Documentation design for probabilistic risk assessment

International Nuclear Information System (INIS)

Parkinson, W.J.; von Herrmann, J.L.

1985-01-01

This paper describes a framework for documentation design of probabilistic risk assessment (PRA) and is based on the EPRI document NP-3470 ''Documentation Design for Probabilistic Risk Assessment''. The goals for PRA documentation are stated. Four audiences are identified which PRA documentation must satisfy, and the documentation consistent with the needs of the various audiences are discussed, i.e., the Summary Report, the Executive Summary, the Main Report, and Appendices. The authors recommend the documentation specifications discussed herein as guides rather than rigid definitions

Software for Probabilistic Risk Reduction

Science.gov (United States)

Hensley, Scott; Michel, Thierry; Madsen, Soren; Chapin, Elaine; Rodriguez, Ernesto

2004-01-01

A computer program implements a methodology, denoted probabilistic risk reduction, that is intended to aid in planning the development of complex software and/or hardware systems. This methodology integrates two complementary prior methodologies: (1) that of probabilistic risk assessment and (2) a risk-based planning methodology, implemented in a prior computer program known as Defect Detection and Prevention (DDP), in which multiple requirements and the beneficial effects of risk-mitigation actions are taken into account. The present methodology and the software are able to accommodate both process knowledge (notably of the efficacy of development practices) and product knowledge (notably of the logical structure of a system, the development of which one seeks to plan). Estimates of the costs and benefits of a planned development can be derived. Functional and non-functional aspects of software can be taken into account, and trades made among them. It becomes possible to optimize the planning process in the sense that it becomes possible to select the best suite of process steps and design choices to maximize the expectation of success while remaining within budget.

Probabilistic Characterization of Adversary Behavior in Cyber Security

Energy Technology Data Exchange (ETDEWEB)

Meyers, C A; Powers, S S; Faissol, D M

2009-10-08

The objective of this SMS effort is to provide a probabilistic characterization of adversary behavior in cyber security. This includes both quantitative (data analysis) and qualitative (literature review) components. A set of real LLNL email data was obtained for this study, consisting of several years worth of unfiltered traffic sent to a selection of addresses at ciac.org. The email data was subjected to three interrelated analyses: a textual study of the header data and subject matter, an examination of threats present in message attachments, and a characterization of the maliciousness of embedded URLs.

A methodology for reviewing probabilistic risk assessments

International Nuclear Information System (INIS)

Derby, S.L.

1983-01-01

The starting point for peer review of a Probabilistic Risk Assessment (PRA) is a clear understanding of how the risk estimate was prepared and of what contributions dominate the calculation. The problem facing the reviewers is how to cut through the complex details of a PRA to gain this understanding. This paper presents a structured, analytical procedure that solves this problem. The effectiveness of this solution is demonstrated by an application on the Zion Probabilistic Safety Study. The procedure found the three dominant initiating events and provided a simplified reconstruction of the calculation of the risk estimate. Significant assessments of uncertainty were also identified. If peer review disputes the accuracy of these judgments, then the revised risk estimate could significantly increase

Cyber Security Risk Evaluation of a Nuclear I&C Using BN and ET

Directory of Open Access Journals (Sweden)

Jinsoo Shin

2017-04-01

Full Text Available Cyber security is an important issue in the field of nuclear engineering because nuclear facilities use digital equipment and digital systems that can lead to serious hazards in the event of an accident. Regulatory agencies worldwide have announced guidelines for cyber security related to nuclear issues, including U.S. NRC Regulatory Guide 5.71. It is important to evaluate cyber security risk in accordance with these regulatory guides. In this study, we propose a cyber security risk evaluation model for nuclear instrumentation and control systems using a Bayesian network and event trees. As it is difficult to perform penetration tests on the systems, the evaluation model can inform research on cyber threats to cyber security systems for nuclear facilities through the use of prior and posterior information and backpropagation calculations. Furthermore, we suggest a methodology for the application of analytical results from the Bayesian network model to an event tree model, which is a probabilistic safety assessment method. The proposed method will provide insight into safety and cyber security risks.

