1,721,380 research outputs found
Le "Osservazioni di Fatto, e di Ragione sulla proibizione delle Paranze a Coppia nell'istesso Mare dell' Adriatico" (1774).
No full textDeterministic Shielding Calculations for the IRIS Reactor: Extended Geometry
Full text linkThis work is the extension to a fuli reactor geometry of a former activity lmited to shielding calculation up to the reactor vessel for the IRIS (International Reactor Innovative and Secure) project The IRIS is a advanced medium size Light Water Reactor (LWR), being developed through an international partnership for a near term deployment to offer a simple nuclear plant with outstanding safety, attractive economics and enhanced proliferation resistance characteristics. It provides a viable bridge to Generation IV reactors and has excellent capability to satisfy in the near/mid-term timeframe the International Global Nuclear Energy Partnership (GNEP-I) requirements for small-scale reactors. The present document extends the Shielding activity carried out during the year 2009 at ENEA by means of the TORT (Three-dimensional discrete ordinates neutron/photon) ver. 3.2 deterministic code. The initial objectives of the analysis were the evaluation of the fast neutron fluence above 1 MeV (and DpA) on Pressure Vessel and a raw estimation of activation in the 'first' concrete. Finaily a full geometrical description has been performed in order to evaluate doses in the control room during normal operation
Intrecci di vite. Pratiche, mercantilismi e razionalità economiche nella Trieste del Settecento
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An intrinsically safe facility for forefront research and training on nuclear technologies — Target profile optimization
No full textA simple 1D algorithm for a spallation target profile optimization is presented. The profile efficacy is tested considering different real particle beams profiles impinging on the target. The results are commented in terms of power non-homogeneity for unit length for different beam/profile choices, showing a non-trivial parameters selection. In details, target shaping optimization is possible knowing the beam parameters with a large benefit for surface power homogeneity, but results of the simulations show that a small increase of the beam dimension, or a beam shift with respect to the assumed one, could rapidly erase the advantages. © 2014, Società Italiana di Fisica and Springer-Verlag Berlin Heidelberg
An intrinsically safe facility for forefront research and training on nuclear technologies — ADS shielding
No full textA detailed study of a very simple Accelerator-Driven System (ADS) shielding concept is carried out by means of the MCNPX Monte Carlo code. The design of a multilayer shielding scheme, together with an underground reactor host room sketch, is shown to be very effective for the exposure levels to ionizing radiations, in the upside experimental building and in the ground all around the reactor host room, being fully negligible. Transient heat is also estimated, founding that no residual radiation leaks out through ADS structures in the host room after shutdown. © 2014, Società Italiana di Fisica and Springer-Verlag Berlin Heidelberg
Study of an intrinsically safe infrastructure for training and research on nuclear technologies
No full textWithin European Partitioning & Transmutation research programs, infrastructures specifically dedicated to the study of fundamental reactor physics and engineering parameters of future fast-neutron-based reactors are very important, being some of these features not available in present zero-power prototypes. This presentation will illustrate the conceptual design of an Accelerator-Driven System with high safety standards, but ample flexibility for measurements. The design assumes as base option a 70 MeV, 0.75 mA proton cyclotron, as the one which will be installed at the INFN National Laboratory in Legnaro, Italy and a Beryllium target, with Helium gas as core coolant. Safety is guaranteed by limiting the thermal power to 200 kW, with a neutron multiplication coefficient around 0.94, loading the core with fuel containing Uranium enriched at 20% inserted in a solid-lead diffuser. The small decay heat can be passively removed by thermal radiation from the vessel. Such a system could be used to study, among others, some specific aspects of neutron diffusion in lead, beam-core coupling, target cooling and could serve as a training facility
Scenario analysis on the benefits of multi-national cooperation for the development of a common nuclear energy system based on pwr and lfr fleets
No full textFinancial aspects, environmental concerns and non-favorable public opinion are strongly conditioning the deployment of new Nuclear Energy Systems across Europe. Nevertheless, new possibilities are emerging to render competitive electricity from Nuclear Power Plants (NPPs) owing to two factors: the first one, which is the fast growth of High Voltage lines interconnecting the European countries' national electrical grids, this process being triggered by huge increase of the installed intermittent renewable electricity sources (Wind and PV); and the second one, determined by the carbon-free constraints imposed on the base load electricity generation. The countries that due to public opinion pressure can't build new NPPs on their territory may find it profitable to produce base load nuclear electricity abroad, even at long distances, in order to comply with the European dispositions on the limitation of the CO2 emissions. In this study the benefits from operating at multinational level with the deployment of a fleet of PWRs and subsequently, at a proper time, the one of Lead Fast Reactors (LFRs) are analyzed. The analysis performed involves Italy (a country with a current moratorium on nuclear power on spite that its biggest utility operates NPPs abroad), and the countries from South East and Central East Europe potentially looking for introduction or expansion of their nuclear power programmes. According to the predicted evolution of their Gross Domestic Product (GDP) a forecast of the electricity consumption evolution for the present century is derived with the assumption that a certain fraction of it will be covered by nuclear electricity. In this context, evaluated are material balances for the front and the back end of nuclear fuel cycle associated with the installed nuclear capacity. A key element of the analysis is the particular type of LFR assumed in the scenario, characterized by having a fuel cycle where only fission products and the reprocessing losses are sent for disposition and natural or depleted uranium is added to fuel in each reprocessing cycle. Such LFR could be referred to as "adiabatic reactor". Owing to introduction of such reactors a substantive reduction in uranium consumption and final disposal requirements can be achieved. Finally, the impacts of the LFR and the economy of scale in nuclear fuel cycle on the Levelized Cost of Electricity (LCOE) are being evaluated, for scaling up from a national to a multinational dimension, illustrating the benefits potentially achievable through cooperation among countries.
Suppliche e petizioni per la storia sociale dei ceti più umili. Alcuni esempi della Marca pontificia in età moderna.
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