Scaling studies for a SITEX negative ion source to produce 200-keV, 10-A, long pulse D-beams are under way at Oak Ridge National Laboratory (ORNL). Designs have been restricted to the use of established techniques and reasonably welldemonstrated scaling. The results show that the 1-A SITEX source can be directly scaled to produce 200-keV, 10-A long pulse ion beams with a source power efficiency of <5 kW of total plasma generator power per ampere of D- beam generated. Extracted electron-to-D- ratios should be <0.06, with all extracted electrons recovered at <10% of the first gap potential energy difference. The close-coupled accelerating structure will be 5 em long and have five electrodes with 21 slits each, with a 50-kV/cm field in each gap. No decel electrode was included because of the transverse magnetic field. Electrons formed in each gap by the ~16% charge-exchange loss of D- in the total accelerator column will be collected by electron recovery structures associated with the gaps at an average energy of 50% of a gap's potential energy difference. Atomic gas efficiency will be >67%. Beam divergence calculations using the ORNL optics code give θrms = ±0.4°. The ion source magnetic field provides momentum dispersion of the extracted beam, separating out both the electrons and all heavy ion impurities and low energy D0 particles formed by charge exchange in the accelerating column. A D2 gas neutralization cell and a charge separation magnet provide 1 MW of D0 beam at 200 keV for injection. The overall beam line dimensions are 2.2 × 1.0 × 5.0 m (H × W × L).