Auslegungskriterien und Konstruktive Gestaltung der Sicherheitsumschliessung bei Siedewasserreaktoren

Abstract

A survey on design, essential criteria and function of the containment system for AEG—Telefunken's present boiling water reactor product line is given. Safety enclosures of other BWR's are in most aspects similar with respect to the basic design principles, so this review might serve as a guide. The system presented consists of a steel primary containment with pressure suppression pool protected by reinforced concrete, of a leak-tight shell around the primary containment with a reventing system, of a reinforced concrete reactor building as secondary containment and of auxiliary systems for air conditioning and filtering and for decay heat removal. A study reveals that the smallest primary containment is the most economic, because primary containment size governs reactor building dimensions. Since the same fuel elements are being used for all plants — the power being proportional to their number —, the hight of the reactor pressure vessel is almost independent of thermal power. There seems to be a potential to size pressure suppression containments nearly independently of thermal power. Therefore the limits of compact construction are shown. Design criteria presented for the overall containment system consider access to components for operation, inspection and recurring tests in order to maintain high plant availability. They take into account system lay-out under all possible loads and operating conditions as well as quality assurance. They consider independence, separation and diversification of systems as well as redundancy. The criteria are aimed at system and — as a consequence — environment protection under accident and, if necessary, external hazard conditions. A flash-light is thrown on some new test results and on conservatively predicted performance of the containment system under reactor accident conditions, showing margins to keep the system safely under control even under highly degraded conditions.