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        <title>Frontiers in Nuclear Engineering | New and Recent Articles</title>
        <link>https://www.frontiersin.org/journals/nuclear-engineering</link>
        <description>RSS Feed for Frontiers in Nuclear Engineering | New and Recent Articles</description>
        <language>en-us</language>
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        <pubDate>2026-09-12T17:32:27.899+00:00</pubDate>
        <ttl>60</ttl>
        <item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fnuen.2026.1966757</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fnuen.2026.1966757</link>
        <title><![CDATA[Editorial: Advanced modeling and management strategies for nuclear and radiological incidents]]></title>
        <pubdate>2026-09-09T00:00:00Z</pubdate>
        <category>Editorial</category>
        <author>Nadja Zeleznik</author>
        <description></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fnuen.2026.1860013</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fnuen.2026.1860013</link>
        <title><![CDATA[Plan alignment and operational interfaces in nuclear security event response: evidence from Türkiye’s all-hazards emergency management system]]></title>
        <pubdate>2026-09-01T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Zeyneb Camtakan</author><author>Didem Saloglu</author>
        <description><![CDATA[Nuclear security event response within all-hazards systems requires coordination among emergency management, regulatory, law enforcement, technical and forensic actors operating under distinct mandates. This study examines how nuclear security event response is specified within Türkiye’s national emergency management system. Based on structured documentary analysis of publicly available planning, regulatory, strategic and review documents, the study applies the Four C framework to assess communication, coordination, collaboration, and cooperation across institutional interfaces. The findings show that Türkiye’s planning architecture provides a coordinated basis for radiological emergency response. However, nuclear security events are less clearly specified as a distinct response problem. Partially specified interfaces include command transition, forensic evidence management, security-sensitive information sharing, detection-to-response activation, and international notification timing. The study does not assess operational performance or classified capabilities. It provides a case-based diagnostic of how formal plan alignment may not translate into clearly specified operational response arrangements when nuclear security events require emergency management, regulatory, law enforcement, technical, and forensic functions to operate simultaneously.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fnuen.2026.1884654</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fnuen.2026.1884654</link>
        <title><![CDATA[Application and validation of a higher-fidelity architecture for coupled neutronic and thermal-hydraulic analysis in the XE-prime nuclear thermal propulsion system]]></title>
        <pubdate>2026-08-31T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Jonathon Thomsen</author><author>Camden Eck</author><author>Dan Kotlyar</author>
        <description><![CDATA[Development of a nuclear thermal propulsion (NTP) engine is pursued by government and industry. Current deployment regulations require that experimental efforts are heavily complemented and guided by modeling and simulation. Challenges arise when directly simulating the physics of such systems at steady-state operation and especially during transients due to strongly coupled local and global effects. Reduced-order methods are commonly used as a practical means for obtaining full-core solutions, however these methods must be verified against higher-fidelity solvers. Therefore, a Python package, ANTHMM, has been developed that is intended for general usability and allows users to externally couple Monte Carlo neutronics solvers and commercial CFD software. In its current state, ANTHMM is optimized for the Serpent Monte Carlo code and Ansys Fluent CFD. Using published data from the XE-Prime NTP engine, a CFD model has been generated, validated, and used as a reference model for a fully coupled reduced-order solver. The CFD model and reduced order solver show excellent agreement for the hot-condition test data in three different regions of the core, which were recorded during the XE-Prime experiment. The neutronic behavior predicted by the fully coupled reduced order solver is very similar to that predicted by the coupled CFD model. Finally, it is shown that informed prediction from a reduced order solver of first-iteration temperatures and densities used in the MC simulation can reduce the coupled simulation from several iterations to a single predictor-corrector step.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fnuen.2026.1900800</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fnuen.2026.1900800</link>
