Plasma parameters for a low-Q tokamak reactor GNOME were studied to meet the allowable heat load constraints of the divertor component. EQLAUS/ERATO codes and DRIVER88 codes were used for the core plasma models to determine the power flux into SOL regions for this calculation. Then, the heat flux to the divertor plate was estimated with a parameter of the radiation power at SOL/divertor regions. A simple Core-SOL-Divertor (C-S-D) model has been used for this purpose. Finally, three operation regions with the required radiation power to meet the allowable peak heat load were proposed.