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Prof. Dr. Guglielmo Lomonaco
DIME, Scuola Politecnica, Università degli Studi di Genova, via all’Opera Pia 15, 16145 Genova, GE, Italy

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0 Nuclear Energy
0 Nuclear Engineering
0 Nuclear Fuel Cycle
0 Nuclear Power Plants
0 Nuclear Technology

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Journal article
Published: 26 May 2021 in Energies
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Hydrogen production is a topical issue in an energy scenario where decarbonization is a priority, especially with reference to the transport sector that has a great weight on global emissions. Starting from this consideration, GIF (Generation-IV International Forum) investigated the possibility to produce hydrogen by nuclear energy. The “classic” strategy is based on the use of nuclear as energy source for the electrolysis; but on the medium-long term, a more sustainable and smart approach could be founded on the use of thermochemical processes (e.g., I-S) that require a direct coupling of a chemical plant to a nuclear reactor. In order to develop this strategy, it is mandatory to design and optimize all the key components involved in this complex plant. In this study, we developed the 3D-CAD and CFD models of the intermediate heat exchanger (IHX) installed in the Japanese HTTR nuclear power plant. This component is extremely important for both the safety of the two plants and the stability of the whole hydrogen production plant. Initially, our model (developed by AutoCAD 3D and implemented in Star CCM+) was validated on the basis of experimental data available in literature; then, an initial optimization of the IHX testing innovative materials, such as Alloy 617 and ODS–MA754, and a different primary coolant (supercritical CO2) was performed.

ACS Style

Lorenzo Bolfo; Francesco Devia; Guglielmo Lomonaco. Nuclear Hydrogen Production: Modeling and Preliminary Optimization of a Helical Tube Heat Exchanger. Energies 2021, 14, 3113 .

AMA Style

Lorenzo Bolfo, Francesco Devia, Guglielmo Lomonaco. Nuclear Hydrogen Production: Modeling and Preliminary Optimization of a Helical Tube Heat Exchanger. Energies. 2021; 14 (11):3113.

Chicago/Turabian Style

Lorenzo Bolfo; Francesco Devia; Guglielmo Lomonaco. 2021. "Nuclear Hydrogen Production: Modeling and Preliminary Optimization of a Helical Tube Heat Exchanger." Energies 14, no. 11: 3113.

Journal article
Published: 15 May 2021 in Applied Sciences
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The topic of Nuclear Safety Culture touches several different aspects with contributions from the main organizations involved in nuclear projects and belonging to vendors, utility and regulators. Two nuclear safety directives issued by the European Commission emphasize the fundamental principle of national responsibility for nuclear safety and are implemented in each member country’s legislation. An example of fission implementation is highlighted, referring to the Czech Republic legislation; an example of application in fusion technology is the implementation of the Nuclear Safety Culture in the ITER project, located in Cadarache, in the south of France. The aim of the paper is to highlight the importance of this field, pointing out the cross reference between fission and fusion technology as applied in two countries, with concrete experiences and future prospects for nuclear technologies.

ACS Style

Guglielmo Lomonaco; Enrico Mainardi; Tereza Marková; Guido Mazzini. Approaching Nuclear Safety Culture in Fission and Fusion Technology. Applied Sciences 2021, 11, 4511 .

AMA Style

Guglielmo Lomonaco, Enrico Mainardi, Tereza Marková, Guido Mazzini. Approaching Nuclear Safety Culture in Fission and Fusion Technology. Applied Sciences. 2021; 11 (10):4511.

Chicago/Turabian Style

Guglielmo Lomonaco; Enrico Mainardi; Tereza Marková; Guido Mazzini. 2021. "Approaching Nuclear Safety Culture in Fission and Fusion Technology." Applied Sciences 11, no. 10: 4511.

Journal article
Published: 15 December 2020 in Sustainability
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The unique design features of the molten salt fast reactor (MSFR) should enable higher coolant temperatures than in conventional water reactors, with a significant improvement in the achievable thermodynamic performance. The use of a molten salt as both fuel and coolant, however, poses several advanced heat transfer challenges, such as the design of innovative heat exchangers and energy conversion systems. In this work, we address a preliminary but quantitative analysis of the energy conversion system for the MSFR, based on reference design data from the SAMOFAR H2020-EURATOM project. We consider three main technologies, i.e., the supercritical steam cycle, the closed helium cycle and the helium/steam combined cycle. Preliminary design results are presented for each technology, based on a simplified modelling approach. The considered cycles show promising efficiency improvements, with the best performance being proven by the supercritical steam cycle. The analysis also highlights the critical issue related to the risk of freezing of the molten salts within the secondary heat exchangers, due to the low inlet temperatures of the working fluids. Results show potential incompatibility between the freezing point of molten salts and the temperatures typical of steam cycles, while helium cycles offer the best chances of freezing avoidance. The combined cycle promises intermediate performance in terms of thermodynamic efficiency and thermal compatibility with molten salts comparable with closed helium cycles.

