Power Generation - Hydrogen and Fuel Cells: Advances in Transportation and Power - page 210

plants can produce thousands of tons of noxious gases, particulates, and
heavy metal bearing radioactive ash along with solid hazardous waste.
There are up to 500,000 tons of sulfur from coal, more than 300,000 tons
from oil, and 200,000 tons from natural gas. A 1,000-MW nuclear plant
releases no noxious gases or other pollutants and much less radioactivity
per capita than is encountered from airline travel, a home smoke detec-
tor, or a television set.
While nuclear power plants use multiple layers of protection from
the radioactive particles inside the reactor core, a serious accident can
cause the release of radioactive material into the environment. It is not
a nuclear explosion, because the uranium fuel used in a nuclear power
plant does not contain a high enough concentration of U-235. For an ex-
plosion to occur, the uranium fuel inside the reactor would have to be
enriched to about 90% U-235, but it is only enriched to about 3.5%.
The amount of radiation that is emitted by nuclear power plants,
with their thick shielding is quite low. Environmental Protection Agency
(EPA) guidelines limit the annual whole body dose to 25 millirems for
uranium fuel operations. The National Council on Radiation Protection
and Measurements (NCRP) and the EPA estimate that the natural back-
ground radiation from the Earth's crust is about 23 millirems per year
at the Atlantic Coast and 90 millirems per year on the Colorado Plateau.
Radiation inside the human body is about 40 millirems per year from the
food and water we take in and can be up to 200 millirems per year from
radon in the air. The annual radiation dose from outer space can be 26
millirems at sea level or 53 millirems at elevations of 7,000 to 8,000 feet.
The dose from a medical X-ray is about 20 millirems, and the dose from
a 1,000-mile airline flight is about 1 millirem. A cross country air trip
and return can be more than 5 millirems. We can also receive 1-2 milli-
rems annually from watching television or using computers and can get
another 7 millirems each year from living in a brick building. We could
receive .03 millirem annually by living 50 miles away from a coal-fired
power plant, but only .009 millirem by living 50 miles away from a nu-
clear power plant.
Radioactivity, radioactive elements and nuclear reactors are found in
nature. There are at least 14 natural fission reactors in the Oklo-Okelobon-
do natural uranium formation in Gabon on the west coast of Africa. These
fossil reactors had sufficient amounts of U-235 to allow chain reactions to
occur.