Coupled structure-fluid analysis for a PWR burst protection design

The burst protection considered is designed to withstand hypothetical ruptures which might occur in certain components of the primary circuit including RPV rupture. It mainly consists of cylindrical concrete vessels for the RPV and the steam generators and steel tubing for the primary pipes. The burst protection structures are placed tight to the primary loop. A hypothetical RPV failure will result in direct excitation of single components and will lead to complex interactions between all components of the protecting structures, the primary loop, reactor core, core support structures and the coolant. The overall investigations to determine the magnitude of deformations and stresses are summarized. Economical aspects with respect to the investigation are treated briefly. The coupled structure-fluid analysis of the core and core support structure due to horizontal and vertical RPV failure are presented in detail. Assumptions for the RPV failure modes are made which are expected to lead to extreme conditions in any part of the system. The assumptions include vertical, horizontal and screw-shaped rupture of the RPV, the detachment of RPV nozzles as well as other types of failure. On the basis of the failure modes, types of credible external load conditions are estimated. (Auth.)