Preliminary study on multiphysics transient calculations for pebble bed reactors using high-fidelity depletion data

This paper introduces an innovative methodology for multiphysics transient analysis in Pebble Bed Reactors (PBRs) using the results of the Hyper-Fidelity Depletion (HxF) as input data.HxF, incorporating Monte Carlo neutron transport and realistic motion, provides detailed insights into pebble-wise flux, power, and temperature distributions.Leveraging HxF depletion data, the study utilizes the MOOSE framework, employing Griffin for neutronic modeling and Pronghorn for thermal-hydraulic modeling.For this work, an equilibrium state of a small molten salt PBR obtained from HxF serves as a test case, and a 3D model is built.Comparisons between HxF and Griffin steady-state calculations reveal promising correlations in power distribution with a difference of 11.65%.More significant discrepancies are presented in the thermal and fast flux, highlighting areas for refinement and emphasizing the need for further investigation.This research sets the stage for future advancements, including the integration of Super Homogenization (SPH)-corrected cross-sections, optimal Griffin solver search, and exploration of varying the number and size of the radial and axial zones.The study lays the groundwork for comprehensive transient studies, including the coupling of Griffin with Pronghorn, for a holistic understanding of PBR dynamics.Detailed temperature and power profiles will be obtained to evaluate the most challenging conditions for the fuel.The ultimate goal is to use this insightful data to perform accurate and detailed TRISO fuel performance analyses during normal and off-normal operating conditions.By pushing the boundaries of traditional analyses, this work contributes to the development and licensing of PBRs, providing a higher level of information on the operating conditions.