ACS Style

Andrea Di Ronco; Francesca Giacobbo; Guglielmo Lomonaco; Stefano Lorenzi; Xiang Wang; Antonio Cammi. Preliminary Analysis and Design of the Energy Conversion System for the Molten Salt Fast Reactor. Sustainability 2020, 12, 10497 .

AMA Style

Andrea Di Ronco, Francesca Giacobbo, Guglielmo Lomonaco, Stefano Lorenzi, Xiang Wang, Antonio Cammi. Preliminary Analysis and Design of the Energy Conversion System for the Molten Salt Fast Reactor. Sustainability. 2020; 12 (24):10497.

Chicago/Turabian Style

Andrea Di Ronco; Francesca Giacobbo; Guglielmo Lomonaco; Stefano Lorenzi; Xiang Wang; Antonio Cammi. 2020. "Preliminary Analysis and Design of the Energy Conversion System for the Molten Salt Fast Reactor." Sustainability 12, no. 24: 10497.

Review
Published: 22 September 2020 in Sustainability
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Nuclear engineering requires computationally efficient methods to simulate different components and systems of plants. The Lattice Boltzmann Method (LBM), a numerical method with a mesoscopic approach to Computational Fluid Dynamic (CFD) derived from the Boltzmann equation and the Maxwell–Boltzmann distribution, can be an adequate option. The purpose of this paper is to present a review of the recent applications of the Lattice Boltzmann Method in nuclear engineering research. A systematic literature review using three databases (Web of Science, Scopus, and ScienceDirect) was done, and the items found were categorized by the main research topics into computational fluid dynamics and neutronic applications. The features of the problem addressed, the characteristics of the numerical method, and some relevant conclusions of each study are resumed and presented. A total of 45 items (25 for computational fluid dynamics applications and 20 for neutronics) was found on a wide range of nuclear engineering problems, including thermal flow, turbulence mixing of coolant, sedimentation of impurities, neutron transport, criticality problem, and other relevant issues. The LBM results in being a flexible numerical method capable of integrating multiphysics and hybrid schemes, and is efficient for the inner parallelization of the algorithm that brings a widely applicable tool in nuclear engineering problems. Interest in the LBM applications in this field has been increasing and evolving from early stages to a mature form, as this review shows.

ACS Style

Johan Bocanegra Cifuentes; Davide Borelli; Antonio Cammi; Guglielmo Lomonaco; Mario Misale. Lattice Boltzmann Method Applied to Nuclear Reactors—A Systematic Literature Review. Sustainability 2020, 12, 7835 .

AMA Style

Johan Bocanegra Cifuentes, Davide Borelli, Antonio Cammi, Guglielmo Lomonaco, Mario Misale. Lattice Boltzmann Method Applied to Nuclear Reactors—A Systematic Literature Review. Sustainability. 2020; 12 (18):7835.

Chicago/Turabian Style

Johan Bocanegra Cifuentes; Davide Borelli; Antonio Cammi; Guglielmo Lomonaco; Mario Misale. 2020. "Lattice Boltzmann Method Applied to Nuclear Reactors—A Systematic Literature Review." Sustainability 12, no. 18: 7835.

Journal article
Published: 17 February 2020 in Energies
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Fuel burnup analysis requires a high computational cost for full core calculations, due to the amount of the information processed for the total reaction rates in many burnup regions. Indeed, they reach the order of millions or more by a subdivision into radial and axial regions in a pin-by-pin description. In addition, if multi-physics approaches are adopted to consider the effects of temperature and density fields on fuel consumption, the computational load grows further. In this way, the need to find a compromise between computational cost and solution accuracy is a crucial issue in burnup analysis. To overcome this problem, the present work aims to develop a methodological approach to implement a Reduced Order Model (ROM), based on Proper Orthogonal Decomposition (POD), in fuel burnup analysis. We verify the approach on 4 years of burnup of the TMI-1 unit cell benchmark, by reconstructing fuel materials and burnup matrices over time with different levels of approximation. The results show that the modeling approach is able to reproduce reactivity and nuclide densities over time, where the accuracy increases with the number of basis functions employed.

ACS Style

Christian Castagna; Manuele Aufiero; Stefano Lorenzi; Guglielmo Lomonaco; Antonio Cammi. Development of a Reduced Order Model for Fuel Burnup Analysis. Energies 2020, 13, 890 .

AMA Style

Christian Castagna, Manuele Aufiero, Stefano Lorenzi, Guglielmo Lomonaco, Antonio Cammi. Development of a Reduced Order Model for Fuel Burnup Analysis. Energies. 2020; 13 (4):890.

Chicago/Turabian Style

Christian Castagna; Manuele Aufiero; Stefano Lorenzi; Guglielmo Lomonaco; Antonio Cammi. 2020. "Development of a Reduced Order Model for Fuel Burnup Analysis." Energies 13, no. 4: 890.

