Francesco Galleni

• Doctor of Philosophy
• University of Pisa

In the WCLL-BB liquid blanket concept, among the postulated accidental scenarios to be investigated regarding the PbLi system, a loss of liquid metal is one of the most crucial for safety purposes. As a consequence of this loss, chemical reactions might occur between lithium, air, and water. These reactions may lead to significant increases in temp...

The Lead-cooled Fast Reactor (LFR) is one of the six advanced reactor system types selected in the Generation-IV (Gen IV) program. Westinghouse (WEC) is developing a highly simplified, passively safe, medium-size, economic Gen-IV LFR as its next-generation utility-scale nuclear power plant. Designed as a pool-type reactor, the Westinghouse LFR has...

In the framework of the activities coordinated by the EUROfusion consortium, the Water thermal-HYDRAulic (W-HYDRA) experimental platform is being built at the ENEA Brasimone Research Centre in order to support the development of the Water-Cooled Lead Lithium (WCLL) Breeding Blanket (BB). In particular, this infrastructure will make possible the ins...

The WCLL Breeding Blanket of DEMO and the Test Blanket Module (TBM) of ITER require accurate R&D activities, i.e., concept validation at a relevant scale and safety demonstrations. In view of this, the strategic objective of the Water Loop (WL) facility, belonging to the W-HYDRA experimental platform planned at C.R. Brasimone of ENEA, is twofold: t...

The Water-Cooled Lithium–Lead blanket concept is a candidate breeding blanket concept for the EU DEMO reactor and it is going to be tested as one of the Test Blanket Modules (TBM) inside the ITER reactor. A major safety issue for its design is the interaction between PbLi and water caused by a tube rupture in the breeding zone, the so-called in-box...

Research activities are continuing between the University of Pisa and ENEA Brasimone Research Center to understand better the phenomena and processes that occur during a postulated in-box LOCA in the Water-Cooled Lead Lithium Breeding Blanket (WCLL BB) and during the system's safety response. Various activities are also going on to strengthen the r...

Liquid metal cooled reactors are among the design proposals accepted by the Generation IV International Forum for the fourth generation of nuclear power plants. During the last decade, many European Union (EU) projects started with the goal to pave the way for the development of this type of reactor. The present research work is performed in the fr...

Under this study, the LIFUS5/Mod3 Series E experiment Test 5.1 is being numerically investigated and compared with the experimental parameters to validate the thermal-hydraulic safety analysis system code "SIMMER III" for the interaction of lead-lithium and water under circumstances similar to those anticipated for the Water-Cooled Lead Lithium Bre...

The in-box LOCA (Loss of Coolant Accident) represents a major safety concern to be addressed in the design of the WCLL-BB (water-cooled lead-lithium breeding blanket). Research activities are ongoing to master the phenomena and processes that occur during the postulated accident, to enhance the predictive capability and reliability of numerical too...

This work presents a thermohydraulic analysis of a postulated accident involving the rupture of the breeder primary cooling loop inside a heat exchanger (once through steam generator). After the detection of the loss of pressure inside the primary loop, a plasma shutdown is actuated with a consequent plasma disruption, isolation of the secondary lo...

The in-box LOCA (Loss of Coolant Accident) represents a major safety concern to be addressed in the design of the WCLL-BB (Water-Cooled Lead-Lithium Breeding Blanket) that will be tested in the Test Blanket Module of the ITER reactor. In this accident, a tube rupture in the coolant circuit would cause a potential disruptive exothermic chemical reac...

The European liquid Test Blanket Module (TBM) concept named Water Cooled Lithium Lead makes use of the liquid metal alloy PbLi as tritium breeder/neutron multiplier and water as coolant. A dedicated PbLi ancillary system feeds the detritiated liquid metal alloy to the TBM and returns the PbLi enriched with tritium. The object of this study is devel...

The In-box LOCA for the WCLL-BB is recognized as a Design Basis Accident (DBA) and is of substantial interest to the DEMOnestration reactor design, therefore, the transient response of such an accident must be carefully investigated and addressed to ensure the safe operation and integrity of the whole system. In this way, the LIFUS5/Mod3 test facil...

In the present paper, coupled STH/CFD calculations are performed addressing two operating conditions in the frame of the NACIE-UP experimental campaign. In order to simulate mixed and natural circulation phenomena related to liquid metals thermal hydraulics, the RELAP5/Mod3.3 STH code and the CFD code ANSYS Fluent are adopted in an integrated manne...

