THE IMPACT OF NUCLEAR PHASE-OUT ON REACTOR SAFETY IN

shut down immediately in 2011, while nine others will follow a graduated phase-out scheme. Thus, it becomes obvious that the operation characteristics of the remaining plants will be changing, with more frequent load changes. These changing conditions raise the question, whether the nuclear phase-out has an impact on reactor safety. Investigations on the learning hypothesis give a detail insight in the development of systemic risk with growing experience. Methods The learning hypothesis is a physical model for human behavior when working in conjunction with a technological system. The hypothesis is based on the assumption that humans learn from events occurring due to mistakes. The failure rate of a homo technological system (HTS) λ therefore declines with growing experience ε when learning occurs proportional to the rate of learning k (Duffey, 2008): λ(ε) λ ( λ- λ)- (ε- ε ) (1). In the Duffey–Saull Method (DSM) approach, a set of rules for analyzing error data based on the learning hypothesis (Duffey, 2008), is used to determine past learning trends in reportable event data of German nuclear reactors. The knowledge acquisition obtained by the humans embedded in a homo technological system reflects its learning trends (Duffey, 2011). Thus, calculating Germany’s cumulative knowledge stock (KS) of nuclear power is used for explanation of past and estimation of future German nuclear reactor event rates (ER). The cumulative knowledge stoc