Application of Digital Computer Systems in Nuclear Power Plants

1. The third-generation digital-process computers using solid-state integrated circuits have demonstrated better than 99 percent system availability and have proven reliable during operation. 2. On-line plant computers in nuclear-power plants are technically and economically justifiable by the ever-increasing requirements of surveillance and assimilation of such a quantity of plant parameters that conventional instrumentation is inadequate and cumbersome. 3. In-core instrument signals are best processed by an on-line real-time computer to yield detailed core information which can be used to maximize core power. 4. The computer is ideally suited for rapid and early detection of abnormal plant conditions, faulty sensors, and malfunctioning equipment. By proper programming, the computer can either alert the operator or initiate corrective action in sufficient time to prevent or minimize equipment failure and plant outages. 5. By performing essentially continuous calibration and checks of instrumentation, the operating limit uncertainties can be reduced with a consequential increase in the plant capacity. This is a particularly important advantage for nuclear plants which must adhere to technical specifications that impose power and other limits which are verified by instrumentation. 6. The trend toward very large and high power nuclear reactors results in core dynamics not previously considered a problem. Axial, azimuthal, and possibly radial xenon oscillations as well as xenon redistribution after power changes must be taken into consideration. With reactors operating close to thermal hydraulic limits, these transient conditions must be coped with relatively quickly.