Environmental Engineering Reference
in a reactor over a period of time, usually about 3 years, and have lost their
ability to provide enough energy. This spent fuel is still radioactive and
must be shielded to prevent any release.
Spent fuel is stored in shielded basins of water or dry vaults. As the
radioactive decay drops to safe levels, it may take hundreds to thousands
of years. Nuclear waste containers are designed for an underground stor-
age period of at least 10,000 years. Spent fuel will be stored on a perma-
nent basis once a national repository is approved. The planned nuclear
waste facility at Yucca Mountain is still involved in ongoing debates and
studies. The opening of a national long-term storage site is becoming de-
cades behind schedule because of opposition.
Other countries, such as France, have progressive nuclear fuel recy-
cling programs where a large percentage of the unused uranium and the
small amount of plutonium produced in the spent fuel is salvaged and
then processed into new reactor fuel. According to the Nuclear Energy In-
stitute (NEI), only 3% of spent fuel is waste. Another 96% is unused ura-
nium and 1% is unused plutonium created during the fuel cycle.
Nuclear fuel recycling allows more efficient nuclear fuel usage and
less buildup of nuclear waste. Nuclear power reactors are designed to
minimize plutonium build up and much of the plutonium that is pro-
duced inside the reactor is used during an ordinary fuel cycle.
It is highly improbable that a nuclear fission power plant would ever
explode like a nuclear bomb, but a loss of coolant accident could result in
a melt down condition. In a melt down, a large amount of radiation can
be released at ground-level. A nuclear or conventional chemical or steam
explosion could disperse much of the radioactive particles into the atmo-
sphere. This is essentially what happened when the Chernobyl gas explo-
sion occurred in the Soviet Union in 1986.
Highly publicized nuclear accidents such as those that occurred at
Chernobyl and Three Mile Island must be considered anomalies. Nuclear
power plants have multiple safety measures in place to prevent radiation
leaks. The small amount of radioactive waste produced by nuclear reac-
tors is controlled and usually contained in the plant facility.
Fossil fuel electrical power plants can be more hazardous to hu-
mans than nuclear power plants because of the pollutants. A 1,000 mega-
watt (MW) coal-fired power plant releases about 100 times as much ra-
dioactivity into the environment as a comparable nuclear plant. A 1,000-
MW power plant will use 2,000 railroad cars of coal or 10 supertankers
of oil but only 12 cubic meters of natural uranium every year. Fossil fuel