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This document provides the methodology used for the relative risk assessment performed in the NIF Preliminary Safety Analysis Report. The safety analysis for a facility of the hazard level of NIF (low hazard, radiological) should ...
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This document provides the methodology used for the relative risk assessment performed in the NIF Preliminary Safety Analysis Report. The safety analysis for a facility of the hazard level of NIF (low hazard, radiological) should be mostly qualitative. This was the approach taken for the NIF risk assessment, where qualitative descriptors were assigned to event consequences and frequencies. The event consequences and frequencies were then combined using a risk matrix to obtain an assessment of the relative risk presented by each event to NIF workers and to the public. The development of the risk matrices is the main subject of this report. The matrices have been applied in the NIF PSAR (LLNL, 1996).
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摘要 :
This document provides the methodology used for the relative risk assessment performed in the NIF Preliminary Safety Analysis Report. The safety analysis for a facility of the hazard level of NIF (low hazard, radiological) should ...
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This document provides the methodology used for the relative risk assessment performed in the NIF Preliminary Safety Analysis Report. The safety analysis for a facility of the hazard level of NIF (low hazard, radiological) should be mostly qualitative. This was the approach taken for the NIF risk assessment, where qualitative descriptors were assigned to event consequences and frequencies. The event consequences and frequencies were then combined using a risk matrix to obtain an assessment of the relative risk presented by each event to NIF workers and to the public. The development of the risk matrices is the main subject of this report. The matrices have been applied in the NIF PSAR (LLNL, 1996).
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This report contains a condensed presentation of the best current estimates of the effects of most of the road safety measures that are included in The Handbook of Road Safety Measures. The tables providing information on the effe...
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This report contains a condensed presentation of the best current estimates of the effects of most of the road safety measures that are included in The Handbook of Road Safety Measures. The tables providing information on the effects of road safety measures are intended for use in road safety impact assessment, i.e. to estimate expected safety benefits when planning the measures. A simple scale for rating study quality has been applied. When planning the measures, safety should be estimated by means of the empirical Bayes method.
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A quantitative model is under development to assess the safety and efficiency of commercial aircraft operations under the Free Flight Program proposed for air traffic control for the US National Airspace System. The major objectiv...
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A quantitative model is under development to assess the safety and efficiency of commercial aircraft operations under the Free Flight Program proposed for air traffic control for the US National Airspace System. The major objective of the Free Flight Program is to accommodate the dramatic growth anticipated in air traffic in the US. However, the potential impacts upon aircraft safety from implementing the Program have not been fully explored and evaluated. The model is directed at assessing aircraft operations at high altitude over the continental US airspace since this action is the initial step for Free Flight. Sequential steps with analysis, assessment, evaluation, and iteration will be required to satisfactorily accomplish the complete transition of US commercial aircraft traffic operations.
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Thousands of safety issues have been collected on-line at the Idaho National Engineering and Environmental Laboratory (INEEL) as part of the Issue Management Plan. However, there has been no established approach to prioritize coll...
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Thousands of safety issues have been collected on-line at the Idaho National Engineering and Environmental Laboratory (INEEL) as part of the Issue Management Plan. However, there has been no established approach to prioritize collected and future issues. The authors developed a methodology, based on hazards assessment, to identify and risk rank over 5000 safety issues collected at INEEL. This approach required that it was easily applied and understandable for site adaptation and commensurate with the Integrated Safety Plan. High-risk issues were investigated and mitigative/preventive measures were suggested and ranked based on a cost-benefit scheme to provide risk-informed safety measures. This methodology was consistent with other integrated safety management goals and tasks providing a site-wide risk-informed decision tool to reduce hazardous conditions and focus resources on high-risk safety issues. As part of the issue management plan, this methodology was incorporated at the issue collection level and training was provided to management to better familiarize decision- makers with concepts of safety and risk. This prioritization methodology and issue dissemination procedure will be discussed. Results of issue prioritization and training efforts will be summarized. Difficulties and advantages of the process will be reported. Development and incorporation of this process into INEEL's lessons learned reporting and the site-wide integrated safety management program will be shown with an emphasis on establishing self reliance and ownership of safety issues.
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Crashes involving large trucks constitute a significant risk to the driving public and an occupational risk to truck drivers. In 2005, some 442,000 large trucks (weighing over 10,000 lbs each) were involved in vehicle crashes; 4,9...