Journal article
Published: 09 May 2019 in The European Physical Journal Plus
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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 spectra to perform various types of measurements without perturbing the ADS core fast characteristics. We also included in the ADS design three irradiation points external to the core, in positions such to have different neutron spectra, for measurements to be performed out of the ADS system. Moreover, we performed a thermal-hydraulic assessment of the behavior of target and core cooling systems. In order to investigate the capabilities of the system, we studied different kinds of possible measurements that could be performed in various positions, both inside and outside the ADS.

ACS Style

Fabio Panza; Walter Borreani; Gabriele Firpo; Guglielmo Lomonaco; Mikhail Osipenko; Marco Palmero; Giovanni Ricco; Marco Ripani; Paolo Saracco; Carlo Maria Viberti. An ADS irradiation facility for fast and slow neutrons. The European Physical Journal Plus 2019, 134, 195 .

AMA Style

Fabio Panza, Walter Borreani, Gabriele Firpo, Guglielmo Lomonaco, Mikhail Osipenko, Marco Palmero, Giovanni Ricco, Marco Ripani, Paolo Saracco, Carlo Maria Viberti. An ADS irradiation facility for fast and slow neutrons. The European Physical Journal Plus. 2019; 134 (5):195.

Chicago/Turabian Style

Fabio Panza; Walter Borreani; Gabriele Firpo; Guglielmo Lomonaco; Mikhail Osipenko; Marco Palmero; Giovanni Ricco; Marco Ripani; Paolo Saracco; Carlo Maria Viberti. 2019. "An ADS irradiation facility for fast and slow neutrons." The European Physical Journal Plus 134, no. 5: 195.

Conference paper
Published: 10 December 2018 in IOP Conference Series: Materials Science and Engineering
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Zirconium based alloys are commonly used as material for fuel claddings in the light water reactors. Claddings act as first metallic barriers against loss of fission products during the nuclear power plant operation, intermittent storage or final dry storage. The integrity of claddings is always critical issue during reactor operation and during storage of spent fuel. In this work, ring compression testing method developed was applied to study hydrogen embrittlement, to evaluate the stress-strain behaviour and hoop fracture properties of E110 (Zr-based) fuel claddings. The results show that the collapse load and the tensile strength values depend strongly on hydrogen concentration. In particular, tensile strength experiment data shows significant change in its trend after reaching the maximum hydrogen solubility limit.

ACS Style

H K Namburi; L Ottazzi; M Chocholousek; Guglielmo Lomonaco; P Gavelova; J Krejci. Study hydrogen embrittlement and determination of E110 fuel cladding mechanical properties by ring compression testing. IOP Conference Series: Materials Science and Engineering 2018, 461, 012059 .

AMA Style

H K Namburi, L Ottazzi, M Chocholousek, Guglielmo Lomonaco, P Gavelova, J Krejci. Study hydrogen embrittlement and determination of E110 fuel cladding mechanical properties by ring compression testing. IOP Conference Series: Materials Science and Engineering. 2018; 461 (1):012059.

Chicago/Turabian Style

H K Namburi; L Ottazzi; M Chocholousek; Guglielmo Lomonaco; P Gavelova; J Krejci. 2018. "Study hydrogen embrittlement and determination of E110 fuel cladding mechanical properties by ring compression testing." IOP Conference Series: Materials Science and Engineering 461, no. 1: 012059.

Journal article
Published: 10 August 2018 in Energies
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Accelerator Driven Systems (ADS) seem to be a good solution for safe nuclear waste transmutation. One of the most important challenges for this kind of machine is the target design, particularly for what concerning the target cooling system. In order to optimize this component a CFD-based approach has been chosen. After the definition of a reference design (Be target cooled by He), some parameters have been varied in order to optimize the thermal-fluid-dynamic features. The final optimized target design has an increased security margin for what regarding Be melting and reduces the maximum coolant velocity (and consequently even more the pressure drops).

ACS Style

Guglielmo Lomonaco; Giacomo Alessandroni; Walter Borreani. Partial Redesign of an Accelerator Driven System Target for Optimizing the Heat Removal and Minimizing the Pressure Drops. Energies 2018, 11, 2090 .

AMA Style

Guglielmo Lomonaco, Giacomo Alessandroni, Walter Borreani. Partial Redesign of an Accelerator Driven System Target for Optimizing the Heat Removal and Minimizing the Pressure Drops. Energies. 2018; 11 (8):2090.

Chicago/Turabian Style

Guglielmo Lomonaco; Giacomo Alessandroni; Walter Borreani. 2018. "Partial Redesign of an Accelerator Driven System Target for Optimizing the Heat Removal and Minimizing the Pressure Drops." Energies 11, no. 8: 2090.

