Beyond design-basis
Beyond design-basis is a term used in engineering, especially the design of nuclear power plants, to describe conditions or a significant event in which a system, structure or component (SSC) was not designed or intended to safely operate, contrasted to a design basis accident. Such conditions could reduce or eliminate the margin of safety of the SSC, possibly resulting in a catastrophic failure. [1]
Common examples of beyond design-basis circumstances include major natural disasters, such as the earthquake and tsunami that disabled virtually all backup and safety systems of the Fukushima Daiichi Nuclear Power Plant, leading to the Fukushima Daiichi nuclear disaster. Other circumstances are man-made; a combination of design features that introduced the possibility of runaway criticality, and operator error while attempting to configure the reactor for an emergency loss-of-power simulation, caused the Chernobyl nuclear disaster in 1986.
References
- ↑ Neil E. Todreas, Nuclear Systems:Elements of Thermal Design, Volume 2, CRC Press 1992, ISBN 1560320885; page 347