Concept of the modular HTR in a dual vessel version

The new concept of the modular pebble bed reactor version introduced 1982 has been confirmed in every respect in the past few years. The positive inherent safety characteristics of the HTR module have been documented beyond any doubt. Plants for the generation of process steam, electricity and district heat have been the objects of extensive planning work and of safety and systems analyses. In addition, the investment costs were determined together with the supplying industries. Major features of the 200 MWth module described in this article are the accommodation in steel pressure vessels separated by concrete walls of the core internals and the steam generator and the positioning of the steam generator below the core. In an accident, the post-decay heat would be removed by thermal conduction and convection to a flat surface cooling system located outside the reactor and continuously in operation. (orig.)