Final Repository Research Articles

Bioaccumulation of trace elements in marine mammals: New data and transplacental transfer on threatened species

Coastal areas are affected by urban, industrial and agriculture pollutants runoff, wastewater and stormwater discharges, making this environment the final repository of chemical contaminants. These contaminants have the potential to spread out to the entire food chain, impacting marine life and the quality of their habitat. In this aspect, the concept of marine mammals as bioindicators provides an approach to the degree of contamination in the environment and to the identification and management of multiple sources of contaminants. The present study analyzed several elements like As, Ba, Cd, Cr, Cu, Hg, Mn, Mo, Ni, Pb, V and Zn in liver tissue from two dolphin species: Sotalia guianensis, a near-threatened species, and the vulnerable Pontoporia blainvillei. In the study, we also investigated if dolphins (population) recorded using the heaviest urban areas have higher concentrations of contaminants in their tissues. Dolphin samples (n = 40 S. guianensis; n = 97 P. blainvillei) were collected by daily monitoring carried out by Santos Basin Beach Monitoring Project (PMP-BS), from stranded individuals found in São Paulo state. The Spearman's rank correlation showed distinct correlations in the accumulation of trace elements by both species, indicating different sources of exposure to the elements studied or distinct biochemical processes between species. Interspecific and intraspecific variations were observed, possibly related to the individual distribution and feeding habits. Correlations were observed between age and concentrations of trace elements, positive for Cd, Hg and Mo. Finally, our findings indicate high levels of Cu, Zn, and concentrations of As, V and Hg in fetuses, in particular, an analysis was performed on a fetus found inside a stranded individual, indicating placental transfer as the first route of exposure for some elements.

High-level radioactive waste repository: How Geology combined with societal principles can lead to public acceptance—the German experiment

Using nuclear power for civil energy generation was a promising idea in the second half of the 20th century. Compared to fossil fuels, nuclear power results in almost no CO 2 bearing emissions, which are known to have triggered and enhanced the global climate change. However, nuclear power bears other risks, e.g. environmental and health damage caused by radiation, unwanted release of nuclides being transported by water, accidents of nuclear power plants, and not to mention the possibility of non-intended military use. In any case, generating power from nuclear fission will always produce radiating waste, albeit in small amounts. Due to its longevity, this waste is a significant challenge for scientists, politicians and for the international social community to find a repository, which can be considered safe for millions of years and is accepted by the public. As the general consensus is that the rocks of earth crust’s are the best option for a controlled storage, scientists including geologists, geophysicists and hydrogeologists are looking worldwide for safe underground repository sites. Given different political preconditions, the nations, especially in the European Union, have developed different strategies. The following article intends to describe the current strategy in Germany, which is based on a specific “Act on the search for and selection of a site for a final repository for highly radioactive waste” (in short: Site Selection Act) and attempts to learn from mistakes in the seventies. It is our strong conviction that fundamental geological aspects are as important as essential societal principles in order to gain maximum public acceptance.

An introduction to Spent Nuclear Fuel decay heat for Light Water Reactors: a review from the NEA WPNCS

This paper summarized the efforts performed to understand decay heat estimation from existing spent nuclear fuel (SNF), under the auspices of the Working Party on Nuclear Criticality Safety (WPNCS) of the OECD Nuclear Energy Agency. Needs for precise estimations are related to safety, cost, and optimization of SNF handling, storage, and repository. The physical origins of decay heat (a more correct denomination would be decay power) are then introduced, to identify its main contributors (fission products and actinides) and time-dependent evolution. Due to limited absolute prediction capabilities, experimental information is crucial; measurement facilities and methods are then presented, highlighting both their relevance and our need for maintaining the unique current full-scale facility and developing new ones. The third part of this report is dedicated to the computational aspect of the decay heat estimation: calculation methods, codes, and validation. Different approaches and implementations currently exist for these three aspects, directly impacting our capabilities to predict decay heat and to inform decision-makers. Finally, recommendations from the expert community are proposed, potentially guiding future experimental and computational developments. One of the most important outcomes of this work is the consensus among participants on the need to reduce biases and uncertainties for the estimated SNF decay heat. If it is agreed that uncertainties (being one standard deviation) are on average small (less than a few percent), they still substantially impact various applications when one needs to consider up to three standard deviations, thus covering more than 95% of cases. The second main finding is the need of new decay heat measurements and validation for cases corresponding to more modern fuel characteristics: higher initial enrichment, higher average burnup, as well as shorter and longer cooling time. Similar needs exist for fuel types without public experimental data, such as MOX, VVER, or CANDU fuels. A third outcome is related to SNF assemblies for which no direct validation can be performed, representing the vast majority of cases (due to the large number of SNF assemblies currently stored, or too short or too long cooling periods of interest). A few solutions are possible, depending on the application. For the final repository, systematic measurements of quantities related to decay heat can be performed, such as neutron or gamma emission. This would provide indications of the SNF decay heat at the time of encapsulation. For other applications (short- or long-term cooling), the community would benefit from applying consistent and accepted recommendations on calculation methods, for both decay heat and uncertainties. This would improve the understanding of the results and make comparisons easier.