        <title><![CDATA[LEACS: lagrange error-adaptive collision sampling for multiphysics coupled Monte carlo transport]]></title>
        <pubdate>2026-08-31T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>W. Reed Kendrick</author><author>Benoit Forget</author>
        <description><![CDATA[In tightly coupled multiphysics simulations, the conventional Monte Carlo assumption of piecewise-constant material properties is no longer valid, as temperature and density fields vary continuously in space. Current approaches to this problem each impose limitations on accuracy, generality, or computational efficiency. This work introduces the Lagrange Error-Adaptive Collision Sampling (LEACS) method, which addresses spatially varying material properties during Monte Carlo neutron transport by dynamically evaluating the coupled finite element solution along the particle’s flight path. Rather than converting the multiphysics solution into a lower-order representation, LEACS accesses native element shape functions directly, with sample positions chosen analytically via the Lagrange error bound to optimally minimize error in the reconstructed collision probability distribution. LEACS is implemented in OpenMC and demonstrated on pin cell and assembly test cases and coupled with MOOSE thermal solutions. Analytical error analysis confirms that Lagrange-adaptive spacing consistently outperforms equidistant spacing, with the greatest gains observed for long axial flight paths. Spatial tally results suggest that as few as three sample points per flight segment are sufficient to capture the radial and axial impact of temperature gradients on the (n,γ) reaction rate distribution. Computational cost analysis reveals slowdown factors vary depending on the model geometry, with finite element point location and inverse mapping as the dominant cost components and primary targets for future optimization.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fnuen.2026.1921673</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fnuen.2026.1921673</link>
        <title><![CDATA[Meaningful dose in geological disposal safety cases: human intrusion and normal evolution as competing exposure pathways]]></title>
        <pubdate>2026-08-24T00:00:00Z</pubdate>
        <category>Hypothesis and Theory</category>
        <author>Claudio Pescatore</author>
        <description><![CDATA[Geological disposal safety assessments distinguish normal evolution from inadvertent human intrusion. Normal evolution is treated as the expected long-term behaviour of the disposal system; human intrusion is treated as a stylised future human action whose probability cannot be forecast reliably over geological timescales. This distinction is justified, but it can obscure a protection-relevant question: which pathway is more likely to produce a meaningful dose over a specified assessment period? This paper proposes comparing both pathways through P(D ≥ D*), the probability that a pathway produces a dose equal to or greater than a specified meaningful-dose threshold. The central claim is architectural: normal-evolution compliance, cumulative boundary-bypass probability, conditional consequence after physical intersection, and likelihood of meaningful dose are distinct quantities that should not be collapsed into a single plausibility judgement. The Finnish TURVA-2012 review illustrates the issue: human intrusion was the only disturbance scenario producing dose within the 10,000-year window. Normal evolution is the most fully modelled pathway, but the repository’s engineered and geochemical barriers are designed to suppress corresponding exposure. Human intrusion is less predictable, but once waste or contaminated material is physically intersected, it may be more exposure-efficient because it can bypass the attenuation sequence on which normal-evolution safety depends. A safety case may therefore be complete as a compliance demonstration while remaining incomplete as a protection claim. This note addresses that architectural gap by reframing human intrusion and normal evolution as competing pathways to meaningful dose.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fnuen.2026.1878296</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fnuen.2026.1878296</link>
        <title><![CDATA[Citizen measurement of ambient dose rate: challenges and opportunities]]></title>
        <pubdate>2026-08-19T00:00:00Z</pubdate>
        <category>Review</category>
        <author>Jean-Marc Bertho</author>
        <description><![CDATA[Radiation measurements by citizen appeared for the first time in the aftermath of the Chornobyl accident and received a renewed interest in the aftermath of the Fukushima accident. At that time, several networks of citizen measurement of radioactivity appeared in Europe, mainly acting for education to radioactivity and the science of measurement and for education, both initial and continuous, to risks associated to radioactivity. However, these networks suffer from a lack of sustainability due to several parameters, including lack of long-term funding, lack of credibility of citizen-led data and lack of applications in data use. This review identifies and details challenges that these networks have to face with, and opportunities they can use to increase the useability of citizen measurement data.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fnuen.2026.1893691</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fnuen.2026.1893691</link>
