Curriculum

Current position:

• Associate Professor of Nuclear Reactor Physics
  Department of Civil and Industrial Engineering, University of Pisa, Pisa.
• Programme Coordinator of the Master’s Degree in Nuclear Engineering
  Department of Civil and Industrial Engineering, University of Pisa, Pisa.

Didactic activity:

• Nuclear Reactor Physics (Module of the course Physics and Numerical Models For Nuclear Reactors, Code 1089I) for the Master’s Degree in Nuclear Engineering (60 hours)
• Numerical Models For Nuclear Reactors (Module of the course Physics and Numerical Models For Nuclear Reactors, Code 1089I) for the Master’s Degree in Nuclear Engineering (60 hours)
• Computational Codes For Nuclear Reactors (Code 1098I) for the Master’s Degree in Nuclear Engineering (30 hours)

Scientific Activity:

• Development of computational codes for nuclear reactor core calculations using a Boundary Element – Response Matrix (BERM) approach;
• Nuclear thermal and electric space propulsion systems;
• Support for the Mu2e experiment design;
• Core calculations for advanced nuclear reactors;
• Neutron sources for Boron Neutron Capture Therapy (BNCT);
• General problems of radiation transport.

The first item listed concerns the implementation of suitable Fortran algorithms to solve the A_N approximation of the neutron transport equation through the Boundary-Element Response-Matrix approach (BERM-AN). The boundary element method reduces the multigroup diffusion equation to an integral equation in terms of the boundary values of the flux and its derivative. After the introduction of partial currents, the integral equation is solved by an iterative procedure based on the Response Matrix formalism. The results demonstrate the robustness of the BERM-AN method, which, for criticality problems (i.e., homogeneous problems), allows for achieving high accuracy with a competitive computational time. Later, the BERM-AN code has been extended to problems involving a fixed external source, as in the case of an accelerator-driven system (i.e., non-homogeneous problems). Such activity required a quite extensive rewriting of the code with the implementation of a different strategy for the whole iterative process, due to the very slow rate of convergence of such non-homogeneous problems. The results have confirmed the remarkable accuracy achievable by the BERM-AN code, keeping the computing time, particularly for the 3D problems, lower than that required by reference codes like PARTISN or MCNP.

A proper treatment of the scattering anisotropy is important when neutrons collide with light nuclei. The BERM-AN code already included a rigorous treatment of the linear anisotropy of the scattering, however, in the case of the light water reactor calculations, it is perhaps advisable to adopt a larger Legendre expansion of the differential scattering cross-section, owing to the slow convergence of this expansion for thermal neutrons in a moderator containing hydrogen (Davison and Sykes, 1957, Ch. XVII). On the other hand, since the A_N method is intrinsically approximate (for N→∞ it does not approach the exact solution), its extension to a very high order of anisotropy may not be worthwhile. That considered, the treatment of the scattering anisotropy has been improved by extending the expansion of the scattering cross-section from the first to the second order. The accuracy significantly improves when the scattering expansion moves from the isotropic to the linearly anisotropic treatment, as shown by previous results. A further, although less pronounced, accuracy gain is, however, obtained when the cross-section expansion rises from the first to the second order. For the BERM-AN method, differently from codes based on the discrete ordinates approximation, this extension does not introduce any extra computational burden; thus, it can always be adopted.

From the point of view of the calculations, it is a fortunate circumstance that a nuclear reactor can be considered, at different levels, as an array of regions of a rather simple shape, like right parallelepipeds or right prisms with a hexagonal basis. Of course, many details do not comply with this description, but it is usually possible to overcome these difficulties by performing some averages or homogenizations. A still-in-progress work attempts to take advantage of this structure of a reactor, or a part of it. Each region is assumed to be homogeneous, or has been previously homogenized, and, other than containing (possibly) an independent source, it is subject to the flux of the neutrons coming from all the surrounding regions. The calculation of such incoming flux is made using an ad hoc “single-flight” Monte Carlo, where the attribute single-flight is because the history of each neutron is stopped after its first collision. For each region, the solution of the Peierls equation is then performed by assuming that the scattering is isotropic. Such a stochastic-deterministic hybrid method is quite original and aims to take advantage of both methodologies. With the perspective of a proof of concept, this method has been developed under the hypothesis of monoenergetic neutrons and isotropic scattering. Preliminary results have shown that it is capable of providing results that match very well with those obtained by a full Monte Carlo simulation performed under the same settings.

The second item concerns a recent and very active research topic: the design of a nuclear reactor for space propulsion, undertaken in collaboration with the Aerospace Section of the Department of Civil and Industrial Engineering. This research is part of the BANTER (Bimodal Ammonia Nuclear Thermal and Electric Rocket) project, granted 3.0 million euros by the Horizon European Innovation Council (EIC) and coordinated by the University of Pisa.