Investigations of aged metal seals for interim storage

Abstract. The storage of spent fuel and high-level radioactive waste in Germany is performed in interim storage containers with double-lid systems. The lids are bolted and equipped with metal seals (e.g. Helicoflex®) to ensure the safe containment of the inventory. The used metal seals have a layered structure consisting of three components as can be seen schematically in the cross-sectional view in Fig. 1. In the centre, a helical spring is positioned that is surrounded by two C-shaped jackets and is mainly responsible for generation of the required restoring force. The inner jacket is made of stainless steel and homogenises the restoring force of the helical spring. The outer jacket is made of silver or aluminium which are both soft metals in comparison to the contact partners (lid and container body). During bolting of the lid to the container body, the seal is compressed. The generated restoring force of the helical spring causes a plastic deformation of the outer jacket and adapts to the surfaces of the lid and the container body. Hence, leakage paths are closed, and the sealing function is generated. Typical durations for existing interim storage licenses in Germany are 40 years, but it can be expected that they have to be extended to longer periods as a final repository will not be available before the end of the running licence periods. This extension of licence periods requires a solid understanding of the long-term behaviour of the seals under storage conditions. To meet this challenge, long-term investigations were started at the Bundesanstalt für Materialforschung und -prüfung (BAM) in 2009. These tests focus on seals assembled in test flanges which are stored at temperatures ranging from room temperature to 150 ∘C for accelerated ageing. The aged seals are tested repeatedly after certain ageing steps, and the leakage rate (as indicator for sealing performance), the remaining seal force, and the useable resilience upon decompression are determined. An update on the performed investigations with respect to earlier publications (Grelle et al., 2019; Goral et al., 2023) will be given, and the implications of the results for resilient, long-term safety will be presented. Additionally, there will be a focus on the currently planned further investigations, and the following question will be addressed. What is additionally needed for evaluation of an interim storage period extension in regard to the used metal seals?

Uranium mining – challenges and lessons to learn for nuclear disposal in view of participation and safety

Abstract. Uranium mining and milling is where the nuclear fuel chain starts. Nevertheless, it is the most disregarded part of this chain when thinking about resilience and safety, both in academic debates and in the process of resource extraction. This workshop aims at addressing this gap in addition to improving our understanding of the lessons we can learn for nuclear waste disposal. Uranium mining and milling is challenging when considering safety, from the first day a mine is in operation to the final day of land rehabilitation. During the operation of the mine and mill, the health of the miners is at risk and so is the well-being of the population living in the surrounding area of the mine and the ore-processing plant. Moreover, environmental issues such as pollution pose a risk during the entire lifetime of a mine. The remnants of mining activities can be regarded as long-term liabilities, since they must be monitored for many generations. Uranium mining and milling facilities are often situated on the land of indigenous people. Their rights to information and their participation in the decision-making processes regarding the mining operations, in addition to being informed about basic health outcomes, were and frequently continue to not be given, leading to injustices by mining companies and governmental authorities. Participation, however, is crucial for positive societal outcomes, such as avoiding the deepening of structural inequalities and the development of violent conflict, and for building trust – and thus also for security. This is not only true for operations at the beginning of the nuclear fuel chain but also for actions taken at the end (i.e., during the quest for the safest possible disposal site for nuclear waste). Based on insights from the processes of uranium extraction, we can draw conclusions about the site selection process of a final repository, specifically regarding licensing, operation and land rehabilitation processes. Bearing this in mind, it is worth having a detailed look at the beginning of the nuclear fuel chain as we move forward to resolve the issues we will face during the final stage of nuclear waste disposal. Learning in this context means looking closely at the processes during the licensing, operation, closure and rehabilitation of uranium mines and mills and drawing conclusions about the site selection process, in particular with respect to inclusion of the individual stakeholders and safety concepts. As a result, we can develop recommendations for the ongoing revision of the search process for a final repository for radioactive waste. Therefore, safety and participation issues are the focus of the uranium mining and milling workshop. The workshop will gather academics and practitioners from different fields in a transdisciplinary setting. We plan about five short inputs (up to 10 min each) based on some visualizations (slides, posters or similar), followed by a World Café related to the input talks and a concluding plenary discussion. The entire workshop will last about 2.5 h. The workshop is topped off by an excursion to the Wismut facilities in Ronneburg (Thüringen/Thuringia, Germany) on the Saturday after the conference. The field trip will be guided by Wismut GmbH, the Church Environmental Group Ronneburg and the local Miners' Association. This workshop will enhance the transdisciplinary capabilities of the participants with respect to the logic and externalities of uranium extraction, in addition to providing opportunities for exchange and networking. We aim to compose a publication format for the Safety of Nuclear Waste Disposal platform, based on the contributions of all workshop participants.

