The German-Swiss high converter concept

In the past couple of decades thermal reactors, and with a certain dominance the PWR type have achieved commercial maturity. In the FRG the Konvoi concept represents an extremely high standard regarding safety and operational performance and hence this technology offers a solid basis to further improvements for the next generation of PWRs. Since enhanced fuel resource utilization will turn out to be the more important the sooner the renaissance of nuclear energy utilization will occur and the faster nuclear expansion will take place, the evolution of the PWR technology to meet this goal will be a logical step, where the HCR will fit in such a strategy since its fuel cycle is basically compatible with that of the breeder. Depending mainly on the degree of moderation in the design, such a reactor theoretically could have a differential conversion ratio of between 0.8 and 0.9, leading to a reduction of 50 - 70 % in fuel consumption compared to the once-through cycle of the standard PWR. For the development of the HCR, which involves the use of PuO2/UO2-fueled tight lattice cores, and for assuring main safety and economic features of this type of reactor, Siemens, the Swiss Paul Scherrer Institute and the Nuclear Research Center at Karlsruhe for the past 5 years during the 'Verification Phase' have been working jointly together with the Technical University of Braunschweig. The goals of the extensive experimental program as well as the essential features of the product are described in detail in the paper. (author)