Calculations form the backbone of every design. Engineers and designers rely on calculations to support the technical adequacy of any system, structure or component (SSC). Without representative calculations, the design, construction, operation, maintenance or modification of any SSC would remain unanalyzed, non-configured and potentially unsafe. In today’s nuclear generating plants, calculations that form the design basis and how that design is translated into drawings and procedures are especially important. Federal regulations mandate that all nuclear generating plant licensees establish a method of design control to assure that regulatory requirements are met. The purpose of this paper is to describe one such method by which a nuclear plant licensee (Southern Nuclear) controls its calculations.