The importance of social science research in nuclear waste management shown by three projects on public participation

Abstract. The disposal of nuclear waste is not only a technical challenge but also a sensitive socio-political issue. Especially in Germany, the search for a final repository for highly radioactive waste is complicated by past and present societal conflicts surrounding the use of nuclear energy. Hence, safe nuclear waste management requires social science research that examines the nuclear waste problem in its social context. We illustrate this claim by presenting the results of three contract research projects dealing with public participation, commissioned by Germany's Federal Office for the Safety of Nuclear Waste Management (BASE). Public participation is central to the safety of nuclear waste management. First, the safety of disposal practices is often improved by the general public's critical input. Second, public participation may increase the acceptability of nuclear waste disposal in a particular region, which is important to ensure the successful implementation of waste management strategies. Third, public participation serves to preserve knowledge and maintain competence, since it keeps the topic of nuclear waste present in people's minds. Therefore, social science research that improves public participation measures makes a significant contribution to the safety of nuclear waste management. This contribution presents three projects that illustrate how social science can improve public participation. The first project surveyed the German population regarding the search for a final repository for highly radioactive waste. The second examined the utility of digital participation tools. The third project dealt with the legal, political, and cultural challenges of cross-border public participation. The first project surveyed a representative sample of the German population. Survey participants answered questions pertaining to the structure and current state of Germany's search for a final repository, their main concerns in relation to this search, and their desire to participate in the search. Results show that Germans are most concerned about safety issues and currently have little desire to actively participate in the search, but instead demand to be well informed. The results of this project allow BASE to adapt its public participation strategy to the German population's needs, thereby increasing its effectiveness. The second project examined the utility of digital participation tools in the context of the search for a final repository. Past events implemented by BASE were marked by the underrepresentation of young people, women, and also people with lower educational attainment and migrant backgrounds. First, the project team carried out a literature review that showed that the use of digital tools does not solve issues of underrepresentation. The team then used focus groups to demonstrate the importance of schools, appealing designs, and gamification when addressing young people. The project ended with a workshop wherein experts discussed the project's results and developed prototypes of digital tools to support BASE's efforts to engage young people. Reaching young people is crucial to preserving knowledge and increasing the acceptability of nuclear waste disposal, since today's younger generations will be affected by and responsible for the final repository. The third project dealt with the legal, political, and cultural challenges of implementing public participation across borders. BASE will have to facilitate public participation in multiple countries if the proposed site for the final repository is in close proximity to Germany's border. The project team first conducted a literature review to analyze the challenges of cross-border public participation. The second part consisted of in-depth case studies of three different planning procedures, conducted in Switzerland, Germany, and the Czech Republic. Finally, researchers conducted five regional case studies, covering regions in Denmark, the Netherlands, the Czech Republic and Poland, Austria, and France. The project resulted in a sketch of a model cross-border participation process, ensuring that BASE will be able to successfully implement such a process. These projects show that social science research can improve the quality of public participation measures. Since public participation is crucial to the safety of nuclear waste management, so are the social sciences.

Proliferation aspects of partitioning and transmutation (P&T) fuel cycles

Abstract. Nuclear fuel is usually irradiated once but sometimes twice (MOX fuel). This procedure leaves a huge amount of spent fuel. Spent fuel is highly radioactive for a long time. Deep geological repositories are considered the best option for final disposal of this high-level radioactive waste. However, no such repository has been put into operation yet. Several countries consider partitioning and transmutation (P&T) a possible alternative. In P&T nuclear fuel cycles, the spent nuclear fuel is chopped into pieces and separated into different material streams such as plutonium, uranium and minor actinides. This process is called partitioning. From plutonium and minor actinides, new fuel elements are fabricated and used in nuclear reactors. If the overall physical conditions there are favorable, most prominently the presence of a fast neutron spectrum, at least a part of the minor actinides is fissioned and thus transmuted into other, hopefully easier-to-handle, nuclides. Especially when looking at the ingestion-based radiotoxicity index, reduction in minor actinides in nuclear waste is beneficial and might ease the requirements for a final repository. There are several drawbacks when looking at the concept of P&T: among others, several irradiation cycles are needed because the transmutation efficiency is so low. The technology for the processing of the spent fuel, the fuel fabrication and the irradiation is far from commercially available, and it is not clear whether this level can be met at all. This presentation focuses on the proliferation risk posed by possible P&T fuel cycles. The nexus between civil and military use of nuclear technology is widely known. If new fuel cycles are implemented, they should be more proliferation-resistant and not less. This would not be true for P&T fuel cycles: they require a closed nuclear fuel cycle with far more advanced reprocessing than today. Fissile material contained in spent nuclear fuel is not sent to final disposal but is separated into its components, which must be made available separately before they can be recombined into new fuel elements. Besides plutonium, this also includes other transuranic elements of small critical mass. The radiation barrier, an essential protection against unauthorized access to fissile material that could be used for nuclear weapons, is no longer present. The handling of those materials requires special facilities to cope with the immense amount of heat and radiation of the fuel containing high fractions of minor actinides. In those facilities, fissile material fitting for military purposes could be handled as well. Even if thorough safeguards are in place, detailed accountancy of all materials is not possible. The quantities needed to build a nuclear weapon are small compared to the quantities that need to be handled in a commercial-sized P&T fuel cycle. P&T technology is a civil application which clearly strengthens military capabilities. It would be hard to argue why it should only be available to a trustworthy partner (whoever that might be). The implementation of P&T fuel cycles would thus increase the risk of unauthorized diversion of nuclear material, technology and knowledge.

