[en] Westinghouse, and other nuclear steam supply system vendors, have made the transition from providing systems design and interface requirements to providing operating systems enhancements. Working with utilities with operating nuclear power plants has shown that there is a continuous need for systems design simplification and systems margin identifications and reductions. Systems design simplification is the process of modifying the design to simplify the operation of the nuclear power plant. Design simplification has been an evolutionary process that has become feasible due to the accumulation of operating experience, diversity of equipment designs and vendors, and advanced industry codes, standards, and analytical tools. This paper evaluates the major systems design simplification areas and available systems margins that have successfully been utilized to enhance plant availability and operation