temporary solution. For high-level radioactive waste, such as spent fuel rods, the plan is that the waste is placed inside of large steel and concrete casks and buried deep inside a geologically-sound site. One such site that has received much attention lately is Yucca Mountain in Nevada.
Lower level wastes (such as waste from radiology departments in hospitals, the clothing worn by nuclear engineers in power plants, etc.) are placed inside sealed containers and buried several meters underground.
Why are our power plants based on fission and not fusion?
Fusion requires that the fuel used be at extreme pressures and temperatures (millions of degrees Celsius). Because it is very difficult to contain matter that reaches those temperatures, large scale fusion reactors for mass-production of electricity have not been built yet
What happens if part of the reactor malfunctions?
When part of the reactor breaks down, such as the moderator or the control rods, an uncontrolled chain reaction can occur. When this happens, heat builds up inside the nuclear reactor core and can melt the fuel rods into a molten state and can also cause an extreme build up of gas pressure. Both of these can have disastrous consequences.
In 1979, the worst nuclear accident in U.S. history occurred at Three Mile Island, just outside of Harrisburg, PA. Portions of the #2 reactor partially melted down. Thankfully, very little radiation was released, and few health effects of this release have been reported.
In 1986, a much more severe accident occurred, in which a large amount of radiation was released, and has led to a large number of health problems. In 1986, a fire in the reactors moderator at Chernobyl in the Ukraine (part of the former Soviet Union) caused a build-up of gases so strong that it blew the 900 ton steel roof off of the containment vessel, allowing radioactive steam and debris to escape into the atmosphere. In the picture below, you can see the damage done to the power plant and the containment vessel.
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