Radiation in Perspective
radiation is energy particles given off by unstable
atoms as they undergo radioactive decay to stabilize.
radiation given off by the radioactive materials
in commercial nuclear power plants is called ionizing
radiation. That means that it causes ion pairs
(positively and negatively charged particles)
to form in the cells that the radiation encounters.
It is important to understand that ionizing radiation
from nuclear power plants is the same as ionizing
radiation from other possible sources, such as
cosmic radiation, medical treatments and the naturally
occurring background radiation from the soil and
building materials around us.
Low-level ionizing radiation is measured in units called millirem (1/1000 of a REM). The average exposure to people living in the US
is approximately 620 millirem per year, (NCRP Report 160, "Ionizing Radiation Exposure of the Population of the U.S." Most people in the U.S. receive about 250-310 millirem per year from
natural background radiation. The sun and stars give off radiation called cosmic radiation and most of us receive about 31 millirem a year from this source. We get another 28 millirem from the
naturally occurring radioactive materials in building materials (usually bricks, stone and mortar) and the soil. There is an additional 229 millirem from the air we breathe, largely from radon.
Medical treatments and examinations are another source of radiation exposure for many people and contribute more than 50% of the average
person's exposure. The majority of medical exposures are from Computerized Axial Tomography, (CAT Scan) and Nuclear Medicine procedures. A chest X-ray is generally about 10 millirem, while a
dental X-ray is usually about 9 millirem.
average person living within 50 miles of a commercial
nuclear power plant will receive about .001 millirem
of additional radiation exposure on an annual
basis. Even people living within a few miles of
a plant rarely get as much as 1 millirem per year.