What is nuclear radiation and is it dangerous?

Tony Armini, PhD.

Naturally occurring radiation has been in our environment since the earth was formed 4.6 billion years ago.  This nuclear radiation is present in the earth’s surface from radioactive elements such as Potassium 40, and Thorium 232 and its daughters (Radon gas).  Another type of natural radiation, called cosmic rays, are also impinging on earth from the sun, stars, and other galaxies. 

The human race and animals evolved over billions of years while exposed to this background radiation and they not only were not harmed but thrived.  The human immune system evolved a mechanism to cleanse the body of any affected cells and replaced them with new ones.  In the past the U. S. Government assumed that radiation effects on humans was linear, meaning no amount of radiation was safe.  Recently the EPA realized that there is a threshold dose of radiation below which there is no detrimental effect at all on humans.  This threshold dose level is now being raised to about 2 to 5 REM per year for the general public. The natural radiation dose is 0.3 REM/yr at sea level and 0.4 to 0.5 REM/yr at an altitude of 1 mile as in Denver Colorado due to additional cosmic rays.1,2

The dose from the Diablo Canyon Power Plant at the perimeter boundary fence is much lower than the natural background at that position.  The reason for this negligible dose is that the radiation from the reactor core is shielded first by several feet of water, then by a thick steel pressure vessel followed by a thick concrete containment dome.  Cancer rates for people living adjacent to a US nuclear power plant have been no different than for the general public.3,4

1 http://web.princeton.edu/sites/ehs/osradtraining/backgroundradiation/background.htm
2 http://www.epa.gov/radiation/index.html
3 Seymour Jablon, MA; Zdenek Hrubec, ScD; John D. Boice Jr, ScD, JAMA 1991;265(11):1403-1408. doi:10.1001/jama.1991.03460110069026
4 http://www.slocounty.ca.gov/Assets/PH/Health+Concerns+from+DCNPP.pdf