When thinking about radioactive waste, we usually have in mind the radioactive residues from the operation of nuclear power plants at the back end of the nuclear fuel chain. We tend to forget the front end of the fuel chain, i.e., the tailings from uranium mining and milling, and the stocks of depleted uranium. Namely, for each metric ton of spent fuel, we are left to manage (a) 7-8 tons of depleted uranium, (b) roughly 2 tons of uranium dispersed in 600 to 800 tons of tailings, including the decay products of natural uranium. [1], [2] Since both isotopes, U-238 and U-235, are extremely long-lived, their stocks need to be managed essentially indefinitely. Uranium is itself a highly chemo-toxic metal. Besides, U-238 and U-235 produce a series of alpha, beta, and gamma emitters, with different solubilities in groundwater and partly as gas. According to the World Health Organization, “of particular significance for human radiation exposure from drinking-water are the naturally occurring radionuclides that originate from the elements of the thorium and uranium decay series, for example Ra-226, Ra-228, Po-210, Pb-210 and Rn.” While spent fuel and vitrified high-level waste retain most of the attention, and resources, the contamination potential from mill tailings and depleted uranium is much larger, considering that their management approach is short-termed – in comparison to the waste management time frame at the back end of the nuclear fuel chain. Besides, being at or close to the surface, these elements are more susceptible to mobilization than radioactive waste in a deep geological repository. Furthermore, the man-made radioactivity in spent fuel will decrease by several orders of magnitude within relatively short time, i.e. 1000 years. [3] By taking care of spent fuel and vitrified high-level waste, we are taking care of only 10% of the chemical and radioactive contamination from the nuclear fuel chain. Consequently, this workshop intends to put a focus on the safe management of the remaining 90%, i.e., the front-end waste [2]. Comparison will be made with the contamination potential of spent fuel and vitrified high-level waste. The workshop shall identify and discuss the issues that arise, the regulatory and management solutions that are called for, as well as the relevant ethical and financial demands in sustainable development context. It will be completed with a site visit to the former Wismut uranium mining site at Bad Schlema in Saxony (Germany). References [1] Bouttes, J-P, Nuclear Waste: A Comprehensive Approach-1, Fondation pour l’Innovation Politique, (2022). https://www.fondapol.org/en/study/nuclear-waste-a-comprehensive-approach-1/ [2] Pescatore, C., Humanity’s Uranium-238 Inventory: A Significant and Enduring Gamma-Radiation Liability, Nukleonika, Vol. 2 (2025), in press. [3] Hedin, A., How dangerous is spent fuel? Swedish Spent Fuel Management Company, Technical Report SKB-TR-97-13 (1997). https://www.skb.com/publication/13607
Work on previously unquantified aspects of uranium waste is presented, including total burden, gamma fields intensification, connection to ecological safety thresholds, and inequitable distribution of uranium waste risks
Nuclear energy mobilizes uranium far beyond natural levels. While natural uranium deposits are geochemically stable, mill tailings (UMT), depleted uranium (DU), and spent fuel (SF) are chemically reactive, bioavailable, and more likely to contaminate water sources. Per ton of U-235 consumed in fission, 288 metric tons of uranium and 200,000 tons of UMT remain, requiring indefinite management. More than 99.5% of all uranium mined remains a perpetual environmental liability.
Traditionally, uranium is seen as inert due to the long half-lives of U-238 and U-235. However, it is highly chemo-toxic, with drinking water thresholds more constrained by toxicity than radiological risk, even compared to Ra-226. Its impact on freshwater biota is even more severe. Humanity has mined approximately 4.48 million metric tons of uranium, distributed as follows: 8.4% in SF, 19.4% in UMT, and 69.2% in DU. The remaining 3%—reprocessed and low-enriched uranium—is managed similarly to DU. While DU and SF are primarily uranium oxide, mill tailings contain 0.03% uranium and nearly 100% of the equilibrium radioactive progeny of all mined uranium. Real-world cases show groundwater contamination from uranium and its progeny will continue, especially from mill tailings. Over time, radioactive progeny will accumulate in SF and DU, making them prone to additional, similar contamination. Gamma fields from these uranium wastes will intensify, reaching levels tens to hundreds of times above background, posing direct exposure risks indefinitely.