BANTER is the first step towards realizing an innovative bimodal nuclear thermal and electric propulsion system based on the same fluid, ammonia, as the propellant for the nuclear thermal and electric propulsion and the working fluid for the power generation system. Due to its ease of storage in non-cryogenic conditions, its presence as an in-situ resource on many targets of future space missions, and its possibility of decomposing to increase its propulsive performance (i.e., the specific impulse), ammonia allows the development of a compact propulsion system capable of transporting tons of payloads for a wide spectrum of missions.

The design of a nuclear reactor implementing a new type of fuel channel based on High-Assay Low Enriched Uranium (HALEU) in the form of a TRISO particle bed, through which the ammonia propellant flows, and a radiator-less power generation system fed by ammonia will constitute the first phase of the project. The ammonia decomposition induced by the combination of thermolysis, catalysis, and radiolysis will be studied in two experimental campaigns carried out on prototypes of the coolant channel, both in a nuclear and non-nuclear environment, to demonstrate propulsive performance capable of outclassing traditional chemical propulsion systems. A parallel study will design, develop, and test newly ammonia-based electric thrusters for long-period operation without excessive cathode erosion, eventually with increased efficiency due to the catalytic decomposition of the propellant. The proposed configuration features an autogenous pressurization of ammonia by exploiting waste heat from the reactor’s radiation. A pressurizing tank, filled with saturated ammonia, is positioned near the nuclear reactor and is heated by the energy deposited by gamma rays and neutrons in the tank wall and the ammonia itself. This thermal input induces the vaporization of the saturated ammonia, which in turn increases the pressure in the tank. A pressure regulator valve connects the pressurizing tank to the propellant run tank. This valve helps set the pressure of the run tank to the level required by the specific mission scenario, ensuring the appropriate propellant mass flow rate into the nuclear reactor during firing. A preliminary lumped-parameter analysis of this propellant management system suggests that it can allow for a constant mass flow rate to the nuclear reactor without the need for an auxiliary turbopump.

The positive outcomes of the project will pave the way for developing a technology that could make Europe a protagonist for the future space race, thanks to a compact, versatile, and high-performance propulsion system. Additionally, any improvement in the production of green hydrogen from ammonia decomposition will also benefit the energy industry. This aspect makes the project highly multidisciplinary, not only in the research approach but also in the results.

The Mu2e (muon-to-electron) experiment, currently under construction at Fermilab, aims to improve the experimental limit for the neutrinoless muon-to-electron conversion in a nuclear field. The theoretical limit for this Charge Lepton Flavour Violating (CLFV) transition is of the order of 10^-50. The current experimental sensitivity is of the order 10^-13. The Mu2e experiment aims to improve this sensitivity by some four orders of magnitude. My research activity has been focused on performing Monte Carlo simulations with the MCNP code (version 6.1 and 6.3) to support/integrate the Geant4 results (the official simulation software of the experiment).

Some of the MCNP simulation subjects have dealt with:

• Improvement of the neutron shield
  Neutrons can damage some components of the experiment, like the electronics of the calorimeters and the cosmic ray veto, as well as induce false positives. In particular, the possibility of improving neutron shielding performance through the combination of concrete with other materials (e.g., bismuth, tungsten, iron, etc.) characterized by a suitably large probability of inelastic interactions with high-energy neutrons (up to 100 MeV) was investigated.
• Study of the primary production target
  Through appropriate simulations, the amount of energy deposited in the target by the primary proton beam and the yield of secondary particles produced by proton interactions with the target were studied.
• Antiproton background
  Within the framework of the SU2020 campaign, an extensive code-to-code comparison involving three Monte Carlo codes (namely MCNP, Fluka, and MARS) has been performed to investigate the consistency of the large background of backscattered antiprotons estimated by the simulation toolkit Geant4. As an outcome of the intercomparison, it has been decided to use the MCNP result to define the acceptance of antiprotons entering the transport solenoids.
• Kaon background
  Another intercomparison, among the three Monte Carlo codes mentioned above, has been performed to estimate the transmission probability of kaons (both K_L and K_S) through the concrete shield of the cosmic ray veto. Preliminary results have shown a large difference among the three codes. Differences that are still not clearly understood.
• Radiation damage to the tungsten production target
  Some concerns arose about the tungsten target’s resistance to radiation damage. To estimate the extent of such damage, DPA calculations have been performed with several Monte Carlo codes using different approaches. In particular, DPA calculations performed with MCNP rely on the use of displacement cross sections, which allow an estimation of the damage from the particle flux to which the body is subjected. Accounting for the same kind of particles, results from MCNP, FLUKA-CERN, and FLUKA agree very well with each other. Unfortunately, the number of DPA is too large to ensure a long-lasting target. Consequently, modifications in the target design are mandatory.
• Electromagnetic calorimeters
  In parallel to the above activities, support has also been provided to the design and construction of the two electromagnetic calorimeters.

