STP Balance of Plant Model Update Experience and Results

Abstract

The South Texas Project (STP) balance of plant (BOP) model for production losses has been converted from an Excel-based software application that uses minimal cutsets from a single large fault tree, to a set of small fault trees used within a risk analysis tool, Riskman® [8]. The Riskman® application provides estimates of interest to plant investors and owners such as potential production losses and plant profitability, as well as production reliability and quality (loss frequency, type of loss, loss duration and standard economic risk metrics). The BOP models and methodologies developed are applicable to both fault-tree linking and event-tree linking styles of risk analysis. The STP BOP model is developed to support configuration risk management in two categories: 1) trip risk and concomitant core damage frequency; and 2) non-trip production risk. The primary purpose for the conversion work is to make the STP BOP model framework and application platform consistent with the STP probabilistic risk assessment model. In the course of the conversion, improvements to the Riskman® software have been implemented and techniques to more efficiently produce BOP modeling (fault tree) improvements were developed. Better methods to accurately calculate initiating event frequencies are studied. New data types added to support BOP modeling are described.

A Discourse on the Incorporation of Organizational Factors into Probabilistic Risk Assessment: Key Questions and Categorical Review

“…The ideal goals of explicit incorporation of organizational factors into PRA are to (a) make risk assessments more accurate by considering the effects of organizational factors in the estimation of human error and equipment failure probabilities, and (b) improve risk management and prevention strategies by identifying and ranking critical organizational factors based on their influences on the technical system (e.g., Core Damage Frequency (CDF) in NPPs) and their impacts on Risk-Informed Performance-Based Applications (RIPBAs). For example, one RIPBA for NPPs is Generation Risk Assessment (GRA) (Blanchard, Brinsfield, & Szetu, 2004;Wang, Nelson, & Kee, 2007)), and the influence of organizational factors could be considered for the elements and structure of production loss scenarios (e.g., Balance of Plant (BOP)) in GRA (Kee, Yilmaz, Wakefield, & Epstein, 2009). The theoretical and methodological aspects of explicit incorporation of organizational factors are further analyzed in Sections 2 to 5 of this paper.…”