Current uranium waste management is inadequate. Policies focus narrowly on radiological risks, ignoring uranium’s chemical toxicity, mobility in groundwater, and long-term ecological impact. DU and UMT are often treated as industrial byproducts rather than perpetual hazards. A new category, uranium waste, must be recognized, subject to strict containment policies, revised drinking water and ecological standards, and long-term environmental monitoring of dispersion and bioaccumulation.
In the 1970s, a scientific panel under President Jimmy Carter recommended that UMT be managed as strictly as high-level waste (HLW). Yet, for over four decades, their large volume has been used as justification for weaker containment. The premise that higher volume warrants weaker controls is flawed. The vast scale and accessibility of mill tailings make them an even greater cumulative hazard than HLW. With an estimated 3 billion metric tons of UMT spread across thousands of sites worldwide, far stricter management and global oversight are needed. This regulatory failure, unaddressed for 45 years, warrants dedicated sociological studies.
Countries managing only SF shift the larger risks of DU and UMT to uranium-producing regions. Long-term safety must be seen as a shared responsibility. Currently, only 10% of humanity’s uranium waste burden is being addressed. Recognizing uranium waste as a specific category is essential. Beyond categorization, it must be managed with containment standards equivalent to HLW, independent global oversight, long-term ecological monitoring, and deeper engagement with environmental justice. Without these measures, humanity is setting the stage for irreversible and perpetual environmental and health crises.
How to cite:
Pescatore, C.: Time for Uranium Waste: a New Radioactive Waste Category , Third interdisciplinary research symposium on the safety of nuclear disposal practices, Berlin, Germany, 17–19 Sep 2025, safeND2025-77, https://doi.org/10.5194/safend2025-77, 2025.
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The foundation "Center for Mountain Ecology" (Centrul de Ecologie Montana, CEM) foundation has been dedicated to the sustainable development of Romania for over 25 years. A central project of CEM is the website nuclearINFO.ro, which deals with the problems, risks and lack of transparency in the the nuclear energy sector of Romania and in particular of the uranium mining and milling sector. The aim of nuclearINFO.ro is to raise public awareness about environmental damages and financial obligations related to the uranium industry.
An urgent matter for CEM and nuclearINFO.ro is the demand for a modern and transparent environmental monitoring system for the uranium processing site in Rotbav, Feldioara (Brasov County, Central Romania) The foundation criticizes the insufficient care of the operators regarding the radioactive tailing ponds and the lack of rehabilitation of the area. The unclear financing of ecological reconstruction is also a problem. CEM demands the lifting of the confidentiality of data related to radioactive processing procedures.
Despite the ceasing of mining in 2021 due to the insolvency of the state operator, the lack of transparency and appropriate rehabilitation measures continues to exist. This results in significant environmental and health risks, particularly at former mining sites. The Romanian uranium industry faces significant challenges, including the need for critical oversight and comprehensive remediation of past mining activities.
Another problem is the confidentiality of environmental reports on the radiological safety assessment of the sites, which are classified as the intellectual property of the mining company and are not made public. This makes it difficult for the public to get a clear picture of the environmental impacts and financial obligations. Despite international obligations raised by Euratom and the IAEA, Romania publishes information only very sporadically.
In regards to health strain, there is data on the health status of employees of the Feldioara uranium processing facilities. However, these data are deleted 30 years after exposed individuals retire – another transparency gap. This means that long-term health effects on former employees are not traceable. An exception law for the Feldioara location allows employees and individuals within an 8-km radius to retire two years earlier, indicating recognition of health risks. However, no financial compensations for former employees within the nuclear sector in Brasov County is in sight.
