The Advanced High Temperature Reactor (AHTR) is a prismatic Fluoride salt cooled High temperature Reactor (FHR) fueled by TRISO particles with a relatively large power of 3400 MW(thermal). Because of its double heterogeneity in fuel element geometry and complexity to model it, transport simulations of AHTR have mostly focused on using Monte Carlo methods. Detailed depletion studies with elements of multiphysics have not been done previously on AHTR, which created the need for a new tool to do so. A C++ script was created to enable such analyses of AHTR, including temperature feedback, thermal expansion, material property changes, and criticality search on control rod position. This paper begins with a brief summary of modeling capabilities and methodologies. Then, attention turns to depletion analysis of AHTR. In this work, five depletion cases of varying degrees of resolution and features are considered with results and comparisons presented. Three-dimensional depletion cases include single material tracking (core average), fine spatial tracking (4032 zones), thermal-hydraulic feedback substeps between burnup steps, criticality iteration substeps via control rod movement between burnup steps, and use of both criticality and thermal-hydraulic iteration substeps between burnup steps. The final case illustrates the full functionality to run detailed depletion studies in an automated fashion with elements of multiphysics. Although only applicable to AHTR, the script enables analyses not previously possible with existing tools and advances the state of the art for AHTR core design.