Assessment of primary piping integrity and leak development characteristics for the Clinch River Breeder Reactor Plant

An interim assessment is presented of factors affecting primary piping integrity and leak development characteristics in the CRBRP in relation to the leak-before-break concept. Factors considered are the mechanical aspects of crack initiation and growth, sodium corrosion and mass transport, caustic corrosion, and fabrication and inspection/surveillance techniques. An assessment of these factors leads to the following conclusions: while the leak-before-break concept appears to have validity, there exist several areas of concern that only further research can resolve: (1) the lack of validation of fracture mechanics to highly ductile alloys operating at elevated temperatures under complex stress conditions; (2) the lack of understanding of the impact of the various degradation modes of the sodium environment; and (3) the limitations of the proposed inspection/surveillance techniques in localizing piping defections and, then the extent, cause and potential for the existance of like conditions elsewhere in the piping system