lnterfacial Materials for Nuclear Component Reliability and Plant Life Extension Initiatives

Abstract

Interfacial materials technologies, (comprised of grain boundary engineering - GBP and nanocrystalline materials - Electrosleeve, Nanoplate), are rapidly finding application in enhancing nuclear component reliability, providing opportunities for nuclear plant life extension, and reducing the costs associated with routine plant maintenance and inspection. In this paper, an overview of the metallurgical concepts associated with grain boundary engineering and nanocrystalline metallic materials is presented. These advanced materials concepts are further discussed in the light of specific nuclear power plant applications and opportunities, including: (1) advanced GBETM microstructural characterization and stochastic modeling techniques for improved maintenance, repair and. replacement scheduling, (2) GBE mill/fabrication processing of replacement nuclear components for minimizing the risk of intergranular cracking and corrosion failures during operation (e.g., reactor head penetrations, steam generator tubes, baffle bolts etc.), (3) in-situ GBETM processing for the potential repair and/or preventive maintenance of critical components (e.g., top of tubesheet steam generator tubing PWSCC, SCC of reactor head penetrations, etc.), (3) electrodeposition of high strength nanocrystalline materials for in-situ component repair (e.g., Electrosleeve repair of nuclear steam generator or heat exchanger tubes, Nanoplate valve repair etc.), and (4) eddy current and ultrasonic inspection probes with nanocrystalline coatings on polymer spacers and centering feet for enhancing probe life, minimizing probe replacement, and reducing the time and cost associated with inspection outages.