Let's do science communication

Abstract. Germany is looking for a final repository for highly radioactive waste. This is a task for society as a whole, requiring a broad participation process and, above all, a scientific basis. The process is still in its early stages, but as the possible siting regions are narrowed down, public attention will increase significantly in the coming years. This workshop explores the role of science communication within the search process. Above all, the complex and scientific process must be transparent, comprehensible and understandable: science communication is a key success factor in communicating scientific subject matter. The search for a repository involves questions of geology as well as questions of scientific planning criteria and the legal basis for participation. Also relevant are questions of ecological, economic and social regional development at the potential site. For the support and participation in this interdisciplinary and transdisciplinary process, it is indispensable to formulate the contents and positions in a generally understandable way. In this workshop we will discuss the complex role of science communication in the repository search process. How can scientific content from different disciplines be communicated? Which formats are suitable for communicating technical content in transdisciplinary discourses? What needs to be communicated in the context of the search for a final repository? What content is essential for understanding the process? The workshop addresses the participants as communicating scientists with practical experience or specific questions and invites the participants to deal with these questions in a playful way: the basis for the workshop is a game plan that depicts and explains the phases and the course of the process and presents the most important information of the scientific process. In the format of a world café, the participants will experience to which extent science communication plays a role as an essential factor in the procedure. There will be two scenarios to play: on the one hand, the participants will be asked to deal with the question of which forms and contents are required for the procedure to be conducted successfully. On the other hand, it is about dealing with the risks and challenges of misguided science communication. For both scenarios, the task is to identify essential formats and content as well as points in time. The participants will be asked to formulate concrete examples. The player will go through each step in the search for a repository and discuss their influence as the communicating scientist on the success of the search. How can people be influenced by communication of risk topics, and therefore how can this influence people's attitude towards the process? In addition to personal experience, scientific questions regarding necessary information during the phases of the search will be generated in that format. How can science or science communication support the different steps of the search?

Hydride reorientation in fuel cladding under interim storage conditions with low hoop stress

Abstract. The restart of the search for a final repository for high-level nuclear waste in Germany and the resulting so-called white map lead to a reassessment of the safety of interim storage as well. Due to the resulting increase in interim storage periods with a prospected timescale until 2068, among other things, renewed consideration of cladding tube integrity is required for the handling of the fuel assemblies during repackaging into the final storage containers. Besides oxide formation during operation, hydrides can have a negative influence on stability during interim storage and handling later on. The hydrides, which are initially precipitated tangentially in the tube material during operation, can reorient during interim storage as a result of the temperature and load history and precipitate again in a radial direction during cooling under load. In recent years, a number of investigations have already been carried out with respect to this topic, with cladding conditions that are present in high burn-up fuel assemblies with corresponding high hydrogen contents. In these cases, reorientation effects did occur with stresses that can be encountered in interim storage, but the proportions of radial hydrides were very low and were classified as not being harmful. In addition to the tests with cladding tubes containing high hydrogen contents, sporadic tests with low hydrogen contents were also carried out, for example, by Hardie and Shanahan (1975) and later by Chu et al. (2008). These indicated that strong reorientation effects could occur because of the complete dissolution of hydrogen under high temperature and tensile stress. In recent years, Kaufholz et al. (2018) also formulated a hypothesis that describes this effect as being the consequence of free nucleation without the presence of precipitates. This results in the possible formation of extremely pronounced radial hydrides, which can even extend through the tube wall. This is possible because residual hydrides that can hinder free precipitation or represent preferential points for nucleation are absent. The results of the present investigations confirm this behaviour. They show that massive reorientations can already occur at stresses at the lower end of the literature values and that, until now, these reorientations were interpreted as being uncritical. Considering the hysteresis in solubility between terminal solid solubility for dissolution (TSSD) and precipitation (TSSP), it becomes apparent that precipitation at hydrogen contents of 100 ppmw (parts per million by weight) already starts at approx. 538 K and that the hydrides precipitate radially under a stress of 52 MPa and form extremely pronounced hydrides. This results in a need for further research, since the thermal and mechanical loads under which the tests were carried out are well below the permissible limit loads in interim storage and below the values expected so far. This applies in particular to materials and cladding tubes that either absorb less hydrogen during operation or have only low burn-ups. The study provides an overview of the status quo, presents part of the investigations carried out during the project MUDZ (Modellierung und Untersuchung der Degradation von Hüllrohrmaterialien aus Zr-Legierungen durch Hydridbildungs- und Hydridverteilungsprozesse im Hinblick auf die Langzeitzwischenlagerung) in the KEK (Kompetenzerhalt in der Kerntechnik) initiative and the results obtained, and discusses the ramifications of the results.

