Visualizing Environmental Science

436 CHAPTER 17 Nonrenewable Energy Resources

Protective cover

Lid with metallic seals

Storage cask (neutron shield)

Canister of steel

Spent fuel rods

Cask length: 5.2 m (17 ft

Peter Essick/Aurora Photos )

a. On-site storage casks at the

Prairie Island nuclear power plant in

Minnesota. Each cask holds 40 spent

fuel assemblies (17.6 tons).

b. Details of a storage

cask. Each cask,

designed to last

at least 40 years, is

monitored and will be

replaced if

leakage occurs.

handling. Secure storage of these materials must be guar-

anteed for thousands of years, until the materials decay

sufficiently to be safe. The safe disposal of radioactive

wastes is one of the main difficulties that must be

overcome if we are to realize the potential of nuclear

energy in the 21st century.

What are the best sites for the long-term storage of

high-level radioactive wastes? Many scientists recommend

storing the wastes in stable rock formations deep in the

ground. People’s reluctance to have radioactive wastes

stored near their homes complicates the selection of these

sites. Meanwhile, radioactive wastes continue to accumu-

late. Commercially operated nuclear power plants store

their spent fuel in huge indoor pools of water or in storage

casks on-site. However, none of these plants was designed

for long-term storage of spent fuel (ˆ}ÕÀiʣǰ£™).

Nuclear waste management is the biggest obstacle

to increased nuclear power in the United States and

abroad. None of the 31 countries that currently have

nuclear power plants has decided where or how to dis-

pose of their high-level nuclear waste. Most countries

expect in the long term to dispose of nuclear power un-

derground, but as of 2012, no sites had been selected. It

will probably be years, if not decades, before an under-

ground high-level nuclear waste storage facility is estab-

lished in the United States.

Yucca Mountain In 1982 the passage of the Nuclear

Waste Policy Act put the burden of developing perma-

nent sites for civilian and military radioactive wastes on

the federal government and required the first site to

Radioactive Wastes

Radioactive wastes are classified as either “low level” or

“high level.” Low-level radioactive wastes include glass-

ware, tools, paper, clothing, and other items contami-

nated by radioactivity. They are produced by nuclear

power plants, university research

labs, nuclear medicine depart-

ments in hospitals, and industries.

Four sites—located in Washing-

ton State, South Carolina, Ne-

vada, and Utah—currently store

most of the country’s low-level ra-

dioactive wastes.

High-level radioactive wastes

produced during nuclear fission

include the reactor metals (fuel

rods and assemblies), coolant

fluids, and air or other gases

found in the reactor. High-level radioactive wastes are

also generated during the reprocessing of spent fuel.

Produced by nuclear power plants and nuclear weapons

facilities, high-level radioactive wastes are among the

most dangerous human-made hazardous wastes.

As the radioisotopes in spent fuel decay, they pro-

duce considerable heat and are extremely toxic to or-

ganisms; they remain radioactive for thousands of years,

and their dangerous level of radioactivity requires special

-̜À>}iÊV>ÎÃÊvœÀÊëi˜ÌÊvÕiÊUʈ}ÕÀiʣǰ£™Ê

low-level

radioactive

wastes Solids,

liquids, or gases that

give off small amounts

of ionizing radiation.

high-level

radioactive

wastes Radioactive

solids, liquids, or

gases that initially

give off large amounts

of ionizing radiation.