ANS President Mary Lou Dunzik-Gougar took to the video screen on November 18 during the 2020 ANS Virtual Winter Meeting for the President’s Special Session on radiation risk, echoing a comment by Exelon Nuclear’s Bryan Hanson, the Winter Meeting’s general cochair, who earlier in the week characterized radiation as one of the most misunderstood aspects of nuclear.
“I think that’s very true,” Dunzik-Gougar said. “So much misconception and misunderstanding. I have always had a passion for communicating about such things as radiation, helping people understand the nature of radiation and the relative risks of nuclear, but mostly about its benefits. But I think we in the industry can better prepare ourselves with knowledge about radiation and its impacts and also educate ourselves on how to talk about the risks of radiation with people not in our own echo chambers to help change the perception among a broader scope of people.”
The panel of experts assembled to help impart some of that knowledge to session attendees included Amir A. Bahadori, assistant professor at Kansas State University; Donald A. Cool, a technical executive at the Electric Power Research Institute and a former senior executive at the Nuclear Regulatory Commission; Paul Locke, associate professor at the Johns Hopkins Bloomberg School of Public Health; and Shaheen Dewji, assistant professor at Texas A&M University.
Data: First up was Bahadori, who focused much of his talk on cancer, calling it “the most prominent health effect that people are concerned about when it comes to low-dose radiation.” He stressed that “life itself” is carcinogenic, noting that the lifetime incidence risk for cancer is about 40 percent for males and females, and that the lifetime mortality risk is approximately 20 percent. He also pointed out that lifestyle choices are associated with about 40 percent of cancers.
“In terms of what we know about low-dose radiation and cancer, what we’re talking about here is less than 100 millisieverts or milligrays for low-LET [linear energy transfer] radiation acute and less than about 5 milligrays per hour in terms of the low-dose rate,” he said. “These are associated with relatively small lifetime risks. We know this information from cancer epidemiology studies. The lifespan study of the atomic bomb survivors has long been considered the gold standard, showing statistically significant increases in cancer incidence in mortality down to about 100 millisieverts.
“Now this has been criticized because of the largely acute nature of the exposures, and so in recent years, particularly since the issuance of the Beir VII report, there has been a heavy focus on lower dose rates and lower doses, and rightly so.”
According to Bahadori, one of the most prominent recent studies is the INWORKS multinational cohort study, which showed career doses of approximately 50 millisieverts resulting in small increases in risk. (For more information on epidemiological studies of low-dose radiation and cancer, Bahadori recommends the National Council on Radiation Protection and Measurements’ Commentary No. 27, published in 2018, and the July 2020 issue of the Journal of the National Cancer Institute Monographs. Both publications, he said, look at the quality of these studies, as well as their biases, which can impact risk estimates.)
Bahadori also said that in the existing radiation protection framework, various panels of experts take into account the most up-to-date epidemiology and radiobiology observations, “and you have to do some evaluation on study quality and biases in order to do this properly. Not everything that makes it through peer review is gospel.” He added that the panels summarize findings and try to summarize the uncertainty associated with the different parameters that are used for radiation protection. Ultimately, he noted, these recommendations are used to implement and enforce radiation protection in the most ethical way possible.
The “three pillars” used in order to accomplish that, Bahadori explained, are justification—the exposure is justified; limitation—doses are limited so that deterministic tissue reactions are prevented and stochastic effects are kept to an acceptable level; and optimization. “Not minimization,” he said. “ALARA [as low as reasonably achievable] is optimization, and that’s really what we want to get to.”
Regulation: Former NRC official Cool termed the path between basic research studies and regulations “a very tortuous process” that can take decades to traverse. “While we might all wish that we could take some science and immediately put it into application, that’s really not the case,” he said. “It’s a very careful, deliberative process, with reasons to make sure that we’ve carefully vetted and thought through the implications of things. It includes early public consultations, proposed rulemaking, final rulemaking, and implementation.”
During that process, several considerations emerge, Cool noted, the first being risk assessment. A series of questions need to be asked: What is the risk? How likely is it? What are the consequences? Can the results of a research study be reproduced and generalized, distributed from one population to another population? “No two of us are the same,” he said, “so why should we think that each individual’s exposure to radiation should be the same?”
Another consideration is risk management. With risk management, Cool said, “you start to do things that are really very different from risk assessment. Instead of just trying to figure out what the risk is, you’re starting to look at how do we take that and actually try to manage risks for individuals or populations. You have to start bringing in other factors. It’s not just the science. What are the experiences, what are the learnings that we have? Radiation protection started because the early radiographers discovered that they were burning their hands. So they started to take actions to eliminate that effect. We just keep learning and growing and applying and responding to things.”
Ethics are also important, Cool said. “What are people thinking about? What’s important to people? How do you involve people? Because in the end, the objects of protection are not really objects, they’re people—ourselves, our friends, our neighbors.”