Biosphere modelling in the calculation basis for dose assessment for a final disposal of high-level radioactive waste

Abstract. The government of Germany decided to isolate high-level radioactive waste (HLW) in deep geological formations. Such a site should guarantee the highest possible level of safety over a period of 1×106 years. The Federal Ministry for the Environment, Nature Conservation, Nuclear Safety and Consumer Protection (BMUV) asked the Federal Office for the Safety of Nuclear Waste Management (BASE) and the Federal Office for Radiation Protection (BfS) to develop a directive for dose assessment for a final disposal of HLW, which has to be used for the site selection process by the Federal Company for Radioactive Waste Disposal (BGE mbH), the operator of the future HLW repository. This regulation contains detailed provisions for the gas-bound and water-bound radionuclide transport in the geosphere and biosphere and for the dose estimation of the public. It is built upon established concepts in radioecology and dosimetry. The comprehensive set of instructions is a toolbox for the dose estimation of a fictive representative person, one of the indicators of the safety of the repository. Modelling of the biosphere over 1×106 years is impossible because natural processes and human activities affect the evolution of the biosphere in an unpredictable way. In addition, human habits like the way of life and agricultural practices cannot be predicted even for only hundreds of years. Therefore, it was laid down in another German regulation that the current human habits have to be assumed over the period under consideration. Existing models and parameters of current German regulations for public dose calculations have been adjusted to the specific conditions of a final repository and complemented where necessary. The challenge of how to take into account the future climate and its implications on the biosphere was solved by using reference biospheres covering all possible evolutions of the biosphere including climate transitions. The application of reference biospheres to cover climate changes is a common approach in comparable safety analyses. Germany favours the enveloping approach described above that implicitly comprises all possible climatic conditions and the corresponding evolutions of the biosphere. The decisions on how to deal with the unknown future were the results of discussions between BMUV, BASE, and BfS. To ensure transparency and participation in the site selection of the HLW repository, the draft regulation was presented to the public, stakeholders, and the scientific community, providing the opportunity to comment on every part of the content. This consultation process and an expert workshop were the basis of the revision of the draft regulation. The final regulation was published at the end of 2022. The participation process helped to improve the document and to achieve a broader public acceptance. BASE and BfS are currently working on a comprehensive explanatory text to address all of the several hundreds of comments in detail.

Geowissenschaftliche Methoden – Datenbank (GeM-DB) – a basis for planning surface exploration programs

Abstract. In phase II of the German site selection procedure for a final repository site for high-level radioactive waste, identified siting regions will be explored above ground. For each siting region, different geoscientific data exist, resulting in various exploration requirements as results of the representative preliminary safety analysis. The exploration requirements, i.e. exploration objectives (Kneuker et al., 2020) and parameters, are based on a legal foundation, especially sections 22–24 of StandAG (2017). The exploration requirements in turn define the methods to be used for surface exploration of siting regions to collect all data needed for the further-developed preliminary safety analyses at the end of phase II. Commissioned by the Federal Company for Radioactive Waste Disposal (BGE), the Federal Institute for Geosciences and Natural Resources (BGR) is developing a database, GeM-DB, which allows the search for different geophysical and geoscientific exploration methods. Among the exploration methods are airborne, ground and borehole methods as well as investigations on obtained samples, e.g. from drill cores. The database entries consist of a general description, different attributes and an evaluation of the suitability and applicability for (1) the different host rocks (claystone, crystalline rock and rock salt) and (2) the exploration objectives deriving from the legal foundations, especially the exclusion criteria, minimum requirements and geoscientific weighing criteria as stated in sections 22–24 of StandAG (2017). This link is the key element of the database and a unique compilation of the collective knowledge of BGR experts. Certain filters and selection options allow queries of the database content, for instance to generate host rock-specific sequences of exploration methods. These sequences of methods can be used as a basis for the exploration programmes to be planned by the BGE.

