September 11, Columbia, Davis-Besse, and PRA: Business as Usual?

摘要

Whenever an event with potentially or actually catastrophic consequences occurs, it is common practice to review these events to identify important, systemic lessons for the affected industries. However, despite recent pushes to make increasing use of risk information in decision making, the scope of these reviews does not always address one important part of the system, the probabilistic risk assessment (PRA) technology supporting the risk assessment models used to develop this information. This paper looks at a set of noteworthy events with this topic in mind. The events reviewed are: the September 11 attacks on the World Trade Center and Pentagon buildings; the Columbia space shuttle accident; and the Davis-Besse nuclear power plant reactor pressure vessel (RPV) head corrosion incident. (The Davis-Besse incident, in which corrosion in the reactor pressure vessel head could have led to an accident, did not lead to any public health and safety consequences. However, it did lead to a serious degradation of existing safety margins and defense-in-depth.) All of these events have occurred in industries in which PRAs are being performed and used, so it is possible to explore how well the PRA technology used in each of these industries addresses the technical issues raised by these events.