A frequent commenter on Atomic Insights is a very experienced nuclear professional who often keeps me on my toes by sharing thoughts that are fairly common in our community. I have recently been posting quite a number of blogs on the need to revise radiation protection standards to base them on a more accurate model of the health effects of low level radiation than the current LNT (linear, no threshold) model that essentially says that every dose, no matter how tiny, carries a measurable amount of avoidable risk.
Here is the concluding thought from one of Kit’s comments that expresses what a lot of nuclear professionals believe about the standards that they are required to meet.
I think not exposing workers and the public to fatal exposures is a good thing. When you get right down to it, I think it costs about the same to limit exposure to less than 5 Rem as it does to prevent acute fatal doses.
It is a good thing that TMI met the standard. While Fukushima exceeded the standard by a marginal amount, it was not enough to hurt anyone.
If we can meet standards why lower them?
That is a very good question. Nuclear plant operators and designers are legitimately proud of the fact that we do not expose the public or the plant operators to any harm. We build systems with multiple redundancies and several layers of protection to ensure that we can confidently continue to achieve an incredibly impressive safety record.
No matter how many documented incidents or issues the antinuclear establishment is able to accumulate into their litany of problems, the bottom line for all nuclear power plants outside of Chernobyl is that we have not hurt anyone by exposure to radiation in the history of the enterprise.
However, Kit’s comment exposes a common ignorance about the way that the regulations are currently written and the way that the rules are being applied. The current standards add enormous costs to both the initial capital investment and the continuing cost of operating nuclear power plants. Here is my response to his comment.
Unfortunately, the standard for new reactor plants is not 5 Rem. If it was, perhaps I would not be so adamant that we need to keep pushing the radiation protection community to recognize that the Linear No-Threshold dose response ASSUMPTION is a bad model that does not reflect the reality of how human bodies (not cells) respond to the damage caused by radiation.
Instead of the standard that you and I were taught, which accepted doses of up to 5 rem per year as being perfectly safe for workers the real standard required by NRC regulation is ALARA as set in 10 CFR 50.34(a) which cites numerical examples from 10 CFR 50 Appendix I.
Here is a quote from 10 CFR 50.34(a)(1)
“An application for a construction permit shall include a description of the preliminary design of equipment to be installed to maintain control over radioactive materials in gaseous and liquid effluents produced during normal reactor operations, including expected operational occurrences. In the case of an application filed on or after January 2, 1971, the application shall also identify the design objectives, and the means to be employed, for keeping levels of radioactive material in effluents to unrestricted areas as low as is reasonably achievable. The term “as low as is reasonably achievable” as used in this part means as low as is reasonably achievable taking into account the state of technology, and the economics of improvements in relation to benefits to the public health and safety and other societal and socioeconomic considerations, and in relation to the use of atomic energy in the public interest. The guides set out in appendix I to this part provide numerical guidance on design objectives for light-water-cooled nuclear power reactors to meet the requirements that radioactive material in effluents released to unrestricted areas be kept as low as is reasonably achievable. These numerical guides for design objectives and limiting conditions for operation are not to be construed as radiation protection standards.” (Emphasis added.)
Here are some numbers from 10 CFR 50 Appendix I.
Calculated annual total quantity of all radioactive material – 3 millirems to the total body or 10 millirems to any organ (emphasis added)
Estimated annual air dose (noble gases) – 10 millirads for gamma radiation or 20 millirads for beta radiation
Calculated annual total quantity of all radioactive iodine and radioactive particulates – 15 millirems to any organ
In a world where the average annual background exposure is 300-600 millirem, those numbers are way, way down in the noise of normal variations. They are the numbers that allow antinuclear idiots like Caldicott to scare people by claiming releases in excess of standards. (I am not sure what the regulation writers were trying to say with the statement that Appendix I numbers “are not to be construed as radiation protection standards.” It does not really matter what they were trying to say because the numbers are accepted as de facto standards that must be achieved.)
Unfortunately, the attitude that the radiation protection community has often taken during the past 40 years is a riff on your final statement. Instead of “If we can meet standards why lower them?” the driving question for them seems to have been “If those nuclear plants can meet standards so easily, why NOT lower them even more?” It is the ratcheting down from what were reasonable and affordable protection standards of the 1950s to the completely irrational protection standards of the 2000s that I am so deeply concerned about.
It is the end result of the regulatory ratcheting that makes the equipment required for the nuclear way of boiling water so much more costly than the fossil fuel combustion way of boiling water. We have to keep our emissions to levels that are almost impossible to measure against normal background quantities. Fossil fuel plants require fluid and waste handling systems that are far less complete than ours. Their system purchases stop at an open hole; they dump their problems up the stack or into the ponds where scrubber waste goes or into the landfills where noncombustible ash goes.
Incomplete systems that end in uncovered ponds, ash piles or our shared atmosphere are far less expensive than those that have to meet what is essentially a zero leakage standard under all normal operating conditions and expected operational occurrences – a condition that includes all design basis events.
I am not even sure if the cheap natural gas turbines that are so attractive to corporate leaders are required to do a probabilistic risk assessment or a safety analysis to prove that they can meet whatever low standard is set for their emissions and public hazards.