Advanced Test Reactor probabilistic risk assessment

International Nuclear Information System (INIS)

Atkinson, S.A.; Eide, S.A.; Khericha, S.T.; Thatcher, T.A.

1993-01-01

This report discusses Level 1 probabilistic risk assessment (PRA) incorporating a full-scope external events analysis which has been completed for the Advanced Test Reactor (ATR) located at the Idaho National Engineering Laboratory

Risk analysis of analytical validations by probabilistic modification of FMEA

DEFF Research Database (Denmark)

Barends, D.M.; Oldenhof, M.T.; Vredenbregt, M.J.

2012-01-01

Risk analysis is a valuable addition to validation of an analytical chemistry process, enabling not only detecting technical risks, but also risks related to human failures. Failure Mode and Effect Analysis (FMEA) can be applied, using a categorical risk scoring of the occurrence, detection...... and severity of failure modes, and calculating the Risk Priority Number (RPN) to select failure modes for correction. We propose a probabilistic modification of FMEA, replacing the categorical scoring of occurrence and detection by their estimated relative frequency and maintaining the categorical scoring...... of severity. In an example, the results of traditional FMEA of a Near Infrared (NIR) analytical procedure used for the screening of suspected counterfeited tablets are re-interpretated by this probabilistic modification of FMEA. Using this probabilistic modification of FMEA, the frequency of occurrence...

A review of probabilistic risk assessment of contaminated land

International Nuclear Information System (INIS)

Oeberg, T.; Bergbaeck, B.

2005-01-01

Background, Aims and Scope. The management and decisions concerning restoration of contaminated land often require indepth risk analyses. An environmental risk assessment is generally described as proceeding in four separate steps: hazard identification, dose-response assessment, exposure assessment, and risk characterization. The risk assessment should acknowledge and quantify the uncertainty in risk predictions. This can be achieved by applying probabilistic methods which, although they have been available for many years, are still not generally used. Risk assessment of contaminated land is an area where probabilistic methods have proved particularly useful. Many reports have appeared in the literature, mostly by North American researchers. The aim of this review is to summarize the experience gained so far, provide a number of useful examples, and suggest what may be done to promote probabilistic methods in Europe and the rest of the world. Methods. The available literature has been explored through searches in the major scientific and technical databases, WWW resources, textbooks and direct contacts with active researchers. A calculation example was created using standard simulation software. (orig.)

Probabilistic aspects of risk analyses for hazardous facilities

International Nuclear Information System (INIS)

Morici, A.; Valeri, A.; Zaffiro, C.

1989-01-01

The work described in the paper discusses the aspects of the risk analysis concerned with the use of the probabilistic methodology, in order to see how this approach may affect the risk management of industrial hazardous facilities. To this purpose reference is done to the Probabilistic Risk Assessment (PRA) of nuclear power plants. The paper points out that even though the public aversion towards nuclear risks is still far from being removed, the probabilistic approach may provide a sound support to the decision making and authorization process for any industrial activity implying risk for the environment and the public health. It is opinion of the authors that the probabilistic techniques have been developed to a great level of sophistication in the nuclear industry and provided much more experience in this field than in others. For some particular areas of the nuclear applications, such as the plant reliability and the plant response to the accidents, these techniques have reached a sufficient level of maturity and so some results have been usefully taken as a measure of the safety level of the plant itself. The use of some limited safety goals is regarded as a relevant item of the nuclear licensing process. The paper claims that it is time now that these methods would be applied with equal success to other hazardous facilities, and makes some comparative consideration on the differences of these plants with nuclear power plants in order to understand the effect of these differences on the PRA results and on the use one intends to make with them. (author)

Engineering aspects of probabilistic risk assessment

International Nuclear Information System (INIS)

vonHerrmann, J.L.; Wood, P.J.

