Complexity of safety

McDermid, J. A., A.J. Vickers, and S.P. Wilson, Managing Analytical Complexity of Safety Critical Systems using Viewpoints, Department of Computer Science, University of York, UK. 

The absence of highly reactive chemicals in the biocatalytic process reduces the complexity of safety measures, which would otherwise be considerable. Phosphorus pentachloride especially poses a problem, because it must be stored and handled with complete exclusion of moisture since it is strongly hygroscopic and decomposes with the liberation of hydrogen chloride gas. 

These contrasting constructions of safety serve to illustrate the complexities of safety itself, and also indicate the very personal nature of the associations and interpretations that ultimately inform interactions and responses to safety within the construction site context. Although it could be suggested that safety management... 

By necessity, a nuclear power plant is composed of the parts required to generate electric power (the process parts or systems) but also of a complexity of safety systems. The name safety systems here indicates all those systems which are not strictly necessary to the plant operation or to health protection under normal conditions, but rather to those... 

Safety analysis (hazard analysis) The entire complex of safety (hazard) analysis methods and techniques ranging from relatively informal job and task safety analyses to large complex safety analysis studies and reports (SSDC). 

Effective nuclear criticality safety programs include cooperation among management, supervision, and the criticality safety staff and rely on the knowledgeable conformance with operating procedures by all employees. Although the extent and complexity of safety-relat< activities may vary greatly with the size and type of operation with fissile material, certain safety elements are common. This standard represents a codification of such elements related to criticality safety. 

Given the importance and the complexity of safety management and given the fact that legislation falls short, the involvement of a professional safety board, consisting of heavy-weight professionals with a mission, with authority, with knowledge, and with skills, seems a useful alternative. 

An important aspect of defence in depth is the construction and operation of the plant in a manner such that challenges to plant safety are minimized and the capability to effectively respond to challenges is assured. The emphasis on inherent features and passive systems discussed above simplify the training, operation, maintenance and surveillance activities necessary to provide assurance of safety by reducing the scope and complexity of safety systems. 

The importance of functional safety has grown steadily in recent years. This, on the one side, is because no other adequate solution to challenges in areas of safety, security and complexity can be observed. And on the other side for fast growing complexity of safety systems e.g. as for fire protection systems a solution to this problem has to be found rapidly as shown in NachtigaU KJingsch (2011). 

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