Understanding the performance of fuel elements, particularly defective ones, in the reactor core quickly and accurately is essential as most radioactive nuclides are produced in the fuel elements and released into the primary circuit. Radioactivity in the primary circuit may result in potential radiation hazards to the maintenance workers and the environment near the nuclear power plant. Therefore, fuel element damage monitoring technology has received wide attention in the field of nuclear fission reactors. Few reviews focus on fuel element damage monitoring technology to facilitate the development of high-temperature gas-cooled reactors (HTGRs). In this study, we investigated the state of fuel element damage monitoring technology in HTGRs and pressurized water reactors (PWRs), summarized their characteristics and parameters, and compared their advantages and disadvantages. The radioactive source terms in HTGRs and PWRs were listed, and the typical nuclides in the primary circuit adopted for the fuel element damage monitoring were illustrated. This study can provide a good reference for developing fuel element damage monitoring technology in HTGRs in the future.