National Ignition Facility

Le National Ignition Facility, ou NIF, est un laser de recherche extrêmement énergétique, construit au sein du laboratoire national Lawrence Livermore, à Livermore (Californie, États-Unis). Le NIF a des usages multiples. Ses deux fonctions principales sont le test des armes nucléaires des États-Unis et les expériences liées à l'énergie de fusion. Présentation générale Le National Ignition Facility utilise la technique du confinement inertiel pour permettre aux scientifiques d'étudier la fusion nucléaire et les autres domaines d'utilisation des plasmas extrêmement denses. La mise en œuvre de ce concept dans le NIF utilise 192 faisceaux laser de grande puissance, qui, après un parcours d'environ , sont focalisés sur une cible située au centre d'une « chambre d'expériences », sphère métallique de dix mètres de diamètre. La cible, constituée d'une capsule recouverte de béryllium renfermant un mélange de deutérium et de tritium servant de combustible de fusion, est ainsi comp

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Experimental investigation of prechamber autoignition in a natural gas engine for cogeneration

Daniel Favrat, Stefan Heyne, Michael Meier

A novel ignition concept based on autoignition in an unscavanged prechamber is currently being developed at the Laboratory for Industrial Energy Systems (LENI). On a single cylinder test engine a series of experimental runs (CR=8.5-14, =1-1.6, RPM=1150/1500 min−1) have been realized with natural gas as fuel, comparing the new ignition concept to standard spark ignition. The comparison is based on fuel efficiency and exhaust emissions (CO, THC, NOx). The feasibility of operating the engine in auto-ignition mode has been demonstrated, and the potential of prechamber autoignition, in particular in the lean combustion regime, is indicated by the trends in fuel efficiency and emission concentration. The resistive heating of the prechamber walls has been shown to be an effective mean to trigger ignition. The prechamber could clearly be identified as primary ignition location. A reduction of the cycle-by-cycle variations - due to mixture fluctuations - is necessary to exploit the full potential of this engine concept.

2009

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Current status of the engineering design of the test modules for the IFMIF

Under Broader Approach (BA) Agreement between EURATOM and Japan, IFMIF/EVEDA (International Fusion Materials Irradiation Facility/Engineering Validation and Engineering Design Activities) has been performed since the middle of 2007. IFMIF presents three main facilities (the Accelerator Facility, Li Target Facility and Test Facilities). A previous design of IFMIF was summarized in the comprehensive design report [1]. The present EVEDA phase aims at producing a detailed, complete and fully integrated engineering design of IFMIF. The delivery of the "Intermediate IFMIF Engineering Design Report" is foreseen mid-2013. The goal of IFMIF is to obtain the indispensable design database to allow the design and licensing of DEMO and ensuring commercial reactors thanks to the materials data set obtained from planned evaluation tests such irradiations in high flux test modules (HFTM-vertical rig, HFTM-horizontal rig), medium flux test modules (creep fatigue test module, tritium release test module, liquid breeder validation module) and low flux test modules of IFMIF. In addition, the Startup Monitoring Module will be used for IFMIF commissioning. This paper is summarizing the overall current progress status of the engineering and conceptual design of the test modules in IFMIF/EVEDA. (C) 2013 Elsevier B.V. All rights reserved.

Elsevier Science Sa2013

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Signatures of asymmetry in neutron spectra and images predicted by three-dimensional radiation hydrodynamics simulations of indirect drive implosions

Fabian Manke

We present the results of 3D simulations of indirect drive inertial confinement fusion capsules driven by the "high-foot" radiation pulse on the National Ignition Facility. The results are post-processed using a semi-deterministic ray tracing model to generate synthetic deuterium-tritium (DT) and deuterium-deuterium (DD) neutron spectra as well as primary and down scattered neutron images. Results with low-mode asymmetries are used to estimate the magnitude of anisotropy in the neutron spectra shift, width, and shape. Comparisons of primary and down scattered images highlight the lack of alignment between the neutron sources, scatter sites, and detector plane, which limits the ability to infer the rho r of the fuel from a down scattered ratio. Further calculations use high bandwidth multi-mode perturbations to induce multiple short scale length flows in the hotspot. The results indicate that the effect of fluid velocity is to produce a DT neutron spectrum with an apparently higher temperature than that inferred from the DD spectrum and which is also higher than the temperature implied by the DT to DD yield ratio. Published by AIP Publishing.

Amer Inst Physics2016

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Fusion par confinement inertiel

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Énergie de fusion nucléaire

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Accelerator physics covers a wide range of very exciting topics. This course presents basic physics ideas and the technologies underlying the workings of modern accelerators. An overview of the new ideas and challenges of the possible paths towards the next generation of accelerators will be given.