Journal article
Published: 01 June 2018 in Thermal Science and Engineering Progress
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The design of compact heat exchangers and their mass flow distributors is still based on empirical approaches and both numerical analyses and experimentations are needed for designing the best geometries useful to reduce the mass flow rate non uniformities in parallel channels. As known, this is indeed a cause of reduction in both thermal and fluid-dynamic performances. In this paper a series of single-phase CFD simulations on water and water with air injection are carried out in order to estimate the capabilities of the solvers implemented in the OpenFOAM code to reproduce (in comparison with experimental data) such kind of configurations and phenomena. The effects of different turbulence models (both RANS and LES) implemented in OpenFOAM are investigated; additionally some general considerations on the differences and analogies among different Reynolds numbers flow and turbulence model effects applied to the present configuration are discussed. Finally, the capability of the code to reproduce the peculiar behaviour of a protrusions based experimental facility is investigated, with the aim of obtaining an acceptable simulation of the non-uniform mass flow distribution in each protrusion. The present paper is an extended version including the main conclusions and observations emerged in the 2nd AIGE-IIETA International Conference in Genoa.

ACS Style

Walter Borreani; Francesco Devia; Guglielmo Lomonaco; Annalisa Marchitto. CFD preliminary assessment of a protrusions based facility. Thermal Science and Engineering Progress 2018, 6, 465 -475.

AMA Style

Walter Borreani, Francesco Devia, Guglielmo Lomonaco, Annalisa Marchitto. CFD preliminary assessment of a protrusions based facility. Thermal Science and Engineering Progress. 2018; 6 ():465-475.

Chicago/Turabian Style

Walter Borreani; Francesco Devia; Guglielmo Lomonaco; Annalisa Marchitto. 2018. "CFD preliminary assessment of a protrusions based facility." Thermal Science and Engineering Progress 6, no. : 465-475.

Journal article
Published: 01 June 2018 in Thermal Science and Engineering Progress
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ACS Style

Guglielmo Lomonaco; Walter Borreani; Maurizio Bruzzone; Davide Chersola; Gabriele Firpo; Mikhail Osipenko; Marco Palmero; Fabio Panza; Marco Ripani; Paolo Saracco; Carlo Maria Viberti. Initial thermal-hydraulic assessment by OpenFOAM and FLUENT of a subcritical irradiation facility. Thermal Science and Engineering Progress 2018, 6, 447 -456.

AMA Style

Guglielmo Lomonaco, Walter Borreani, Maurizio Bruzzone, Davide Chersola, Gabriele Firpo, Mikhail Osipenko, Marco Palmero, Fabio Panza, Marco Ripani, Paolo Saracco, Carlo Maria Viberti. Initial thermal-hydraulic assessment by OpenFOAM and FLUENT of a subcritical irradiation facility. Thermal Science and Engineering Progress. 2018; 6 ():447-456.

Chicago/Turabian Style

Guglielmo Lomonaco; Walter Borreani; Maurizio Bruzzone; Davide Chersola; Gabriele Firpo; Mikhail Osipenko; Marco Palmero; Fabio Panza; Marco Ripani; Paolo Saracco; Carlo Maria Viberti. 2018. "Initial thermal-hydraulic assessment by OpenFOAM and FLUENT of a subcritical irradiation facility." Thermal Science and Engineering Progress 6, no. : 447-456.

Journal article
Published: 12 December 2017 in EPJ Nuclear Sciences & Technologies
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In this work, we report studies on a fast low power accelerator driven system model as a possible experimental facility, focusing on its capabilities in terms of measurement of relevant integral nuclear quantities. In particular, we performed Monte Carlo simulations of minor actinides and fission products irradiation and estimated the fission rate within fission chambers in the reactor core and the reflector, in order to evaluate the transmutation rates and the measurement sensitivity. We also performed a photo-peak analysis of available experimental data from a research reactor, in order to estimate the expected sensitivity of this analysis method on the irradiation of samples in the ADS considered.

ACS Style

Fabio Panza; Gabriele Firpo; Guglielmo Lomonaco; Mikhail Osipenko; Giovanni Ricco; Marco Ripani; Paolo Saracco; Carlo Maria Viberti. A low power ADS for transmutation studies in fast systems. EPJ Nuclear Sciences & Technologies 2017, 3, 36 .

AMA Style

Fabio Panza, Gabriele Firpo, Guglielmo Lomonaco, Mikhail Osipenko, Giovanni Ricco, Marco Ripani, Paolo Saracco, Carlo Maria Viberti. A low power ADS for transmutation studies in fast systems. EPJ Nuclear Sciences & Technologies. 2017; 3 ():36.

Chicago/Turabian Style

Fabio Panza; Gabriele Firpo; Guglielmo Lomonaco; Mikhail Osipenko; Giovanni Ricco; Marco Ripani; Paolo Saracco; Carlo Maria Viberti. 2017. "A low power ADS for transmutation studies in fast systems." EPJ Nuclear Sciences & Technologies 3, no. : 36.

