Conceptual Model of a CANDU Fuel Channel with Improved Axial Temperature Distribution (64)

Abstract

Optimal nuclear reactor performance is critical to ensure adequate operation and extend its operating life while lessening the financial burden on power generation companies. Currently, fuel channel sag, axial elongation, and variation in axial and radial temperature distribution negatively impact the longevity of the CANDU reactor fuel channels. This project aims to address such by redesigning the existing fuel channels and supporting assemblies by reducing the radial temperature gradient through the iterative design of various model modifications utilized testing methods of Finite Element Method (FEM) Analysis, Computational Fluid Dynamics (CFD) Analysis, reactor neutronics, and Virtual Reality (VR). These simulations will provide valuable insight concerning the changes over time as the pressure tube sags and the effectiveness of each potential solution. From our preliminary results, the sag discovered from the pressure tube was approximately 5 mm due to gravity. In addition, this correlates to the hot spots seen along the pressure tube as the space above the fuel bundle increases. The correlation further confirms that the problem is sourced from the forces the pressure tube experiences. Future work will create FEM, CFD, and Neutronics simulations of the improved model that can be utilized in the existing virtual reality model of the CANDU calandria to facilitate the visualization and understanding of the problem and proposed solution. It will be a tool to facilitate learning and understanding of the phenomena associated with fuel channel sag.