        <title><![CDATA[Securing cloud-enabled radiation detection systems: a risk-informed cybersecurity framework for nuclear sensor networks]]></title>
        <pubdate>2026-08-04T00:00:00Z</pubdate>
        <category>Perspective</category>
        <author>Nelson Kodzotse Agbemava</author><author>Etornam Ann Mensah</author><author>Kwame Appiah</author><author>Christopher M. Spirito</author>
        <description><![CDATA[Cloud computing is increasingly being adopted in nuclear and radiological monitoring systems to address the limitations of traditional on-premises infrastructures. Radiation Detection Systems (RDS), which rely on distributed sensor networks, generate large volumes of data requiring scalable storage, real-time processing, and secure transmission. While cloud integration enhances flexibility, mobility, and cost efficiency, it introduces significant cybersecurity challenges, particularly in high-consequence nuclear environments. This conceptual study evaluates the integration of cloud computing architectures with nuclear sensor networks and proposes a risk-informed cybersecurity framework tailored for cloud-enabled RDS, using a structured STRIDE threat-to-layer mapping and a qualitative likelihood-impact risk scoring exercise grounded in documented case studies. Key enabling technologies, including Sensor Cloud architectures, Everything-as-a-Service (XaaS), and multi-tenancy models, are examined alongside the Shared Responsibility Model governing cloud security. Threat scenarios such as supply chain compromise, advanced persistent threats, and cyber-physical attacks are analyzed using real-world case studies, including Operation Cloud Hopper and the Triton incident. This analysis indicates that cloud platforms enhance scalability, data availability, and disaster recovery capabilities, but introduce risks related to reduced system visibility, expanded attack surfaces, and dependency on third-party service providers, with supply-chain compromise and sensor-data falsification emerging as the highest-priority risks under the qualitative scoring applied here. A layered cybersecurity framework aligned with IAEA Nuclear Security Series guidance and international cybersecurity standards is proposed, addressing data protection in transit, at rest, and during processing. This study suggests that cloud computing may be securely adopted in nuclear sensor networks when supported by robust governance, regulatory alignment, and risk-informed cybersecurity controls; this conclusion is conceptual and desk-based, and would require expert validation, simulation, or pilot deployment before being treated as an operational recommendation.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fnuen.2026.1783403</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fnuen.2026.1783403</link>
        <title><![CDATA[Neutronics model developments for the IFMIF-DONES test cell]]></title>
        <pubdate>2026-07-30T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Yuefeng Qiu</author><author>Arkady Serikov</author><author>Irene Alvarez</author><author>Fernando Mota</author><author>Aljaž Čufar</author><author>Santiago Becerril</author><author>Jesus Castellanos</author>
        <description><![CDATA[This work presents the development and evolution of the test cell (TC) neutronics geometry models for IFMIF-DONES (International Fusion Materials Irradiation Facility–Demo Oriented Neutron Source), supporting detailed Monte Carlo–based nuclear analyses for design assessment and optimization. Beginning with the IFMIF/EVEDA configuration, successive model versions have been developed to reflect major DONES design updates, including the design changes to a single accelerator and test module, revised target assembly (TA) and High Flux Test Module (HFTM) designs, relocation of the quench tank, and the introduction of removable biological shielding blocks (RBSBs). To balance modeling accuracy and computational efficiency, both high-fidelity and lightweight geometry representations were investigated. Sensitivity studies on geometry boundaries and levels of simplification demonstrate that key irradiation performance metrics, such as neutron flux and damage doses, are well preserved when essential TA and HFTM features are retained. Simplified yet representative target and HFTM models were validated for use in accelerated simulations. In parallel, an unstructured mesh-based HFTM model was successfully implemented and benchmarked against conventional CSG-based models, showing excellent agreement.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fnuen.2026.1779804</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fnuen.2026.1779804</link>
