Coupling analysis on a new SCWR core design

A previous study shows that the two-row fuel assembly has much more favorable neutron-physical and thermal-hydraulic behaviour than the conventional one-row fuel assemblies. Based on the new developed two-row fuel assembly, an SCWR core is proposed and analyzed. The core contains 249 fissile fuel assemblies in the inner zone and 52 reflector assemblies in the peripheral area. The inner zone has fissile assemblies of different enrichments, to flatten the radial power profile. The total core thermal power is 3500 MW, and the average linear power density is 19 kW/m. The performance of the proposed core is investigated with 3-D coupled neutron-physical and thermal-hydraulic core calculations. During the coupling procedure, the thermal-hydraulic behaviour is analyzed using a sub-channel analysis code and the neutron-physical performance is computed with a 3-D diffusion code. This paper presents the main results achieved so far related to the distribution of some neutronic and thermal-hydraulic parameters. It shows that with adjustment of coolant and moderator mass flow in different assemblies, both optimized neutron-physical and thermal-hydraulic behaviour of the SCWR core is achieved. A sensitivity study of some important parameters (e.g. heat transfer correlation) is carried out. (authors)