Design details of HTR-Module and HTR-500

The modular HTR power plant is a universally applicable energy source for the co-generation of electricity, process steam or district heat. The modular HTR concept is characterized by the fact that standardized reactor units with power ratings of 200 MJ/s (so-called modules) can be combined to form power plants with a higher power rating. Consequently, the special safety features of small high-temperature reactors are also available at higher power ratings. The safety features and the technical design are briefly described. The principal safety feature of the HTR-Module is based on the fact that, even in the case of failure of all active cooling systems and complete loss of coolant, the fuel element temperatures remain within limits at which there is practically no release of radioactive fission products from the fuel elements. The HTR-500 has been developed as a nuclear power plant for medium-sized and large power grids, either as a base load plant or for load-following applications according to the requirements of the grid. Furthermore, the HTR-500 is well suited for the cogeneration or supply of process steam for industrial applications. The HTR-500 has a thermal power output of 1390 MJ/s, which corresponds to an electrical rating of 550 MW. The reactor plant concept is marked by the integrated arrangement of all primary-system components within a burst-proof pre-stressed concrete reactor vessel in single-cavity design. The integrated arrangement provides protection against impacts from internal incidents as well as radiation shielding. (author)