1,721,041 research outputs found
Descrizione delle configurazioni alternative del reattore LFR-AS-30
No full textIl presente rapporto descrive il progetto del nocciolo del reattore LFR-AS-30 alla fine della fase di progettazione concettuale. Il rapporto si concentra sulla versione del sistema che sfrutta l'uso di nuovi elementi di combustibile prodotti ad hoc (opzione "C"). Il rapporto copre la progettazione dell’assemblaggio di combustibile, in quanto unico componente del nocciolo il cui progetto è stato elaborato al momento della stesura. Vengono inoltre descritte le principali interfacce meccaniche del nocciolo e alcune proposte per il monitoraggio del nocciolo e per la sorgente di start-up
Descrizione della configurazione di riferimento del reattore LFR-AS-30
No full textIl presente rapporto descrive il nocciolo del reattore LFR-AS-30 alla fine della fase di progettazione concettuale. Il rapporto si concentra sulla versione del sistema che sfrutta, come sono, gli spilli di combustibile SPX ancora disponibili (opzione "A"), ovvero lavora in un regime di bassa potenza e bassa temperatura per evitare problemi di corrosione. Il rapporto copre la progettazione di tutti i componenti del nocciolo, come l’assemblaggio di combustibile, il sistema di controllo della reattività e i dispositivi di spegnimento. Vengono inoltre descritte le principali interfacce meccaniche del nocciolo e alcune proposte per il monitoraggio del nocciolo e per la sorgente di start-up
UOX-Fueled CLFR: core design
No full textThis document presents the results for the first Task in the Scope of Work of the purchase order in reference above. The report specifically deals with the UOX-fueled CLFR core
Intossicazione acuta da ossido di carbonio. Esperienze del settorato medico legale milanese nel periodo 1961 1972
No full textDevelopment and preliminary validation of TIFONE, a design-oriented code for the inter-wrapper flow and heat transfer in liquid-metal-cooled reactors
Full text linkAmong the goals of the core design for Lead-cooled Fast Reactors (LFRs) exploiting the closed Sub-Assembly (SA) option, cold by-passes should be minimised and excessive thermal gradients among opposite faces of the assembly ducts prevented. To this aim, given an Inter-Wrapper (IW) gap determined by the core thermo- mechanical design, a suitable coolant flow outside the assemblies themselves must be guaranteed. Moreover, the designer has the opportunity to introduce flow restrictions to tune the intra-wrapper flow fraction at the SA level, possibly allowing to reduce temperature differences at the outlet of the assemblies.
Therefore, the designer needs to be aware of the axial and radial temperature profiles of the IW coolant throughout the whole core (i.e., including all core SAs), as well as of the axial and perimetrical temperature profiles of the wrapper of each SA. Notably, the possibly different temperature values of each side of the wrapper itself should be assessed, since they could induce SA bowing. To address these needs, a Design- Oriented Code (DOC), TIFONE, was developed and verified in compliance with current best practices in terms of software quality assurance.
TIFONE adopts the sub-channel method, leading to a sufficient level of spatial resolution while retaining the key features of a DOC, namely equilibrium, a low computational time and a clear application domain. The paper describes the code structure, governing equations and solution method. It also reports the preliminary validation of TIFONE against data from inter-wrapper flow and heat transfer experiments performed in the frame of the SESAME project at the THESYS loop within the KALLA laboratory, confirming the code capability to reproduce the measured data in its anticipated validity domain
I protocolli operativi per gli artt. 186 e 187 del Codice della Strada: un incipit necessario da sottoporre a verifica attuativa
No full textOn the viability of In-Vessel Storage in the new ALFRED configuration
No full textIl presente studio analizza le condizioni che rendono possibile effettuare in sicurezza la movimentazione di elementi esausti in aria, nel loro trasferimento dal sistema primario alla piscina di raffreddamento, come base di partenza per la valutazione dell’opzione di parcheggio temporaneo degli elementi esausti in una zona di “decantazione” dedicata, da ricavarsi nelle prossimità del nocciolo.
La configurazione di riferimento di ALFRED è assunta per le valutazioni puntuali, così che fosse possibile ricavare valori specifici per guidare la valutazione della fattibilità di tale opzione
Neutron propagation experiments with a lead test section inserted in the core of the LR-0 reactor
No full textValidation of neutronic parameters for lead-cooled systems, by integral and local experiments, became of primary interest with advances in ALFRED lead cooled reactor demonstrator design. Notably, aiming at advancing the core design from the conceptual to the basic stage, the assessment of uncertainties coming from numerical simulation, with respect to real experiments, was of paramount importance to support the claims of outstanding safety demonstration meant for ALFRED. Among the required evidences, the assessment of the spatial distribution of the neutron flux and power in fuel pins required conceiving ad-hoc experiments, and disposing of state-of-the-art post-irradiation examination capabilities. For all these reasons, these experiments were one of the main focuses of the collaboration between the Research Centre Rez and ENEA. This paper presents the conception phase of the test and discusses some of the main results of the first phase of the experimental campaign, dealing with neutrons propagation, collected during its execution at the LR-0 research reactor (hence before the post-irradiation examination of the experimental pins placed in the lead test rig). The experimental work involved at first neutron spectrum measurements in the energy range from 0.1 to 10 MeV. Additionally, measurement of basic neutronic parameters of lead were performed, such as its reactivity worth, its effect on the neutron spectrum and its slowing-down properties. The comparison of calculations and experimental results shows good agreement. In case of calculation in benchmark model with different nuclear data libraries, the criticality is systematically over-predicted by approximately 150 pcm, which is, however, in the 1σ of the uncertainty interval. Neutron spectrum measurement shows only slight variations being around 10% most of the time. © 2018 Elsevier B.V
Development and preliminary validation of TIFONE, a design-oriented code for the inter-wrapper flow and heat transfer in liquid-metal-cooled reactors
Full text linkAmong the goals of the core design for Lead-cooled Fast Reactors (LFRs) exploiting the closed Sub-Assembly (SA) option, cold by-passes should be minimised and excessive thermal gradients among opposite faces of the assembly ducts prevented. To this aim, given an Inter-Wrapper (IW) gap determined by the core thermo-mechanical design, a suitable coolant flow outside the assemblies themselves must be guaranteed. Moreover, the designer has the opportunity to introduce flow restrictions to tune the intra-wrapper flow fraction at the SA level, possibly allowing to reduce temperature differences at the outlet of the assemblies. Therefore, the designer needs to be aware of the axial and radial temperature profiles of the IW coolant throughout the whole core (i.e., including all core SAs), as well as of the axial and perimetrical temperature profiles of the wrapper of each SA. Notably, the possibly different temperature values of each side of the wrapper itself should be assessed, since they could induce SA bowing. To address these needs, a Design-Oriented Code (DOC), TIFONE, was developed and verified in compliance with current best practices in terms of software quality assurance. TIFONE adopts the sub-channel method, leading to a sufficient level of spatial resolution while retaining the key features of a DOC, namely equilibrium, a low computational time and a clear application domain. The paper describes the code structure, governing equations and solution method. It also reports the preliminary validation of TIFONE against data from inter-wrapper flow and heat transfer experiments performed in the frame of the SESAME project at the THESYS loop within the KALLA laboratory, confirming the code capability to reproduce the measured data in its anticipated validity domain
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