Session T6a

T6a | Alternative disposal methods: possibilities to simplify the need for a deep geological disposal?

Alternative disposal methods: possibilities to simplify the need for a deep geological disposal?

Main Session Organizer: Allison Macfarlane

Orals

| Wed, 17 Sep, 17:25–18:25 (CEST)|Room Plenary

Posters

| Attendance Wed, 17 Sep, 14:40–15:40 (CEST)|Poster area

Concepts for partitioning and transmutation (P&T) argue that it is possible to reduce significantly the amount of high-level radioactive waste and the half-life of the radionuclides within the waste. Under what circumstances and concepts would it be possible to reduce the safety timeline for nuclear disposal if these technical approaches would be implemented?
This session invites contributions which discuss questions related to P&T and their possible advantages and disadvantages for deep geological disposal strategies.

Orals: Wed, 17 Sep, 17:25–18:25 | Room Plenary

17:25–17:45

safeND2025-121

State of play: Accelerator-driven Transmutation of High-level waste

Friederike Frieß

Pretreatment of waste by partitioning and transmutation (P&T) is repeatedly mentioned in connection with the search for a deep geological repository for high-level radioactive waste from the civilian use of nuclear energy. This approach promises to significantly reduce the requirements and risks associated with a - still necessary - final repository.

Partitioning separates spent fuel into different material streams such as uranium, plutonium and minor actinides. Selected radionuclides are then converted into other (radio)nuclides by nuclear physical transformations, in particular by nuclear fission (transmutation).

The idea of partitioning and transmutation as a technological solution to the challenge of radioactive waste management is not new. It was proposed decades ago. For various reasons, it has not yet been implemented. Then, as now, the question was not only one of technical feasibility, but also one of potential benefits. Nevertheless, the idea of using accelerator-driven systems to transmute certain components of high-level radioactive waste has recently received new impetus.

To implement a transmutation cycle, suitable fuels, irradiation facilities and reprocessing technologies are required. One possibility is a subcritical, lead-cooled system with appropriate reprocessing and fuel fabrication processes. Looking at the individual components, it is particularly interesting to see how the concept has evolved since the original proposals and what approaches have been proposed to solve known problems. However, there is still a lack of experience with the operation of subcritical systems and the use of lead as a coolant. There has also been little progress in the area of fuel fabrication and qualification with high minor actinide content. The necessary separation technology is also not yet available on the required industrial scale.

At the same time, the benefits of a large-scale P&T approach are still unclear at best. There is no doubt that a repository for high-level radioactive waste is still needed. Some of the promised improvements could be achieved independently of a possible transmutation scheme, provided that the associated drawbacks are accepted. The fundamental problem of certain long-lived radionuclides, the safe containment of which must be ensured, remains according to the present state of science and technology.

How to cite: Frieß, F.: State of play: Accelerator-driven Transmutation of High-level waste, Third interdisciplinary research symposium on the safety of nuclear disposal practices, Berlin, Germany, 17–19 Sep 2025, safeND2025-121, https://doi.org/10.5194/safend2025-121, 2025.

17:45–18:05

safeND2025-93

The objectives and scope of the technical and safety options report for assessing the feasibility of shallow disposal on the Communauté of Communes of Vendeuvre-Soulaines (CCVS) site (France, dep. 10)

Bérengère Cordier and Virginie Wasselin

Background to the studies carried out to prepare the report

France currently has solutions for the disposal of VLL and LIL-SL radioactive waste, with surface disposal in operation, and a deep geological disposal solution (Cigéo facility project) is currently under study for IL-LL and HL waste. For LL-LL waste, which represents volumes of over 200,000 m³, Andra has been studying a shallow depth disposal solution in a clay formation for several years.

In France, shallow depth disposal is considered to be the most appropriate solution for the disposal of LL-LL wastes, proportionate to their hazardous nature. In 2013, Andra identified a site with geological characteristics suitable for hosting such a repository (outcropping clay formation), on which geological investigations were carried out. The site is located to the north of the Vendeuvre-Soulaines community of communes (CCVS) in the Aube department (10).

Since, Andra has been conducting studies to design a shallow-depth disposal on this site, which would constitute one of the solutions to manage a part of LL-LL waste. Andra has constituted a report submitted to the French government in March 2024, presenting the studies carried out, the results obtained and the lessons learned regarding the technical feasibility and post-closure safety of a shallow depth disposal in clay formation for waste candidates.

Objectives and scope of the studies

At this early stage of the project's development, Andra has focused its safety studies on the post-closure period including large time scales (over 50 000 years), taking also into account the current environmental issues, constructional and geological aspects of the CCVS site.