Intra- vs. intergenerational justice tradeoffs in nuclear waste storage (W01)

Abstract. We propose a workshop in two parts (approx. 90 min each) to discuss (i) general dilemmas due to the long time range until an operable solution for the waste problem is found and (ii) an ethics-inspired discussion on the extra burden for communities hosting interim storage sites (based on empirical data). In the first part, we highlight the twofold responsibility concerning the current generation's decision-making perspective for present and future generations. According to our survey data and a debate with citizens, we see the need to discuss the respective weighing of directly affected generations during the next few decades (until the repository's closure, which affects about four to five generations) compared to the justice for (five+) future generations in the following decades and centuries (see the figure in the Supplement). Questions are, for instance, is discounting the ethical relevance of future generations justified, necessary or forbidden? In the second part, we explore the consequences of the delayed final storage in Germany on the current interim storage sites. Following conversations with citizens (in Brokdorf, October 2022, and in Lubmin, March/April 2023) we investigate the tradeoffs between guaranteeing the safety in these sites and developing and implementing new concepts for long-term storage at these or new sites before commencing with final storage. In terms of safety and fairness, invasive monitoring of casks or storage in a new centralized interim repository would be welcomed by some. However, both possible measures conflict with long-term practices (e.g., approving licenses for several decades or the long-term planning for the final repository). Important questions to be discussed are, among others, how much time may current generations take to identify the most suitable site? How can addressing all three time horizons specified in the Site Selection Act help to contextualize delays in the initial steps? What are the risks and opportunities associated with delayed deep geological disposal (economic, social, political, etc.)? To what extent may intragenerational (current generations) justice discount for generations in the far future? How can the prolongation of interim storage be justified? We propose a specific format during the workshop in which participants work in small groups using the rich picture methodology (https://naturwissenschaften.ch/co-producing-knowledge-explained/methods/method_factsheets/rich_picture, last access: 12 June 2023). This format is suitable for work in small groups to visualize (consensus or divergent views on) complex problems, structures and interrelationships between agents. The results from the small groups are then presented and discussed in the plenary. The respective answers to the key questions may provide possible practice-oriented results for responsible decision-makers (e.g., at BASE Bundesamt für die Sicherheit der nuklearen Entsorgung (Federal Office For The Safety Of Nuclear Waste Management)).

Monitoring the Sustainability of Building Renovation Projects—A Tailored Key Performance Indicator Repository

This study aims to assist in the identification of suitable key performance indicators (KPIs) that can be used to assess the sustainability performance of buildings given their transition into zero-carbon, resource-efficient, and resilient structures. To that end, a four-step methodology is proposed in this work; the first step includes the development of a KPI repository, which builds upon commonly accepted targets derived from the needs of different stakeholders as well as targets imposed by external factors. The second step refers to the expansion of the initial KPI repository, capitalizing on information from the literature. The third step includes the refinement of the repository based on predefined criteria (relevance, availability, measurability, reliability, and familiarity) and tailored feedback from key stakeholders. The final step concerns the development of KPI cards, which include all the necessary information for understanding and estimating the KPIs included in the final repository. This four-step methodological approach implementation was tested during the EU-funded HORIZON project ‘InCUBE’. The implementation of the first two steps of the proposed methodology resulted in a pool of 68 KPIs. Nearly half of these KPIs were extracted from Step 1 to fully support the monitoring of all InCUBE outcomes, while the rest of the KPIs were extracted from highly relevant Horizon frameworks, the B4P partnership, Level(S) framework, publications, and ETSI standards (Step 2). The implementation of Step 3 resulted in a shortlisted KPI pool which eventually defined the final InCUBE KPI repository, including 31 KPIs. To help with the coordination of the data gathering process and a shared understanding of the sort of information to be monitored among various stakeholders, selected KPI cards (Step 4) are presented.

Climate adaptation in the spent fuel storage and disposal facilities: A literature review

Climate adaptation is part of the process our society is using to cope with climate change and the changes that it will bring to our environment over the coming years. Unfortunately, in some ‘high-risk’ industries (e.g., nuclear) and specifically in some areas such as spent fuel management, climate adaptation has received little attention. In 2016, the total spent fuel inventory was 265, 000 tonnes of heavy metal (HM) in storage and 127, 000 t HM was sent to reprocessing. In general, the spent fuel reduces its radiotoxicity to a natural level after hundreds to thousands of years. This timeframe surpasses that of severe changes that are expected to occur on our planet because of climate change. So, climate adaptation should be considered.As such, a literature review has been performed to acquire knowledge and identify gaps in the literature related to climate adaptation measures in long-term spent fuel storage. For this, a systematic review was performed that included the screening of 693 studies and a full-text analysis (e.g., purpose, methodology, findings, limitations) of 67 studies. Several literature gaps were revealed that included the lack of (1) local climate vulnerability assessment for nuclear power plants, (2) climate adaptation for spent fuel storage (e.g., on-site and centralized facilities (3) climate adaptation measures for long-term storage or final repositories.

