Search results for " impianti nucleari"

Influence of Rayleigh Number and End Wall Boundary Conditions on Free Convection Heat Transfer in a Rectangular Enclosure

2000

WCLL breeding blanket design and integration for DEMO 2015: status and perspectives

2017

Abstract Water-cooled lithium-lead breeding blanket is considered a candidate option for European DEMO nuclear fusion reactor. ENEA and the linked third parties have proposed and are developing a multi-module blanket segment concept based on DEMO 2015 specifications. The layout of the module is based on horizontal (i.e. radial-toroidal) water-cooling tubes in the breeding zone, and on lithium lead flowing in radial-poloidal direction. This design choice is driven by the rationale to have a modular design, where a basic geometry is repeated along the poloidal direction. The modules are connected with a back supporting structure, designed to withstand thermal and mechanical loads due to norma…

A neutron point kinetic model for fusion relevant calculations

2012

Abstract In the framework of research activities on fusion reactors a great effort is dedicated by the scientific community to the development of tritium breeding blankets. One of the main goals is to assess the neutronic behaviour of such devices to analyse their tritium breeding performance and to evaluate the required data for their thermal–mechanic and thermal–hydraulic design. Many papers have been published on this topic considering some stationary condition to calculate such important quantities as heating power, gas production and dpa rates, tritium breeding ratio, etc., but not much attention has been focussed to neutronic transport analyses in transient conditions. The present pap…

Automated parametric neutronics analysis of the Helium Cooled Pebble Bed breeder blanket with Be 12 Ti

2017

The Helium Cooled Pebble Bed (HCPB) breeder blanket is being developed as part of the European Fusion Programme. Part of the programme is to investigate blanket designs relevant for future demonstration fusion power plants. This paper presents neutronics analyses of the HCPB with an alternative neutron multiplier, Be12Ti which is incorporated into the design, replacing the current Be multiplier. A parameter study was performed for a range of geometries to identify the optimal heights of the lithium ceramic and neutron multiplier pebble beds. Automated creation of CAD models followed by conversion to constructive solid geometry (CSG) and unstructured mesh (UM) geometry allows the models to b…

Investigation of the DEMO WCLL Breeding Blanket Cooling Water Activation

2020

Abstract Within the framework of the activities foreseen by the EUROfusion action on the cooling water activation assessment for a DEMO reactor equipped with a Water Cooled Lithium Lead Breeding Blanket (WCLL BB), the University of Palermo is involved in the assessment of dose rates induced by the decay of nitrogen radioisotopes produced by water activation, nearby the main components (e.g. isolation valves) of both First Wall (FW) and Breeder Zone (BZ) cooling circuits. In particular, the aim of this work is to evaluate the spatial distribution of nitrogen isotopes (16N and 17N) in the WCLL BB cooling circuits. To this purpose, a coupled neutronic/fluid-dynamic problem is solved following …

Computational thermofluid-dynamic analysis of DEMO divertor cassette body cooling circuit

2018

Abstract Within the framework of the Work Package Divertor, Subproject: Cassette Design and Integration (WPDIV-Cassette) of the EUROfusion action, a research campaign has been jointly carried out by ENEA and University of Palermo to investigate the thermal-hydraulic performances of the DEMO divertor cassette cooling system. The research activity has been carried out following a theoretical-computational approach based on the finite volume method and adopting a qualified Computational Fluid-Dynamic (CFD) code. Fully-coupled fluid-structure CFD analyses have been carried out for the recently-revised cassette body cooling circuit under nominal steady state conditions, imposing a non-uniform sp…

Analysis, by RELAP5 code, of Boron Dilution Phenomena in Small Break LOCA and in Mid Loop Operation Transients, Performed in PKL III Test Facility

2008

Analysis, by TRACE code, of Natural Circulation Phenomena in the MASLWR-OSU-002 Test.

2008

On the thermal dynamic behaviour of the helium-cooled DEMO fusion reactor

2019

Abstract The EU-DEMO conceptual design is being conducted among research institutions and universities from 26 countries of European Union, Switzerland and Ukraine. Its mission is to realise electricity from nuclear fusion reaction by 2050. As DEMO has been conceived to deliver net electricity to the grid, the choice of the Breeding Blanket (BB) coolant plays a pivotal role in the reactor design having a strong influence on plant operation, safety and maintenance. In particular, due to the pulsed nature of the heat source, the Primary Heat Transfer System (PHTS) becomes a very important actor of the Balance of Plant (BoP) together with the Power Conversion System (PCS). Moreover, aiming to …

Analyses of single- and two-phase flow pressure drops in helical pipes using a modified RELAP5 code

2012

Abstract Thermal fluid dynamics analyses on single- and two-phase flows in helical pipes of steam generators to be used in Generation III and IV nuclear reactors have been performed. The study concerned with experimental activities as well code simulations carried out in the framework of a collaboration between the Department of Energetics of the Polytechnic of Torino and the Department of Energy of the University of Palermo. The goal was the validation of models implemented in Relap5/Mod3.2β thermal–hydraulic advanced code to simulate the hydrodynamic behaviour of helical pipe components in spite of the one-dimensional nature of the code. It is shown that much of the experimental data obta…