French developments for improving In Service Inspection of SFRs

International audienceIn Service Inspection (ISI) is a major issue to be taken into account for future Sodium Fast Reactors safety, thus, a large R&D work is performed since 2010 in France for the future SFRs. ISI requirements have been taken into account since the early pre-conceptual design phase (specific rules for design have been merged into RCC-MRx design rules until 2012), then consolidated through the basic design phase with more detailed specifications leading to increase the ISI tools ability for immersed sodium structures of SFRs, at about 200°C (shut down conditions). Inspection within the main vessel are planned with transducers immersed in sodium and also with transducers located out of sodium medium. Finally, the qualification of ISI ultrasonic transducers (for Non Destructive Examination, Telemetry and Imaging) is being performed with experimental water and sodium testing, to be compared to simulation with CIVA software platform results. A pluri-annual R&D program mainly deals with the reactor block structures, the primary components and circuit, and the Power Conversion System. Specific developments have been performed for NDE of thick austenitic steel welds, NDE using guided Lamb waves, telemetry from the outside of reactor vessel, imaging of immersed structures and components within the large primary vessel (in a pool type reactor concept) and associated in sodium robotics (with in-sodium tightness). Some results of testing and simulation are given for some ASTRID project applications

Detecting the translocation of DNA through a nanopore using graphene nanoribbons

Solid-state nanopores can act as single-molecule sensors and could potentially be used to rapidly sequence DNA molecules. However, nanopores are typically fabricated in insulating membranes that are as thick as 15 bases, which makes it difficult for the devices to read individual bases. Graphene is only 0.335 nm thick (equivalent to the spacing between two bases in a DNA chain) and could therefore provide a suitable membrane for sequencing applications. Here, we show that a solid-state nanopore can be integrated with a graphene nanoribbon transistor to create a sensor for DNA translocation. As DNA molecules move through the pore, the device can simultaneously measure drops in ionic current and changes in local voltage in the transistor, which can both be used to detect the molecules. We examine the correlation between these two signals and use the ionic current measurements as a real-time control of the graphene-based sensing device

Label-Free Optical Detection of Biomolecular Translocation through Nanopore Arrays

In recent years, nanopores have emerged as exceptionally promising single-molecule sensors due to their ability to detect biomolecules at subfemtomole levels in a label-free manner. Development of a high-throughput nanopore-based biosensor requires multiplexing of nanopore measurements. Electrical detection, however, poses a challenge, as each nanopore circuit must be electrically independent, which requires complex nanofluidics and embedded electrodes. Here, we present an optical method for simultaneous measurements of the ionic current across an array of solid-state nanopores, requiring no additional fabrication steps. Proof-of-principle experiments are conducted that show simultaneous optical detection and characterization of ssDNA and dsDNA using an array of pores. Through a comparison with electrical measurements, we show that optical measurements are capable of accessing equivalent transmembrane current information

Erreur d'estimation intervenant dans l'analyse de fluctuations accessibles sous de faibles rapports signal sur bruit

On compare l'erreur d'estimation due au temps de mesure fini pour différentes méthodes d'analyse spectrale : estimation de la corrélation directe ou croisée, ou estimation de la densité spectrale de puissance par filtrage dans une fenêtre étroite, ou transformation de Fourier, le plus souvent F.F.T., directement sur le signal ou sur la corrélation. Dans toutes les méthodes, on peut approximer dans le cas gaussien la variance de l'estimateur par une expression déjà connue. En introduisant la notion de bande équivalente du second ordre on peut généraliser les résultats. Dans le cas pratique où l'on cherche à estimer le signal constitué par la partie corrélée de deux voies de mesure bruitées, on donne l'influence du bruit sur cette variance par l'intermédiaire d'un rapport signal sur bruit, de définition différente selon la méthode. Ceci permet de préciser l'avantage en rapidité de convergence de l'intercorrélation sur l'auto-corrélation corrigée du bruit, ou même de l'interspectre sur l'autospectre corrigé, qui apparaît dans le cas d'un rapport signal sur bruit faible. La validité de ce calcul est vérifiée par la mesure de l'erreur d'estimation dans le cas d'une analyse spectrale directe et croisée du bruit thermique de résistances, effectuée par F.F.T. dans un domaine de rapport signal sur bruit allant de 0,01 à 20

French developments for improving In Service Inspection of SFRs

International audienceIn Service Inspection (ISI) is a major issue to be taken into account for future Sodium Fast Reactors safety, thus, a large R&D work is performed since 2010 in France for the future SFRs. ISI requirements have been taken into account since the early pre-conceptual design phase (specific rules for design have been merged into RCC-MRx design rules until 2012), then consolidated through the basic design phase with more detailed specifications leading to increase the ISI tools ability for immersed sodium structures of SFRs, at about 200°C (shut down conditions). Inspection within the main vessel are planned with transducers immersed in sodium and also with transducers located out of sodium medium. Finally, the qualification of ISI ultrasonic transducers (for Non Destructive Examination, Telemetry and Imaging) is being performed with experimental water and sodium testing, to be compared to simulation with CIVA software platform results. A pluri-annual R&D program mainly deals with the reactor block structures, the primary components and circuit, and the Power Conversion System. Specific developments have been performed for NDE of thick austenitic steel welds, NDE using guided Lamb waves, telemetry from the outside of reactor vessel, imaging of immersed structures and components within the large primary vessel (in a pool type reactor concept) and associated in sodium robotics (with in-sodium tightness). Some results of testing and simulation are given for some ASTRID project applications

Correction to Nonlinear Optical Response in Single Alkaline Niobate Nanowires

Correction to Nonlinear Optical Response in Single Alkaline Niobate Nanowire

DETERMINISTIC LATERAL DISPLACEMENT FOR THE SORTING OF EXTRACELLULAR VESICLES FROM COMPLEX BIOLOGICAL SAMPLES

International audienc

Nanopore Detection of Single Molecule RNAP–DNA Transcription Complex

In the past decade, a number of single-molecule methods have been developed with the aim of investigating single protein and nucleic acid interactions. For the first time we use solid-state nanopore sensing to detect a single <i>E. coli</i> RNAP–DNA transcription complex and single <i>E. coli</i> RNAP enzyme. On the basis of their specific conductance translocation signature, we can discriminate and identify between those two types of molecular translocations and translocations of bare DNA. This opens up a new perspectives for investigating transcription processes at the single-molecule level