TSUNAMI Analyses of the Similarity and Applicability of Zero Energy Deuterium 2 Critical Experiments for Reactor Physics Code Benchmarking for a Pressurized Water Reactor Small Modular Reactor Design Concept

Abstract This paper presents the findings of studies conducted at Canadian Nuclear Laboratories (CNL) to support the development of small modular reactor (SMR) designs. The primary focus of this research was to evaluate the suitability of the zero energy deuterium 2 (ZED-2) critical facility in replicating the reactor physics environment for a pressurized water reactor small modular reactor (PWR-SMR) design concept through similarity and nuclear data sensitivity studies, using the TSUNAMI code suite. It was found that previous ZED-2 experiments would be quite promising for application to a PWR-SMR design. Further similarity and sensitivity studies of hypothetical mixed-lattice substitution experiments, where PWR-SMR fuel assemblies were placed into a substitution region of the ZED-2 critical facility demonstrated improved similarity. Subsequent analyses focused on the impacts of dissolved Gadolinium (Gd) and boron (B) neutron absorbers, suggesting the feasibility of using future ZED-2 experiments to more closely replicate PWR-SMR reactor physics behavior. Building on these initial findings, the design for PWR-SMR fuel assembly substitution experiments in the ZED-2 facility were explored further. These hypothetical experiments feature water-cooled PWR-type fuel assemblies inside a shroud, surrounded by heavy-water-moderated CANdu FLEXible, Low Enriched Uranium, Recovered Uranium (CANFLEX-LEU/CANFLEX-RU) fuel channels. Similarity and sensitivity studies indicate a very high level of similarity of these experiments for PWR-SMR design applications.