Development of system design in recent Siemens/KWU PWR influenced by PSA results

This paper reports on the design of the latest Siemens/KWU PWRs (Convoy plants) which is checked by a PSA, performed as a Δ-analysis to the German Risk Study (GPRA), which used a PWR 1300 MW in commercial operation since 1977 as a reference plant. The 10 years difference in the design between the reference plant and the Convoy plants, led to design changes, due to operational experience and findings from GPRA, Phase A. These are evaluated quantitatively by a PSA with respect to plat safety level and balance of the safety concept. The results gained from the Convoy PSA showed the importance and appropriateness of these modifications. Even if the latest results from GPRA, Phase B are considered with respect to additional accident sequences, it can be demonstrated that the new design is balanced with respect to these additional sequences. So no need exists to improve the new design any more