Spent nuclear fuel and high-level radioactive waste are
materials from nuclear power plants and government defense programs.
These materials contain highly radioactive elements, such as cesium,
strontium, technetium, and neptunium.
Some of these elements will remain radioactive for a few years,
while others will be radioactive for millions of years.
Scientists worldwide agree that the safest way to manage these
materials is to dispose of them deep underground in what is called
a geologic repository.
To make electricity, nuclear reactors use fuel made of solid ceramic
pellets of enriched uranium that are sealed in strong metal tubes.
The tubes are bundled together to form a nuclear fuel assembly.
The uranium pellets are about the size of the tip of your little
finger. Although small, the pellets release a tremendous amount
of energy when used in a nuclear reactor. For example, one pellet
has an amount of energy equivalent to almost one ton of coal.
The energy released by the nuclear fuel produces great heat, which
boils water into steam. The steam turns giant turbines, which generate
the electricity. About 20 percent of the nation’s electricity
is generated by nuclear power.
After three or four years in a reactor, however, the uranium pellets
are no longer efficient for producing electricity and the assembly
is removed from the reactor. After removal, the entire assembly
(now called spent nuclear fuel) is highly radioactive.
All nuclear reactors produce spent fuel. Currently, there are reactors
at commercial power plants, at government research facilities, and
on about 40 percent of the U.S. Navy’s submarines and ships.
If we were to take all the spent fuel produced to date in the United
States and stack it side-by-side, end-to-end, the fuel assemblies
would cover an area about the size of a football field to a depth
of about five yards.
When spent fuel is first removed from a reactor, it is placed in
a special pool of water contained in a steel-lined concrete basin.
The water cools the spent fuel and protects workers and the public
After it has cooled considerably, some commercial power plants
and government facilities move the fuel to dry-storage containers
made of steel and/or concrete to shield radiation.
The containers are either placed upright on concrete pads, or stored
horizontally in metal canisters in concrete bunkers.
With the end of the Cold War, the United States has been working
to close and clean up obsolete weapons plants and dispose of nuclear
weapons materials. This has created a need to dispose of highly
radioactive material associated with weapons production. This material
is called high-level radioactive waste.
Until the late 1970s, the United States acquired materials for
nuclear weapons by reprocessing spent nuclear fuel from government-owned
nuclear reactors. Reprocessing is a method of chemically treating
spent fuel to separate out uranium and plutonium. The byproduct
of reprocessing is a highly radioactive sludge-like residue.
The Department of Energy will not ship such residue to a repository
until it is solidified and sealed in stainless steel canisters.
* All high-level nuclear waste is currently stored at government
Nuclear waste must be properly managed to minimize risk to the
environment and to the health and safety of future generations.
Since the mid-1940s, spent nuclear fuel and high-level radioactive
waste have accumulated throughout the country. Currently, they are
stored in temporary facilities at some 121 sites in 39 states. These
storage sites are located in a mixture of urban, suburban, and rural
environments — most are located near large bodies of water.
In the United States today, over 161 million people reside within
75 miles of temporarily stored nuclear waste.
Current storage methods shield any harmful radiation and are presently
safe. However, modern aboveground storage structures are designed
for temporary storage only, and will not withstand rain, wind, and
other environmental factors for the tens of thousands of years during
which the waste will be hazardous.
For decades, experts throughout the world have studied many options
for permanently disposing of nuclear waste — including:
- Leaving the material at current storage sites
- Burying it in the ocean floor
- Putting it in polar ice sheets
- Sending it into outer space
- Placing it deep underground in a geologic repository
After analyzing these options, most scientists agree that disposal
in an underground repository is the best long-term solution for
safely managing highly radioactive wastes.
This opinion is reflected in a 1990 report from the National Research
Council of the National Academy of Sciences, which states that there
is “a worldwide scientific consensus that deep geological
disposal, the approach being followed by the United States, is the
best option for disposing of highly radioactive waste.”
In 2001, the National Research Council again reaffirmed that conclusion:
“Geologic disposal remains the only scientifically and
technically credible long-term solution available to meet the need
for safety without reliance on active management.” **
As long as nuclear waste remains in a solid form and is properly
shielded, it will not harm people or contaminate the environment
— and over time it produces less and less radiation. The idea
behind deep geologic disposal, therefore, is to keep the waste as
dry and isolated as possible, for as long as possible, so that its
radiation can diminish to safe levels.
Isolated in a deep underground repository, the waste would not
be subject to the many environmental factors that on the earth’s
surface would cause it to break down into radioactive particles
that could be dispersed by air or water into the accessible environment.
Nuclear Waste: The Facts
Spent nuclear fuel and high-level radioactive waste present
a challenge society must address. The Department of Energy
bases its plans for a proposed repository at the Yucca Mountain
site on several key facts about the radioactive materials
that would go into it. Among these facts are the following:
Key Fact: The wastes DOE plans to put in the proposed
Yucca Mountain Repository are solid (not liquid).
The nuclear waste destined for disposal at a repository will
be in the form of solid metals, ceramics, and glass with small
amounts of radioactive gases.
Key Fact: Spent nuclear fuel and high-level radioactive
waste cannot cause an explosion.
Spent nuclear fuel and high-level radioactive waste are not
explosive. Even if these materials were involved in an explosion
(like a transportation accident involving an oil tanker),
it is physically impossible for them to cause a nuclear chain
reaction like a nuclear bomb.
Key Fact: Spent nuclear fuel and high-level radioactive
waste are not flammable.
Since these materials are composed of metals, ceramics, and
glass, they cannot fuel a fire.
* In the U.S., all nuclear waste must be in solid
form before it can be shipped to a repository.
** Board on Radioactive Waste Management, Rethinking
High-Level Radioactive Waste Disposal, National Academy Press:
Washington, D.C., 1990, p. vii. And: Disposition of High-Level
Waste and Spent Nuclear Fuel: Continuing Societal and Technical
Challenges, National Academy Press: Washington, D.C., 2001,