Overall, CEM with nuclearINFO.ro highlights the challenges associated with lacking transparency and information provision in the field of nuclear energy in Romania. The secrecy and insufficient publication of data make it difficult for the public to make informed decisions and assess the accountability of the nuclear industry. The work of CEM aims at closing these information gaps and to inform the public The collaboration with international partners and support from NGOs are crucial to increasing transparency and minimizing environmental impacts.
Preparation of the abstract was assisted by the AI project KIPITZ (property of the Federal republic of Germany)
How to cite:
Orleanu, M.: Centrul de Ecologie Montana and NuclearINFO.ro: civic commitment to force transparency in the nuclear industry of Romania, Third interdisciplinary research symposium on the safety of nuclear disposal practices, Berlin, Germany, 17–19 Sep 2025, safeND2025-179, https://doi.org/10.5194/safend2025-179, 2025.
In Canada, radioactive waste is defined as any material that contains a radioactive substance, as defined in section 2 of the Nuclear Safety and Control Act, for which no further use is foreseen. There are four general classes of radioactive waste in Canada with uranium mine and mill waste as a particular class.
Uranium mining and milling in Canada dates back to the mid-20th century, with operations in Ontario, Saskatchewan and Northwest Territories. Currently, all operating uranium mines and mills in Canada are located in northern Saskatchewan. Waste rock and uranium tailings exist at operating uranium mine and mill sites in northern Saskatchewan and at closed or decommissioned sites in Saskatchewan, Ontario and the Northwest Territories. In 2019, the total inventory of tailings is 218,308,905 tons (NRC, 2021). This includes about 201 million tons at closed/ decommissioned sites, and about 17.5 million tons from the operating sites.
In situ decommissioning with a disposal end state is an accepted practice for uranium mines and mills waste. Owing to the large volumes of generated tailings and low activity levels, long-term management of tailings in tailings management facilities (TMFs) adjacent to mines and mills is the only practical option for these wastes. At the newer operations in Saskatchewan, tailings are typically managed in (1) in-pit TMFs that feature hydraulic containment during operation, and passive long-term containment following decommissioning, (2) near surface TMFs that includes construction of dams or embankments with engineered surface to provide long-term containment, and (3) purpose-built underground TMF.
The CNSC requires that planning for TMF decommissioning take place throughout the lifecycle of a mine and mill project. The licensee shall perform a safety assessment to identify any radiological or non-radiological hazards to workers, the environment and the public for decommissioning. From a technical perspective, TMF decommissioning typically involves placement of a cover system and implementation of water management plan. Tailings should be consolidated enough before installing a cover system to ensure long-term stability, minimal settlement, and adequate support for the cover system, and most importantly to achieve a lower target permeability than the purpose-built or natural pervious surround to minimize long-term leaching of contaminants. Safety assessment should consider the potential impacts of seismicity, flooding and climate change. The licensee is responsible for implementing and maintaining the post-decommissioning plans and institutional controls unless that responsibility was transferred to a third party with their agreement and the Commission’s approval.
Historically, tailings were placed in natural containment areas, or disposed of as backfill in underground mines, or placed in engineered surface containment areas. Long-term monitoring and maintenance are ongoing at these tailing sites. Remediation efforts have been carried out at certain sites. For example, Project CLEANS (Cleanup of Abandoned Northern Sites) was conducted to assess and reclaim Gunnar mine and mill site and Lorado mill in northern Saskatchewan, which were abandoned with little decommissioning in mid-1960s.
Reference:
Natural Resources Canada (NRC), 2021. Inventory of Radioactive Waste in Canada 2019.
How to cite:
Zheng, Q. and Nguyen, S.: Uranium tailings management in Canada, Third interdisciplinary research symposium on the safety of nuclear disposal practices, Berlin, Germany, 17–19 Sep 2025, safeND2025-181, https://doi.org/10.5194/safend2025-181, 2025.
Coffee break
Chairpersons: Carlo Dietl, Claudio Pescatore
17:25–18:25
World Café
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