[en] The Phase A effort produced an initial description of the overall plant, structures and systems. During Phase A, General Electric developed the overall nuclear steam supply system (NSSS) conceptual design. It defined specific design approaches for selected NSSS components and subsystems after analyzing various design alternatives. Bechtel assumed responsibility for the intermediate sodium piping arrangement, the access area above the reactor deck and the Balance of Plant (BOP). The resulting integrated plant design provided the necessary seismic data for both the NSSS and BOP