1,721,035 research outputs found
Analisi di uno scenario di parziale congelamento del sistema primario
Get PDFIn the context of GEN-IV Heavy Liquid Metal safety studies, the lead freezing in the pool is considered one of the main issues to be addressed and a realistic accident for LFR. The present document is a first step towards a detailed analysis of such phenomena, and a CFD model and approach is presented to have a detailed thermo-fluid dynamic picture in the case of freezing. In particular, a numerical methodology is presented to model the freezing of lead and the heat transfer in a proper way. Then, the model is applied to the shell and tube Heat Exchanger of the NACIE-UP facility
Experimental tests in the solidification facility SOLIDX
No full textThe test matrix and the numerical pre-test analysis in the SOLIDX facility is presented. The facility SOLIDX was commissioned to start investigation in the solidification of heavy liquid metals. The facility was procured and it will be installed at the ENEA Brasimone R.C.. In order to have a reasonable experimental test matrix a numerical model of the whole primary vessel was made and a pre-test analysis was carried out to provide correct conditions for freezing
Main process of the solidification facility SOLIDX
No full textIl presente documento riporta una descrizione della facility SOLIDX presso il CR ENEA del Brasimone e dettagli sul processo e l’operatività della stessa. La facility si pone come obiettivo lo studio della solidificazione del metallo liquido pesante (Piombo), quando utilizzato come fluido termovettore nei sistemi nucleari di quarta generazione
Analisi di uno scenario di flow-blockage
Get PDFIn the context of GEN-IV Heavy Liquid Metal-cooled reactors safety studies, the flow blockage in a Fuel sub-assembly is considered one of the main issues to be addressed and the most important and realistic accident for LFR Fuel Assembly. The present document is a first step towards a detailed analysis of such phenomena, and a CFD model and approach is presented to have a detailed thermo-fluid dynamic picture in the case of blockage. In particular the closed hexagonal, grid-spaced fuel assembly of the LFR ALFRED has been modeled and computed. At this stage, the details of the spacer grids have not been included, but a conservative analysis has been carried out based on the current main geometrical and physical features. Reactivity feedback, as well as axial power profile, have not been included in this analysis. Results indicate that critical conditions, with clad temperatures exceeding~1000°C, are reached with blockage larger than 30% in terms of area fraction
Specifica tecnica di fornitura ed installazione del circuito secondario ad acqua in pressione dell’impianto a metallo liquido pesante NACIE
No full textIl presente documento riporta la Specifica Tecnica di fornitura, installazione e collaudo del circuito secondario dell’impianto a metallo liquido pesante (piombo-bismuto, LBE) NACIE-UP, come upgrade dell’impianto NACIE, presso il C.R. ENEA del Brasimone
Freezing of the LFR primary pool: CFD modeling and preliminary analysis on prototypical configuration
Get PDFIn the context of GEN-IV Heavy Liquid Metal safety studies, the lead freezing in the pool is considered one of the main issues to be addressed and a realistic accident for LFR. The present document is a first step towards a detailed analysis of such phenomena, and a CFD model and approach is presented to have a detailed thermo-fluid dynamic picture in the case of freezing. In particular, a numerical methodology is presented to model the freezing of lead and the heat transfer in a proper way. At this stage, examples are given on a very simplified and prototypical geometry representing the primary pool of the LFR DEMO
Specifica tecnica per la fornitura e installazione della facility SOLIDX
No full textIl presente documento riporta la Specifica Tecnica di fornitura, installazione e collaudo della facility SOLIDX presso il CR ENEA del Brasimone. La facility si pone come obiettivo lo studio della solidificazione del metallo liquido pesante (Piombo), quando utilizzato come fluido termovettore nei sistemi nucleari di quarta generazione
Pre-test CFD analysis of the blockage fuel pin simulator (BFPS) test section for the nacie-up facility
Get PDFThe present report is focused on the CFD pre-test analysis and design of the new experimental facility ‘Blocked’ Fuel Pin bundle Simulator (BFPS) that will be installed into the NACIE-UP (NAtural CIrculation Experiment-UPgrade) facility located at the ENEA Brasimone Research Center (Italy).
The BFPS test section will be installed into the NACIE-UP loop facility aiming to carry out suitable experiments to fully investigate different flow blockage regimes in a 19 fuel pin bundle providing experimental data in support of the development of the ALFRED (Advanced Lead-cooled Fast Reactor European Demonstrator) LFR DEMO. In particular, the ‘Blocked’ Fuel Pin bundle Simulator (BFPS) cooled by lead bismuth eutectic (LBE), was conceived with a thermal power of about 250 kW and a uniform wall heat flux up to 0.7 MW/m2, relevant values for a LFR. It consists of 19 electrical pins placed on a hexagonal lattice with a pitch to diameter ratio of 1.4 and a diameter of 10 mm.
The geometrical domain of the fuel pin bundle simulator was designed to reproduce the geometrical features of ALFRED, e.g. the external wrapper in the active region and the spacer grids. Pre-tests calculations were carried out by applying accurate boundary conditions; the conjugate heat transfer in the clad is also considered.
The numerical simulation test matrix covered the envisioned experimental range in terms of mass flow rate; the wall heat flux was imposed in order to have a fixed temperature difference across the BFPS in unblocked conditions.
The blockages investigated are internal blockages of different extensions and in different locations (central sub-channel blockage, corner sub-channel blockage, edge sub-channel blockage, one sector blockage, two sector blockage).
The CFD pre-test analysis allowed also investigating the temperature distribution in the clad to operate the test section safely
Pre-test CFD analysis of the rod bundle experiment in the HLM facility NACIE-UP
No full textAt ENEA-Brasimone R.C., large experimental facilities exist to study HLM free, forced and mixed convection in loops and pools: e.g. NACIE-UP is a large scale LBE loop for mixed convection experiments. In the context of the SEARCH FP7 project, an experiment has to be performed in the NACIE-UP facility to assess the coolability of a 19-pin wire-wrapped electrical bundle (Fuel Pin Simulator, FPS), with heat flux up to 1 MW/m2. The bundle is representative of the one adopted in the MYRRHA concept.
The present paper is devoted to the Computational Fluid Dynamic (CFD) analysis of Heavy Liquid Metal (HLM) cooled Fuel Bundles to be adopted in the Gen-IV nuclear reactors.
A CFD analysis of fluid flow and heat transfer was carried out in the heavy liquid metal (LBE) cooled bundle test section of the NACIE-UP facility. The model includes the details of the wire-spacers as well as the entry region of the test section. A turbulence closure approach is adopted for all the simulations with ≈ 3.5∙107 nodes and a resolution of y+ =
Progetto del Circuito secondario ad acqua in pressione dell’impianto a metallo liquido pesante HELENA
Get PDFIl presente documento riporta il rapporto tecnico di descrizione relativo al circuito secondario ad acqua in pressione dell’impianto a metallo liquido pesante HELENA presso il C.R. ENEA del Brasimone
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