Within the last decades, not only the technology of salt production and the range of its uses have largely developed ‒ also the technical options of experimental and field investigations have improved intensely. This calls for a joint focus: both, salt industry and research are needed to capture and discuss new challenges to the usage of salt deposits.
Depending on the application, the unique characteristics of salt deposits ‒ low permeability, mainly high water solubility and the visco-plastic behavior ‒ can be either an advantage or a challenge. The high water solubility of salt rock offers the option to construct salt solution caverns, the impermeability allows for the temporary storage of various energy-rich fluids – a concept that contributes to a stable energy supply in the course of fluctuating availabilities from renewables. Waste disposal in salt benefits from impermeability to assure a safe long term storage. On the other hand, the occurrence of pressurized gas and migrating waters present potential risks for mining activities.
The session welcomes contributions presenting studies and applications of the numerous aspects related to subsurface reservoir exploitation, solution mining, cavern operation and waste disposal in salt deposits – from “still under debate” to “tested and practiced”. This includes geophysical, geomechanical, hydrological, and geochemical investigations as well as modelling approaches and geotechnical advances in the broad context of process understanding and monitoring which contribute to an increasing environmental and work safety and a sustainable utilization of salt deposits.

A number of pilot, demonstration and full scale projects, have demonstrated the geological storage of CO2, as the last link in the CCS (Carbon Capture and Storage) chain over the past two decades. Natural analogues have provided additional evidence of the feasibility of long-term containment of carbon dioxide in geological formations. Various nations are currently preparing for the implementation of CCS as one measure to reduce greenhouse gas emissions, supported by research programmes focussing on the transfer of experiences from pilot or demonstration projects to full scale. In addition to CCS as a part of the portfolio of measures to reduce greenhouse gas emissions, bio-energy with CCS (BECCS) offers the potential of negative emissions.
This session addresses CO2 storage field projects at all scales, from small field tests to full scale storage projects. Initiatives and active projects integrating all elements of the CCS chain are invited as well as field projects focused on the geological storage.
Individual studies on testing methods, analysis of field data and natural analogues of CO2 storage, site characterization and monitoring of CO2 storage sites are welcome along with reviews of large integrated projects.

Relevant topics include but are not limited to:
• Regional and local characterization of storage formations and their behaviour during CO2 injection and storage, including long-term behaviour.
• Identification and determination of key site parameters for CO2 storage, such as parameters for trapping.
• Characterization of the cap-rock and its properties.

Suitable contributions can address, but are not limited to:
• Field testing and experimental approaches aimed at characterizing the site, its key characteristics and the behaviour of the injected CO2.
• Modelling studies for test design and analyses and integrating field data.
• Studies of natural analogue sites and lessons learnt from them for site characterisation and monitoring techniques.

Thermal and mechanical processes in aquifers are of increasing interest for hydrogeological analysis for development of innovative field and laboratory experiments. Both in research and in practice, accurate characterization of subsurface flow and heat transport, observations of induced or natural variations of the thermal regime. The seasonal and long-term development of thermal and mechanical conditions in aquifers, and heat transfer across aquifer boundaries are focus points. This also includes the role of groundwater in the context of geothermal energy use for predicting the long-term performance of geothermal systems (storage and production of heat), and integration in urban planning. There are many ongoing research projects studying heat as a natural or anthropogenic tracer, and which try to improve thermal response testing in aquifers. Such techniques are of great potential for characterizing aquifers, flow conditions, and crucial transport processes, such as mechanical dispersion. Understanding the interaction of hydraulic, thermal and mechanical processes is a major challenge in modern hydrogeology. Deep underground constructions, tunnels, CO2 storage, hydro- and enhanced geothermal applications are prominent subjects. We invite contributions that deliver new insight into advances in experimental design, reports from new field observations, as well as demonstration of sequential or coupled modeling concepts. The session aims to provide an overview of the current and future research in the field, covering any temporal or spatial scale, and seeks to address both separate and coupled processes.