Communication: Locke’s comments dealt with how best to communicate the risk of low-dose radiation to non-scientists and non-engineers. He began with a little myth-busting:
■ Myth: Radiation-risk communicators need only concern themselves with providing scientific and engineering truth.
Fact: Effective risk communication should not be focused on filling the deficits in people’s knowledge of radiation. “We instead need to be seeking to engage in a dialogue with people and communities, because risk communication has got to be a two-way street,” Locke said. “We need to really find out and get to the bottom of what people are concerned about. Often, fears of radiation are covers for other issues, and these tend to be social justice and fairness issues.”
■ Myth: People want to hear from experts and learn about science and engineering.
Fact: Trust is more important than technical expertise, particularly at first. “People need to know that you care, before they care what you know,” Locke said, quoting risk communicator Vincent Covello. “Communication efforts always need to start with a conversation, an information exchange, where you create a level playing field with people and communities.”
■ Myth: People irrationally fear all radiation.
Fact: People are concerned with certain sources of radiation and generally judge the danger of the radiation based on the source. “For example, radiation that comes from industrial sources, like nuclear power plants, or from radioactive waste, is often perceived as more dangerous and risky than the same level of radiation and the same type of radiation coming from naturally occurring sources or from diagnostic or therapeutic radiation,” Locke noted. “Now, we all know this assumption is wrong, of course, but it is the way people think of radiation, and we have to face that fact.”
In Locke’s view, the first thing that needs to be done when communicating radiation risk is to think about how to structure the conversation. “We really need to find out, right out of the box, what matters to people in communities,” he said. “It might take some time, and it might take some effort to gain trust and understand community needs, but once that threshold is crossed, you then have an opportunity to share your knowledge, and you can find that you’ve a receptive audience.”
Gaining the trust of people or communities will make it much easier for the nuclear advocate to introduce concepts of low-dose radiation risks and hazards into the conversation, according to Locke. “And it’s also going to be possible to introduce other ideas that are really important, such as the reasons why we use nuclear technologies,” he added.
It is also useful, Locke said, to think about the “big picture,” i.e., the role of nuclear in moving toward a decarbonized energy future. “We need to position low dose and low-dose rate questions within this larger issue and other larger issues,” he said.
A low-dose program: Dewji, a former chair of ANS’s Radiation Protection and Shielding Division and an advocate for resurrecting the DOE’s low-dose radiation research program, suggested the following for structuring a low-dose program:
■ Maintain scientific infrastructures.
■ Integrate epidemiological studies with the basic sciences and with dosimetry and risk communication.
■ Design well-controlled molecular epidemiological studies.
■ Address concerns of the public, as well as radiation workers, related to low-dose risks.
■ Support research on mechanisms of radiation actions and multi-scale biology.
■ Educate and train future generations of radiation and protection experts/researchers.
■ Effectively communicate risks to the public.
Placing special emphasis on the last two points, Dewji stated, “If we are not able to develop a generation or a next generation of subject-matter experts to make high-level policy decisions and communicate with the public, how is it that we are going to be able to make important policy decisions or refine our radiation protection regulations? I think that from a public perspective, our next generation, especially our students, become our most innocuous ambassadors, and so we should be fostering their expertise.”
Dewji said that the principles of the radiation protection philosophy outlined by the International Commission on Radiological Protection (ICRP)—justification, optimization, and limitation—must be properly examined. “One string that I want you to pull here is that optimization is not minimization,” she said. “And we need to really focus on this as a professional society. . . . We can’t just have a very simplistic interpretation of dose minimization, but instead, practices in radiation protection have to be inclusive of broader societal benefit, so that they can be economic and social as comprehensively and originally envisioned by our system of radiation protection.”
Dewji also called for the United States to harmonize its system of radiation protection with that of the ICRP. “This might be a little bit provocative,” she said. “Our NRC system is using regulations from the 1990s and older and using ICRP Publications 26 and 60. And the EPA is moving toward developing the federal guidance that will hopefully be translated to the other federal agencies, reflecting the most recent recommendations from ICRP under Publication 103.
“This also poses a question: How does detriment from 1 millisievert from ICRP 60 compare to one millisievert from ICRP 103? And what is the impact if we have different regulation generation being implemented in different federal authorities? So there might be a consideration to open rulemaking, which might also be another provocative recommendation.”
Regarding the linear-no-threshold (LNT) model, Dewji said that “we need to stop throwing stones,” and offered criticism of the original text of the ANS Grand Challenge initiative’s call to establish a scientific basis for modern low-dose regulation. “In the original text of the Grand Challenge, it says specifically to replace the current LNT approach with a modern science-backed model for nuclear radiation safety,” she said. “As a scientist, I say that this is a fallacious statement, because you are putting the conclusion that LNT is not a possible scientific hypothesis. We do need to discern that it is currently being used as a regulatory model, and some of the studies looking at 1 million workers and veterans that is being conducted by the NRC say that their data is certainly consistent with LNT.”