The characteristics of the PCRV of the HHT demonstration plant

The prestressed concrete pressure vessels (PCPV) for Nuclear Power Plants planned or constructed up to now were either of a single-cavity type (THTR 300) or symmetrical multi-cavity design vessels (HTR 1160, Hartlepool). The former contains the core and the heat exchanger in a single cavity whereas in the latter the components are arranged seperately in vertical cavities. The vertical cavities in the HHT-Plant-PCRV cannot be arranged in a rotational-symmetric configuration. The cavities which are of different lengths have variously, diameters of 2, 3 up to 5,8 m and each is subject to different pressure loadings. The cavity arrangement is mainly dictated by the requirements for the gas-ducting and to a much lesser extent by the civil engineering aspects. In addition to the vertical cavities, the bottom cap contains horizontal cavities for the turboset (5,8 m dia.) and the generator (ca. 9 m dia.). The turboset cavity is designed for pressure; the cavity for the generator is not subject to pressure. (orig.)