Reduced Life Cycles Cost and Improved Analysis Accuracy Utilizing WESTEMS™ Integrated Modeling Methods

Abstract

Traditional methods of qualifying pressure vessel components to ASME stress and fatigue requirements often involve complex and lengthy calculation processes. The costs of individually analyzing every specified transient can be prohibitive if large numbers of transients are considered, with each one having varied loading conditions acting on the components. In addition, the time dependent nature of real transient loads results in a significant computational and bookkeeping problem. In most cases the analyst uses a number of simplifying and enveloping assumptions to develop stresses to represent all transient conditions. He relies on his experience and judgment to make simplifications with respect to the timing of applied mechanical loads, as well as the relationship between the applied mechanical loads and the timing of the thermal loads. The analyst’s skill governs the length and complexity of the qualification process. The WESTEMS™ Integrated Modeling approach dramatically simplifies this effort and improves analysis accuracy, while reducing the overall time necessary to perform the analysis. WESTEMS™ Integrated Models can reduce the process of analyzing a list of transients defined by global parameter time histories and reporting final design stress and fatigue to a few steps. This paper discusses how WESTEMS™ overcomes the technical difficulties encountered in automating such tasks, and shows the technical superiority of WESTEMS™ over the current traditional methods. It also demonstrates how applying the WESTEMS™ technology to NSSS equipment can reduce engineering life cycle costs.