Proceedings of ICONE15: 15th International Conference on Nuclear Engineering April 22-26, 2007, Nagoya, Japan ICONE15-10707 OPERATIONAL PERFORMANCE INDICATORS OF PWR STEAM GENERATORS T. Viglasky R. Awad S. Milivojevic Canadian Nuclear Safety Commission Canadian Nuclear Safety Commission Vinca Institute of Sciences P.O.B 1046, Station B P.O.B 1046, Station B P.O.B. 511 Ottawa, ON K1P 5S9, CANADA Ottawa, ON K1P 5S9, CANADA Belgrade 11000, Serbia (613) 995-2503 (613) 995-2759 (+381)-1-2458-070 tom.viglasky@cnsc-ccsn.gc.ca raoul.awad@cnsc-ccsn.gc.ca J. Riznic Canadian Nuclear Safety Commission P.O.B 1046, Station B Ottawa, ON K1P 5S9, CANADA (613) 943-0132 jovica.riznic@cnsc-ccsn.gc.ca Keywords: steam generators, reliability, failure, operational performance, PWR reactors. ABSTRACT In the early days of design of generation I, II or III nuclear power plants, it was assumed that the operational life cycle of steam generators would be the same or similar to that of the other key components in the reactor primary heat transport system (reactor vessel, core, piping, primary coolant pumps, etc.). However, the widespread degradation of the steam generator tubing that has occurred at a number of plants has shown this original assumption was incorrect or at least too optimistic. Traditionally, the tube plugging rate is the most commonly used indicator of the extent of tube degradation and overall steam generator fitness-for-service. However, the tube plugging rate does not provide a complete picture about the extent of degradation and its impact on steam generator and power plant performance. This paper seeks to identify the more appropriate steam generator performance indicators, namely the steam generator failure rate and the steam generator repair rate. In this paper we analyzed the performance history of steam generators in operation, e.g., their malfunctions during the plant life cycle, with the aim of identifying characteristics of failure rate and repair rate. These are necessary parameters to determine the reliability and availability of steam generators and their effect on the safety and efficiency of the nuclear power plant. The raw data used in this analysis come from experience at various nuclear power plants collected in the International Atomic Energy Agency (IAEA) Power Reactor Information System (PRIS) and published in the Agency’s annual reports on operating experience since 1971. In total, data for 799 steam generators (SG) from the onset of their commercial operation up to year 2000 were analyzed. The analysis of SG performance indicators was performed along two timeframes: over unit lifetime and over calendar years. The data on steam generator failures are presented in uniform format, allowing for the consistency in failure classification and data reporting. Operational performance of the analyzed steam generators is tracked through a plant lifetime and the failure rate λ and repair rate μ with associated boundaries were calculated. The empirical probability distribution of failure rates and repair rates were observed and general trends in performance indicators (λ, μ) analyzed, from the point of their influence on plant reliability and availability. 1. INTRODUCTION The steam generators (SG) in pressurized water reactor Copyright © 2007 by JSME 1