First 3D numerical simulations validated with experimental measurements during a LOVA reproduction inside the new facility STARDUST-Upgrade

Ciparisse, Jean-François; Malizia, A.; Poggi, Luigi Antonio; Gelfusa, M.; Murari, A.; Mancini, A.; Gaudio, P.

doi:10.1016/j.fusengdes.2015.09.002

Cited by 16 publications

(7 citation statements)

References 8 publications

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“…Pressurization rates obtained were 218.9 Pa/s (27 L/min) and 319.3 Pa/s (40 L/min). A typical run lasted several minutes, however, only the first few seconds are crucial for the dust re-suspension studies [33][34][35], because in less than 5 seconds all the dust is usually mobilized due to the air velocity peak occurring [22][23][24][25][26]. Therefore, data presented is focused on the first 10 seconds of the accident replicated.…”

Section: Jinst 11 C07012 3 Results and Discussionmentioning

confidence: 99%

“…Nowadays, among the advanced tools for nuclear fusion safety there are the numerical codes developed to describe and predict the dust mobilization phenomena in case of accidents. Recently, the thermo-fluid dynamic consequences of LOVAs, including dust re-suspension phenomena, have been described by several commercial codes [31][32][33][34][35][36][37][38][39][40][41][42]. However, there is still a lack of experimental data sufficient to validate the models.…”

Section: Introductionmentioning

confidence: 99%

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STARDUST-U experiments on fluid-dynamic conditions affecting dust mobilization during LOVAs

et al. 2016

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Since 2006 the Quantum Electronics and Plasma Physics (QEP) Research Group together with ENEA FusTech of Frascati have been working on dust re-suspension inside tokamaks and its potential capability to jeopardize the integrity of future fusion nuclear plants (i.e. ITER or DEMO) and to be a risk for the health of the operators. Actually, this team is working with the improved version of the "STARDUST" facility, i.e. "STARDUST-Upgrade". STARDUST-U facility has four new air inlet ports that allow the experimental replication of Loss of Vacuum Accidents (LOVAs). The experimental campaign to detect the different pressurization rates, local air velocity, temperature, have been carried out from all the ports in different accident conditions and the principal results will be analyzed and compared with the numerical simulations obtained through a CFD (Computational Fluid Dynamic) code. This preliminary thermo fluid-dynamic analysis of the accident is crucial for numerical model development and validation, and for the incoming experimental campaign of dust resuspension inside STARDUST-U due to well-defined accidents presented in this paper. K: Data acquisition concepts; Nuclear instruments and methods for hot plasma diagnostics 1Corresponding author.

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Section: Jinst 11 C07012 3 Results and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

STARDUST-U experiments on fluid-dynamic conditions affecting dust mobilization during LOVAs

et al. 2016

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“…The fluid dynamics of these events has been experimentally and numerically investigated inside the scaled experimental facilities. The authors carried out, in old works [18,27,[29][30][31], campaigns, where pressure, velocity, and temperature have been measured and analysed. Then, different numerical models have been developed to replicate properly LOVA events.…”

Section: Discussionmentioning

confidence: 99%

“…In previous works, the authors tested different Computational Fluid-Dynamics models and boundary conditions and compared the numerical results with experimental measurements that were performed in a scaled vacuum vessel, called STARDUST [30], before and using an improved STADUST-Upgrade, the results showed a good capability of the numerical simulation to replicate well the real case [31,32].…”

Section: Introductionmentioning

confidence: 99%

3D Simulation of a Loss of Vacuum Accident (LOVA) in ITER (International Thermonuclear Experimental Reactor): Evaluation of Static Pressure, Mach Number, and Friction Velocity

et al. 2018

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ITER (International Thermonuclear Experimental Reactor) is a magnetically confined plasma nuclear reactor. Inside it, due to plasma disruptions, the formation of neutron-activated powders, which are essentially made out of tungsten and beryllium, occurs. As many windows for diagnostics are present on the reactor, which operates at very low pressure, a LOVA (Loss of Vacuum Accident) could be possible and may lead to dust mobilisation and a toxic and radioactive fallout inside the plant. This study is aimed at reproducing numerically the first seconds of a LOVA in ITER, in order to get information about the dust resuspension risk. This work has been carried out by means of a CFD (Computational Fluid Dynamics) simulation of the beginning of the pressurisation transient inside the whole Tokamak. It has been found that the pressurization transient is extremely slow, and that the friction speed on the walls is very high, and therefore a high mobilization risk of the dust is expected on the entire internal surface of the reactor. It has been observed that a LOVA in a real-scale reactor is more severe than the one reproduced in reduced-scale facilities, as STARDUST-U, because the speeds are higher, and the dust resuspension capacity of the flow is greater.

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“…Modeling of a fusion reactor vacuum vessel is crucial for accident analysis and to predict materials inventory and mobilization, both from the experimental and numerical point of view. For that reason, along with experimental facilities to reproduce source term mobilization phenomena [26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36] it is also very important to develop a numerical model [37, 38] in order to predict particles quantities, velocity and direction in case of accidents such as a loss of vacuum, and not referring just to administrative limits but to estimates based on a more accurate methodology.…”

Section: Introductionmentioning

confidence: 99%

A novel integrated approach for the hazardous radioactive dust source terms estimation in future nuclear fusion power plants

Poggi

Malizia

Ciparisse

et al. 2016

Heliyon

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An open issue still under investigation by several international entities working on the safety and security field for the foreseen nuclear fusion reactors is the estimation of source terms that are a hazard for the operators and public, and for the machine itself in terms of efficiency and integrity in case of severe accident scenarios. Source term estimation is a crucial key safety issue to be addressed in the future reactors safety assessments, and the estimates available at the time are not sufficiently satisfactory. The lack of neutronic data along with the insufficiently accurate methodologies used until now, calls for an integrated methodology for source term estimation that can provide predictions with an adequate accuracy. This work proposes a complete methodology to estimate dust source terms starting from a broad information gathering. The wide number of parameters that can influence dust source term production is reduced with statistical tools using a combination of screening, sensitivity analysis, and uncertainty analysis. Finally, a preliminary and simplified methodology for dust source term production prediction for future devices is presented.

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First 3D numerical simulations validated with experimental measurements during a LOVA reproduction inside the new facility STARDUST-Upgrade

Cited by 16 publications

References 8 publications

STARDUST-U experiments on fluid-dynamic conditions affecting dust mobilization during LOVAs

STARDUST-U experiments on fluid-dynamic conditions affecting dust mobilization during LOVAs

3D Simulation of a Loss of Vacuum Accident (LOVA) in ITER (International Thermonuclear Experimental Reactor): Evaluation of Static Pressure, Mach Number, and Friction Velocity

A novel integrated approach for the hazardous radioactive dust source terms estimation in future nuclear fusion power plants

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