STRUCTURAL INTEGRITY ISSUES IN HIGH TEMPERATURE NUCLEAR PLANT: EXPERIENCE FROM OPERATION OF THE UK ADVANCED GAS COOLED REACTOR FLEET

摘要

The Advanced Gas Cooled Reactor (AGR) fleet operated by EDF Energy in the UK are a unique example of high temperature civil nuclear plant that has operated commercially over significant timescales. AGR plant contain a graphite core with carbon dioxide used as the primary coolant and importantly key metallic boiler, reactor internal and fuel route components operate within the creep range, at temperatures up to 650°C. Some of the AGR plant have now operated for periods in excess of 250,000 hours. This paper first describes the important features of a typical AGR power station and outlines the key degradation mechanisms that need to be considered when assessing the lifetime of key metallic components. This is followed by a brief summary of the Component Life Assessment (CLA) process that is used by EDF Energy to monitor and review the fractional life usage of AGR boiler and reactor internal components. Then some examples of issues that have affected the structural integrity of key high temperature AGR components are discussed, focussing on how these issues have been managed. Finally, consideration is given to ways that experience from operation of the UK AGR fleet can be used to inform the design and operation of future high temperature reactors.