**2. Background**

Chemical, manufacturing, and nuclear processes rely on instrumentation, such as pressure, temperature, and flow sensors, to measure and monitor process parameters. These industrial processes are then maintained by control systems that operate physical equipment, such as valves, pumps, and heaters, to keep the process parameters within predefined limits. Nuclear reactors vary by type (e.g., pressurized water reactor, pool-type reactor, liquid metal cooled reactor, molten salt reactor, gas cooled reactor) and purpose (e.g., power reactor, research reactor, nuclear propulsion). The remainder of this section first describes the fundamentals of generic nuclear reactor I&C prior to discussing the transition to digital technology, including its benefits and challenges. The section concludes with an overview of future DI&C applications, including those in new and advanced reactors, as well as integrated systems and decision support systems.
