Application of Computers to the Remote Control of Cooling Towers at the Tennessee Valley Authority Sequoyah Nuclear Plant

A computer-based control system is described, wherein the nonvolatility of a hardware system is combined with the flexibility of a computer-based system by the use of nonalterable memory for program storage and alterable memory for manually entered alarm limits and channel deletions. Functional and reliability requirements are presented, and the system design which evolved to meet these requirements is described.