Abstract: Since the production mechanism of the ¹⁴C in spherical fuel elements was similar to that of fuel-free graphite spheres, in order to obtain the amount of ¹⁴C in fuel elements and graphite spheres of HTR-10, the production mechanism of the ¹⁴C in graphite spheres was studied. The production sources of the ¹⁴C in graphite spheres and fuel elements were summarized, the amount of ¹⁴C in the post-irradiation graphite spheres was calculated, the decomposition techniques of graphite spheres were compared, and experimental methods for decomposing the graphite spheres and preparing the ¹⁴C sample were proposed. The results can lay the foundation for further experimental research and provide theoretical calculations for comparison.