Beyond U/Pu separation: Separation of americium from the highly active PUREX raffinate

This review provides a comprehensive overview of published hydrometallurgical chemical processes capable of separating americium from curium and the lanthanides. A search for highly selective and robust americium separation methods is motivated by the fact that americium isotopes contribute significantly to the long-term heat load and residual radiotoxicity of high level waste originating from the PUREX process, nowadays still the key reprocessing technology to recycle uranium and plutonium from spent nuclear fuel. The separation (partitioning) and subsequent nuclear transmutation (or burning) of americium would allow a substantial improvement in the construction of an underground final repository and provide safety benefits – highly relevant for the exploitation of such a facility over extended periods of time. Besides the discussion of basic properties of the various separation methods, an evaluation of their compatibility with upstream and downstream processes as well as the treatment of secondary waste streams is also provided.

Application of a CNN to the Boda Claystone Formation for high-level radioactive waste disposal

Nations relying on nuclear power generation face great responsibilities when designing their firmly secured final repositories. In Hungary, the potential host rock [the Boda Claystone Formation (BCF)] of the deep geological repository is under extensive examination. To promote a deeper comprehension of potential radioactive isotope transport and ultimately synthesis for site evaluation purposes, we have efficiently tailored geospatial image processing using a convolutional neural network (CNN). We customized the CNN according to the intricate nature of the fracture geometries in the BCF, enabling the recognition process to be particularly sensitive to details and to interpret them in the correct tectonic context. Furthermore, we set the highest processing scale standards to measure the performance of our model, and the testing circumstances intentionally involved various technological and geological hindrances. Our presented model reached ~ 0.85 precision, ~ 0.89 recall, an ~ 0.87 F1 score, and a ~ 2° mean error regarding dip value extraction. With the combination of a CNN and geospatial methodology, we present the description, performance, and limits of a fully automated workflow for extracting BCF fractures and their dipping data from scanned cores.

MP40-10 CREATING HIGH QUALITY SYNTHETIC GENITOURINARY TISSUE IMAGES FROM HISTOLOGY REPOSITORIES TO OVERCOME LIMITATIONS WITH THE USE OF CLINICAL TRIAL DATA IN AI MODELS

You have accessJournal of UrologyCME1 Apr 2023MP40-10 CREATING HIGH QUALITY SYNTHETIC GENITOURINARY TISSUE IMAGES FROM HISTOLOGY REPOSITORIES TO OVERCOME LIMITATIONS WITH THE USE OF CLINICAL TRIAL DATA IN AI MODELS Derek Van Booven, Yasamin Mirzabeigi, and Himanshu Arora Derek Van BoovenDerek Van Booven More articles by this author , Yasamin MirzabeigiYasamin Mirzabeigi More articles by this author , and Himanshu AroraHimanshu Arora More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003278.10AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Timely diagnosis and assessment of prognosis are challenges for prostate cancer (PCa)—this results in many deaths and increases the overall disease risk and cost of treatment. Although clinical testing strategies are effective, recent advancements in machine learning suggest promising strategies that could allow the generation of synthetic data to avoid the need to rely on using data from clinical trials to develop training models. Our study is the first to use the generative adversarial network technology to generate synthetic digital histology data of high quality from 9 genitourinary organs. METHODS: We downloaded digital pathology images for 9 genitourinary tissues from the GTEx Portal, a repository of 25,713 images from 39 unique tissue classes. Downloaded images were subjected to color normalization within each tissue to ensure that all images have the same range of expected colors and that none are too light or dark, which could lead to post-analysis issues. These were then run through HistoQC to determine baseline quality and then through PyHist for single patch creation. This led to a data repository of over 10,000 patches on average per tissue. These patches were then run through our custom deep convolutional GAN implemented in PyTorch and run on a local GPU cluster to create models for which we can generate new synthetic images. RESULTS: 2700 images were obtained from GTEx. Segmentation was done on these images in 96×96 blocks resulting in 32,411 patches, and 256×256 blocks resulting in 163,916 patches. These patches were used as the training database in a standard deep convolutional GAN (dcGAN) to create synthetic images per tissue. Upon creation, a color gradient PCA was done on the images to show a dropout rate of 21.2%. Images were subjected to further quality control of random manual inspection, where file sizes of a certain threshold were discarded. Post-image inspection, pathologists were also asked to assess the quality of the images resulting in 80% of the images being deemed good enough quality. After the entire QC process, inception distance (FID) was calculated, and a simple classification module was created to determine image similarity within a tissue and image distinctness between tissues. The lowest FID was determined at 54.2 at 5,000 synthetic images. The classification module was able to separate the images with an accuracy of 74%, with similar tissues being classified together being the most common mistake. CONCLUSIONS: We have created a deep convolutional GAN that can create new synthetic images with a reliability rate of 80%. This needs to be enhanced, and quality needs to be improved before a final repository can be created. Source of Funding: AUA Research Scholar Award to HA © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e548 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Derek Van Booven More articles by this author Yasamin Mirzabeigi More articles by this author Himanshu Arora More articles by this author Expand All Advertisement PDF downloadLoading ...