To this end, Andra has established a post-closure safety approach for a shallow depth disposal beyond 50,000 years, and applied it to the CCVS site for LLW-LL, in order to assess the radiological impact of the repository on large time scales using a conservative approach. The effects of erosion on the study area over these long time scales were also studied to assess the loss of cover thickness that could occur, with the aim of justifying the 30 m depth at the top of the storage cells to isolate the waste from man and the environment on long enough time scales. To do this, Andra has taken into account the climatic changes that may occur in the very long term, in order to provide a framework for the site's geodynamic evolution. These assessments led to evaluate the waste’s compatibility with a shallow depth disposal and the site's capacity

The Andra’s studies have established the feasibility of shallow depth disposal on this site, for some of the waste studied. In particular, the assessments carried out had clarified the main phenomenological and design determinants driving post-closure performance and safety indicators. These studies have also shed light on the characteristics of a site suitable for the disposal of LL-LL wastes that are not eligible to be disposed of on the CCVS site.

How to cite: Cordier, B. and Wasselin, V.: The objectives and scope of the technical and safety options report for assessing the feasibility of shallow disposal on the Communauté of Communes of Vendeuvre-Soulaines (CCVS) site (France, dep. 10), Third interdisciplinary research symposium on the safety of nuclear disposal practices, Berlin, Germany, 17–19 Sep 2025, safeND2025-93, https://doi.org/10.5194/safend2025-93, 2025.

18:05–18:25

safeND2025-9

Opportunities and risks of partitioning and transmutation of the long-lived fission product I-129

Gašper Žerovnik, Maximilian Becker, and Lena Maerten

The radioactive isotope of iodine, I-129, is among the radionuclides in spent nuclear fuel (SNF) which pose the highest risk of long-term radiation release into the biosphere from the final SNF repository, mainly due to its very long half-life, about 16 million years, and its relatively high mobility. Several possibilities to minimise this risk were proposed in the literature, e.g. additional barriers in the final repository, vitrification or transmutation. The latter two approaches however require the chemical partitioning of SNF, which can lead to additional discharges of radioactive substances to the biosphere. The purpose of this work is, on one hand to estimate the transmutation times, rates and efficiencies of I-129 in different types of irradiation facilities, including thermal and fast reactors, accelerators and lasers, and on the other hand compare the typical releases of I-129 during partitioning and transmutation to the reduction of its inventory by transmutation. The transmutation times were calculated based on typical neutron fluxes and spectra, adopted from the literature, in corresponding irradiation facilities. In addition, for some specific examples with typical light-water reactor fuel, absolute transmutation rates were calculated using a 2D Serpent model of a fuel assembly. Thereby, in addition to the assessment of the I-129 transmutation, its impact on the reactor operation can be observed. In all calculations, nuclear data from the ENDF/B-VII.1 library were used.

How to cite: Žerovnik, G., Becker, M., and Maerten, L.: Opportunities and risks of partitioning and transmutation of the long-lived fission product I-129 , Third interdisciplinary research symposium on the safety of nuclear disposal practices, Berlin, Germany, 17–19 Sep 2025, safeND2025-9, https://doi.org/10.5194/safend2025-9, 2025.

Posters: Wed, 17 Sep, 14:40–15:40 | Poster area

P27

safeND2025-13

Impact of Electrochemical Partitioning & Accelerator-Driven Transmutation of HAW on the Necessity for Deep Geological Storage

Guido Houben

In a recent study commissioned by Germany’s Federal Agency for Breakthrough Innovation, the impact of a plant for electrochemical partitioning & accelerator-driven transmutation developed by the Swiss company Transmutex on the HAW of a specific German interim storage facility was evaluated (www.sprind.org/en/words/magazine/sprind-and-transmutex). Applying such a circular economy concept as we do in all other parts of society enables to recycle most of the so-called waste (ruthenium, rhodium, uranium, cesium, strontium) i.e. no need to store it away.

The non-recyclable HAW would essentially be transmuted within the plant’s minimum operating lifetime of 50 years. Subsequent generations would be protected by reducing the radioactivity of the waste from 1 million to less than 1 thousand years: all minor actinides and the water-soluble fission products such as Se-79, I-129 and Tc-99 would be transmuted to over 99 % in a safe, environmentally friendly and proliferation-resistant process. A solution to the problem of the last core is proposed as well.

A deterministic instead of probabilistic safety analysis of the repository and the reduction in volume of long-lived nuclear waste by almost 90 % should enable further cost savings in interim and (less deep) final storage and consequently geothermal use of the disposal containers.

This concept can particularly be applied in countries like Germany and the U.S. where final storage solutions only exist on paper and have essentially been postponed to the next century.

How to cite: Houben, G.: Impact of Electrochemical Partitioning & Accelerator-Driven Transmutation of HAW on the Necessity for Deep Geological Storage, Third interdisciplinary research symposium on the safety of nuclear disposal practices, Berlin, Germany, 17–19 Sep 2025, safeND2025-13, https://doi.org/10.5194/safend2025-13, 2025.