Journal article
Published: 07 December 2017 in Energies
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Although Lead-cooled Fast Reactor (LFR) is not a new concept, it continues to be an example of innovation in the nuclear field. Recently, there has been strong interest in liquid lead (Pb) or liquid lead–bismuth eutectic (LBE) both critical and subcritical systems in a relevant number of Countries, including studies performed in the frame of GENERATION-IV initiative. In this paper, the theoretical and computational findings for three different designs of Primary Circulation Pump (PCP) evolving liquid lead (namely the jet pump, the Archimedean pump and the blade pump) are presented with reference to the ALFRED (Advanced Lead Fast Reactor European Demonstrator) design. The pumps are first analyzed from the theoretical point of view and then modeled with a 3D CFD code. Required design performance of the pumps are approximatively around an effective head of 2 bar with a mass flow rate of 5000 kg/s. Taking into account the geometrical constraints of the reactor and the fluid dynamics characteristics of the molten lead, the maximum design velocity for molten lead fluid flow of 2 m/s may be exceeded giving rise to unacceptable erosion phenomena of the blade or rotating component of the primary pumping system. For this reason a deep investigation of non-conventional axial pumps has been performed. The results presented shows that the design of the jet pump looks like beyond the current technological feasibility while, once the mechanical challenges of the Archimedean (screw) pump and the fluid-dynamic issues of the blade pump will be addressed, both could represent viable solutions as PCP for ALFRED. Particularly, the blade pump shows the best performance in terms of pressure head generated in normal operation conditions as well as pressure drop in locked rotor conditions. Further optimizations (mainly for what the geometrical configuration is concerned) are still necessary.

ACS Style

Walter Borreani; Alessandro Alemberti; Guglielmo Lomonaco; Fabrizio Magugliani; Paolo Saracco. Design and Selection of Innovative Primary Circulation Pumps for GEN-IV Lead Fast Reactors. Energies 2017, 10, 2079 .

AMA Style

Walter Borreani, Alessandro Alemberti, Guglielmo Lomonaco, Fabrizio Magugliani, Paolo Saracco. Design and Selection of Innovative Primary Circulation Pumps for GEN-IV Lead Fast Reactors. Energies. 2017; 10 (12):2079.

Chicago/Turabian Style

Walter Borreani; Alessandro Alemberti; Guglielmo Lomonaco; Fabrizio Magugliani; Paolo Saracco. 2017. "Design and Selection of Innovative Primary Circulation Pumps for GEN-IV Lead Fast Reactors." Energies 10, no. 12: 2079.

Conference paper
Published: 25 September 2017 in EPJ Web of Conferences
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EPJ Web of Conferences, open-access proceedings in physics and astronomy

ACS Style

Paolo Saracco; Walter Borreani; Davide Chersola; Guglielmo Lomonaco; Gianni Ricco; Marco Ripani. A useful observable for estimating keff in fast subcritical systems. EPJ Web of Conferences 2017, 153, 05017 .

AMA Style

Paolo Saracco, Walter Borreani, Davide Chersola, Guglielmo Lomonaco, Gianni Ricco, Marco Ripani. A useful observable for estimating keff in fast subcritical systems. EPJ Web of Conferences. 2017; 153 ():05017.

Chicago/Turabian Style

Paolo Saracco; Walter Borreani; Davide Chersola; Guglielmo Lomonaco; Gianni Ricco; Marco Ripani. 2017. "A useful observable for estimating keff in fast subcritical systems." EPJ Web of Conferences 153, no. : 05017.

Conference paper
Published: 25 September 2017 in EPJ Web of Conferences
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ACS Style

Fabio Panza; Gabriele Firpo; Guglielmo Lomonaco; Mikhail Osipenko; Giovanni Ricco; Marco Ripani; Paolo Saracco; Carlo Maria Viberti. New infrastructure for studies of transmutation and fast systems concepts. EPJ Web of Conferences 2017, 153, 5003 .

AMA Style

Fabio Panza, Gabriele Firpo, Guglielmo Lomonaco, Mikhail Osipenko, Giovanni Ricco, Marco Ripani, Paolo Saracco, Carlo Maria Viberti. New infrastructure for studies of transmutation and fast systems concepts. EPJ Web of Conferences. 2017; 153 ():5003.

Chicago/Turabian Style

Fabio Panza; Gabriele Firpo; Guglielmo Lomonaco; Mikhail Osipenko; Giovanni Ricco; Marco Ripani; Paolo Saracco; Carlo Maria Viberti. 2017. "New infrastructure for studies of transmutation and fast systems concepts." EPJ Web of Conferences 153, no. : 5003.

Journal article
Published: 20 September 2017 in International Journal of Heat and Technology
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ACS Style

Walter Borreani; Francesco Devia; Guglielmo Lomonaco; Annalisa Marchitto. CFD initial assessment of a protrusions based experimental facility. International Journal of Heat and Technology 2017, 35, 1 .

AMA Style

Walter Borreani, Francesco Devia, Guglielmo Lomonaco, Annalisa Marchitto. CFD initial assessment of a protrusions based experimental facility. International Journal of Heat and Technology. 2017; 35 (Special 1):1.