        <title><![CDATA[Multiphysics methods for species tracking in molten salt reactors]]></title>
        <pubdate>2026-07-22T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Samuel A. Walker</author><author>Mauricio Tano</author><author>Parikshit Bajpai</author><author>Abdalla Abou-Jaoude</author>
        <description><![CDATA[Recent advancements in nuclear energy, particularly in the development of Molten Salt Reactors (MSRs), emphasize a shift towards integrating advanced technology for enhanced safety and efficiency. MSRs utilize unique fuel cycles and offer significant advantages over traditional reactors, including flexibility in fuel utilization and improved safety mechanisms. This study introduces a multiphysics species tracking framework developed within the Multiphysics Object-Oriented Simulation Environment (MOOSE), designed to model the intricate behaviors of species within MSR systems. The framework integrates neutron transport, thermal-hydraulics, and thermochemical dynamics, allowing for the analysis of species transport phenomena, including leaching, plating, and corrosion. The framework was applied to a generic Molten Salt Fast Reactor (MSFR) model, revealing critical insights into temperature-driven material leaching and plating processes. It demonstrated how temperature gradients and redox potential changes significantly influence the behavior of corrosion products, with specific concentrations tracked over time. Notably, the introduction of beryllium as a redox control measure was shown to mitigate corrosion by reducing the redox potential of the fuel salt. The findings underscore the importance of species tracking in MSRs for reactor safety, design optimization, and regulatory compliance. This research not only elucidates the dynamic interactions between various species in molten salt systems but also highlights the framework’s potential to guide future developments in MSR technology. The results indicate a clear pathway for enhancing reactor design and operational safety through informed modeling, paving the way for advanced nuclear reactor deployment in the near future. Future work will focus on validation against experimental data and further refinement of the framework to support ongoing advancements in MSR technology.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fnuen.2026.1861381</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fnuen.2026.1861381</link>
        <title><![CDATA[Research on the stratification characteristics of binary inert gas mixture]]></title>
        <pubdate>2026-07-17T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Xiang Shi</author><author>Zhouyang Xu</author><author>Fulong Zhao</author><author>Shuo Wang</author><author>Ruifeng Tian</author><author>Sichao Tan</author>
        <description><![CDATA[Gas-cooled reactors are among the most promising Generation IV nuclear energy systems, and helium-based binary mixtures are attractive candidate coolants because of their favorable thermophysical and chemical properties. In this work, a numerical investigation was conducted to study the distribution evolution and thermal stratification of a He–Ar gas mixture in a closed cylindrical vessel. The effects of the mixing ratio, initial pressure, vessel aspect ratio, initial temperature, and axial temperature difference on the species distribution were systematically analyzed. The results indicate that the mixing ratio, initial pressure, vessel aspect ratio, and initial temperature exert only minor effects on the overall gas distribution. By contrast, the axial temperature difference is identified as the key factor controlling the onset and intensity of stratification. A larger temperature gradient induces stronger compositional non-uniformity and results in more pronounced axial stratification within the vessel. In addition, temperature non-uniformity further amplifies the stratification process. These results provide a quantitative basis for evaluating composition non-uniformity in closed gas systems. The present study improves the mechanistic understanding of coupled thermal and compositional stratification in confined binary rare-gas mixtures and provides a reference for evaluating similar transport phenomena in gas-cooled nuclear systems.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fnuen.2026.1843718</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fnuen.2026.1843718</link>
        <title><![CDATA[The safety case for a deep geological repository in Switzerland: development of safety scenarios]]></title>
        <pubdate>2026-07-16T00:00:00Z</pubdate>
        <category>Methods</category>
        <author>Hoda Javanmard</author>
