A project to implement a life-cycle engineering approach to tritium reservoirs has been initiated through the DOE - Technology Investment Projects. The first task in the project was to develop a comprehensive list of microstructural features that impact the aging performance of the tritium reservoirs. Each of the participating sites (SRNL, SNL, LANL, KCP) independently developed a list of features deemed integral to tritium reservoir performance based upon operational and design experience. An integrated list of features was ultimately developed by the project team that could be included in the modeling process. The features of interest were chosen based upon their impact on the following key factors in controlling crack growth: (1) the H/He solubility or diffusivity within the materials, (2) the stress/strain state at the crack tip, (3) material threshold for crack extension, and (4) microstructure based fracture distance, commonly estimated by grain size for intergranular fracture. Wherever possible, key references were identified to substantiate the effects on the tritium embrittlement phenomenon of the various microstructural features. Each of these features was chosen based upon their impact to the cracking phenomenon of interest. The features chosen were typically associated with orientation, morphology, and distribution of phases and inclusions, grain …