• Coordinator of Work Package 3 “Nuclear Thermal Propulsion” for the Horizon EIC Banter project. The work package aims to evaluate nuclear thermal propulsion solutions that comply with the imposed mission requirements, to build lab-scale demos of both the reactor’s coolant and thrust channel, and to develop the necessary test rig.
• Co-coordinator of Work Package 6 “FNAL Muon Campus experiments” for the H2020 European Project NEWS-RISE, coordinated by INFN Pisa and the University of Pisa, and aimed to promote the collaboration between European, US, and Japanese research institutions in some key areas of fundamental physics.
• Participation, in collaboration with NINE S.r.l., in the IAEA coordinated research project (CRP) on neutronics benchmark analysis of the start-up tests performed at the China Experimental Fast Reactor (CEFR) in 2010-2011.
• Participation in work package 4 “Neutron physics of Super-Critical Water Small Modular Reactor (SCW-SMR)” of the ECC-SMART project funded by Euratom Research and Training Program 2019-2020, under Grant Agreement n.945234. The project closed at the end of February 2025, among the activities perfomed there is: i) a code-to-code comparison of three Monte Carlo codes (namely, OpenMC, MCNP and Serpent) to check their consistency using a computational benchmark based on a supercritical water fuel assembly; ii) reactor-core enrichment optimization to keep the peak cladding temperature below the limit and to allow for a two-year long fuel cycle before refuelling and/or shuffling; iii) fuel assembly optimization using both burnable absorbers and the enrichment zoning.
• A relevant application of neutrons in medicine is represented by the Boron Neutron Capture Therapy (BNCT). Since 1999, many activities have been performed in this field. Particularly relevant has been the collaboration in the development of the BNCT facility at Studsvik (Sweden), where more than 50 patients bearing a malignant glioblastoma were treated. Other than contributing to the characterization of the clinical (epithermal) neutron beam, the full design of an experimental beam with variable radiation field characteristics was carried out.
• Still in this field, an important activity was devoted to the validation, as a consultant of Hammercap AB (Sweden), of the neutron filters in a Chinese BNCT facility based on a compact low-power nuclear reactor. Particular attention was payed at improving the design of the epithermal filter to enhance the neutron flux within the 10 eV – 20 kev energy interval.

Awards:

Master of Science Thesis tutoring:

1. Candidate: Belli Giovanni
   Title: Radiation Shielding and Orbital Safety Strategies for a Space Nuclear Propulsion System
2. Candidate: Chessa Luigi
   Title: Radiation Shielding and Orbital Safety Strategies for a Space Nuclear Propulsion System
3. Candidate: Sainati Giacomo
   Title: Toward High-Fidelity multi-physics solutions – set up of APOLLO3® et TrioCFD coupling
4. Candidate: Mannucci Stefano
   Title: Conceptual Design of a Particle Bed Nuclear Reactor for Aerospace Application
5. Candidate: Gomez Rodriguez Juan Jose
   Title: Determination of Integral Cross Sections using the Pile Oscillator Experiment at the AKR-2 Nuclear Training Reactor
6. Candidate: Santangelo Antonino
   Title: Synthetic diagnostics for neutron cameras in tokamak plasmas
7. Candidate: Cozzarizza Davide
   Title: Benchmarking of Monte Carlo tools for modeling radiation damage induced by ions and neutrons in matter
8. Candidate: Piccolo Antonio
   Title: Identification of radioisotopes using Artificial Intelligence techniques for gamma-ray spectra measurements
9. Candidate: Mohamed Ahmed Abdelrahman Mohamed
   Title: Validation of the thermal-hydraulic Subchannel code COBRA-TF
10. Candidate: Cosimi Jacopo
    Title: Metodo ibrido stocastico-deterministico per la risoluzione dell’equazione del trasporto dei neutroni in forma integrale
11. Candidate: Tulino Paolo
    Title: GEANT4 study of the particle-induced X-ray emission (PIXE) using laser-driven protons
12. Candidate: Ratti Luca
    Title: Neutronic analysis for VVER-440 type reactor using PARCS code
13. Candidate: Lampunio Lisa
    Title: Monte Carlo neutronic design of the ETNA irradiation facility at the High Flux Reactor Petten
14. Candidate: Ulissi Cristina
    Title: Progettazione concettuale del nocciolo di un SMR refrigerato a piombo
15. Candidate: Dambrosio Antonio
    Title: Neutronic analysis for LVR-15 research reactor using PARCS code
16. Candidate: Giannoni Luca
    Title: Design, Development, and Investigations of a Novel X-ray Fluorescence and X-ray Luminescence Computed Tomography System for Theranostic Applications
17. Candidate: Facchini Alberto
    Title: Analysis of European sodium fast reactor core under an unprotected transient of overpower
18. Candidate: Pedretti Francesco
    Title: Multichannel transient analysis of SEALER
19. Candidate: Venturini Alessandro
    Title: Neutronic investigations of MOX and LEU fuel assemblies for VVER reactors
20. Candidate: Luca Pasquale de Ruvo
    Title: A hybrid deterministic-stochastic method for the solution of the neutron transport
21. Candidate: Cossa Giulia
    Title: Boundary elements for three-dimensional calculations
22. Candidate: Di Fulvio Angela
    Title: Development of an optoelectronic system for neutron bubble detectors