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Crashes involving large trucks constitute a significant risk to the driving public and an occupational risk to truck drivers. In 2005, some 442,000 large trucks (weighing over 10,000 lbs each) were involved in vehicle crashes; 4,951 of these large-truck crashes resulted in fatalities. Driver impairment due to drowsiness is a known contributing factor in many crashes involving commercial motor vehicle (CMV) drivers (Maycock, 1997). The Large Truck Crash Causation Studies found that 13 percent of truck drivers were coded as having been fatigued at the time of the crash (Federal Motor Carrier Safety Administration (FMCSA), 2006). On April 28, 2003, FMCSA published a revised set of regulations concerning the Hours-of- Service (HOS) of CMV drivers. These published regulations were amended on September 30, 2003 and implemented on January 4, 2004. One central component of the revisions was a twohour extension of off-duty time from eight to 10 hours. One rationale given in an FMCSA posting in the Federal Register (2005) was that the additional two hours of off-duty time would provide drivers with substantially more opportunity to obtain restorative sleep (p. 3342). The results from Hanowski, Dingus, Sudweeks, Olson, and Fumero (2005) indicated that this indeed may be the case; their research found that drivers may be getting more sleep under the revised 2003 HOS regulation (6.28 h per day) as compared to the old regulations (5.18 h per day; Mitler et al., 1997).
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The Office of Health Technology Assessment (OHTA) emphasizes three basic principles in its assessment activities: (1) broad and open participation both within and outside of the Federal government, (2) reliance on the expertise an...
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The Office of Health Technology Assessment (OHTA) emphasizes three basic principles in its assessment activities: (1) broad and open participation both within and outside of the Federal government, (2) reliance on the expertise and research abilities of outside organizations and individuals, and (3) broad dissemination of assessment reports. This assessment focuses on computer enhanced perimetry. Perimetry is the process of measuring and quantitating visual field loss. Computer assisted perimetry is a safe and sensitive method of assessing visual fields. It is more effective in identifying small visual field defects than are the manual methods. Moreover, it is able to do so with greater objectivity, consistency, reproducibility, reliability, and accuracy. In addition to being safe and clinically effective, computer assisted perimetry has gained widespread clinical acceptability and use.
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Safety of traffic facilities is most often measured by counting the number (and severity) of crashes that occur. It is not possible to apply such a measurement technique to traffic facility designs that have not yet been built or ...
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Safety of traffic facilities is most often measured by counting the number (and severity) of crashes that occur. It is not possible to apply such a measurement technique to traffic facility designs that have not yet been built or deployed in the real world. This project has resulted in the development of a software tool for deriving surrogate safety measures for traffic facilities from data output by traffic simulation models. This software is referred to as SSAM, an acronym for the Surrogate Safety Assessment Model. The surrogate measures developed in this project are based on the identification, classification, and evaluation of traffic conflicts that occur in the simulation model. By comparing one simulated design case with another, this software allows an analyst to make statistical judgments about the relative safety of the two designs. The method is based on processing detailed trajectories of all vehicles in the simulation environment and identifying conflicts that occur between any two vehicles. An open-standard vehicle trajectory data format was designed, and support for this format has been added as an output option by four simulation model vendors/developers PTV (VISSIM), TSS (AIMSUN), Quadstone (Paramics), and Rioux Engineering (TEXAS). Eleven 'theoretical' validation tests were performed to compare the surrogate safety assessment results of pairs of simulated design alternatives. In some cases, these comparative tests showed clear agreement with traditional results from crash prediction models; and, in other cases, the results from SSAM utilizing the traffic simulation models were counterindicative. Typically, one design would exhibit a statistically significant lower number of conflicts, but the severity of conflicts that did occur would be higher. Nevertheless, SSAM does provide metrics for use by analysts in comparing traffic facility designs that do not have established crash statistics. More research work is necessary to refine the metrics for broader consumption by a general audience. A field validation exercise was completed to compare the output from SSAM with real-world crash records. Eighty-three intersections from British Columbia, Canada were modeled in VISSM and simulated under AM-peak traffic conditions. The processed conflict results were then compared with the crash records in a number of different statistical validation tests. In general, the correlation results between the outputs from the simulation models and the crash records were significant, with the regression model predicting crashes from conflict data exhibiting a correlation (R-squared) value of = 0.41. However, the simulation modeling effort did present a number of issues. Sensitivity analysis was performed to identify differences between the SSAM-related outputs of each simulation model vendors system on the same traffic facility designs. These comparative analyses provide some guidance to the relative use of surrogate measures data from each simulation system. For more information regarding the SSAM tool and user manual (FHWA-HRT-08-050) see companion report, PB2008-111196.
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The report presents the safety priority rankings for generic safety issues related to nuclear power plants. The purpose of these rankings is to assist in the timely and efficient allocation of NRC resources for the resolution of t...
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The report presents the safety priority rankings for generic safety issues related to nuclear power plants. The purpose of these rankings is to assist in the timely and efficient allocation of NRC resources for the resolution of those safety issues that have a significant potential for reducing risk. The safety priority ranking are HIGH, MEDIUM, LOW, DROP, and CONTINUE, and have been assigned to the basis of risk significance estimates, the ratio of risk to costs and other impacts estimated to result if resolution of the safety issues were implemented, and the consideration of uncertainties and other quantitative and qualitative factors. To the extent practical, estimates are quantitative.
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