Nuclear industry definitions

This nuclear technology is based on both the nuclear and the chemical properties of the atom. At the beginning of the twentieth century fewer than 90 chemical elements were known and there was only a dawning awareness of isotopes. Today, largely because of the nuclear industry, thousands of isotopes (or nuclides, depending on the properties of interest) have been identified. Brief definitions of several chemical and nuclear terms are given in Table 21.1. 

At first sight, then, complex mechanical setups as we propose for semicon-tinuous or continuous freeze-drying seem susceptible to serious hazards in the sterility control of the operation. However, this is not as dramatic as it looks since the essential part of the process—if not the entire process—is carried out automatically and can be done entirely within a sterile environment by remote control. Indeed, today highly sophisticated automation can be achieved if we resort to the advanced technologies developed for the nuclear industry and profit by the experience of their operators. However, this sophistication will definitely bear on the cost and this can be a serious drawback for conventional low-priced products. 

To establish a common understanding of the terminology associated with the development and use of EOPs, a clarification of the basic concepts is provided in the following sections. A specific and detailed definition of EOPs will be presented, consistent with international practice and with their common usage in the nuclear industry. 

Operating experience This source results from a thorough review of the operational feedback from experience collected by the nuclear industry worldwide and application of engineering judgement. All pertinent events should be evaluated in the definition of the scope of EOPs. Examples include ... 

Hence high-integrity systems are defined as those with reliability requirements more onerous than 10 on demand (for low demand systems) or 10 per year (for high demand systems). These are normally referred to as SIL 3 and SIL 4 systans. The exact definitions of these terms may vary from industry to industry, and from country to country. For example, the aviation industry tends to refer to failure rates per hour, whereas the process plant industries tend to refer to failure rates per year. Since there are (24 x 365) = 8760 h in a year - or roughly 10,000 - this means that 10 failures per year (fpy) equates to approximately 10 failures per hour, etc. Also, the European nuclear industry has imposed a more restrictive reliability limit on the SIL band definitions, as shown in the right hand column of Table 2.1. 

Safety systems for Nuclear Power Plants are governed by strong requirements, which cannot be fulfilled by products designed for normal industrial applications. That s why in all countries, safety classified systems and non-safety classified systems for NPPs use different technologies even if the classification standards give several definitions and gradations for systems. 

A1. In para. 201 risk was taken to be the probability that a specified harmful effect will occur within a specified period. It was furthermore noted that complex industrial activities, such as the operation of nuclear installations, usually have associated risks of various types, relating to different types of harm to individuals, society and the environment. Therefore, any evaluation of risk starts with a definition of the types of harmful effects that need to be taken into account. 

The main purpose of the literature review was to investigate the state of the art for methods for determining model parameters of CCF models. Very comprehensive approaches like what is used in the nuclear power industry to support multiple-Greek letter CCF models, see e.g., NUREG/CR-5485 (1998) and NUREG/CR-6268 (2007), have not been studied in detail in this paper. Instead, the focus has been on identifying methods available for determining the P in the beta factor model, and on the definitions of CCF that may be useful as assistance in the analysis and classification of failures reported for safety-critical components. Literature referenced in a study by Rausand and Hokstad (2008) has been key for the review. 

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