Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Bentaib, A.*; Chaumeix, N.*; Nyrenstedt, G.*; Bleyer, A.*; Maas, L.*; Gastaldo, L.*; Kljenak, I.*; Dovizio, D.*; Kudriakov, S.*; Schramm, B.*; et al.
Proceedings of 19th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-19) (Internet), 11 Pages, 2022/03
In case of a core melt-down accident in a light water nuclear reactor, hydrogen is produced during reactor core degradation and released into the reactor building. In case of failure of in-vessel corium retention, a large amount of carbon monoxide (CO) in addition to H
and other gases may be produced during molten core concrete interaction (MCCI). This subsequently creates a combustion hazard. A local ignition of the combustible mixture may generate standing flames or initially slow propagating flames. Depending on geometry, mixture composition and turbulence level, the flame can accelerate or be quenched after a certain distance. The pressure and temperature loads generated by the combustion process may threaten the integrity of the containment building and safety equipment. The evaluation of such loads requires validated codes which can be used with a high level of confidence. Currently, turbulence and steam effect on flame propagation mechanisms are not well reproduced by combustion models usually implemented in safety tools and further model enhancement and validation are still needed. For this purpose and at the initiative of the SAMHYCO-NET project consortium and of the European Technical Safety Organization Network (ETSON), a benchmark on hydrogen combustion was organized with the goal to identify the current level of the computational tools in the area of hydrogen combustion simulation under conditions typical for safety considerations in a Nuclear Power Plant (NPP). This benchmark is composed of four main steps with increasing difficulty starting from flame propagation in homogenous dry atmosphere and finishing with more representative conditions with (H/HO/O/N) stratified mixtures. In this paper, only experiments related to flame propagation in homogenous atmosphere are considered.
Studer, E.*; 安部 諭; Andreani, M.*; Bharj, J. S.*; Gera, B.*; Ishay, L.*; Kelm, S.*; Kim, J.*; Lu, Y.*; Paliwal, P.*; et al.
Proceedings of 12th International Topical Meeting on Nuclear Reactor Thermal-Hydraulics, Operation and Safety (NUTHOS-12) (USB Flash Drive), 16 Pages, 2018/10
Nuclear engineering research groups were interested in the phenomena of the interaction between a rising jet and a stratified layer located above in order to better understand the underlying mechanisms of hydrogen accumulation and dispersion in a nuclear reactor containment. Previous studies were performed with an upward jet of fluid heavier or lighter than the upper stratified layer. However, in real configurations i.e. the inner part of a nuclear containment, obstacles such as pipes, components as pumps or reservoirs and walls are present, and they can dissipate the initial momentum of the gas release. Consequently, the upward flow pattern can be considered "diffuse" and buoyant, neither pure jet nor pure plume. Therefore, this challenging issue was part of a project called HYMERES, which was launched and conducted in the OECD/NEA framework. Dedicated experiments were performed to study the interaction between a diffuse buoyant jet and two-layer stratification. In the large-scale MISTRA facility, the HM1-1 test series were conducted in which the erosive flow pattern came from a horizontal hot air jet impinging on a vertical cylinder. These experimental results were offered for a blind and open benchmark exercise.
Bentaib, A.*; Chaumeix, N.*; Grosseuvres, R.*; Bleyer, A.*; Gastaldo, L.*; Maas, L.*; Jallais, S.*; Vyazmina, E.*; Kudriakov, S.*; Studer, E.*; et al.
Proceedings of 12th International Topical Meeting on Nuclear Reactor Thermal-Hydraulics, Operation and Safety (NUTHOS-12) (USB Flash Drive), 11 Pages, 2018/10
In the framework of the French MITHYGENE project, the new highly instrumented ENACCEF2 facility was built at the Institut de Combustion Aerothermique Reactivite et Environnement (ICARE) of the Centre National de la Recherche Scientifique (CNRS) in Orleans (France) to address the flame propagation in hydrogen combustion during a severe accident. The ENACCEF2 facility is a vertical tube of 7.65 m height and 0.23 m inner diameter. In the lower part of the tube, annular obstacles are installed to promote turbulent flame propagation. At the initiative of the MITHYGENE project consortium and the European Technical Safety Organisation Network (ETSON), a benchmark on hydrogen combustion was organised with the goal to identify the current level of the computational tools in the area of hydrogen combustion simulation under conditions typical for safety considerations for NPP. In the proposed paper, the simulation results obtained by participating organizations, using both Computational Fluid Dynamics (CFD) and lumped-parameter computer codes, are compared to experimental results and analysed.
Bolton, P.; Borghesi, M.*; Brenner, C.*; Carroll, D. C.*; De Martinis, C.*; Fiorini, F.*; Flacco, A.*; Floquet, V.*; Fuchs, J.*; Gallegos, P.*; et al.
Physica Medica; European Journal of Medical Physics, 30(3), p.255 - 270, 2014/05
被引用回数：77 パーセンタイル：88.84(Radiology, Nuclear Medicine & Medical Imaging)Suitable instrumentation for laser-accelerated proton (ion) beams is critical to the development of integrated, laser-driven ion accelerator systems. Instrumentation aimed at beam diagnostics and control must be applied to the driving laser pulse, the laser-plasma that it forms at the target and the emergent proton (ion) bunch in a correlated way to develop these novel accelerators. This report is a brief overview of established diagnostic techniques and new developments based on material presented at the first workshop on "Instrumentation for Diagnostics and Control of Laser-accelerated Proton (ion) Beams" in Abingdon, UK. It includes radiochromic film (RCF), image plate (IP), the micro-channel plate (MCP), the Thomson spectrometer, prompt inline scintillation, time and space-resolved interferometry (TASRI) and nuclear activation schemes. Repetition-rated instrumentation requirements for target metrology are also addressed.