        <description><![CDATA[This paper presents Nagra’s systematic methodology for developing safety scenarios for the post-closure safety case in support of the Swiss general licence application for deep geological disposal of radioactive waste. The approach builds on the assessment basis, performance assessment outcomes, and international guidelines. It combines top-down safety-function reasoning with bottom-up FEP screening to ensure comprehensive and traceable coverage of system evolutions. Four safety scenario categories are defined: the reference safety scenario describing expected evolution, alternative safety scenarios addressing credible deviations, hypothetical “what-if?” cases testing system robustness, and stylised safety scenarios of future human actions. Each scenario is complemented by variants and calculation cases designed to capture conceptual and parametric uncertainties relevant for post-closure safety. The resulting scenario set provides a structured and manageable input for radiological consequence analyses and confidently bounds the radiological consequences of a comprehensive range of plausible and hypothetical evolutions. Through conservative assumptions, bounding variants, and structured safety scenario categorisation, the methodology robustly supports the demonstration of post-closure safety and ensures regulatory compliance. The work establishes a defensible and scientifically grounded safety scenario framework that underpins the post-closure safety assessment for deep geological disposal in Switzerland.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fnuen.2026.1868886</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fnuen.2026.1868886</link>
        <title><![CDATA[Thermodynamics for radiation-induced segregation and phase change needed]]></title>
        <pubdate>2026-07-09T00:00:00Z</pubdate>
        <category>Opinion</category>
        <author>Reza Darvishi Kamachali</author>
        <description></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fnuen.2026.1822290</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fnuen.2026.1822290</link>
        <title><![CDATA[Full-core high-burnup BWR LOCA fuel performance analysis and FFRD susceptibility]]></title>
        <pubdate>2026-06-24T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Ian Greenquist</author><author>Aaron Wysocki</author><author>Pierre-Clément A. Simon</author><author>Ryan Sweet</author><author>Kyle Gamble</author><author>Mehdi Asgari</author><author>Asher Hansen</author><author>Baris Sarikaya</author><author>Ian Porter</author><author>James Tusar</author><author>Nathan Capps</author><author>Robert Salko</author>
        <description><![CDATA[The susceptibility of the boiling water reactor (BWR) Limerick Unit 1 to fuel fragmentation, relocation, and dispersal during a postulated large-break loss-of-coolant accident (LBLOCA) was calculated using a multiphysics framework. The simulations include full-core, rod-resolved neutronic, thermal hydraulic, and fuel performance models using the VERA, TRACE, and BISON codes. This work focused on the transient BISON simulations, which include both the normal operation and LBLOCA periods in the same simulations. Cladding integrity was assessed using two correlations that are included with BISON. make page break Several new BWR-specific features were recently added to BISON. This work represents the first time these features have been included in a core-scale set of simulations. This study hence evaluates the performance of these new models for an operating reactor with realistic operating conditions. Simulation results showed that cladding integrity was maintained (i.e., no rods burst). Finally, future work to improve BWR and PWR predictions using this framework is suggested.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fnuen.2026.1758465</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fnuen.2026.1758465</link>
        <title><![CDATA[On the feasibility of fissile material production with inertial electrostatic confinement fusion devices]]></title>
        <pubdate>2026-06-19T00:00:00Z</pubdate>
        <category>Hypothesis and Theory</category>
        <author>Alex Little</author><author>Yannick Verbelen</author><author>Mahmoud Bakr Arby</author><author>Thomas B. Scott</author>
        <description><![CDATA[Inertial electrostatic confinement fusion devices (fusors) are becoming increasingly attractive neutron sources, and are well suited for global distribution with great humanitarian benefits. However, such neutrons are agnostic to the user’s intent, so could in theory be used for malicious means. This paper discusses the feasibility of using fusors to convert fertile thorium-232 or uranium-238 into fissile material for the purpose of proliferating a nuclear weapon, and whether this is a simple, convenient, and subtle method compared to existing means such as nuclear piles or enrichment plants. Such an effort would require one or more fusors to produce in excess of 1016 neutrons per second. This neutron production rate is out of range of contemporary device technologies, and would be drastically inferior to conventional proliferation techniques. Without significant breakthroughs in fusor technology, this paradigm is expected to remain.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fnuen.2026.1843726</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fnuen.2026.1843726</link>
