117 research outputs found

    Fabrication routes for advanced first wall design alternatives

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    In future nuclear fusion reactors, plasma facing components have to sustain specific neutron damage. While the majority of irradiation data provides a relatively clear picture of the displacement damage, the effect of helium transmutation is not yet explored in detail. Nevertheless, available results from simulation experiments indicate that 9%-chromium steels will reach their operating limit as soon as the growing helium bubbles extent a critical size. At that point, the material would most probably fail due to grain boundary embrittlement. In this contribution, we present a strategy for the mitigation of the before-mentioned problem using the following facts. (1) The neutron dose and related transmutation rate decreases quickly inside the first wall of the breeding blankets, that is, only a plasma-near area is extremely loaded. (2) Nanostructured oxide dispersion strengthened (ODS) steels may have an enormous trapping effect on helium, which would suppress the formation of large helium bubbles for a much longer period. (3) Compared to conventional steels, ODS steels also provide improved irradiation tensile ductility and creep strength. Therefore, a design, based on the fabrication of the plasma facing and highly neutron and heat loaded parts of blankets by an ODS steel, while using EUROFER97 for everything else, would extend the operating time and enable a higher heat flux. Consequently, we (i) developed and produced 14%Cr ferritic ODS steel plates and (ii) optimized and demonstrated a scalable industrial production route. (iii) We fabricated a mock-up with five cooling channels and a plated first wall of ODS steel, using the same production processes as for a real component. (iv) Finally, we performed high heat flux tests in the Helium Loop Karlsruhe, applying a few hundred short and a few 2 h long pulses, in which the operating temperature limit for EUROFER97 (i.e. 550 â—¦C) was finally exceeded by 100 K. (v) Thereafter, microstructure and defect analyses did not reveal critical defects or recognizable damage. Only a heat affected zone in the EUROFER/ODS steel interface could be detected. However, a solution to prohibit the formation of such heat affected zones is given. These research contributions demonstrate that the use of ODS steel is not only feasible and affordable but could make a decisive difference in the future design and performance of breeding blankets

    Impact of materials technology on the breeding blanket design – Recent progress and case studies in materials technology

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    A major part in the EUROfusion materials research program is dedicated to characterize and quantify nuclear fusion specific neutron damage in structural materials. While the majority of irradiation data gives a relatively clear view on the displacement damage, the effect of transmutation – i.e. especially hydrogen and helium production in steels – is not yet explored very well. However, few available results indicate that EUROFER-type steels will reach their operating limit as soon as the formation of helium bubbles reaches a critical amount or size. At that point, the material would fail due to embrittlement at the considered load. This paper presents a strategy for the mitigation of the before-mentioned problem using the following facts: • the neutron dose and related transmutation rate decreases quickly inside the first wall, that is, only a plasma-near area is extremely loaded • nanostructured oxide dispersion strengthened (ODS) steels may have an enormous trapping effect on helium and hydrogen, which would suppress the formation of large helium bubbles • compared to conventional steels, ODS steels show improved irradiation tensile ductility and creep strength In summary, producing the plasma facing, highly neutron and heat loaded part of blankets by an ODS steel, while using EUROFER97 for everything else, would allow a higher heat flux as well as a longer operating period. Consequently, we (1) developed and produced 14 % Cr ferritic ODS steel plates. (2) We fabricated a mockup with 5 cooling channels and a plated first wall of ODS steel, using the same production processes as for a real component. And finally, (3) we performed high heat flux tests in the HELOKA facility (Helium Loop Karlsruhe at KIT) applying short and up to 2 h long pulses, in which the operating temperature limit for EUROFER97 (i.e., 550 °C) was finally exceeded by 100 K. Thereafter, microstructure and defect analyses did not reveal defects or recognizable damage. Only a heat affected zone in the EUROFER/ODS steel interface could be detected. This demonstrates that the use of ODS steel could make a decisive difference in the future design and performance of breeding blankets

    Analysing Port Community System Network Evolution

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    Ports have played an important role in facilitating exchanges among countries since the day when inland transportation was poor. As ports become hubs for global supply chain, they have to maintain their competitiveness not only by reassuring their efficiency, reliability, accessibility to hinterland, and sustainability. In addition, there is a constant challenge from all operational parties of the port to acquire needed information or to trust information received, due to multiple legacy systems and platforms that do not integrate with each other, and to the lack of real time updates. There are differing agendas between parties and, sometimes, distrust within the multi-stakeholder ecosystem leads to working in silos. This jeopardises seamless data exchange and cooperation across the port value chain, resulting in significant inefficiencies. Port community system (PCS) can enhance communication and simplify administrative process resulting economic and environmental benefit for actors in the supply chain. The invisibility of the benefit, actors’ heterogeneity and significant investment to develop the system resulting a reluctance in implementing PCS. This chapter aims to study the evolution mechanism behind the process of PCS network development using lessons learned from industrial symbiosis network development and network trajectories theory. The PCS network development follows a serendipitous and goal-oriented process that can be categorised into three stages: pre-PCS network, PCS network emergence, and PCS network expansion. This chapter contributes to the exploration of network evolution and documents lesson learned to foster PCS implementation.© 2020 Springer. This is a post-peer-review, pre-copyedit version of an article published in European Port Cities in Transition: Moving Towards More Sustainable Sea Transport Hubs. The final authenticated version is available online at: http://dx.doi.org/10.1007/978-3-030-36464-9_10fi=vertaisarvioitu|en=peerReviewed