P28

safeND2025-45

iMAGINE – or why we need to know what influence new technologies can have on the final disposal

Bruno Merk, Lakshay Jain, Omid Noorikalkhoran, Elfriede Derrer-Merk, and Dzianis Litskevich

The way to a final disposal for highly-active waste and the disposal strategy has been laid down in the Standortauswahlgesetz (StandAG) and the Standortauswahlverfahren (StandAV). The core focus has been put on a deep geological disposal for the heat producing waste. However, the mandate from the StandAG is also to examine whether alternative disposal routes could make a positive contribution to the task. Previously, Germany invested heavily in deep geological disposal by concentrating research and development on what seemed to be the in-time choice. However, the decision to delay the site selection process must now be used prudently by examining alternative innovative technologies which could make a positive contribution to final disposal. The delay, coupled with the emergence of novel technologies like iMAGINE - which promise to completely avoid the need for the deep geological disposal for heat producing waste - opens a unique, unmissable opportunity. These new, advanced technologies have the potentially a much stronger influence on the process as well as the final outcome than what has been expected for advanced reactors.

In the wider context, as a society, Germany needs to know how to best solve the waste handling/storage problem; to do this, we need to understand if the very promising, recently published scientific results can be demonstrated to deliver in the real-world.

Due to significant investmentsof the past, modern simulation technologies in nuclear have a very high standard and level of quality assurance for conventional reactors. Even for unknown systems, IAEA gives a trusted standard of ± 10%. But we have to keep in mind, there is a difference between the real-world and the related computer model, which is an approximate abstract representation of the problem. Especially for highly innovative systems like Molten Salt Reactors, there are no specifically developed and validated codes yet. Thus, what we simulate can be a high-quality representation of a maybe incomplete system since we may not be aware of all the relevant phenomena.

The conclusion of this can only be: we need to demonstrate promising new technologies and then evaluate them against the existing solution, deep geological disposal, to understand the potential opportunities.

Only with this acquired understanding can we assure that the required future political decision on the handling of nuclear waste is fact-based, while without this, we can only decide on perception, identity, and/or ideology. Thus, as socially responsible scientists, our aim must be to create the facts on highly society-relevant problems and support political decision making based on scientific evidence-base. As highlighted by Krogsgaard-Larsen et al. in 2011, social responsibility is the "responsibility of scientists of all disciplines to direct their research activities in such a way that they can contribute to the well-being of society and to meeting the challenges of our time".

To support the understanding and to facilitate a scientific discussion a short overview on the key opportunities and technical challenges, as well as a development plan for iMAGINE will be given.

How to cite: Merk, B., Jain, L., Noorikalkhoran, O., Derrer-Merk, E., and Litskevich, D.: iMAGINE – or why we need to know what influence new technologies can have on the final disposal, Third interdisciplinary research symposium on the safety of nuclear disposal practices, Berlin, Germany, 17–19 Sep 2025, safeND2025-45, https://doi.org/10.5194/safend2025-45, 2025.

P29

safeND2025-171

Modular Plasma Mass Separation System for Sustainable High-Level Radioactive Waste Management

Nikola Ganchev and Michel Kreins

The increasing volume of High-Level Radioactive Waste (HLRW) presents significant challenges for storage and disposal, both in terms of cost and environmental safety. A large proportion of the waste consists of low or non-radioactive elements, while most of the radioactivity originates from a small fraction of fission products. For high-level liquid waste, bulk elements account for 98.9% of the mass but only 0.1% of the radioactivity. Similarly, spent fuel (SF) contains over 95% transuranium elements, with fission products contributing 4–5%. Efficient separation of waste into mass groups could dramatically reduce storage requirements and optimize the nuclear fuel cycle.

This study investigates a novel modular Plasma Mass Separation System (PMSS) designed to manage HLRW by leveraging atmospheric pressure Inductively Coupled Plasma (ICP) technology. The system utilizes the principles of a Band Gap Ion Mass Filter (BGIMF), where an axial magnetic field and radial electric field enable ion separation based on mass. Unlike traditional high-vacuum plasma separation, the atmospheric pressure approach enhances scalability and operational feasibility.

One of the core components, the Inductively Coupled Plasma Torch (ICPT), has additional applications beyond mass separation. For instance, it can be used in the thermal plasma treatment of low-radioactivity waste, such as polyvinyl chloride (PVC) and polyethylene (PE), which constitute approximately 80% of the total radioactive waste volume from nuclear power plants. These materials, while contributing minimally to radioactivity, are non-biodegradable and pose significant storage challenges. Thermal plasma treatment using ICPT can achieve a mass reduction of 40% and a volume reduction of up to 99%, offering a practical solution to reduce waste storage needs and enhance manageability.

The proposed PMSS offers a sustainable and versatile solution to radioactive waste management, addressing the dual objectives of reducing storage volume and advancing nuclear fuel cycle efficiency. This work represents a significant step toward cost-effective, environmentally responsible HLRW processing.

How to cite: Ganchev, N. and Kreins, M.: Modular Plasma Mass Separation System for Sustainable High-Level Radioactive Waste Management, Third interdisciplinary research symposium on the safety of nuclear disposal practices, Berlin, Germany, 17–19 Sep 2025, safeND2025-171, https://doi.org/10.5194/safend2025-171, 2025.