Identification and categorisation of safety issues for ESNII reactor concepts. Part I: Common phenomena related to materials

International audience; With the aim to develop a joint proposal for a harmonised European methodology for safety assessment of advanced reactors with fast neutron spectrum, SARGEN-IV (Safety Assessment for Reactors of Gen IV) Euratom coordination action project gathered together twenty-two partners' safety experts from twelve EU Member States. The group consisted of eight European Technical Safety Organisations involved in the European Technical Safety Organisation Network (ETSON), European Commission's Joint Research Centre (JRC), system designers, industrial vendors as well as research and development (RandD) organisations. To support the methodology development, key safety features of four fast neutron spectrum reactor concepts considered in Deployment Strategy of the Sustainable Nuclear Energy Technology Platform (SNETP) were reviewed. In particular, outcomes from running European Sustainable Nuclear Industrial Initiative (ESNII) system projects and related Euratom collaborative projects for Sodium-cooled Fast Reactors, Lead-cooled Fast Reactors, Gas-cooled Fast Reactors, and the lead-bismuth eutectic cooled Fast Spectrum Transmutation Experimental Facility were gathered and critically assessed. To allow a consistent build-up of safety architecture for the ESNII reactor concepts, the safety issues were further categorised to identify common phenomena related to materials. Outcomes of the present work also provided guidance for the identification and prioritisation of further RandD needs respective to the identified safety issues. © 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-NDlicense

General Synthesis Report of the Different ADS Design Status. Establishment of a Catalogue of the R&D needs

This document is a General Synthesis Report of the Different ADS Design Status being designed within the EUROTRANS Integrated Project; an FP6 European commission partially funded programme. This project had the goal to demonstrate the possibility of nuclear waste transmutation/burning in Accelerator Driven Systems (ADS) at industrial scale.The focus is on a Pb-cooled ADS for the European Facility on Industrial scale Transmuter (ETD/EFIT) with a back-up solution based on an He cooled ADS.As an intermediate step towards this industrial-scale prototype, an eXperimental Transmuter based on ADS concept (ETD/XT-ADS) able to demonstrate both the feasibility of the ADS concept and to accumulate experience when using dedicated fuel sub-assemblies or dedicated pins within a MOX fuel core has been also studied.The two machines (XT-ADS and Pb cooled EFIT) have been designed in a consistent way bringing more credibility to the potential licensing of these plants and with sufficient details to allow definition of the critical issues as regards design, safety and associated technological and basic R&D needs. The different designs fit rather well with the technical objectives fixed at the beginning of the project in consistency with the European Roadmap on ADS development.For what concerns the accelerator, the superconducting LINAC has been clearly assessed as the most suitable concept for the three reactors in particular with respect to the stringent requirements on reliability. Associated R&D needs have been identified and will be focused on critical components (injector, cryomodule) long term testing.The design of the different ADS has been performed in view of what is reasonably achievable pending the completion of R&D programmes. The way the EUROTRANS Integrated Project has been organised with other domains than the DM1 Design being specifically devoted to R&D tasks in support to the overall ETD/EFIT and ETD/XT-ADS design tasks has been helpful. The other domains were centred on the assessment of reactivity measurement techniques (DM2 ECATS), on the development of U-free dedicated fuels (DM3 AFTRA), on materials behaviour and heavy liquid metal technology (DM4 DEMETRA) and on nuclear data assessment (DM5 NUDATRA). Pending questions associated to technology gaps have been identified through the different appropriate R&D work programmes and a Catalogue of the R&D needs has been established.Finally, the work within the EUROTRANS integrated project has provided an overall assessment of the feasibility at a reasonable cost for an ADS based transmutation so that a decision can be taken to launch a detailed design and construction of the intermediate step Experimental ADS now already launched within the 7th FP programme under the name of Common Design Team (CDT)

Determination of the Young's modulus of a TiN Thin Film by nanoindentation: analytical models and numerical FEM simulation.

International audienc

Determination of the Young's modulus of a TiN Thin Film by nanoindentation: analytical models and numerical FEM simulation.

International audienc

Development of a new phase for lab-on-a-chip extraction of polycyclic aromatic hydrocarbons from water

International audienceThis work reports on the improved performance using nanoporous organosilicate (SiOCH) for lab-on a-chip extraction of organic pollutants from natural waters. Validations were carried out for polycyclic aromatic hydrocarbons (PAHs) extraction, and the results were compared with the commonly used SBSE laboratory technique (Stir-Bar Sorptive Extraction). While a previous study performed with PDMS coated lab-on-a-chips had showed limitations for the most polar PAHs (log K-ow < 5.5) and real matrices, we demonstrate here that, thanks to the novel phase, there is a good affinity for PAHs, even in natural waters. An improved microfluidic device in term of channel width and chip total area could be selected. Most importantly, the extraction time of 20 min still used with this type of microfluidic device is very short compared to the 24 h needed with the SBSE laboratory technique. Moreover, the high specific surface area of the nanoporous phase reduces the matrix effects related to interferences with dissolved organic matter. Therefore these new porous SiOCH coated extraction microchips appear as a good alternative to PDMS-based extraction techniques such as SBSE and should be used for further development of field analysis devices

Modelling of environmentally assisted crack growth in ceramics

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Stability of polymers under ionising radiation: The many faces of radiation interactions with polymers

International audienceIonising radiations have dramatic effects on the properties of polymers commonly used in hard radiation environments. From the early radiolysis studies, polymers have been classified into those undergoing mainly chain scissions and those being cross-linked. Real situations are however far more complex due to the semi-crystalline organisation of most polymers implying transition temperatures (glass transition, fusion temperature of the crystalline fraction), oxygen diffusion driven formation of oxidised species and effects of the polymer formulation (anti-oxidants, influence of the fillers). Progress has been made in the understanding of such phenomena and different examples have been considered illustrating the different faces of the polymer evolution under ionising radiation. Particular emphasis has been given to the changes of the final polymer properties in their conditions of use. Two examples of materials of widespread importance in nuclear technology: elastomers and epoxy resins, will be discussed

Thin hybrid pixel assembly fabrication development with backside compensation layer

The ATLAS and CMS experiments will both replace their entire tracking systems for operation at the HL-LHC in 2026. This will include a significantly larger pixel systems, for example, for ATLAS approximately 15 m2. To keep the tracker material budget low it is crucial to minimize the mass of the pixel modules via thinning both the sensor and readout chip to about 150 μm each. The bump yield of thin module assemblies using solder based bump bonding can be problematic due to wafer bowing during solder reflow at high temperature. A new bump-bonding process using backside compensation on the readout chip to address the issue of low yield will be presented. The objective is to compensate dynamically the stress of the front side stack by adding a compensating layer to the backside of the wafer. A SiN and Al:Si stack has been chosen for the backside layer. The bow reducing effect of applying a backside compensation layer will be demonstrated using the FE-I4 wafer. The world's first results from assemblies produced from readout wafers thinned to 100 μm with a stress compensation layer are presented with bond yields close to 100% measured using the FE-I4 readout chip