    An Examination of Officer Stress: Should Police Departments Implement Mandatory Counseling?

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    This study suggests that police departments who promote counseling benefit from officer stress reduction. Officers from sixteen municipal police departments (n = 1,114) across the state of Alabama possessed moderate stress, but were influenced significantly by organizational demographics (including counseling opportunities). A majority of officers believed that stress signs were not predictive of police suitability but remained reluctant to share fears and anxieties with fellow colleagues, suggesting that officers feared the stigma associated with the need for stress counseling. Officers working in supportive counseling climates had significantly less stress, a reduced need for counseling, and a greater willingness to use counseling. Officers who engaged in counseling (at least occasionally) also reported more stress, indicating an awareness of their need for counseling. The authors concluded that police departments should consider requiring mandatory and periodic counseling for all officers, a procedural tactic that camouflages counseling need while concurrently treating the source of officer stress. © 2008 Springer Science + Business Media, LLC

    Automatic application of ICRP biokinetic models in voxel phantoms for in vivo counting and internal dose assessment

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    As part of the improvement of calibration techniques of in vivo counting, the Laboratory of Internal Dose Assessment of the Institute of Radiological Protection and Nuclear Safety has developed a computer tool, 'OEDIPE', to model internal contamination, to simulate in vivo counting and to calculate internal dose. The first version of this software could model sources located in a single organ. As the distribution of the contamination evolves from the time of intake according to the biokinetics of the radionuclide, a new facility has been added to the software first to allow complex heterogeneous source modelling and then to automatically integrate the distribution of the contamination in the different tissues estimated by biokinetic calculation at any time since the intake. These new developments give the opportunity to study the influence of the biokinetics on the in vivo counting, leading to a better assessment of the calibration factors and the corresponding uncertainties. © The Author 2007. Published by Oxford University Press. All rights reserved

    Développements apportés au logiciel OEDIPE de simulation de mesures anthroporadiamétriques pour la prise en compte des données biocinétiques dans la modélisation de la contamination interne

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    Dans le cadre de l’amélioration des techniques d’étalonnage en anthroporadiamétrie, le Laboratoire d’Évaluation de la Dose Interne de l’IRSN a développé un outil numérique, « OEDIPE », pour modéliser la contamination interne dans des fantômes numériques voxélisés, simuler la mesure anthroporadiamétrique et estimer la dose interne. Si la précédente version d’OEDIPE permettait de bien modéliser des géométries de source comprenant un seul radionucléide localisé dans un organe particulier, elle était cependant limitée pour la modélisation d’une contamination formée d’un mélange de radionucléides dont la localisation évolue à partir de l’incorporation pour se distribuer dans plusieurs organes. Cet article a pour but de décrire les nouveaux modules développés pour permettre la définition de sources hétérogènes en composition et en répartition ainsi que l’importation automatique de distributions d’activité dérivées du calcul biocinétique. Ces nouveaux outils vont permettre d’étudier des cas de contamination plus complexes et l’influence de la biocinétique en mesure in vivo, afin de mieux estimer les coefficients d’étalonnage et les incertitudes correspondantes

    Future Law Enforcement Officers and Social Workers: Perceptions of Domestic Violence

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    This study compares perceptions of domestic violence for college students planning to work in law enforcement with students aspiring to careers in social work and non-law-enforcement criminal justice (N = 491). The study involves students attending four public universities across one Southern state who completed a survey (spring of 2006) measuring whether various scenarios were (1) related to domestic violence, and (2) worthy of being reported to law enforcement. Findings indicate that all student groups (law enforcement, non-law-enforcement criminal justice, and social work) tended to identify the various scenarios as domestic violence (and worthy of being reported) regardless of the person\u27s sexual orientation, violence severity, and offender\u27s or victim\u27s gender. However, law enforcement students are less sensitive to domestic violence when compared with social work and non-law enforcement criminal justice students. Findings reveal that (1) graduate students, (2) female students, and (3) White students (compared with African American students in general) attending majority White universities were more likely to identify domestic violence and its worthiness of being reported. The data in this study indicate that criminal justice programs produce graduates who are reasonably sensitive toward the importance of appropriate domestic violence response but could still improve using the techniques employed within social work programs
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