        <title><![CDATA[The safety case for a deep geological repository in Switzerland: engineered barriers for low- and intermediate-level waste disposal]]></title>
        <pubdate>2026-06-18T00:00:00Z</pubdate>
        <category>Review</category>
        <author>Lukas Martin</author><author>Georg Kosakowski</author><author>Typhaine Guillemot</author><author>Alexandros Papafotiou</author>
        <description><![CDATA[The safe geological disposal of low- and intermediate-level radioactive waste relies on a passive multi-barrier system. This paper presents the provisional Swiss design for the low- and intermediate-level waste (L/ILW) emplacement caverns and their expected evolution. In the current design, containers are stacked within the L/ILW disposal caverns, and the remaining void space is backfilled with a porous mortar. Because cementitious materials are used in large quantities, they largely determine the geochemical conditions in the L/ILW near field. A key property of these cementitious materials is their ability to maintain a high-pH porewater environment. Such conditions limit the degradation of organic materials and suppress microbial activity. They also promote the passivation of metal surfaces, resulting in slow corrosion rates and consequently reduced gas generation. The chemical evolution of the near field is strongly coupled to the repository’s saturation history, as water is required for chemical reactions such as for the corrosion of metals, degradation of organic matter or pozzolanic reactions. Given the low permeability of Opalinus Clay, water availability in the caverns is limited, and partially saturated conditions are expected to persist for several hundreds of thousands of years. These conditions help maintain elevated pH levels, particularly in the unsaturated regions of the emplacement caverns. The substantial presence of cementitious materials also enhances the retention and slow release of radionuclides from the L/ILW near field into the host rock, once the waste packages breach. As a result, the L/ILW near field contributes to key safety functions, including immobilization, retention, and controlled release of radionuclides, as well as ensuring compatibility among repository components. The properties and long-term behaviour of these components are sufficiently well understood to allow a robust description of their evolution over extended timescales, supporting the demonstration of their barrier function and long-term performance.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fnuen.2026.1849685</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fnuen.2026.1849685</link>
        <title><![CDATA[The safety case for a deep geological repository in Switzerland: site and geological barrier characteristics]]></title>
        <pubdate>2026-06-18T00:00:00Z</pubdate>
        <category>Review</category>
        <author>Raphael A. J. Wüst</author><author>Michael Schnellmann</author><author>Angela Landgraf</author><author>Silvio Giger</author><author>Nicolas Roy</author><author>Daniel Traber</author><author>Gaudenz Deplazes</author><author>Raphael Schneeberger</author><author>Jens K. Becker</author><author>Nathan Looser</author><author>Urs H. Fischer</author><author>Valentina Zampetti</author><author>Tim Vietor</author>
        <description><![CDATA[Deep geological repositories for radioactive waste rely on geological barriers to isolate waste and impede or limit radionuclide migration over long geological timescales or until radioactivity has decreased to natural radiation levels. This study summarises the main geological evidence and arguments for the containment-providing rock zone (CRZ), including the host rock Opalinus Clay, as effective geological barriers for Switzerland’s deep geological repository. The information and data are part of Nagra’s comprehensive safety case within the framework of the general licence application. The geological assessment basis contains an integrated multi-scale site characterisation, covering data from 3D-seismic investigations and nine deep boreholes from the latest exploration campaign. Highlights of the geological data include: 1) high-resolution 3D-seismic datasets that image the subsurface structure, including undisturbed structural domains, key stratigraphic horizons, and the geometry of faults; 2) a comprehensive field and laboratory dataset that demonstrates that the hydraulic conductivities of the Opalinus Clay and remaining CRZ units are extremely low, that solute transport is diffusion-dominated, and that key properties have high vertical and lateral continuity; 3) independent natural-tracer profiles that developed over millions of years and confirm slow, diffusion-dominated transport across the CRZ; 4) a laboratory-derived mechanistic understanding and field evidence of self-sealing processes in the Opalinus Clay that show that fracture transmissivities decrease relatively rapidly after mechanical perturbation; 5) a systematic abstraction approach that groups geological units with similar properties and provides a modelling framework for evaluating safety- and performance-relevant processes; and 6) broad-ranging evidence that demonstrates the long-term geological stability of the Opalinus Clay with respect to the expected tectonic, geomorphological and hydrological changes during glacial-interglacial cycles over the next one million years. The synthesis presented here demonstrates how the geological data and its abstraction provide a robust and internally consistent basis for the safety assessment supporting the Swiss general licence application.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fnuen.2026.1842834</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fnuen.2026.1842834</link>
