System effectiveness model formulation with application to nuclear safeguards systems

Evaluation of a given system\u27s effectiveness has numerous pitfalls. System objectives may be poorly defined, may shift during the system life, or may be hard to quantify. Further, individual perceptions of the quantifications may differ. Whatever the cause, system effectiveness has been an elusive term to quantitatively define. This research posits a quantitative system effectiveness model and establishes a utilitarian approach for use with an illustrative application to n operating nuclear safeguards system.The Department of Energy (DOE) defines domestic safeguards, which are applied to nuclear material as; an integrated system of physical protection, material accounting, and material control measures designed to deter, prevent, detect, and respond to unauthorized possession, use, or sabotage of nuclear materials. This research includes the investigation of the utility coefficients and simulation of a domestic nuclear safeguards system, as well as simulation of an airport passenger screening system consisting of: an identification screening system; an X-ray system for checking bags and computers; and a walk through metal detector. Expert judgment was used to determine the relative importance (utility) of the individual subsystems through a statistically analyzed web survey. The survey population is nuclear material protection, control, accounting, and plant management experts.The mean utility coefficients determined during the survey were applied to the system components developed assigned randomly generated values of component effectiveness and combined to produce an overall system effectiveness. Simulated Type I and Type II error rates are used for illustration of the probabilistic methodology currently used by DOE (calculating protection effectiveness) and the posited and heuristically based methodology (system effectiveness). Use of the heuristically based system effectiveness methodology illustrates an approach that combines the subsystem components of plant management, physical protection, material accounting, and material control for a domestic safeguards system. The system effectiveness methodology is complimentary to and more robust than the protection effectiveness calculation and can offer opportunities for cost savings during the system lifecycle

Supply chain risk analysis

A new decision support system is proposed and developed that will help sustaining business in a high-risk business environment. The system is developed as a web application to better integrate the supply chain entities and to provide a common platform for performing risk analysis in a supply chain. The system performs a risk analysis and calculates risk factor with each activity in the supply considering its interrelationship with other activities. Bayesian networks along with fault tree structures are embedded in the system and logical rules are used to perform a qualitative fault tree analysis, as the data required to calculate the frequency of occurrence is rarely available. The developed system guides the risk assessment process: from asset identification to consequence analysis before estimating the risk factor associated with each activity in the supply chain. The system is tested with a sample case study on a highly explosive product. Results show that the system is capable of identifying high-risk threats. The system further needs to be developed to add a safeguard analysis module and to enable automatic data extraction from the enterprise resource planning and legacy databases. It is expected that the system on complete development and induction will help supply chain managers to manage business risks and operations more efficiently and effectively by providing a complete picture of the risk environment and safeguards required to reduce the risk level

Safeguards Methodology Development History

The development of models for the evaluation and design of fixed-site nuclear facility, physical protection systems was under way in 1974 at Sandia Laboratories and has continued to the present. A history of the evolution of these models and the model descriptions are presented. Several models have been and are continuing to be applied to evaluate and design facility protection systems

Development of a human factors hazard model for use in system safety analysis

2021 Fall.Includes bibliographical references.Traditional methods for Human Reliability Analysis (HRA) have been developed with specific applications or industries in mind. Additionally, these methods are often complicated, time consuming, costly to apply, and are not suitable for direct comparison amongst themselves. The proposed Human Factors Hazard Model (HFHM) utilizes the established and time-tested probabilistic analysis tools of Fault Tree Analysis (FTA) and Event Tree Analysis (ETA), and integrates them with a newly developed Human Error Probability (HEP) predictive tool. This new approach is developed around Performance Shaping Factors (PSFs) relevant to human behavior, as well as specific characteristics unique to a system architecture and its corresponding operational behavior. This updated approach is intended to standardize, simplify, and automate the approach to modeling the likelihood of a mishap due to a human-system interaction during a hazard event. The HFHM is exemplified and automated within a commercial software tool such that trade and sensitivity studies can be conducted and validated easily. The analysis results generated by the HFHM can be used as a standardized guide to SE analysts as a well as design engineers with regards to risk assessment, safety requirements, design options, and needed safety controls within the system architecture. Verification and evaluation of the HFHM indicate that it is an effective tool for HRA and system safety with results that accurately predict HEP values that can guide design efforts with respect to human factors. In addition to the development and automation of the HFHM, application within commonly used system safety Hazard Analysis Techniques (HATs) is established. Specific utilization of the HFHM within system or subsystem level FTA and Failure Mode and Effects Analysis (FMEA) is established such that human related hazards can more accurately be accounted for in system design safety analysis and lifecycle management. Lastly, integration of the HFHM within Model-Based System Engineering (MBSE) emphasizing an implementation into the System Modeling Language (SysML) is established using a combination of existing hazard analysis libraries and custom designed libraries within the Unified Modeling Language (UML). The FTA / ETA components of the hazard model are developed within SysML partially utilizing the RAAML (Risk Analysis and Assessment Modeling Language) currently under development by the Object Management Group (OMG), as well as a unique recursive analysis library. The SysML model successfully replicates the probabilistic calculation results of the HFHM as generated by the native analytical model. The SysML profiles developed to implement HFHM have application in integration of conventional system safety analysis as well as requirements engineering within lifecycle management

