PhD Thesis: “Modeling and Design of Nuclear Systems for Space Electric Propulsion: A Study of Gas-Cooled Reactor (GCR) and Liquid Metal Reactor (LMR) Technologies (M/F)

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PhD Thesis: “Modeling and Design of Nuclear Systems for Space Electric Propulsion: A Study of Gas-Cooled Reactor (GCR) and Liquid Metal Reactor (LMR) Technologies (M/F) Sintesi in italiano (traduzione automatica): Il laboratorio di fisica subatomica e cosmologia di Grenoble (LPSC) cerca un candidato per un dottorato di ricerca nel gruppo di fisica dei reattori. Il progetto si concentra sulla modellazione e progettazione di sistemi nucleari per la propulsione elettrica spaziale, in particolare reattori raffreddati a gas (GCR) e reattori a metallo liquido (LMR). Il candidato lavorerà su un progetto cofinanziato dal CNES, sviluppando strumenti numerici per ottimizzare le tecnologie di propulsione nucleare. Le principali mansioni includono la creazione di modelli per GCR e LMR, studi comparativi delle tecnologie e l'integrazione di vincoli di progettazione per applicazioni di potenza superficiale. È richiesta una laurea in ingegneria nucleare o un campo correlato. The Grenoble Laboratory of Subatomic Physics and Cosmology (LPSC) ( http://lpsc.in2p3.fr ) is a joint research unit operated by the CNRS-IN2P3, Université Grenoble Alpes (UGA), and Grenoble INP, employing approximately 230 staff members. The PhD candidate will join the Reactor Physics Group, which comprises ten researchers and engineers at LPSC. The research will be carried out within the FEST (Fluids Experiments and Simulations in Temperature) experimental platform, under the direct supervision of the Head of the Reactor Physics Group. Since 2019, the Reactor Physics Group at LPSC has been working on the design of microreactors for Nuclear Electric Propulsion (NEP) as well as on the development of dedicated numerical tools (NepFOAM and PRESTO) for modeling such systems. PRESTO plays a central role in the design process by helping identify the most promising concepts and determine the optimal parameters (size, materials, fuel enrichment, operating temperature, flow rate, etc.) for all NEP subsystems. These preliminary designs are subsequently refined through high-fidelity multiphysics simulations using NepFOAM. During the ongoing PhD project, co-funded by the French National Centre for Space Studies (CNES), PRESTO has been significantly enhanced through the integration of a new reactor technology: the Heat Pipe Reactor (HPR). The present PhD project aims to continue and extend this development in order to cover the full range of reactor technologies envisioned for Nuclear Electric Propulsion while also accounting for surface power applications. Two additional reactor concepts will be incorporated into PRESTO: Gas-Cooled Reactors (GCRs) and Liquid Metal Reactors (LMRs). In parallel, a new power conversion system based on the Brayton cycle will be implemented. Although the Brayton cycle is particularly well suited to GCRs, it is also a relevant option for HPRs, Molten Salt Reactors (MSRs), and LMRs. In a later phase of the PhD project, PRESTO will be further extended to enable the preliminary optimization of surface power systems, such as those envisioned for permanent lunar or Martian bases. These new capabilities will allow PRESTO to address fundamental design questions that go far beyond simple performance comparisons between technologies. By incorporating the specific design constraints associated with surface power systems, the tool will also make it possible to assess the extent to which technologies developed for Nuclear Electric Propulsion can be adapted for applications on the Moon or Mars. Key activities: To achieve the objectives described above, the PhD project will be structured into four main stages: 1. Development and implementation of a Gas-Cooled Reactor (GCR) model and the Brayton power conversion cycle in PRESTO (Year 1). 2. Development of a Liquid Metal Reactor (LMR) model, considering reactor concepts cooled by sodium (Na), sodium-potassium alloy (NaK), or lithium (Li) (Year 2). 3. Comparative performance studies of the four main Nuclear Electric Propulsion technologies—LMRs, GCRs, HPRs, and MSRs (Years 2–3). Existing models will be improved and refined whenever necessary. 4. Depending on the progress of the project, integration of additional design constraints and models—in particular radiation shielding models—to enable the optimization of systems intended for surface power applications (Year 3), together with the preparation of the PhD dissertation. The design of the GCR and LMR concepts, carried out during Stages 1 and 2, will require the development of neutronic, thermal-hydraulic, and mechanical numerical models specifically adapted to these reactor technologies. These models will account for different materials for the fuel, cladding, coolant, reflector, and, where applicable, moderator. They will be used to evaluate operating conditions (power, temperature, pressure, mass flow rate, etc.), as well as the dimensions, masses, and design and safety limits of the main reactor components. The neutronic mo Annuncio in inglese. Fon