Plant statistics with updated CFM and NSF channels in reload cores

GNF developed the cell friction methodology as a means to analyze the potential for channel - control blade interference in boiling water reactors (Ref. 1). Overall plant statistics for 50 plant cycles, that spans different reactor designs, core lattices, and GNF channel designs, were originally presented (Refs. 2 & 3) to illustrate the magnitude of the issue and to assess the predictive capability of the cell friction methodology. GNF has since updated the cell friction methodology for recent cell friction observations (Ref. 4). The purpose of this paper is to assess the original database with this most recent update to the cell friction methodology. The database is then re-evaluated for different channel materials - specifically Zircaloy-4 and NSF (GNF's latest offering for channel material Ref. 5). The benefits of NSF over Zircaloy-2 & -4 channel materials are demonstrated. The second part of this paper is to provide an insight into the ongoing challenges of cell friction in the fuel cycle core design stage. Within this framework, an assessment of potential benefits of moving to the NSF channel material and the relief provided for core designers is presented. A sample set of core design cell friction metric maps are compared for the actual cycle and with all-NSF channel material. Another study presents reload core designs for transition from current channel material to NSF channels. This includes different scenarios; for example, a full reload batch of NSF channels and a gradual transition from the enhanced lead use channel program for NSF channels (i.e. up to 8% Ref. 6).