Modular High Temperature Gas Cooled Reactor (HTGR) is considered as a kind of catastrophe free nuclear reactor and because of its meltdown-immune feature, the practical elimination of large radioactive release from nuclear power plants becomes reliable with this technology. Following the concept of design to safety, the first demonstration project of modular HTGR in the world (HTR-PM) is under construction in Shidao Bay (in Shandong, China) and is planned to operate at the end of 2017. With advances in engineering of modular HTGR, the studies of safety features of HTGR also deepen step by step. Recently, there are lots of academic achievements related to the field of HTGR safety features, including beyond design basis accident (BDBA) of HTGR, multiscale source term analysis of HTGR, behavior of tritium in primary and secondary circuit of HTGR, and minimizing emergency for modular HTGR, which is essential for the future improvements of the design, operation, and maintenance of the modular HTGR.

The main aim of this special issue is to provide a platform for sharing the latest and significant research achievements on safety features of HTGR. Original research articles on topics mentioned above are welcomed and other related studies are also solicited.

Potential topics include but are not limited to the following:

• Performances of HTGR fuel
• Safety and accident analysis of HTGR (reactor physics analysis, thermal-hydraulics analysis, and PSA)
• Source term analysis of HTGR
• Control of multimodular HTGRs and related human factor analysis
• Optimizing radiation protection of HTGR
• Emergency management of HTGR