Principles of Plant Safety and Fundamental Concepts

Starting point for the safe design and operation of a process plant is a safety concept. This is understood to comprise aU the organizational and technical measures in a plant and its operation aimed at 

The underlying objective is, as has been stated above, to design processes and plants in such a way that there is no relevant danger for man, environment and valuable property. This is the protection objective for plant design and operation [2]. 

In order to achieve this, a strategy to minimize risk is developed, which comprises measures for reducing the frequency of accidents, the associated damage or both. 

In this context the safe containment of the materials present in the plant is of special importance, since its loss is, as a rule, the starting point for accident consequences, the source term. Additionally, fires and explosions inside the containment (pipework, vessels, casings etc.) have to be avoided, because its destruction implies a release. 

Possible measures may be categorized as follows (cf. [9]) they are ordered in decreasing reliability 

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Principles of Plant Safety and Fundamental Concepts dCnNOa... 

In process industry plants, the concept of more inherently safe design is a recurring theme in the three reports of the Advisory Committee on Major Hazards (ACMH - set up in the UK after the Flixborough accident). These reports set the general principles of new process industry safety in the UK and they represent in their field what, for example, the IAEA Safety Fundamentals documents do in the nuclear industry. 

The use of defence in depth in nuclear power plant design and operation involves three fundamental principles. Defence in depth provides the basic framework for most nuclear power plant safety. The concept has been refined and strengthened through years of application. All safety analysis for nuclear power plants, both deterministic and probabilistic, revolves around evaluating the performance of the plant subject to different modes of defence in depth, and the reliability of these modes [1]. 

The importance of the concept of defence in depth is underlined in IAEA Safety Standards, in particular in the requirements set forth in the Safety Standards Safety of Nuclear Power Plants Design (NS-R-1) and Safety Assessment and Verification for Nuclear Power Plants (NS-G-1.2). A specific report. Defence in Depth in Nuclear Safety (INSAG-10), describes the objectives, strategy, implementation and future development in the area of defence in depth in nuclear and radiation safety. In the report Basic Safety Principles for Nuclear Power Plants (INSAG-12), defence in depth is recognized as one of the fundamental safety principles that underlie the safety of nuclear power plants. 

This concept has long standing in the nuclear safety field. This fundamental safety principle is applicable to all activities and organizations related to nuclear power. This principle is understood and accepted globally as an essential element of safety for both current and future plants. 

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