By A. David Rossin, PhD
The June 2013 issue of Nuclear News (page 35) carried an article under the heading “Performance Indicators—WANO/INPO 2012 data show reduced radiation exposure.” A pair of companion graphics titled “Collective Radiation Exposure” are presented, one for boiling water reactors and a similar one for pressurized water reactors. What for?
Collective dose is simply not a Performance Indicator” at all.
All U.S. nuclear power plants have as-low-as-reasonably-achievable (ALARA) programs and continue to apply ALARA to their planning and work. Inspection by the Institute for Nuclear Power Operations (INPO) can review the quality of the program. But the total millirems of personnel exposure accumulated over a period of months or years is no indicator of anything. It is certainly neither a measure of health effects nor a predictor of potential cancers.
There is extensive ferment in the radiation research and medical communities about the validity of the Linear Non-Threshold Theory of Radiation Exposure (LNT) that predicts health effects even at very at low doses. Its step-child, Collective Dose, cannot be calculated without the LNT.
Several decades ago, the nuclear industry made a commitment to minimize unnecessary radiation exposure. Several different ideas were devised to guide planning. The survivor is the ALARA concept: which is used at power plants, research laboratories, and medical facilities. Radiation exposure numbers based on personal film badges or other monitoring devices are recorded. Most of the individual doses are very low for radioactivity tasks such as walk downs, inspections, equipment maintenance and calibration checks. With the exception of carefully planned work in identified radiation areas, the exposures are well below any health-based standards. If there are any above-standards exposures, they are promptly reported, analyzed and studied.
We are left with collective dose—a meaningless number. One industry executive told me, “It’s the devil we know.” That devil will bite us if we ever have an accident during which radiation leaks out and any widespread contamination takes place. We have seen the headlines from Fukushima and years ago from Chernobyl, and Three Mile Island as well, even though no worker or civilian was exposed to more radiation than is allowed in the standards for a dental technician.
While ALARA raises awareness of radiation and supports the practice of careful planning and reducing unnecessary exposures, it has been placed on a par with safety, quality, work schedules, and costs by using collective dose itself as a performance indicator.
It is unnecessary and self-defeating to let collective dose dominate the minds of planners and managers. (I remember one NN article a few years ago about the ALARA program at a plant and the manager who chased after “every single little millirem.”)
There have been hundreds of papers at ANS meetings about why and how we should change our approach to radiation exposure and to eliminate the LNT and collective dose, which have perpetuated the use of a fraudulent indicator that bears no relation to the onset or likelihood of health effects or cancer. Instead they have become an invitation to activists, journalists, and opportunistic politicians to raise public fears and doubts about nuclear power.
Editor’s note: Dr. A. David Rossin is a past president of the American Nuclear Society. He holds a doctorate degree in metallurgy from Case Institute of Technology/Case Western.
The above commentary first appeared as a letter to the editor in the November 2013 issue of Nuclear News.