This Safety Guide provides recommendations and guidance on instrumentation and control systems and software important to safety for research reactors, including instrumentation and control system architecture and associated components, from sensors to actuators, operator interfaces and auxiliary equipment. It also provides recommendations on computer based systems and software, including software requirements and design, verification and validation, integration, and operation. This publication also addresses safety classification, design, implementation, qualification and operation of instrumentation as well as control systems. The recommendations and guidance apply to both the design and configuration management of instrumentation and control systems for new research reactors and the modernization of the instrumentation and control systems to existing research reactor facilities. In addition this Safety Guide provides recommendations and guidance on human factors engineering and human machine interfaces, and for computer based systems and software for use in instrumentation and control systems important to safety.