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There are 11 Chinese NPPs units in operation. Ageing management activities are performed for different SSCs.
For piping in secondary system, those susceptible to Flow-Accelerated Corrosion (FAC) need to be paid more attention on. In this paper, ageing management and research on FAC of secondary system piping is summarized. Usually ageing management consists of material selection, pipe analysis, wall thickness measurement, result evaluation, and replacement for susceptible pipes. During design period, material selected for secondary system piping is an important factor to mitigate FAC. Sometime research on FAC is done for selection of the right material. In alloy compositions, chromium is the most beneficial element to resist FAC. During operation period, FAC management procedure mainly consists of analysis, inspection, evaluation and replacement etc. Analyzed form the aspects of material component, flow temperature, flow velocity, pH value, two-phase flow, and flow geometry, the pipes susceptible to FAC are determined. For these pipes, wall thickness measurements are performed more frequently during outage. After measurement data are evaluated, those pipes, which remaining service life does not satisfy requirement, are replaced by new pipes.
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