This work aims to review the general guidelines to be adopted to perform coupled System Thermal Hydraulics (STH)/CFD calculations. The coupled analysis is often required when complex phenomena characterized by different characteristic time and length scales are investigated. Indeed, by STH/CFD coupling the main drawbacks of both stand-alone codes a...

The in-box Loss of Coolant Accident (LOCA) scenario is considered as one of the most affecting safety concerns for the Water-Cooled Lead Lithium Breeding Blanket (WCLL-BB) modules of the DEMOnstration (DEMO) reactor, which is sequentially followed by a multi-phase multi-component physical and chemical interaction. Therefore, the transient behavior...

In this paper, a CFD analysis of the Fuel Pin Simulator (FPS) of the CIRCE-HERO facility built at the ENEA research centre in Brasimone was performed. STAR-CCM + code was used with the purpose of reproducing steady-state and transient experimental conditions adopting LBE as working fluid. RANS and URANS simulations were performed comparing the calc...

The present work deals with simulations carried out at the University of Pisa by using the System Thermal Hydraulics code RELAP5/Mod3.3 to support the experimental campaign conducted at the ENEA (Energia Nucleare ed Energie Alternative) Brasimone Research Centre on the CIRColazione Eutettico—Heavy liquid mEtal pRessurized water cOoled tubes (CIRCE-...

The paper presents the application of a coupling methodology between Computational Fluid Dynamics (CFD) and System Thermal Hydraulic (STH) codes developed at the University of Pisa. The methodology was applied to the CIRCE-HERO facility in order to reproduce the recently performed experimental conditions simulating a Protected Loss Of Flow Accident...

The paper describes the application of a coupled methodology between Fluent CFD code and RELAP5 System Thermal-Hydraulic code developed at the DICI (Dipartimento di Ingegneria Civile e Industriale) of the University of Pisa. The methodology was applied specifically to the LBE-water heat exchanger HERO located inside the S100 vessel of the CIRCE fac...

A major safety issue in the Water-Cooled Lead-Lithium Breeding Blanket (WCLL-BB) system foreseen for fusion reactor is the interaction concerning the primary coolant (water) and the neutron multiplier (PbLi), due to a hypothetical tube rupture in the coolant circuit. This scenario involves an exothermic chemical reaction between PbLi and water with...

In the present paper, CFD simulations related to the operating conditions considered during the experimental campaign on CIRCE-HERO facility, a LBE large pool recently run at ENEA Brasimone RC, are presented. The main purpose is to investigate the temperature stratification phenomena observed inside the CIRCE pool. Calculations are performed using...

The paper concerns about CFD calculations of LBE flowing in the wire-wrapped hexagonal array electrical pin bundle of NACIE-UP facility. Pressure drop and friction factor analyses are performed in order to find possible matching between CFD results and available correlations to be used in the frame of forthcoming applications involving CFD/System C...

In this article the results of the application of two numerical approaches-the Method of Moments and the nodal method-for the prediction of the evaporation phenomena in the synthesis of nanoparticles are presented and compared, in order to evaluate the limits of the moment methods and to determine the usability of the method in plasma environments...

This article presents a unified physical mathematical approach to the modelling nanoparticles dynamic used by the Authors as a foundation to develop a software framework for modelling entities and phenomena occurring at mesoscopic length scale in a generic Gas-Phase (GP) nanoparticle synthesis processes (e.g. plasma, hot-wall and flame reactors) an...

The present research extends theapplication of the“slug capturing” technique, already extensively validated for the prediction of horizontal slug flow,to the case of vertical pipes.In this technique, the one-dimensional two fluid modelis solved numericallyin order to simulate mechanistically the growth and development of the structures which charac...

In this paper, an extension of the "slug capturing" technique to vertical slug flow is presented. In this method, the initiation and development of the slugs are obtained by solving the 1D transient two-fluid model equations. This approach has the advantage of being almost entirely mechanistic: The flow develops naturally as part of the transient c...

In this paper, a Von Neumann analysis of the discretized form of the 1D two-fluid model is presented for slug flow in vertical pipes in order to study the effect of the discretization scheme on the ill-posedness of the system. The resulting growth rate is compared to that obtained from a stability analysis of the parent system of differential equat...