The current status of the development effort on the Hybrid Sulfur Process (HyS, also called the Westinghouse Sulfur Process or WSP) is presented. Included are current efficiency and cost estimates for the HyS and other processes. Areas that are undergoing development are discussed. The current baseline HyS configuration extracts 195 MWt of the available thermal energy from the Pebble 500 MWt Bed Modular Reactor (PBMR) reactor to decompose H2SO4 to H2O, O2 and SO2 Since the operating pressure is ~9 MPa, residual thermal energy can utilized to preheat the feed to a Rankine steam cycle which is operated on the remaining 305 MWt output of the PBMR. High pressure (~9 MPa) is maintained in the decomposition reactor to minimize the pressure drop across the tubes and minimize strength of materials issues in the 850°C to 900°C range. At the same time, lower operating pressures (4 MPa) were established in the remaining plant by using five stages of SO2 absorption, each followed by oxidation of the absorbed SO2 to SO3 in electrolysis cells.

Development work is proceeding on the HyS electrolyzer (by Savannah River National Laboratory), SO2 scrubbers (Sheffield University) and on the design of the H2SO4 decomposition reactor (Westinghouse and others). This development work is aimed at producing a well documented design basis for the construction of a large demonstration test loop.