Chicago/Turabian Style

Walter Borreani; Francesco Devia; Guglielmo Lomonaco; Annalisa Marchitto. 2017. "CFD initial assessment of a protrusions based experimental facility." International Journal of Heat and Technology 35, no. Special 1: 1.

Journal article
Published: 20 September 2017 in International Journal of Heat and Technology
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ACS Style

Walter Borreani; Maurizio Bruzzone; Davide Chersola; Gabriele Firpo; Guglielmo Lomonaco; Marco Palmero; Fabio Panza; Marco Ripani; Paolo Saracco; Carlo Viberti. Preliminary thermal-fluid-dynamic assessment of an ADS irradiation facility for fast and slow neutrons. International Journal of Heat and Technology 2017, 35, 1 .

AMA Style

Walter Borreani, Maurizio Bruzzone, Davide Chersola, Gabriele Firpo, Guglielmo Lomonaco, Marco Palmero, Fabio Panza, Marco Ripani, Paolo Saracco, Carlo Viberti. Preliminary thermal-fluid-dynamic assessment of an ADS irradiation facility for fast and slow neutrons. International Journal of Heat and Technology. 2017; 35 (Special 1):1.

Chicago/Turabian Style

Walter Borreani; Maurizio Bruzzone; Davide Chersola; Gabriele Firpo; Guglielmo Lomonaco; Marco Palmero; Fabio Panza; Marco Ripani; Paolo Saracco; Carlo Viberti. 2017. "Preliminary thermal-fluid-dynamic assessment of an ADS irradiation facility for fast and slow neutrons." International Journal of Heat and Technology 35, no. Special 1: 1.

Journal article
Published: 20 September 2017 in International Journal of Heat and Technology
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ACS Style

Walter Borreani; Davide Chersola; Guglielmo Lomonaco; Mario Misale. Assessment of a 2D CFD model for a single phase natural circulation loop. International Journal of Heat and Technology 2017, 35, 1 .

AMA Style

Walter Borreani, Davide Chersola, Guglielmo Lomonaco, Mario Misale. Assessment of a 2D CFD model for a single phase natural circulation loop. International Journal of Heat and Technology. 2017; 35 (Special 1):1.

Chicago/Turabian Style

Walter Borreani; Davide Chersola; Guglielmo Lomonaco; Mario Misale. 2017. "Assessment of a 2D CFD model for a single phase natural circulation loop." International Journal of Heat and Technology 35, no. Special 1: 1.

Original
Published: 03 June 2017 in Heat and Mass Transfer
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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 10·103÷100·103. Square and chamfered rib shapes with different arrangements are analyzed in terms of various dimensionless heights and pitches of elements. The investigation is accomplished by using a CFD code and its aim consists in finding of arrangements to obtain a high Performance Evaluation Criterion (PEC). Results are presented in terms of temperature and velocity fields, profiles of average Nusselt number, average heat transfer coefficients and required pumping power. Heat transfer enhancement increases with the ribs presence, but it is accompanied by an increasing pumping power. In particular, the best performances in terms of Nusselt are shown for p/e = 4 and 12 for both the square and chamfered cases. The heat transfer improves as Reynolds number raises, but a substantial increase of pumping power is also observed. The utilization of chamfered ribs allows to increase the PEC, especially at low Re. The maximum PEC is equal to 1.3 and it is obtained for Re = 104 and p/e = 4.

ACS Style

Vincenzo Bianco; Walter Borreani; Guglielmo Lomonaco. Numerical investigation of turbulent flow within a channel with chamfered edge ribs in stream-wise direction. Heat and Mass Transfer 2017, 53, 3211 -3223.

AMA Style

Vincenzo Bianco, Walter Borreani, Guglielmo Lomonaco. Numerical investigation of turbulent flow within a channel with chamfered edge ribs in stream-wise direction. Heat and Mass Transfer. 2017; 53 (10):3211-3223.

Chicago/Turabian Style

Vincenzo Bianco; Walter Borreani; Guglielmo Lomonaco. 2017. "Numerical investigation of turbulent flow within a channel with chamfered edge ribs in stream-wise direction." Heat and Mass Transfer 53, no. 10: 3211-3223.

