Uncertainty quantification with ANICCA fuel cycle code & Application to Belgium Case

Since the early days of nuclear power, the idea of small and medium-sized reactors has been considered, but the general trend has always gone toward larger units, mainly because of the lower specific cost of energy due to the economy of scale. However, in more recent times Small Modular Reactor (SMR) started to be appealing because of some advantages of theirs: mainly their convenience in terms of initial capital cost and proliferation resistance if safeguard by design is applied from the very beginning as recommended by IAEA, the safety level they can reach, their adaptability to medium and low power (remote) electrical grids, and also a dismantling procedure that is, hypothetically, easier. However, due to their small size, we know that neutron leakage will be higher than in a large reactor, leading to greater activation of the structure outside the reactor per MWh produced. In November 2023, Belgium (through SCK CEN), Italy (via Ansaldo Nucleare and ENEA), and Romania (via RATEN) signed a memorandum of understanding to collaborate on the development, demonstration, and commercialization of lead-cooled small modular reactors (Lead-cooled Small Modular Reactor (SMR-LFR)). The initiative outlined a phased approach, beginning with the LEANDREA small-scale prototype at the Belgian Studiecentrum voor kernenergie / Centre d’étude de l’énergie nucléaire (SCK CEN) site, aimed at validating key technological and engineering aspects of a commercial SMR-LFR. This effort was framed by the Belgian government as a strategic investment in the future of nuclear energy. Building on this, in June 2025, a major step was taken with the formation of the EAGLES consortium to develop and commercialize EAGLES-300, a next-generation lead-cooled fast SMR. With a target output of around 350 MWe, EAGLES-300 is designed for flexible deployment, industrial heat and hydrogen production, and the use of MOX fuel with recycled materials, enhancing sustainability. The consortium plans to complete its first prototype, LEANDREA (at SCK CEN), by 2035. Following the construction of the ALFRED demonstration reactor in Romania — intended as a springboard for commercial deployment — it aims to launch commercialization by 2039, using LEANDREA for fuel and material testing, while upgrading ALFRED as part of key development milestones. 1 SCK CEN/95349098 Rev. 2.0 Moreover, under the new coalition agreement, the government is planning to develop a concrete strategy to support the construction and commissioning of Belgium’s first SMR in the course of 2025. This strategy will be developed in partnership with nuclear industry leaders and business groups for consideration in contributing to the targeted extra 4 GWe of nuclear power, using both existing nuclear reactors and new initiatives. It is important to note that “SMR” in this context does not necessarily refer to fast neutron SMRs (such as lead-cooled reactors); it can also encompass conventional light-water SMR designs. However, from a long-term perspective, the deployment of a future SMR-LFR reactor fleet in Belgium would require comprehensive technical, economic, and environmental assessments of potential advanced fuel cycle scenarios. To support such evaluations, the use of fuel cycle simulation codes is essential. Thus, to answer the mandate by the Government to research in Partitioning & Transmutation (P&T) and Partitioning & Conditioning (P&C), and to study the future implementation of an SMR-LFR fleet in Belgium, SCK CEN is proposing a new advanced fuel cycle scenario study. In this scenario, several assumptions are made regarding the present Belgian Pressurized Water Reactor (PWR) fleet that require the update of the current reference Belgian fuel cycle scenario in Advanced Nuclear Inventory Cycle Code (ANICCA). In previous MSc Theses, the Belgium reference scenario was updated to reflect the extension of two of Belgium’s reactors (Doel-4 and Tihange-3) until 2035. Moreover, ANICCA’s irradiation module has been recently updated with Machine Learning (ML) prediction capabilities for Light-Water Reactor (LWR) fuel and is currently being updated for SMR-LFR Mixed Oxide fuel (MOX). At present, a new scenario, in which Doel 4 and Tihange 3 are extended until 2045 and Doel 1, Doel 2, and Tihange 1 nuclear reactors are extended for ten more years (until 2035), is being developed. Afterwards, the new advanced Belgian fuel cycle scenario study will be implemented. Different advanced fuel cycle strategies will be studied, with the introduction of SMR-LFR and/or Accelerator Driven System (ADS), as well as the inclusion of multi-recycling in order to close the cycle and maximize the better use of the primary resources hence increasing sustainability. The objective of this MSc thesis is to complement these works. Parametric uncertainty quantification studies for different technology options and parameters will be carried out. This work will provide the best estimate plus uncertainty values and will assist decisionmakers in identifying the strengths and weaknesses of different strategies for a Belgian SMR-LFR nuclear fleet evolution and then proposing possible evolution trajectories for the nuclear industry according to constraints from physics, economics, industry, societal acceptability, and security of supply of raw materials.