REATRAN sensitivity calculations for anticipated transient without scram

Best estimate analyses were performed for a loss of feedwater transient without scram and turbine trip without scram on Kori unit 1 using RETRAN-3D/MOD3.1 computer code. The results showed that the peak pressure for loss of feedwater ATWS and turbine trip ATWS with AMSAC did not exceed the ASME Code Level C limit criterion (3200psig) when MTC was less than -7pcm/F. For the ATWS analysis, particular effort was given to the effects of varying the nodalization of steam generator secondary side and maximum time step size on primary side pressure response. The sensitivity of primary pressure response to moderator reactivity feedback coefficients, turbine trip time, auxiliary feedwater supply time, pressurizer relief capacity, auxiliary feedwater supply capacity, and steam generator level setpoint for AMSAC actuation was also studied