The Chebyshev rational approximation method (CRAM) is an important numerical solution algorithm for the burnup equation. Since high complexity of nuclide depletion calculation, its outputs are almost impossible to predict accurately. Therefore, the traditional testing methods are inapplicable, even invalid. The metamorphic testing (MT) is one of promising method to solve such typical testing oracle problem. However, the absent meta-morphic relations (MRs) seriously hinders its application.
In response to the nuclear software development process, we established a nuclear MR hierarchical model (NMHM). From top to bottom, it divides MRs into three layers: physics, algorithm and code. From the burnup equation and the CRAM, we carried out a group of MRs according to the NMHM. Employing these MRs, we verified the Nuclide Inventory Tool (NUIT) which implements the CRAM by MT. The MRs adopted can certainly be used for other CRAM programs, and the NMHM will extend to more nuclear science software for guiding the MR identification and classification.