Development of the HTR modular structure in the FRG

The specific features of the modular structure of a NPP with four 200 MW(t) helium cooled HTR reactors are described. The problems of such plant licensing and safety are discussed. The main advantage of these reactors is their rather small dimensions (the core diameter is 3 m, its height is equal to 9.6 m). Basic components of the reactors used in the modular variant as to safety level are considered to be more reliable than the units and components of the THTR-300 and LWR reactors. It is supposed that the modular variant is less expensive than the nowadays accepted monoblock one. This is connected with application of standard reactor vessel (less expensive than the vessel of presbressed reinforced concrete); simplification of the reactor components related to the decrease in its diameter and refusal of special emergency cooling system; simplification of the reactor shut-down system (due to exclusion of expensive control rods passing through the fuel element pebble bed); standardization of all basic components and their mass production