GaInSn, a eutectic alloy, has been successfully used in the Magneto-Thermofluid Research Laboratory at the University of California-Los Angeles and at the Princeton Plasma Physics Laboratory for the past six years. This paper describes the handling and safety of GaInSn based on the experience gained in these institutions, augmented by observations from other researchers in the liquid metal experimental community. GaInSn is an alloy with benign properties and shows considerable potential in liquid metal experimental research and cooling applications.
Fusion power holds the promise of electricity production with a high degree of safety and low environmental impact. Favourable characteristics of fusion as an energy source provide the potential for this very good safety and environmental performance. But to fully realize the potential, attention must be paid in the design of a demonstration fusion power plant (DEMO) or a commercial power plant to minimize the radiological hazards. These hazards arise principally from the inventory of tritium and from materials that become activated by neutrons from the plasma. The confinement of these radioactive substances, and prevention of radiation exposure, are the primary goals of the safety approach for fusion, in order to minimize the potential for harm to personnel, the public, and the environment. The safety functions that are implemented in the design to achieve these goals are dependent on the performance of a range of materials. Degradation of the properties of materials can lead to challenges to key safety functions such as confinement. In this paper the principal types of material that have some role in safety are recalled. These either represent a potential source of hazard or contribute to the amelioration of hazards; in each case the related issues are reviewed. The resolution of these issues lead, in some instances, to requirements on materials specifications or to limits on their performance.
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ABSTRACTThis report presents the results of a study to define several types of sensors in use, the qualitative reliability (failure modes) and quantitative reliability (average failure rates) for these types of process sensors. Temperature, pressure, flow, and level sensors are discussed for water coolant and for cryogenic coolants. The failure rates that have been found are useful for risk assessment and safety analysis. Repair times and calibration intervals are also given when found in the literature. All of these values can also be useful to plant operators and maintenance personnel. Designers may be able to make use of these data when planning systems. The final chapter in this report discusses failure rates for several types of personnel safety sensors, including ionizing radiation monitors, toxic and combustible gas detectors, humidity sensors, and magnetic field sensors. These data could be useful to industrial hygienists and other safety professionals when designing or auditing for personnel safety...
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SUMMARYThis report is a review of sensor technology and sensor reliability. Several types of sensors are described, first their operating principles and then the reliability features. A qualitative reliability analysis has been carried out for five types of process sensors: temperature, pressure, flow, level, and water quality. The qualitative failure modes and effects analysis (FMEA) gives insights into what designers should consider when incorporating a sensor into a process or safety system. The qualitative reliability was approached in two Stages. First, judgment was used on the sensor operating principles to identify what the possible failure modes are, then a FMEA was performed to give an . exhaustive set of possible failures. The FMEA was supported by articles and reports on operating experiences. With a firm definition of possible failures, another literature search was made to find the failure rates for these five types of sensors. Several literature sources were found to give failure rates for typically used sensors; however, these sensors represent older technology that has been in use for many years. No data were found on the reliability of digital sensors. Therefore, for the current time, it is suggested to use the average failure rates of existing equipment to bound the digital sensor failure rates. If a sensor is determined to be an important or crucial component in a risk assessment or safety analysis, then more effort can be put toward locating a data set to better describe the digital components.Table S-1 presents an overview of the failure rate results of this report. References for the sensor failure rates given in this table are found in their respective chapters. It is noted that many of the sensor failure rates for fail to operate are the same values. This is attributed to the fact that sensors reported in the literature are reasonably matured technology, and most of the data originate from the same area, namely the fission power industry. The data for other failure mo...
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