        <title><![CDATA[The safety case for a deep geological repository in Switzerland: engineered barriers for high-level waste disposal]]></title>
        <pubdate>2026-06-12T00:00:00Z</pubdate>
        <category>Review</category>
        <author>Nikitas Diomidis</author><author>Typhaine Guillemot</author><author>Lukas Martin</author><author>Alexandros Papafotiou</author><author>Olivier X. Leupin</author>
        <description><![CDATA[The safe geological disposal of high-level radioactive waste requires a passive multi-barrier system. This paper describes the engineered barriers foreseen in the provisional Swiss repository concept, covering both design aspects as well as evidence for their long-term performance. Disposal canisters made of carbon steel will be used for the encapsulation of spent nuclear fuel and vitrified high-level waste. The canisters are designed to corrode slowly and predictably in the repository as well as to withstand external mechanical loads, leading to long lifetimes. The bentonite buffer surrounding the canisters, upon saturation with water, will swell and provide a stable environment around the high-level waste disposal canisters, limiting corrosion, inhibiting microbial activity, and ensuring an even distribution of mechanical loads. Furthermore, after the breaching of the canisters and the release of radionuclides, the buffer ensures diffusion-dominated transport and promotes sorption and immobilisation by precipitation. In addition, a compacted bentonite sealing element seals the drift and limits water flow along the repository components. The properties of these components are understood well enough to allow an adequate description of their evolution over long time-scales, thus allowing to demonstrate their barrier function and long-term performance.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fnuen.2026.1854910</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fnuen.2026.1854910</link>
        <title><![CDATA[Neutronic and safety evaluation of a hybrid UO2-U3Si2 accident tolerant fuel assembly for VVER-1000 reactors]]></title>
        <pubdate>2026-06-11T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>S. M. Saidur Rahman Turjak</author>
        <description><![CDATA[This paper evaluates the neutronic feasibility and multi-physics safety of a hybrid Accident Tolerant Fuel (ATF) assembly in a VVER-1000 reactor. The proposed design strategically employs standard UO2 within the inner core and a high-density U3Si2 matrix in the peripheral pins to take advantage of inter-assembly thermalization for cycle length extension. Coupled evaluations were performed using OpenMC continuous-energy Monte Carlo transport and OpenFOAM steady-state conjugate heat transfer Computational Fluid Dynamics (CFD). The hybrid assembly meets the target of extending the depletion cycle to 540 days through the rapid breeding of peripheral Pu-239. Although this configuration induces intensely localized radial power peaking (399.18 W/cm3), the superior metallic thermal conductivity of U3Si2 (>15.0 W/m⋅K) completely eliminates the thermal penalty. OpenFOAM simulations of the ATF pins demonstrate that the peak centerline temperatures are reduced by 50 K compared to the interior of the UO2 core (690 K vs. 740 K), yielding a drastic reduction in localized sensible stored energy. Neutronic safety is strictly preserved, maintaining deeply negative Fuel and Moderator Temperature Coefficients (−1.895 pcm/K and −36.533 pcm/K) alongside a robust B4C Control Rod Worth (65,323.56 pcm). These results demonstrate that the hybrid ATF assembly fundamentally improves LOCA coping times while enhancing the overall economics of the reactor.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fnuen.2026.1857667</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fnuen.2026.1857667</link>
        <title><![CDATA[RADRISK Inspector: a mobile application for shielding design and safety distance calculation in industrial gamma radiography]]></title>
        <pubdate>2026-06-10T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>M. Suffo</author><author>D. Brea-Piñero</author><author>J. F. Molina-Pérez</author><author>J. M. Mota-Macías</author>
