Research Support on the Study of Local Heat Transfer Co-Efficient on Peripheral PWR Assembly Fuel in the Event of Touching Spacer Grids

Descriptions

Identify the base phenomena defining the CHF limit for both flow reduction and overpower fault conditions in the PWR core, considering the potential for TSG. This analysis should consider the limitations of CHF test rigs in representing core cross-flow and assembly-periphery conditions. Review the options (methods, tools and models) that are currently available for CHF prediction and their development status. The review should cover the practices of the leading PWR vendors, operators and fuel providers as well as independent research establishments and academic institutions. Recommend a reasonable strategy allowing ONR to assess the adequacy of safety margins in set points for CHF mitigation arrangements of current and new built PWRs against the criterion that protection should be demonstrated with a high level of confidence. Provide conclusions and recommendations