Download Free Preparing And Conducting Review Missions Instrumentation And Control Systems In Nuclear Power Plants Book in PDF and EPUB Free Download. You can read online Preparing And Conducting Review Missions Instrumentation And Control Systems In Nuclear Power Plants and write the review.

The guidelines outlined in this publication provide a basic structure, common reference and checklist across the various areas covered by an IERICS mission.
IAEA work in the area of research reactor operation and maintenance is aimed at enhancing the capabilities of Member States to utilize good engineering and management practices to improve research reactor reliability and availability. In particular, the IAEA supports activities addressing ageing management of research reactor instrumentation and control (I&C) systems. The purpose of this publication is to provide engineering guidance on the design, and operational aspects of digital I&C systems for the refurbishment of existing facilities and for new research reactors. Key areas addressed include codes and standards applicability, licensing issues, dealing with the change in human-system interface from analogue to digital technology, software verification and validation activities, periodic testing and inspection, and configuration management. The publication contains technical descriptions and summaries of available digital systems that have been utilized in both new research reactor designs, and in the upgrading of older analogue safety and control systems. This guidance is foreseen for the broad spectrum of research reactors types existing today.
Integrated digital instrumentation and control (I & C) systems in new and advanced nuclear power plants (NPPs) will support operators in monitoring and controlling the plants. Even though digital systems typically are expected to be reliable, their potential for degradation or failure significantly could affect the operators performance and, consequently, jeopardize plant safety. This U.S. Nuclear Regulatory Commission (NRC) research investigated the effects of degraded I & C systems on human performance and on plant operations. The objective was to develop technical basis and guidance for human factors engineering (HFE) reviews addressing the operator's ability to detect and manage degraded digital I & C conditions. We reviewed pertinent standards and guidelines, empirical studies, and plant operating experience. In addition, we evaluated the potential effects of selected failure modes of the digital feedwater control system of a currently operating pressurized water reactor (PWR) on human-system interfaces (HSIs) and the operators performance. Our findings indicated that I & C degradations are prevalent in plants employing digital systems, and the overall effects on the plant's behavior can be significant, such as causing a reactor trip or equipment to operate unexpectedly. I & C degradations may affect the HSIs used by operators to monitor and control the plant. For example, deterioration of the sensors can complicate the operators interpretation of displays, and sometimes may mislead them by making it appear that a process disturbance has occurred. We used the findings as the technical basis upon which to develop HFE review guidance.
This publication defines a framework that represents the state of the art in assessment methodologies for safety and instrumentation and control software used at nuclear power plants. It describes an approach for developing and communicating assessments based on claims, argument and evidence. The assessment of software dependability, which encompasses properties such as safety, reliability, availability, maintainability and security, is an essential and challenging aspect of the safety justification. Guiding principles for a dependability assessment are established to provide the basis for defining an assessment strategy and implementing the assessment process. Sources of evidence for the assessment are provided and lessons learned from past digital instrumentation and control system implementation in areas such as software development, operational usage, regulatory review and platform certification are also described.
This report provides key results of a three-year experimental and theoretical research and development effort performed under the auspices of the U.S. Nuclear Regulatory Commission. The goal of the R&D was to establish the validity of online calibration monitoring of process instrumentation channels in nuclear power plants. The author concludes that the normal outputs of instrument channels in nuclear plants can be monitored over a fuel cycle while the plant is operating and during startup and shutdown periods to verify the calibration of the instruments, thereby improving plant efficiency and safety, eliminating unnecessary calibrations, and reducing operations and maintenance costs.
Computer security is increasingly recognized as a key component in nuclear security. This publication outlines a methodology for conducting computer security assessments at nuclear facilities. The methodology can likewise be easily adapted to provide assessments at facilities with other radioactive materials.
The objective of this chapter is to discuss two approaches for reliability analysis of digital instrumentation and control systems in nuclear power plants taking into account the regulatory side. Dynamic Flowgraph Methodology (DFM) and Markov/Cell-to-Cell Mapping Technique (CCMT) are discussed and case studies developed are presented. These case studies involve simplified control systems for a steam generator and a pressurizer of a Pressurized Water Reactor (PWR) plant for the purpose of evaluating each method. Advantages and limitations of each approach are addressed. For the DFM approach, three concerns in the literature are addressed: modeling of the system itself, incorporation of the methodology results into existing Probabilistic Safety Assessments (PSA), and identification of software failures. The Markov/CCMT, which has been used in dynamic probabilistic safety assessments, is approached by means of a simplified digitally controlled water volume control system. The Markov/CCMT methodology results in detailed data of the system reliability behavior in relation to time. However, it demands a higher computational effort than usual as the complexity (id est, number of components and failure states) of the system increases. As a regulatory research conclusion, the methodologies presented can be used on PSA risk informed assessment, contributing to the regulatory side.