[en] Burnup credit (BUC) is a concept applied in the criticality safety analysis of spent nuclear fuel in which credit or partial credit is taken for the reduced reactivity worth of the fuel due to both fissile depletion and the buildup of actinides and fission products that act as net neutron absorbers. Typically, a two-step process is applied in BUC analysis: first, depletion calculations are performed to estimate the isotopic content of spent fuel based on its burnup history; second, three-dimensional (3-D) criticality calculations are performed based on specific spent fuel packaging configurations. In seeking licensing approval of any BUC approach (e.g., disposal, transportation, or storage) both of these two computational procedures must be validated. This report was prepared in support of the validation process for depletion methods applied in the analysis of spent fuel from commercial light-water-reactor (LWR) designs. Such validation requires the comparison of computed isotopic compositions with those measured via radiochemical assay to assess the ability of a computer code to predict the contents of spent fuel samples. The purpose of this report is to address the availability and appropriateness of measured data for use in the validation of isotopic depletion methods. Although validation efforts to date at ORNL have been based on calculations using the SAS2H depletion sequence of the SCALE code system, this report has been prepared as an overview of potential sources of validation data independent of the code system used. However, data that are identified as in use in this report refer to earlier validation work performed using SAS2H in support of BUC. This report is the result of a study of available assay data, using the experience gained in spent fuel isotopic validation and with a consideration of the validation issues described earlier. This report recommends the suitability of each set of data for validation work similar in scope to the earlier work