In this study, a multi-physics framework is developed to advance the predictive capabilities concerning Corrosion-Related Unidentified Deposits (CRUD). The framework integrates three components: a neutronic model, a thermal–hydraulic model, and a CRUD model, meticulously developed for Neutronic-Thermal-CRUD coupling. This innovative approach utilizes virtual grids, enhanced heat conduction modeling, and a refined iterative strategy, aiming to significantly improve the accuracy and efficiency of the simulations. Employing this framework, the study performs a coupling analysis on a 17 × 17 Pressurized Water Reactor (PWR) fuel assembly subjected to 180 days of steady-state operation. The findings elucidate the profound impact of CRUD on fuel assembly behavior, highlighting an approximate 0.21% increase in peak power, − 6.27% axial offset and a consequential 21 cm downward shift in the location of the power peak. Radially, the CRUD predominantly accumulates in the central region adjacent to the guide tubes, correlating with a localized power peaking of about 12.8%. Axially, SNB (sub-cooled nucleate boiling) is initially observed at a height of 210 cm in the central region, with CRUD deposition progressively expanding across the entire assembly as the height increases. The study indicates that the CRUD layer's thickness and the associated neutron absorption are most significant at the initial deposition locations and diminish progressively with increasing axial height. This study underscores the utility of the developed multi-physics framework in enhancing the understanding of CRUD dynamics, providing a robust tool for predicting and mitigating potential safety risks in nuclear reactor operations.