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[en] Many nuclear power plants use instrument and control systems based on analog electronics. The state of the art in process control and instrumentation has advanced to use digital electronics and incorporate advanced technology. This technology includes distributed microprocessors, fiber optics, intelligent systems (neural networks), and advanced displays. The technology is used to optimize processes and enhance the man-machine interface while maintaining control and safety of the processes. Nuclear power plant operators have been hesitant to install this technology because of the cost and uncertainty in the regulatory process. This technology can be directly applied in an operating nuclear power plant provided a surety principle-based open-quotes administratorclose quotes hardware system is included in parallel with the upgrade Sandia National Laboratories has developed a rigorous approach to High Consequence System Surety (HCSS). This approach addresses the key issues of safety, security, and control while satisfying requirements for reliability and quality. HCSS principles can be applied to nuclear power plants in a manner that allows the off-the-shelf use of process control instrumentation while maintaining a high level of safety and enhancing the plant performance. We propose that an HCSS administrator be constructed as a standardized approach to address regulatory issues. Such an administrator would allow a plant control system to be constructed with commercially available, state-of-the-art equipment and be customized to the needs of the individual plant operator

[en] In this paper, the authors present a digital system requirements specification method that has demonstrated a potential for improving the completeness of requirements while reducing ambiguity. It assists with making proper digital system design decisions, including the defense against specific digital system failures modes. It also helps define the technical rationale for all of the component and interface requirements. This approach is a procedural method that abstracts key features that are expanded in a partitioning that identifies and characterizes hazards and safety system function requirements. The key system features are subjected to a hierarchy that progressively defines their detailed characteristics and components. This process produces a set of requirements specifications for the system and all of its components. Based on application to nuclear power plants, the approach described here uses two ordered domains: plant safety followed by safety system integrity. Plant safety refers to those systems defined to meet the safety goals for the protection of the public. Safety system integrity refers to systems defined to ensure that the system can meet the safety goals. Within each domain, a systematic process is used to identify hazards and define the corresponding means of defense and mitigation. In both domains, the approach and structure are focused on the completeness of information and eliminating ambiguities in the generation of safety system requirements that will achieve the plant safety goals

[en] Several studies indicate that in software-based systems, more than 50% of latent defects originate in the software requirements specification. Latent software defects that can lead to unacceptable system behavior have their origin in the inability to completely and unambiguously specify the intended system functionality. This includes (a) the omission of required functionality, (b) the inclusion of undesired functionality, (c) the incorrect specification of functionality, and (d) incorrect design assumptions and dependencies on the performance of the underlying electronic system and its architecture

[en] Many nuclear power plants use instrument and control systems based on analog electronics. The state of the art in process control and instrumentation has advanced to use digital electronics and incorporate advanced technology. This technology includes: distributed microprocessors, fiber optics, intelligent systems (neutral networks), and advanced displays. The technology is used to optimize processes and enhance the man-machine interface while maintaining control and safety of the processes. Nuclear power plant operators have been hesitant to install this technology because of the cost and uncertainty in the regulatory process. This technology can be directly applied in an operating nuclear power plant provided a surety principle-based 'administrator' hardware system is included in parallel with the upgrade. Sandia National Laboratories has developed a rigorous approach to High Consequence System Surety (HCSS). This approach addresses the key issues of safety, security, and control while satisfying requirements for reliability and quality. We believe that HCSS principles can be applied to nuclear power plants in a manner that allows the off-the-shelf use of process control instrumentation while maintaining a high level of safety and enhancing the plant performance. We propose that an HCSS Administrator be constructed as a standardized approach to address regulatory issues. Such an administrator would allow a plant control system to be constructed with commercially available, state-to-the-art equipment and be customized to the needs of the individual plant operator. (author)