"Assessment of barrier integrity in geological repositories for nuclear waste disposal and contaminant isolation":

Barrier integrity is a crucial aspect for the assessment of subsurface technologies. For the storage of thermal energy and other energy carriers, or the deposition of high-level nuclear or chemotoxic waste, different repository concepts in diverse geological candidate formations such as rock salt, clay stone and crystalline rock are being discussed. Computational methods and numerical simulations, in conjunction with experimental studies across scales from micro-scale to field scale, are an integral part of safety and environmental-impact assessment concepts involving barrier integrity as a key component. Reliable comparative analyses of potential technological options require coupled physical (thermo-hydro-mechanical chemical) models capturing the individual particularities of each rock type and associated geotechnical repository and barrier concept to a comparable level of sophistication. Structural as well as process complexity and large computational domains combine to render a reliable and efficient analysis a major challenge. This complexity is often met by data scarcity and variability, necessitating the theoretical and computational treatment of uncertainties and variability at different scales involved in numerical analyses at different levels.

This session provides a platform for the exchange of geophysical, geochemical, geotechnical knowledge for assessing the integrity of barriers and multi-barrier systems considering equally conceptual, theoretical, computational and experimental aspects.

"Towards a safe nuclear waste repository – geoscientific, technological, social and regulatory challenges and approaches":

The successful implementation of safe, deep geological disposal of spent fuel, high-level waste and other long-lived radioactive waste is one of the currently most pressing and important environmental challenges in several countries in Europe and worldwide. Site exploration and assessment are primarily geoscientific tasks that require interdisciplinary collaboration of different geoscientific disciplines, like geophysics, geochemistry, mineralogy, geomechanics, and geological as well as THMC modelling. Successful and socially accepted site selection and implementation, however, not only depend on geoscientific state-of-the-art results and R&D programs but to a large extend on targeted, adequate and well-designed public outreach and public involvement/participation activities as well as on suitable regulatory frameworks. Both, geoscientific and technological as well as social and regulatory aspects complement each other and need to be addressed.
This session therefore welcomes contributions from research organizations, NGOs, waste management organizations, and regulatory bodies. Topics may include, but are not limited to, advances in exploration and modelling tools and approaches, safety assessment strategies, disposal concepts, national and transnational public outreach and public involvement programs, national regulatory frameworks. Preference will be given to contributions that highlight the interdisciplinary and especially transdisciplinary character of deep geological disposal research

The session gathers geoscientific aspects such as dynamics, reactions, and environmental/health consequences of radioactive materials that are massively released accidentally (e.g., Fukushima and Chernobyl nuclear power plant accidents, wide fires, etc.) and by other human activities (e.g., nuclear tests).

The radioactive materials are known as polluting materials that are hazardous for human society, but are also ideal markers in understanding dynamics and chemical/biological/electrical reactions chains in the environment. Thus, the radioactive contamination problem is multi-disciplinary. In fact this topic involves regional and global transport and local reactions of radioactive materials through atmosphere, soil and water system, ocean, and organic and ecosystem, and its relation with human and non-human biota. The topic also involves hazard prediction and nowcast technology.

By combining >30 year (halftime of Cesium 137) monitoring data after the Chernobyl Accident in 1986, >5 year dense measurement data by the most advanced instrumentation after the Fukushima Accident in 2011, and other events, we can improve our knowledgebase on the environmental behavior of radioactive materials and its environmental/biological impact. This should lead to improved monitoring systems in the future including emergency response systems, acute sampling/measurement methodology, and remediation schemes for any future nuclear accidents.

The following specific topics have traditionally been discussed:
(a) Atmospheric Science (emissions, transport, deposition, pollution);
(b) Hydrology (transport in surface and ground water system, soil-water interactions);
(c) Oceanology (transport, bio-system interaction);
(d) Soil System (transport, chemical interaction, transfer to organic system);
(e) Forestry;
(f) Natural Hazards (warning systems, health risk assessments, geophysical variability);
(g) Measurement Techniques (instrumentation, multipoint data measurements);
(h) Ecosystems (migration/decay of radionuclides).

The session consists of updated observations, new theoretical developments including simulations, and improved methods or tools which could improve observation and prediction capabilities during eventual future nuclear emergencies. New evaluations of existing tools, past nuclear contamination events and other data sets also welcome.

Public information:
The release of radioactive materials by human activity (such as nuclear accidents) are both severe hazard problem as well as ideal markers in understanding geoscience at all level of the Earth because it cycles through atmosphere, soil, plant, water system, ocean, and lives. Therefore, we must gather knowledge from all geoscience field for comprehensive understanding.