Advanced tritium transport modeling and verification, validation, and benchmarking from component level to fuel cycle scale using TMAP8

Tritium transport and accountancy are central challenges for the design, safety, and performance assessment of fusion energy systems, requiring predictive modeling across multiple spatial and temporal scales. This paper presents recent developments in the Tritium Migration Analysis Program, version 8 (TMAP8), an open-source tritium transport modeling tool built on the Multiphysics Object-Oriented Simulation Environment (MOOSE) framework following high software quality assurance standards. TMAP8 enables fidelity-flexible simulations spanning from pore microstructure length scale to component-scale transport and up to system-level fuel cycle modeling within a single application. We introduce new modeling capabilities together with a substantially expanded suite of verification, validation, and benchmarking cases. The verification cases demonstrate accurate numerical solutions, while the validation cases assess predictive capability against experimental measurements. In addition, TMAP8 reproduces and benchmarks a recent tritium fuel cycle model, demonstrating ability over a wide range of scales. All verification and validation cases, input files, and analysis scripts are released as open source, supporting rigorous software quality assurance, transparent benchmarking, workforce development, and community reuse. These developments, in addition to the deployment of a simplified physics-based syntax, further establish TMAP8 as a robust multiscale modeling application for tritium transport analysis in fusion energy systems.