A recent study by MIT scientists has quantitatively compared the environmental release of iodine-129 (I-129), a long-lived radioactive isotope, under different nuclear waste management approaches worldwide. Iodine-129, which remains radioactive for millions of years and can accumulate in human thyroid glands, poses significant risks if released into the environment.
In the United States, spent nuclear fuel containing I-129 is planned to be safely isolated in deep underground repositories, a strategy found to minimize long-term release substantially. Conversely, France routinely discharges low-level radioactive iodine-129 into oceans through its nuclear fuel reprocessing plants, releasing approximately 153 kilograms annually—within regulatory limits but resulting in measurable, low-level contamination of nearby waters like the English Channel and North Sea.
The study examined three scenarios: direct deep underground disposal as in the U.S., dilution and release used by France, and a filter-based capture method followed by shallow disposal. Findings indicate that France’s dilution practice releases about 90% of iodine-129 into the biosphere, while the U.S. underground disposal method limits release to minute fractions over one million years. The filter-capture approach reduces environmental emissions but carries risks of future human intrusion in shallow disposal sites.
Researchers also analyzed environmental concentrations of iodine-129 near reprocessing and disposal sites, warning that while dilution can lower contaminant concentration by spreading it out, localized disposal failures risk higher human exposure. They urge careful design of waste isolation to protect communities and highlight the importance of enhanced waste capture technologies.
This research, published in Nature Sustainability, emphasizes balancing nuclear energy benefits with robust waste management strategies, recommending increased filtration and responsible disposal to mitigate long-term radiological impacts worldwide.
The study shines light on the complexities and trade-offs in nuclear waste policy decisions globally, contributing valuable insights for policymakers and the nuclear industry on minimizing iodine-129’s environmental footprint.
Author
