Analysis of Xenon-Induced Power Oscillations in an Integral Pressurized Water Reactor Using MCNP Code Coupled with Single Channel Thermal Feedback

Nuclear energy is an attractive source of energy because it decreases our dependence on fossil fuels. Emission of greenhouse gases by burning fossil fuels and the limited supply of oil, gas, and coal, makes nuclear energy an attractive alternative to carbon-based fuels. Nuclear fuel contains much more energy than a equivalent mass of hydrocarbons or coal, hence making it a reliable energy resource. The advanced small modular reactors come with improved safety through various design features such as lower fuel inventory, passive heat removal systems, reduced length of large core cooling piping, etc. The smaller physical size contributes to added flexibilities in fabrication, construction, lower capital cost and shorter construction time contribute to reduced investment risks. The main objective of this study is to assess xenon-induced power oscillations in a generic small modular reactor (SMR) of the integral pressurized water reactor (iPWR) type. The Monte Carlo neutronics code MCNP is used to model the reactor core and carry out the fuel irradiation simulations. The goal is to develop a methodology for analyzing the dynamic phenomenon of xenon-induced power oscillation by coupling MCNP with a thermal feedback algorithm characterizing the temperature effects using a single fuel-coolant channel. A multi-physics coupling algorithm developed will incorporate the effect of thermal-hydraulic feedback (temperature dependent neutron cross-section of fuel and change in axial coolant density) on xenon-oscillation phenomenon induced by a neutron reactivity change in the reactor core. Establishing high fidelity thermal-neutronics coupled methodologies are important for analyzing reactor transients featuring significant variations in localized neutron flux