Research article
Published: 01 June 2017 in Science and Technology of Nuclear Installations
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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 detail 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 experimental data: the test results were used to confirm the reliability of the CFD model, which, in turn, was used to improve the interpretation of the experimental data. The Venturi nozzle is modeled with a 3D CFD code (STAR-CCM+). Later on, the CFD model has been used to assess the performance of the component in conditions different from the ones tested in CIRCE: the performance of the Venturi is presented, in terms of pressure drops, for various operating conditions. Finally, the CFD analysis has been focused on the evaluation of the effects of the injection of an inert gas in the flow of the liquid coolant on the performance of the Venturi nozzle. 1. IntroductionAmong the GEN-IV proposed concepts [1], the gas cooled [2, 3] and Heavy Metal (HM) cooled [4] reactors seem to be particularly interesting, also for fuel cycle closure purposes [5, 6]. Regarding HM reactors, many experiments have been and are carried out in order to improve the knowledge of the coolant behavior and to validate the simulations tools (codes).CIRCE (Circulation Experiment, shown in Figure 1(a)) is a large-scale test facility designed for studying key operating principles of the 80 MW Experimental Accelerator-Driven System (XADS) located in Brasimone, Italy. The activities planned for this facility aims at investigating the hydraulic, chemical, and mechanical issue related to the use of the eutectic mixture of lead and bismuth (LBE) as a coolant, in a pool configuration. The test facility was extensively instrumented and tested in order to reliably perform the subsequent campaign of thermal-hydraulic experiments [7].Figure 1: (a) CIRCE facility plant layout and (b) schematic representation of the tank with the indication of the Venturi test section [12].CIRCE plant is filled with LBE, which is a eutectic alloy of lead (44.5%) and bismuth (55.5%) used as a coolant in some nuclear reactor and in this facility, too. One of the key features of LBE is that the melting temperature (125°C) is definitely lower than the one of pure Pb (327°C). This fact is particularly useful because it reduces heating requirements and the risk of unintended solidification of the coolant. Moreover, at lower temperature, the corrosion rates of materials are significantly reduced and so this allows the use of conventional code-qualified materials for very long test durations. A disadvantage is the neutron capture of Bi209 and its subsequent beta decay that form Po210 which is an α emitter. One of the main drawbacks of using LBE (or, similarly, pure lead) as coolant is that it has a strong effect of corrosion and erosion on steel, which limits the range of the velocity and of the temperature of the coolant [8].In this frame, it is particularly interesting to evaluate the performance of the static devices, such as jet pumps (Figure 1(b)) and ejectors, at low velocity, low mass flow rates, and low-Reynolds numbers. Jet pumps and ejectors are static pumping devices, which exploit the pressure and momentum of a little mass flow rate to move, and pump, a larger one. The effectiveness of the jet pump directly depends on the process of mixing of the two confined jets, which regulates the way in which the fast jet transfers its momentum and its kinetic energy to the entrained slow fluid [9].2. Flow Equations and Numerical ModelThe classical form of Reynolds-Averaged Navier-Stokes equations stands for liquid metals, too, as far as their rheological behavior corresponds to the Newtonian fluid model. The governing equations of fluid flow represent mathematical statement of the conservation laws of mass and momentum for isothermal flow, and, in the case of stationary motion, the form is as follows: Mass conservation is Momentum equation isThe thermal conditions of the test facility were carefully controlled to prevent the solidification of the mixture; therefore, in the Venturi nozzle, which is placed inside of the facility, heat transfer to the surroundings is negligible and the temperature is constant through the fluid domain. For this reason, the energy equation has not been solved and the flow is assumed isothermal and adiabatic.The turbulence is treated by a RANS approach. The RANS models implemented in STAR-CCM+ [10] and used for these simulations are as follows:(i)Standard model(ii)Realizable model(iii)Standard model(iv)SST modelThe turbulent boundary layer can be divided into three zones: viscous sublayer, log layer, and outer layer [11].STAR-CCM+ uses a wall treatment to deal with the turbulent boundary layer. As is known, a wall treatment is the set of near-wall modeling assumptions for each turbulence model.Three types of near-wall treatment are provided [10]:(i)The high- wall treatment implies the wall-function-type approach. It is suitable for use with models that do not explicitly damp the turbulence in the near-wall region.(ii)The low- wall treatment is suitable for low-Reynolds number turbulence models. It is possible to use this treatment only if the entire mesh is fine enough.(iii)The all- wall treatment is a hybrid treatment that attempts to emulate the high- wall treatment for coarse meshes and the low- wall treatment for fine meshes. It is also formulated with the desirable characteristic of producing reasonable answers for meshes of intermediate resolution.3. CFD Analysis of the Venturi NozzleOne of the studies carried out at Brasimone Research Center is the calibration of a large Venturi nozzle flow meter (Figure 2) operating in LBE [12]. Such flow meter has been selected to provide flow rate measurements during thermal-hydraulic test on eutectic Pb-Bi (LBE) fluid. Because of the features of this fluid, and the importance of the tests, the Venturi nozzle underwent to a specific calibration aimed at the definition of the characteristic response of the device, with LBE as working fluid [13]. The aim of this calibration is to define the correlation among the differential pressure evaluated between the inlet and the throat, and the Pb-Bi mass flow evolving in it.Figure 2: Venturi geometry CAD representation [7, 12].As already anticipated, the CFD software used in these simulations is STAR-CCM+ by CD-Adapco [10]. The 3D-CAD tool provided by this software allows modeling the fluid domain. As shown in Figure 3, the geometry was created with a 360° revolution of a 2D sketch.Figure 3: Venturi 3D and 2D geometry.The boundary conditions set for the simulations are as follows:(i)Mass flow inlet: imposed mass flow rate [kg/s](ii)Pressure outlet: 0 (imposed)(iii)Wall: no-slip conditionIn any flow condition of the present paper, the Reynolds number is always greater than 4000 (the lower limit for turbulence regime), so a turbulent approach is fully justified.The first set of simulations were devoted to a sensitivity analysis of the effect the mesh, of the turbulence models, and of the variation of the physical properties caused by different operating temperatures.Figure 4 plots the results obtained with various mesh sizes and realizable turbulence model: this figure reports in abscissa the ratio between the calculated pressure drop and the dynamic pressure at the inlet of the throat section and in ordinate, Figure 4(a) the ratio between the design flow rate, (equal to m3/s), and two different off-design conditions, due also to density variations of the operating fluid, and Figure 4(b) the grid size in kNodes (logarithmic scale). The starting point for the base size (grid dimensions) was a value of 0.02 m, halving this parameter for each simulation reaching the final (and much heavier in terms of computational effort) value of 0.0025 m.Figure 4: Mesh comparison.The sensitivity analysis of the mesh size shows that results are fairly grid independent; that is, that the solution would not be significantly influenced by a further mesh refinement.It was found that the mesh with about 70000 cells and a mesh size of 0.01 m gives the best compromise between calculation time and precision. The wall treatment used is the All- provided by STAR-CCM+ and the values are between 1.5 and 3.1.Under the hypotheses of steady, inviscid, incompressible fluid, adiabatic flow and negligible change in height, the Bernoulli’s equation (see (3)) was used for the estimation of the pressure drop among the throat: The results of this simple evaluation are in very good agreement with the experimental data (Figure 4).As a second step, different turbulence models have been considered. The models used were a realizable , standard, and SST. The results obtained by varying the turbulence models are substantially the same obtained with models, as Figure 5 shows (percentage difference lower than 20%).Figure 5: Comparison between different turbulence models and experimental results.After these preliminary analyses, a series of new tests have been performed in order to consider the variation of Venturi nozzle correlation with different nominal temperature (200°C, 300°C, and 385°C) and consequently different densities, dynamic viscosities, and mass flow rates at the inlet. For each temperature, three values of flow rates (a minimum value equal to 0.015 , a nominal value equal to 0.0225 , and a maximum value equal to 0.035 ) were chosen to compare the different tests. As Figure 6 shows, the pressure drop and mass flow rate values are quite similar so it can be concluded that the effect of temperature is negligible, at least in the investigated temperature range: so this justifies the adoption of a single best fit line.Figure 6: Comparison for different temperature values.According to the obtained results, Figure 7 shows the trend obtained with the STAR-CCM+ simulations. This