Impact of Environmental Stresses on the Antibacterial Activity of Graphene Oxide (GO) Nanoparticles against P. putida Biofilms.

As the production of graphene-based nanomaterials such as GO is increasing, it is expected that a large amount of GO waste will be generated. The environment (i.e., soil and aquatic systems) will be amongst the final repositories of these wastes which means important natural microbial communities in such environments will be at risk of GO exposure. However, little is known about how these communities respond to environmental stresses in synergy with the presence of GO. In this study, the effect of three different stress conditions: temperature (5, 25 and 40 °C); pH (5 to 9) and osmotic stress (51, 219 and 320 mM NaCl) in addition to GO treatment was investigated on the viability and physiology of biofilms and planktonic cells of soil bacterium P. putida. It was found that planktonic cells were more resistant to GO alone compared to biofilms. However, the cells were sensitive to GO when exposed to pH or osmotic stresses. Temperature was not found to influence the survival of biofilm with or without exposure to GO. However, low pH caused a reduction in colony-forming units (CFU) at pHs 5 and 6 for the pre-treated samples, while biofilms at pH 7-9 did not show any decrease. Interestingly, the post-treatment of planktonic cells or biofilms with GO showed a significant reduction in CFU at all pH ranges. The effect of higher osmotic stress in combination with GO resulted in a significant reduction in biofilms. These results show that the effect of stresses naturally occurring in the environment can be affected and changed when in combination with GO and can potentially affect the balance of natural biofilms.

Exploring the impact of temperature and oxygen partial pressure on the spent nuclear fuel oxidation during its dry management

The management of Spent Nuclear Fuel (SNF) comprises different stages in which security is demonstrated. Nevertheless, fundamental research can lead to other design options that must be considered. Currently, one of the focuses is the dry interim storage option, as the shortest-term solution until final repositories are available. During this stage, one concern is the oxidation of the fuel. If UO2 (SNF matrix) is exposed to air at high-enough temperature, formation of U3O8 takes place. The larger volume of this phase could entail stresses on the SNF clad, which is the first barrier to prevent radioactive material release. It is known that this oxidation is a temperature-dependent reaction and ensuring an inert atmosphere discards any effect during SNF dry management. However, at what extent temperature and oxygen concentration would have an impact on the U3O8 formation is not established, being the available experimental data very scarce. We follow this oxidation in representative ranges of temperature and oxygen concentration of dry storage facilities by using in-situ Raman spectroscopy. The results show that temperature is a more-affecting factor than the oxygen concentration at the studied conditions. Therefore, efforts to limit temperatures would yield more benefits in preserving fuel matrix integrity.

Reconstructing late Miocene depositional environments in the central High Plains, USA: Lithofacies and architectural elements of the Ogallala Formation

The late Miocene Ogallala Formation hosts much of the High Plains aquifer of North America, though it is poorly studied in the central High Plains region where only a small fraction of its total thickness is exposed. One exception is in western Kansas, where up to 40 m of the Ogallala Formation crop out along the bluffs of Ladder Creek Canyon. These deposits consist of stacked and laterally extensive, multistory channel bodies dominated by sandy bedforms with little or no intervening floodplain mudstone. We interpret each ~2–4 m-thick story as a sandstone bed that formed during a single depositional episode and infilled a broad and relatively shallow braided river channel. Each story preserves elements suggesting high discharge conditions, followed by low discharge or the complete abandonment of the river channel after active streamflow either migrated away from the study area or ceased regionally for a relatively long period of time. High discharge conditions are characterized by channel-filling, current-formed transverse bars, gravel-rich longitudinal bars, and sand sheets deposited while the channel was largely flooded and nearly the entire riverbed mobilized. Low discharge conditions are indicated by lens-shaped, trough cross-stratified channels scoured into previously deposited bars. Channel-fill deposits were formed when the remaining flow was confined to one or more narrow streams that braided across the exposed channel belt. Persistent low discharge conditions are suggested by channel-belt-wide subaerial exposure of bar surfaces for a period of time sufficient to promote colonization by soil-burrowing organisms and moderate soil development. Abandonment of the broader channel belt is indicated by advanced calcretization within a story and the presence of aerially restricted and fossiliferous mud-filled channel pools where the final repositories of surface water attracted local paleofauna before infilling or drying completely. The depositional environment of the Ogallala Formation in the study area is most similar to “Platte type” fluvial systems characterized as shallow, perennial, and sand-dominated braided rivers. Comparisons with previously studied localities in the northern and southern High Plains reveal differences in fluvial style, sediment source areas, cut-and-fill geometries, and eolian input.