Current State of Research on Pressurized Water Reactor Safety

For more than 40 years, IPSN then IRSN has conducted research and development on nuclear safety, specifically concerning pressurized water reactors, which are the reactor type used in France. This publication reports on the progress of this research and development in each area of study – loss-of-coolant accidents, core melt accidents, fires and external hazards, component aging, etc. –, the remaining uncertainties and, in some cases, new measures that should be developed to consolidate the safety of today’s reactors and also those of tomorrow. A chapter of this report is also devoted to research into human and organizational factors, and the human and social sciences more generally. All of the work is reviewed in the light of the safety issues raised by feedback from major accidents such as Chernobyl and Fukushima Daiichi, as well as the issues raised by assessments conducted, for example, as part of the ten-year reviews of safety at French nuclear reactors. Finally, through the subjects it discusses, this report illustrates the many partnerships and exchanges forged by IRSN with public, industrial and academic bodies both within Europe and internationally

État des recherches dans le domaine de la sûreté des réacteurs à eau sous pression

Depuis plus de quarante ans, l'IPSN puis l'IRSN mènent des travaux de recherche et de développement dans le domaine de la sûreté nucléaire pour ce qui concerne tout particulièrement les réacteurs à eau sous pression, réacteurs qui équipent le parc électronucléaire français. Ce livre fait état de l'avancement de ces travaux pour chaque thématique abordée - accidents de perte de réfrigérant primaire, accidents de fusion du cœur, incendies et agressions d'origine externe, ou encore vieillissement des composants, etc.-, des incertitudes qui subsistent et, dans certains cas, de nouvelles dispositions qu'il serait opportun de développer pour consolider la sûreté des réacteurs d'aujourd'hui et aussi ceux de demain. Ce livre consacre également un chapitre à la recherche menée dans le domaine des facteurs humains et organisationnels, et plus généralement des sciences humaines et sociales. Tous ces travaux sont mis en regard des questions de sûreté soulevées par le retour d'expérience d'accidents majeurs tels que ceux de Tchernobyl ou de Fukushima Daiichi, aussi bien que de celles soulevées par les expertises menées dans le cadre, par exemple, des réexamens décennaux de sûreté des réacteurs nucléaires français. Enfin ce livre illustre, au travers des thématiques abordées, les très nombreux partenariats et échanges concrétisés par l'Institut avec le monde institutionnel, industriel ou universitaire, au plan européen ou international. La réalisation de cet ouvrage s'inscrit dans la volonté de l'IRSN de pérenniser ses acquis et de faire partager ses connaissances

Rapic project: toward a new generation of inexpensive heat exchanger-reactors for process intensification

Process intensification (PI) in chemical production is a major concern of chemical manufacturers. This alternative technology involves transposing syntheses into continuous plug flow reactors with process intensification, leading to a multifunctional heat exchanger-reactor. In this context, the RAPIC R&D project aims to develop an innovative low-cost component (in the 10 kg/hour range). This project deals with the design from the local to the global scale and with testing, from elementary mock-ups to pilot scale. The present paper gives a detailed description of this research project and presents the main results on specification and definition of the reaction channel and the first simple mock-ups

FPGA Implementation Of Diffusive Realization For A Distributed Control Operator

International audienceWe focus on the question of real-time computation for optimal distributed filtering or control applicable to MEMS Arrays. We present an algorithm for the realization of a linear operator solution to a functional equation through its application to a Lyapunov operatorial equation associated to the heat equation in one dimension. It is based on the diffusive realization, and turns to be well suited for fined grained parallel computer architecture as Field Programmable Gate Arrays (FPGA). An effective FPGA implementation has been successfully carried out. Here, we report the main implementation steps and the final measured performances

A cost effective AFM setup, combining interferometry and FPGA

International audienceAtomic force microscopes (AFM) provide high resolution images of surfaces. In this paper, we focus on an interferometry method for estimation of deflections in arrays of cantilever in quasi-static regime. We propose a novel complete solution with a least square based algorithm to determine interference fringe phases and its optimized FPGA implementation. Simulations and real tests show very good results and open perspectives for real-time estimation and control of cantilever arrays in the dynamic regime

LTTng CLUST: A System-Wide Unified CPU and GPU Tracing Tool for OpenCL Applications

As computation schemes evolve and many new tools become available to programmers to enhance the performance of their applications, many programmers started to look towards highly parallel platforms such as Graphical Processing Unit (GPU). Offloading computations that can take advantage of the architecture of the GPU is a technique that has proven fruitful in recent years. This technology enhances the speed and responsiveness of applications. Also, as a side effect, it reduces the power requirements for those applications and therefore extends portable devices battery life and helps computing clusters to run more power efficiently. Many performance analysis tools such as LTTng, strace and SystemTap already allow Central Processing Unit (CPU) tracing and help programmers to use CPU resources more efficiently. On the GPU side, different tools such as Nvidia’s Nsight, AMD’s CodeXL, and third party TAU and VampirTrace allow tracing Application Programming Interface (API) calls and OpenCL kernel execution. These tools are useful but are completely separate, and none of them allow a unified CPU-GPU tracing experience. We propose an extension to the existing scalable and highly efficient LTTng tracing platform to allow unified tracing of GPU along with CPU’s full tracing capabilities

Implementation of ‘chaotic’ advection for viscous fluids in heat exchanger/reactors

When viscous fluids are involved, laminar hydraulic conditions and heat and mass transfer intensification are conflicting phenomena. A channel geometry based on Split-And-Recombine (SAR) patterns is experimentally investigated. The principle implements the Baker’s transformation and ‘chaotic’ structures are generated to promote heat and mass transfer. This work assesses the energy efficiency of different heat exchanger/reactors integrating these SAR patterns. The heat transfer capacity is assessed and compared with the energy consumption of each mock-up. It is sensitive to the cooling mode and to the number of SAR patterns per length unit as well. The continuous oxidation of sodium thiosulfate with hydrogen peroxide has been implemented. Conversions up to 99% are reached according to the utility fluid temperature and the residence time. Finally, the whole performances of the SAR geometries are compared to a plate-type heat exchanger/reactor with a corrugated pattern. The more viscous the fluid, the more the energy efficiency of the SAR design increases compared to the corrugated design because of the balance between advection and diffusion mechanisms. The interest in terms of energy efficiency in working with SAR heat exchanger/reactor appears from Reynolds numbers below 50

Virage : Une réflexion pluridisciplinaire autour du temps dans la création numérique

We present in this article the development of the Virage project. This project aims to create a platform software for writting time and interaction in the context of digital stage management for living art. This project tries to answer some questions risen by a work group of AFIM (the french association for computer music). The project intends to produce a state of the art of the digital stage management, and to use this state to develop a prototype sotware. This propotype will be used in real conditions of stage management to get manager's points of view about our choices

Graphical Temporal Structured Programming for Interactive Music

International audienceThe development and authoring of interactive music or applications , such as user interfaces for arts & exhibitions has traditionally been done with tools that pertain to two broad metaphors. Cue-based environments work by making groups of parameters and sending them to remote devices , while more interactive applications are generally written in generic art-oriented programming environments, such as Max/MSP, Processing or openFrameworks. In this paper, we present the current version of the i-score se-quencer. It is an extensive graphical software that bridges the gap between time-based, logic-based and flow-based interactive application authoring tools. Built upon a few simple and novel primitives that give to the composer the expressive power of structured programming, i-score provides a time line adapted to the notation of parameter-oriented interactive music, and allows temporal scripting using JavaScript. We present the usage of these primitives, as well as an i-score example of work inspired from music based on polyvalent structure