Institutional activities:

• Programme Coordinator of the Master’s Degree in Nuclear Engineering from 16/09/2024.
• Deputy Director of the Master of Science in Nuclear Engineering from 24/11/2015 to 15/09/2024.
• Member of the Scientific and Organizing Committees of the 11th International Symposium on Super Critical Water-Cooled Reactors (ISSCWR-11), 03-05 February 2025, Pisa (Italy)
• Co-Chairman of the Reactor Physics and Coupling with Thermal-Hydraulics session at the 11th International Symposium on Super Critical Water-Cooled Reactors (ISSCWR-11), 03-05 February 2025, Pisa (Italy)
• Member of the Scientific Committee of the 9th International Conference on Advancements in Nuclear Instrumentation Measurement Methods and their Applications (ANIMMA), 09-13 June 2025, Valencia (Spain)
• Member of the Scientific Committee of the 8th International Conference on Advancements in Nuclear Instrumentation Measurement Methods and their Applications (ANIMMA), 12-16 June 2023, Lucca (Italy)
• Member of the Scientific Commission of Area 09 from 2012 to 2016 and from 2023 to 2024.
• Member of the Industrial Engineering Doctorate Board from 2014 to 2017.
• Department of Civil and Industrial Engineering delegate at the Interdepartmental Language Center (CLI) from 2012 to 2017.
• President of the Language Commission of the Engineering School of Pisa University from 2012 to 2017.
• Member of the Joint Teacher-Student Commission of the Engineering Faculty from 24/11/2011 to 19/09/2012.
• Member of the Editorial Board of the International Journal of Science and Technology of Nuclear Installations from 2011 to 2017.
• Expert member, for the years 2011 and 2015, of the Commission for the qualifying examination to the engineering profession in Italy.
• Topic editors for Frontiers in Energy Research, section Nuclear Energy, of the research topic in Light Water Reactor Technology of the Next Decade, published in 2023.
• Reviewer for the following international journals:
  • Annals of Nuclear Energy
  • Nuclear and Engineering Design
  • Nuclear Science and Engineering
  • Nuclear Science and Technology Open Research
  • Transaction on Nuclear Science
  • Medical Physics
  • Radiation Measurements
  • Physics in Medicine and Biology
  • European Journal of Medical Physics

Education:

Professional experiences:

From 01/12/2017 to the present: Associate Professor in the field of Nuclear Reactor Physics at the University of Pisa.

From 28/12/2010 to 30/11/2017: Assistant Professor in the field of Nuclear Reactor Physics at the University of Pisa.

From 01/04/2010 to 31/10/2010:  Contract with the Department of Mechanical, Nuclear, and Production Engineering to set up computational codes to analyze nuclear reactor cores.

From 01/02/2007 to 31/01/2010: Position as a fixed-term researcher at the Department of Mechanical, Nuclear, and Production Engineering in the field of Nuclear Reactor Physics (SSD ING-IND/18).

From 18/08/2004 to 31/12/2006: Owner of the consulting company E.Co. (Engineering Consulting), focused on the design of tools or facilities dealing with radiation or radioactive materials.

From 01/08/2005 to 31/01/2006: Grant from the Department of Mechanical, Nuclear, and Production Engineering of Pisa University on ”Neutron dosimetry of mixed fields: industrial, medical and research applications”.

From 01/07/2003 to 30/06/2005: Research Fellowship from the Department of Mechanical, Nuclear and Production Engineering on “Radiation transport models for neutron spectrometry and dosimetry”.

From 01/02/2003 to 30/04/2003: Contract from the Department of Radiation Physics of Lund University (Lund, Sweden) to perform Monte Carlo simulations aimed at the optimization of a prompt gamma-ray spectroscopy facility for the online measurement of the boron in the healthy and tumor tissue during BNCT treatments.

From 2001 to 2003: Consultant of the Eurosea Committee (Torino) and Politechnic of Torino on the computational procedures for the project ”Boroterapia Piemonte”.