Is EPA About To Relax Radiation Protections From Nuclear Power?

Both proponents and opponents of nuclear power expect the Environmental Protection Agency in coming months to relax its rules restricting radiation emissions from reactors and other nuclear facilities. EPA officials say they have no such intention, but they are willing to reconsider the method they use to limit public exposure—and the public's level of risk.
At issue is a 1977 rule that limits the total whole-body radiation dose to any member of the public from the normal operation of the uranium fuel cycle—fuel processing, reactors, storage, reprocessing or disposal—to 0.25 millisieverts per year. (This rule, known as 40 CFR part 190, is different from other EPA regulations that restrict radionuclides in drinking water and that limit public exposure during emergencies. Those are also due for revision.)
"We have not made any decisions or determined any specifics on how to move forward with any of these issues. We do, however, believe the regulation uses outdated science, and we are thinking about how to bring the regulation more in line with current thinking," said Brian Littleton, a chemical engineer with EPA's Office of Radiation and Indoor Air.
Proponents of nuclear power want the EPA to abandon the Linear No-Threshold (LNT) model of radiation risk, which holds that the cancer risk from ionizing radiation is proportional to the dose. Based on LNT, regulators and many scientists consider any additional exposure to ionizing radiation, however small, to increase cancer risk.
EPA officials say the agency is not reconsidering the LNT model.
"The agency support for the LNT concept has not changed," Littleson said during a May webinar for the public (audio), "and this is not one of the topics we are asking you to comment on in this notice of proposed rule making."
But the EPA has not closed the door to considering different levels of acceptable risk to populations, Littleton said.
"We could specify an acceptable risk range within the standard," he said, mentioning 1 excess cancer in 10,000 people, or 1 excess cancer in one million people, as examples of possible risk coefficients.
"Revised risk estimates are now available which provide the most recent and peer reviewed estimates of risk that exposure to different radionuclides pose."
(To see how different risk coefficients result in different standards, compare EPA's strict standard for drinking water to FDA's more relaxed standard for food).
My Forbes colleague James Conca, senior scientist for the Institute for Energy and the Environment at New Mexico State University, believes the radiation emissions permitted by EPA "may increase more than tenfold."
But EPA officials say it's premature to make assumptions.
"We want you to know EPA is not proposing any changes to the standards at this time," said Jessica Wieder of EPA's Office of Radiation. "We've issued the ANPR just to solicit public input and information early as we evaluate whether the standards need to be changed at all."
EPA has concerns about several other deficiencies in the current rule, Littleton said, including:
Water Resource Protection: When the 1977 rule was written, regulators believed exposure to ionizing radiation was most likely to occur through the air. Since then, EPA has had to grapple with leaks of tritium and other radionuclides into groundwater at nuclear power plants and other facilities.
"In addition to finding groundwater contamination in the vicinity of several nuclear power plants, radioactive contaminants including uranium, strontium, and cesium have been found in groundwater in other uranium fuel cycle facilities," Littleton said. "These environmental problems could linger on long past the operational phase of these facilities."
Spent Fuel Storage: When the 1977 rule was written, regulators expected used fuel rods to be stored at nuclear plants for no more than 18 months before being transported to reprocessing plants or a long-term waste depository. Now regulators expect fuel rods to continue to accumulate in increasingly crowded conditions at power plants until at least 2050.
"Since these wastes are stored for much longer duration, there's a possibility that these wastes could contribute to higher public doses," Littleton said. "The agency believes that storage is a covered activity, but if we revise it could be prudent to state that the rule is applicable to long-term storage on site."
Radionuclides: Because regulators in 1977 expected spent fuel to be reprocessed, the rule specifically restricts radionuclides likely to be emitted during reprocessing: krypton-85, iodine-129, plutonium-238 and other alpha emitters. The U.S. no longer considers reprocessing viable for most existing spent fuel.
"Are the radionuclides for which the limits are imposed in the standard still appropriate," Littleton asked, "and if not, which ones should be added or subtracted?"
Alternative Technologies: The 1977 rule applies only to the uranium fuel cycle, so it does not apply to facilities that use other fuels, like thorium, and it may not be suited to emerging technologies like small modular reactors, Littleton said.
"Do small modular reactors pose unique environmental considerations, or do existing limits adequately address concerns with small modular reactors?"
The EPA is collecting public comments on the proposed rule revision until Aug. 3. The public may submit comments at regulations.gov.
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