Analysis of IHX Vertical Position Effects in the Reactor Vessel of KALIMER-600

In this research the vertical position effects of an IHX (Intermediate Heat eXchanger) during a loss of normal heat sink accident were investigated by varying the distance between the thermal centers of core and IHX. The conceptual design data of KALIMER(Korea Advanced Liquid Metal Reactor)-600(Hahn et al., 2007) was utilized as the reference reactor design. The thermal-hydraulic calculations for the steady and transient state have been done using the COMMIX-1AR/P code(Garner et al., 1992). In order to evaluate the effects of the IHX vertical position, the elevation of the IHX was increased by 1m and 2m respectively in comparison to the reference design and the required numerical analysis was completed. Several coastdown flow conditions were also considered to investigate the variation of the IHX elevation effect. The thermo-hydrodynamic behaviors in a steady and transient state were compared during early-phase of an accident. It was found that the IHX elevation enhances the circulation flow rate and contributes to the decrease of early-phase peak temperature for non-reverse flow coastdown conditions. IHX elevation also contributed to the extension of the non-reverse flow coastdown flow time range.