Reliability Analysis in the Design of Safe Nuclear Power Plants [and Discussion]

G. M. Ballard, B. Littlewood, K. Sachs, J. Bibby
1989 Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences  
The requirement for all potentially hazardous plant is to achieve high reliability of engineering systems by design. The process of reliability analysis is a fundamental part of the design process in the nuclear power industry. Such analysis recognizes that there is always some possibility of engineering equipment failing and therefore the ability of the plant to be reasonably tolerant of such failures is investigated. In this paper the methods and philosophy underlying reliability analysis are
more » ... bility analysis are briefly explained with examples of qualitative techniques such as failure modes and effects analysis, and fault tree analysis. In addition some of the quantitative models of equipment reliability are discussed and the need for robust statistical techniques for data analysis explained. I n t r o d u c t i o n The need to achieve safe operation of potentially hazardous plant or equipment is not new. After almost every accident in recent industrial history someone has suggested that we should ensure 'that this never happens again'. However, a more recent need is to be able to achieve the reliability of plant and equipment required for safety without invoking the ' trial and error ' process which has been the foundation of many industrial developments, but also, unfortunately, the cause of many accidents. The engineering design of bridges is perhaps a notable example of our ability to build very technically advanced systems, but only with the benefit of experience from a significant number of catastrophic failures. The task in the nuclear industry has therefore been to develop a new technology involving a number of pioneering engineering innovations, while at the same time ensuring that the safety of both workforce and public is protected. The development of new technology necessarily means that we must learn from experience, and some of that experience will undoubtedly include significant failures of plant and equipment. Our plant must, however, be designed to be tolerant, in a safety sense, of such failures. The requirement has been to achieve a high reliability of engineering systems by design rather than by trial and error. The techniques of reliability analysis have played a significant role in the pursuit of that objective. R e l i a b i l i t y a n a l y s i s What are the fundamental elements of a reliability analysis? (i) First and foremost it involves an engineering analysis of a system from a different perspective; not that of the designer who asks how he can make the system work, but that of a reliability analyst who asks how it might fail. Underlying this analysis is the recognition that there is always a ' chance ' of failure no matter how good the engineering is. [ 71 ]
doi:10.1098/rsta.1989.0010 fatcat:qk7j5txlerb7tksbeekdyt7ery