ACS Style

Matteo Lizzoli; Walter Borreani; Francesco Devia; Guglielmo Lomonaco; Mariano Tarantino. Preliminary CFD Assessment of an Experimental Test Facility Operating with Heavy Liquid Metals. Science and Technology of Nuclear Installations 2017, 2017, 1 -11.

AMA Style

Matteo Lizzoli, Walter Borreani, Francesco Devia, Guglielmo Lomonaco, Mariano Tarantino. Preliminary CFD Assessment of an Experimental Test Facility Operating with Heavy Liquid Metals. Science and Technology of Nuclear Installations. 2017; 2017 ():1-11.

Chicago/Turabian Style

Matteo Lizzoli; Walter Borreani; Francesco Devia; Guglielmo Lomonaco; Mariano Tarantino. 2017. "Preliminary CFD Assessment of an Experimental Test Facility Operating with Heavy Liquid Metals." Science and Technology of Nuclear Installations 2017, no. : 1-11.

Journal article
Published: 01 August 2016 in Annals of Nuclear Energy
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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 coolant level and boron concentration. Some important nuclear parameters are evaluated in different positions of the mock-up, in order to know how the level of coolant influences the flux, the fission density, the reaction rate and the neutron spectrum changes, although the reactor remains with keff around 1.0 to less than 300 pcm of reactivity.

ACS Style

D. Chersola; G. Mazzini; Michal Košťál; B. Miglierini; M. Hrehor; Guglielmo Lomonaco; Walter Borreani; M. Ruščák. Application of Serpent 2 and MCNP6 to study different criticality configurations of a VVER-1000 mock-up. Annals of Nuclear Energy 2016, 94, 109 -122.

AMA Style

D. Chersola, G. Mazzini, Michal Košťál, B. Miglierini, M. Hrehor, Guglielmo Lomonaco, Walter Borreani, M. Ruščák. Application of Serpent 2 and MCNP6 to study different criticality configurations of a VVER-1000 mock-up. Annals of Nuclear Energy. 2016; 94 ():109-122.

Chicago/Turabian Style

D. Chersola; G. Mazzini; Michal Košťál; B. Miglierini; M. Hrehor; Guglielmo Lomonaco; Walter Borreani; M. Ruščák. 2016. "Application of Serpent 2 and MCNP6 to study different criticality configurations of a VVER-1000 mock-up." Annals of Nuclear Energy 94, no. : 109-122.