Research report series, no. 1

In this research the relationship between people and the space they occupy will be looked at. In doing so, we shall see how people enter into a relationship with their environment in order to create out of material at their disposal, a shelter wherein they can live. By erecting a structure which serves as a house, the people involved in this project do essentially the same as other people in other parts of the world, who create a dwelling that provides protection against the climate and the elements in nature. A question to be raised, is extent their (i.e. the people involved in this project) entering into a relationship with their environment, was forced into a particular direction because of a set of political and economic factors. What are the political and economic factors which impact on the manner of building houses in the informal residential areas of Grahamstown? Traditional housing in France, for example, differs from region to region and has been shaped over long periods of time by the climate, family structures, the availability of land, modes of production, etc. One finds that large vine-growing families from the Mediterranean South of France live in fairly big villages; individual farmers of Brittany dwell in small, slate-roofed houses which are isolated among enclosed fields; pastoral communities in the Alps undertake seasonal moves up or down the slopes of the mountains and share their space during winter with their cattle. The way in which these families and/or communities have come to shape their lifeworlds, was not exposed to the same kind of determining factors as, for instance, in South Africa in general and in Grahamstown in particular. Notwithstanding political and economic determinants, it is clear that residents of informal houses in the Grahamstown area draw to a large extent from tradition with regards to the kind of shelters which they build (cf. the many mud-and-stick constructions). Similarly the settlement of people impacts on nature. Elements of the environment inform certain choices, but people interpret their natural environment and will erect shelters in terms of these interpretations. In addition there are the issues of how people orientate themselves in terms of important landmarks, what kind of representation they have of the future they are moving towards and which values do they draw from or attribute to their physical environment. The landscape surrounding people, contains and reflects cultural information. Important landmarks express aspects of life: the past, the present and the future.Digitised by Rhodes University Library on behalf of the Institute of Social and Economic Research (ISER

Proceedings of PVP2005 2005 ASME Pressure Vessel and Piping Division Conference PROBABILISTIC ANALYSIS OF A PREEMPTIVE REPLACEMENT OF AN NPP COMPONENT WITH A COMPONENT OF SUPERIOR MATERIAL

ABSTRACT The Westinghouse proactive aging management tool, PAM, considers three major sets of variables when calculating the NPV or economic value of age replacement: (a) the projected time to failure, (b) the economic consequences of unplanned failure and (c) the cost of the replacement. All of these variables will typically be uncertain; particularly the time to part failure. A not uncommon complication in evaluating whether and when to replace a degrading component or part in a plant is that the replacement part is thought to have a longer expected life (be more resistant to degradation) but, to date, there is little field experience to substantiate that belief. This paper shows how two different approaches for statistical estimation of a Weibull failure distribution can be used in tandem to surmount this problem, and illustrates it within the context of the replacement of a nuclear power plant component tube bundle with a tube bundle expected to provide superior corrosion resistance. INTRODUCTION Age-based or "proactive" replacement of a part or component before it actually fails can be an effective strategy for reducing plant downtime under certain conditions that include a failure rate that increases with component age, and economically-meaningful consequences (e.g., forced or extended plant outage) associated with component failure. Westinghouse has developed a model called Proactive Aging Management Tool™ (PAM

L'Afrique

A. Volvey (dir.