The nuclear industry and the U.S. Nuclear Regulatory Commission (USNRC) have been working for several years on development of an adequate process to guide the replacement of aging analog monitoring and control instrumentation in nuclear power plants with modern digital instrumentation, without introducing off-setting safety problems. This final report of a two-phased study identifies criteria for the USNRC's review and acceptance of digital applications in nuclear power plants. The book focuses on eight areas: software, quality assurance, common-mode software failure potential, systems aspects of digital instrumentation and control technology, human factors and human-machine interfaces, safety and reliability assessment methods, dedication of commercial off-the-shelf hardware and software, the case-by-case licensing process, and adequacy of technical infrastructure.