BORREANI , Walter

The present paper reports a numerical investigation of a forced convection water flow within a two-dimensional ribbed channel. A uniform heat flux is applied on the external walls. The flow regime is turbulent and Reynolds numbers are in the range 10·10^3÷100·10^3. Square and chamfered rib shapes with different arrangements are analyzed in...

The fusion-fission hybrid reactor is a promising technology that is likely to assume more and more importance in the global energy scenario in the coming years. Although this kind of nuclear system dates back to the earliest times of the fusion projects (when it was recognized that using fusion neutrons to "support" nuclear fission fuel cycle...

Lead-cooled fast reactor (LFR) has both a long history and a penchant of innovation. With early work related to its use for submarine propulsion dating to the 1950s, Russian scientists pioneered the development of reactors cooled by heavy liquid metals (HLM). More recently, there has been substantial interest in both critical and subcritical...

Heavy-liquid metals, such as lead and lead–bismuth eutectic, are promising candidates as coolant for advanced GEN-IV fast reactors as well as for Accelerator-Driven Systems. The advancing knowledge of the thermal-hydraulic behavior of these fluids leads to explore new geometries and new concepts aimed at optimizing the key components of a...

The design of compact heat exchangers and their mass flow distributors is still based on empirical approaches and both experimentations and numerical analyses are needed for defining the best geometries able to reduce the mass flow rate non uniformities in parallel channels. This is a cause of reduction in both thermal and fluid-dynamic...

The use of passive safety systems are more and more diffused in many technological fields. Natural circulation is probably one of the main phenomenon applied in this kind of systems: indeed, as known, by means of gravity and buoyancy forces, the fluids can circulate without any external power sources. In this paper a preliminary analysis (also...

The CFD analysis of a Venturi nozzle operating in LBE (key component of the CIRCE facility, owned by ENEA) is presented in this paper. CIRCE is a facility developed to investigate in details the fluid-dynamic behavior of ADS and/or LFR reactor plants. The initial CFD simulations have been developed hand in hand with the comparison with...

In this presentation, a theoretical and computational analysis is presented of a multi-blade screw pump evolving liquid Lead as primary pump for the reference conceptual design of the Advanced Lead Fast Reactor European Demonstrator (ALFRED). The pump is analyzed at design operating conditions from the theoretical point of view to determine...

The neutron multiplication factor k-eff is a key quantity to characterize subcritical neutron multiplying devices and for understanting their physical behaviour, being related to the fundamental eigenvalue of Boltzmann transport equation. Both the maximum available power-and all quantities related to it, like, e.g. the effectiveness in burning...

This paper shows some results obtained through simulating a VVER-1000 mock-up installed within the LR-0 research reactor in the Research Centre Řež (Czech Republic): the simulations have been performed by using the Serpent 2 and MCNP6 Monte Carlo codes. The mock-up is analysed in 6 different critical configurations, obtained with variation of...

Aim of this work is the preliminary thermal-fluid-dynamic assessment of a subcritical system to perform integral measurements on transmutation processes, designed in the frame of EU CHANDA project: in particular, a low power Accelerator Driven System (ADS) may represent an attractive intermediate step to fill the gap between existing and future...

We studied a flexible ADS-based irradiation facility with fast neutrons inside the core and slow neutrons in the composite reflector containing light materials. The fast reactor core has been designed using MCNP-6 code with a mixed reflector formed by three concentric cylindrical layers (lead+graphite+lead) in order to have different neutrons...