Object-Oriented Bayesian Networks (OOBN) for Aviation Accident Modeling and Technology Portfolio Impact Assessment

The concern for reducing aviation safety risk is rising as the National Airspace System in the United States transforms to the Next Generation Air Transportation System (NextGen). The NASA Aviation Safety Program is committed to developing an effective aviation safety technology portfolio to meet the challenges of this transformation and to mitigate relevant safety risks. The paper focuses on the reasoning of selecting Object-Oriented Bayesian Networks (OOBN) as the technique and commercial software for the accident modeling and portfolio assessment. To illustrate the benefits of OOBN in a large and complex aviation accident model, the in-flight Loss-of-Control Accident Framework (LOCAF) constructed as an influence diagram is presented. An OOBN approach not only simplifies construction and maintenance of complex causal networks for the modelers, but also offers a well-organized hierarchical network that is easier for decision makers to exploit the model examining the effectiveness of risk mitigation strategies through technology insertions

Investigating the Electrodeposition of Plutonium and Curium for Safeguarding the Electrorefiner

This research investigated the electrochemical deposition behavior of plutonium (Pu) and curium (Cm) for safeguarding the electrorefiner (ER) in a pyroprocessing facility. The main goal of this investigation was to evaluate the feasibility of using a safeguards concept called the neutron balance method to account for Pu in the ER. The neutron balance method relies on a known Pu/Cm ratio and measures neutrons from Cm-244 coming into and leaving a unit operation to track Pu. The application of the neutron balance approach for pyroprocessing facilities requires that Pu and Cm remain together in all extraction, product recovery, and waste streams. The electrochemical deposition experiments conducted, using a surrogate system of Tb and Gd, revealed that the Tb to Gd ratio was inconsistent between the electrolyte and the cathode deposit under different electrolyte concentrations. The Enhanced REFIN with Anodic Dissolution (ERAD) computer simulations of the same Tb/Gd surrogate system also found that the Tb to Gd ratio varied. ERAD simulations of a large-scale pilot facility also revealed that the Pu to Cm ratio was not constant between the electrolyte salt and the metal deposit when Pu co-deposition occurs. The safeguards assessment concluded that the neutron balance method was an insufficient safeguards approach for the eletrorefiner and working under the assumption that the Pu/Cm ratio was invariable resulted in the loss of significant quantities of special nuclear material (SNM) after processing only a few batches

Institute for the Protection and Security of the Citizen Activity Report 2002.

Abstract not availableJRC.G-Institute for the Protection and the Security of the Citizen (Ispra

Consensual security risk assessment: Overcoming bias, conflicting interests and parochialism

In a risk assessment process, insular methods of data collection and analysis may lead to an inaccurate risk assessment as stakeholders hold individual biases, conflicting interests and parochial approaches to certain risks. The article considered these issues and tested a consensual risk assessment approach that can overcome many of these issues. A staged risk assessment process was applied within an entertainment complex in the Security, and Food and Beverage Departments. Eight supervisors from the two departments participated in the study, with each participants individually interviewed on their view of predefined risks followed by the same risks discussed within a facilitated group. The study first identified a list of the twenty most important risks according to the two departmental managers. From this initial identification of risks, four supervisors from each department ranked, from highest to lowest, all twenty risks as individuals. Following this stage, the consensus activities involved four supervisors from one department who ranked all twenty risks as a group and with the aim that all participants had to agree. Finally, the consensus activity was repeated with all eight participants present. Such a staged approach allowed the various approaches and resulting outcomes from the various risk assessment methods to be compared. Such a comparison found that there was a need to gain common understanding or clear definition of risks within the group, that an individual’s assessment of a risk was driven by their own perceptions and that less important risks held a more common view, whereas higher risk had a greater diversity of views