SREL Reprint #3846

The iodine-129 paradox in nuclear waste management strategies

Haruko M. Wainwright1,2, Kate Whiteaker1, Hansell Gonzalez-Raymat3,
Miles E. Denham4, Ian L. Pegg5, Daniel I. Kaplan6, Nikolla P. Qafoku7,8,
David Wilson9, Shelly Wilson9, and Carol A. Eddy-Dilek3

1Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
2Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
3Savannah River National Laboratory, Aiken, SC, USA
4Panoramic Consulting, Aiken, SC, USA
5Vitreous State Laboratory, The Catholic University of America, Washington DC, USA
6Savannah River Ecology Laboratory, University of Georgia, Aiken, SC, USA
7Pacific Northwest National Laboratory, Richland, WA, USA
8Department of Civil and Environmental Engineering, University of Washington, Seattle, WA, USA
9Longenecker and Associates, Las Vegas, NV, USA

Abstract: Nuclear energy has an important role in the low-carbon energy transition, but the safety of spent nuclear fuel (SNF) management remains a public concern. Here we investigate the interplay between waste management strategies and their environmental impacts with a particular focus on a highly mobile and persistent radionuclide, iodine-129 (I-129), which is the dominant risk contributor from SNF disposal and at existing groundwater contamination sites. The results show that the current recycling practice releases more than 90% of I-129 in SNF into the present-day biosphere using an isotropic dilution strategy, whereas the direct disposal of SNF in geological repositories is likely to delay and reduce the release by 8 orders of magnitude. In addition, our data synthesis of surface water concentrations near four nuclear facilities shows that the release-dilution strategy results in lower concentrations than regulatory standards, while insufficient waste isolation in the past has resulted in locally high concentrations within one site. Our analysis suggests that it is essential to consider effluents more explicitly as a part of the waste, that as society moves from dilution to isolation of waste, the potential risks of waste isolation to local regions should be carefully evaluated, and that excessive burdens of proof could hinder or discourage waste isolation. Comprehensive waste management strategies—considering not just volume but also mobility, isolation technologies and ultimate fates—are needed for persistent contaminants. This study offers valuable insights for optimizing the management of SNF and other persistent contaminants.

SREL Reprint #3846

Wainwright, H. M., K. Whiteaker, H. Gonzalez-Raymat, M. E. Denham, I. L. Pegg, D. I. Kaplan, N. P. Qafoku, D. Wilson, S. Wilson, and C. A. Eddy-Dilek. 2025. The iodine-129 paradox in nuclear waste management strategies. Nature Sustainability 8: 1391-1399.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).