Lauriston S. Taylor Lecture: Yucca Mountain Radiation Standards, Dose/Risk Assessments, Thinking Outside the Box, Evaluations, and Recommendations

Abstract

The Yucca Mountain high-level radioactive waste repository is designed to contain spent nuclear fuel and vitrified fission products. Due to the fact that it will be the first such facility constructed anywhere in the world, it has proved to be one in which multiple organizations, most prominently the U.S. Congress, are exercising a role. In addition to selecting a site for the facility, Congress specified that the U.S. Environmental Protection Agency (U.S. EPA) promulgate the associated Standards, the U.S. Nuclear Regulatory Commission establish applicable Regulations to implement the Standards, and the U.S. Department of Energy (U.S. DOE) design, construct, and operate the repository. Congress also specified that U.S. EPA request that the National Academy of Sciences (NAS) provide them guidance on the form and nature of the Standards. In so doing, Congress also stipulated that the Standards be expressed in terms of an "equivalent dose rate." As will be noted, this subsequently introduced serious complications. Due to the inputs of so many groups, and the fact that the NAS recommendations conflicted with the Congressional stipulation that the limits be expressed in terms of a dose rate, the outcome is a set of Standards that not only does not comply with the NAS recommendations, but also is neither integrated, nor consistent. The initial goals of this paper are to provide an independent risk/dose analysis for each of the eight radionuclides that are to be regulated, and to evaluate them in terms of the Standards. These efforts reveal that the Standards are neither workable nor capable of being implemented. The concluding portions of the paper provide guidance that, if successfully implemented, would enable U.S. DOE to complete the construction of the repository and operate it in accordance with the recommendations of NAS while, at the same time, provide a better, more accurate, understanding of its potential risks to the public. This facility is too important to the U.S. nuclear energy program to be impeded by inappropriate Standards and unnecessary regulatory restrictions. As will be noted, the sources of essentially all of the recommendations suggested in this paper were derived through applications of the principles of good science, and the benefits of "thinking outside the box."

Groundwater Radioiodine: Prevalence, Biogeochemistry, and Potential Remedial Approaches

“…These findings from Wilhite et al (1998) and especially from Zvonova (1989) greatly weakens the simplified argument discussed above; namely, 129 I has a long half-life, low biological half-life, and the body can take up only a limited mass of iodine in the presence of an omnipresent background of 127 I. Yet, this argument is often made (Rogers and Associates Engineering Company 1987; Bhattacharyya and Janati 1987;IAEA 1987;Soldat 1976;Kocher 1981;Kocher 1991;Moeller 2005;Cohen 1988). At issue, is that this relatively new finding by Zvonova (1989) demonstrated that at elevated iodine environments, the thyroid shrinks and the rate of uptake decreases, compromising our ability t o m ake linear extrapolations and assumptions regarding thyroid iodine uptake.…”

Geologic Disposal of High-Level Radioactive Waste: Status, Key Issues, and Trends

“…There is ongoing discussion on the uncertainty of dose-torisk factors, caused by the difficulty of assessing health effects resulting from chronic radiation exposure (26,72). It has also been pointed out that health impacts might change in the not-too-distant future because of the expected progress in preventing and curing cancer (73).…”