Coupled analysis and improvements for Canadian-SCWR core design

• Coupled neutronics/thermal hydraulics analysis for recent Canadian-SCWR.
• Coolant density variation inside central flow tube of assembly was considered.
• An improved core design for Canadian-SCWR.
• Lower MCST and more flat radial power distribution.

A coupled neutronics and thermal hydraulics analysis have been done for the recent Canadian SCWR, high efficiency re-entrant channel (HERC) design. The neutronics analysis was carried out by using a 3D fine mesh diffusion theory code and thermal hydraulics calculations were done by using single channel model. These two codes were coupled with each other by a link code. The axial variation of water density in the central flow tube has also been considered in the analysis. The maximum clad surface temperature for the original design was calculated to be very high, so some improvements in the channel design have also been proposed in this study. Moreover, a new core-loading scheme has been searched in order to get more flat radial power distribution and lower cladding surface temperature.