Abstract:
This research focuses on the utilization of nanofluids as coolants in Pressurized Water Reactors (PWRs). By focusing on two distinct reactor designs, the AP-1000 with its characteristic square array fuel subchannel and the VVER-1000 with a triangular array, a comprehensive analysis is conducted to evaluate the neutronic and thermal-hydraulic performance of various nanofluids. A diverse range of nanofluids, including Al2O3, TiO2, SiO2, CNT, Cu, and their hybrid combinations, are assessed across multiple volume fractions ranging from 0% to 2%. The study meticulously examined key parameters such as the Effective Multiplication Factor (Keff) using OpenMC and Nusselt Number, Surface Heat Transfer Co-efficient, Pressure Drop, and Pumping Power using ANSYS Fluent solver. Among the findings, particularly noteworthy is the performance of hybrid nanofluids compared to homogenous ones, especially the one incorporating CNT and Cu, which demonstrates significant heat transfer enhancements. This is quantified by an increase in the Nusselt Number by up to 15.68% for the AP-1000 and 18.35% for the VVER-1000 reactor, relative to the best-performing homogenous nanofluid, CNT-based nanofluid. These improvements, however, are coupled with an incremental rise in pressure drop, by 9.81% for the AP-1000 and 5.48% for the VVER-1000, suggesting a nuanced balance between thermal performance and hydraulic resistance. On the other hand, SiO2, in both reactors, showcases the highest Keff, indicating its potential to maintain a stable and efficient nuclear reaction. Conversely, Cu-based nanofluids, particularly at higher concentrations, are found to be less optimal, due to their lower Keff, which is 0.92% and 0.97% lower for AP-1000 and VVER-1000 respectively than the highest performer SiO2, combined with increased pumping power, which highlights challenges that need addressing for their effective use in PWRs. By judiciously selecting the type and concentration of nanofluids, significant enhancements in reactor performance can be achieved. However, the study also emphasizes the need for further research, especially in understanding the long-term stability, and interaction of nanofluids with reactor internals in real-world reactor environments.