        <description><![CDATA[Industrial gamma radiography is a widely used non-destructive testing (NDT) technique, but it involves significant radiological risks that require precise planning of shielding and safety distances. Current practices rely heavily on in-situ radiometric measurements, which are time-consuming and may increase unnecessary operator exposure during setup and verification stages. This work presents RADRISK Inspector (RRI), a cross-platform mobile application that enables real-time radiological safety planning through physics-based calculations. The system estimates minimum safety distances, required shielding thickness, and risk zoning based on radionuclide activity, exposure parameters, and material attenuation properties. In addition, RRI integrates interactive zoning maps, exposure timers, and automated dosimetric reporting compliant with international standards (IAEA, CSN), supporting full digitalization of radiological risk management workflows. The application was preliminarily verified under real industrial conditions during pipeline weld inspections using an Ir-192 source. In this field case, RRI estimated an operator safety distance of 66 m, compared with 22 m obtained from in-situ dose-rate measurements, indicating conservative behaviour consistent with its safety-first planning approach. Accordingly, RRI is not intended to replace in-situ radiometric verification or high-fidelity radiation transport modelling, but to support conservative pre-inspection planning, risk zoning and traceable professional reporting in industrial gamma radiography. RRI represents a novel and beneficial application of radioactivity in modern industry, enabling proactive radiological protection, reducing unnecessary exposure, and improving operational efficiency in gamma radiography. Its compatibility with ATEX-certified devices further supports deployment in hazardous environments. This work supports a shift in radiographic NDT from reactive measurement-based practices to predictive, physics-based safety planning.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fnuen.2026.1840800</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fnuen.2026.1840800</link>
        <title><![CDATA[The safety case for a deep geological repository in Switzerland: assessment and modelling of the biosphere]]></title>
        <pubdate>2026-06-01T00:00:00Z</pubdate>
        <category>Methods</category>
        <author>Ashley Brown</author><author>Raphael A. J. Wüst</author><author>Russell Walke</author><author>Rebecca Newson</author><author>Louise Bruffell</author><author>Valentyn Bykov</author><author>Priska A. Hunkeler</author><author>Angela Landgraf</author><author>Urs H. Fischer</author><author>Jens K. Becker</author><author>Michael Schnellmann</author>
        <description><![CDATA[The post-closure biosphere assessment and modelling in support of the general licence application for a deep geological repository for radioactive waste provides the basis for evaluating radiological consequences should radionuclides released from the geological repository reach the surface and near-surface environments. The assessment approach comprises the modelling of radionuclide migration in the biosphere following potential releases from the geosphere to a local aquifer over timescales of tens of thousands to more than a million years. A stylised approach is adopted, including reference and alternative biosphere conditions, consistent with both national and international regulations and guidelines. The model is implemented in Nagra’s SwiBAC code, which allows radionuclide fluxes to the biosphere to be translated into potential doses to humans. This process yields equilibrium biosphere dose conversion factors (BDCFs) for each radionuclide for use in the analysis of radiological consequences, which occurs in a separate assessment step. Reference biosphere calculations are based on present-day conditions in Northern Switzerland, represented by a valley setting with a temperate climate. These conditions support a wide range of potential radionuclide transport and exposure pathways, including agricultural water use, soil-plant transfer, and local food consumption. Three alternative biospheres are also assessed to address uncertainties in long-term climate and geomorphology, including (i) a warmer-drier climate, where aquifer and surface flows are reduced while irrigation is increased, (ii) a cold climate with permafrost, where the exchange between soil and the aquifer is reduced, and (iii) a drained farmland setting with a high water table. BDCFs vary significantly between these cases, increasing by up to about an order of magnitude in warmer-drier conditions and decreasing by up to about five orders of magnitude under cold-climate conditions. These results highlight the key role of the shallow aquifer and transfer pathways within the valley agriculture system. Deterministic and probabilistic sensitivity analyses further highlight the influence of sorption in the shallow aquifer, hydrological fluxes, and agricultural transfer pathways. Together, the reference and alternative cases constrain key uncertainties and provide a robust, conservative basis for evaluating long-term radiological safety.]]></description>
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