The Role of Two-Phase Coolant in Moderating Fretting in Nuclear Steam Generators

This paper expands the principal of coolant-cushioning in Nuclear Steam Generators whereby the two-phase coolant, especially the bubble film on the tube surface, moderates the vibration of coolant tubes against their supports. This thesis was advanced by the author in JSME ICONE-11 paper #36443 “Fretting in Nuclear Steam Generators – A New Approach”. The current paper addresses tube bundle and AVB geometry issues; examines the tube bundle-coolant-AVB interfaces and examines implications for recirculation flow, AVB design and boiler size. The need for research to confirm empirical findings is reiterated.