A SURVEY ON DISCRETE LIFETIME DISTRIBUTIONS

This paper presents a comprehensive survey of discrete probability distributions used in reliability for modeling discrete lifetimes of nonrepairable systems. The basic properties of each model are given. A classification into two families is proposed, highlighting the interest of using a Pólya urn scheme. The quality of the estimation of models parameters is numerically assessed. Some criteria are given in order to select among the presented distributions the most useful for applications.

Strategies for Improved Nuclear Plant Reliability

This paper presents a methodology for identifying cost-effective failure prevention strategies for components or systems in nuclear power plants. Two strategies identified are the improvement of component reliability and the addition of redundant components. These two strategies are evaluated within the context of both repairable and nonrepairable systems. Capacity/demand and continuous time models are used to analyze the two strategies and systems. An example problem is developed for a continuous time, repairable system. It is clearly shown that large expenditures are justified to improve the reliability of some major systems in nuclear power plants and that these expenditures, exceeding the original capital cost of the system, could save tens of millions of dollars.