1984-01-01

Over the last decade, the use of probabilistic risk assessment (PRA) in the nuclear industry has expanded significantly. In these analyses the probabilities of experiencing certain undesired events (for example, a plant accident which results in damage to the nuclear fuel) are estimated and the consequences of these events are evaluated in terms of some common measure. These probabilities and consequences are then combined to form a representation of the risk associated with the plant studied. In the relatively short history of probabilistic risk assessment of nuclear power plants, the primary motivation for these studies has been the quantitative assessment of public risk associated with a single plant or group of plants. Accordingly, the primary product of most PRAs performed to date has been a 'risk curve' in which the probability (or expected frequency) of exceeding a certain consequence level is plotted against that consequence. The most common goal of these assessments has been to demonstrate the 'acceptability' of the calculated risk by comparison of the resultant risk curve to risk curves associated with other plants or with other societal risks. Presented here are brief descriptions of some alternate applications of PRAs, a discussion of how these other applications compare or contrast with the currently popular uses of PRA, and a discussion of the relative benefits of each

Cyber security risk evaluation of a nuclear I and C using BN and ET

Energy Technology Data Exchange (ETDEWEB)

Shin, Jin Soo; Heo, Gyun Young [Dept. of Nuclear Engineering, Kyung Hee University, Yongin (Korea, Republic of); Son, Han Seong [Computer and Game Science, Joongbu University, Geumsan (Korea, Republic of)

2017-04-15

Cyber security is an important issue in the field of nuclear engineering because nuclear facilities use digital equipment and digital systems that can lead to serious hazards in the event of an accident. Regulatory agencies worldwide have announced guidelines for cyber security related to nuclear issues, including U.S. NRC Regulatory Guide 5.71. It is important to evaluate cyber security risk in accordance with these regulatory guides. In this study, we propose a cyber security risk evaluation model for nuclear instrumentation and control systems using a Bayesian network and event trees. As it is difficult to perform penetration tests on the systems, the evaluation model can inform research on cyber threats to cyber security systems for nuclear facilities through the use of prior and posterior information and backpropagation calculations. Furthermore, we suggest a methodology for the application of analytical results from the Bayesian network model to an event tree model, which is a probabilistic safety assessment method. The proposed method will provide insight into safety and cyber security risks.

Cyber security risk evaluation of a nuclear I and C using BN and ET

International Nuclear Information System (INIS)

Shin, Jin Soo; Heo, Gyun Young; Son, Han Seong

2017-01-01

Cyber security is an important issue in the field of nuclear engineering because nuclear facilities use digital equipment and digital systems that can lead to serious hazards in the event of an accident. Regulatory agencies worldwide have announced guidelines for cyber security related to nuclear issues, including U.S. NRC Regulatory Guide 5.71. It is important to evaluate cyber security risk in accordance with these regulatory guides. In this study, we propose a cyber security risk evaluation model for nuclear instrumentation and control systems using a Bayesian network and event trees. As it is difficult to perform penetration tests on the systems, the evaluation model can inform research on cyber threats to cyber security systems for nuclear facilities through the use of prior and posterior information and backpropagation calculations. Furthermore, we suggest a methodology for the application of analytical results from the Bayesian network model to an event tree model, which is a probabilistic safety assessment method. The proposed method will provide insight into safety and cyber security risks

Probabilistic risk assessment, Volume I

International Nuclear Information System (INIS)

Anon.

1982-01-01

This book contains 158 papers presented at the International Topical Meeting on Probabilistic Risk Assessment held by the American Nuclear Society (ANS) and the European Nuclear Society (ENS) in Port Chester, New York in 1981. The meeting was second in a series of three. The main focus of the meeting was on the safety of light water reactors. The papers discuss safety goals and risk assessment. Quantitative safety goals, risk assessment in non-nuclear technologies, and operational experience and data base are also covered. Included is an address by Dr. Chauncey Starr

Exploration Health Risks: Probabilistic Risk Assessment

Science.gov (United States)

Rhatigan, Jennifer; Charles, John; Hayes, Judith; Wren, Kiley

2006-01-01

Maintenance of human health on long-duration exploration missions is a primary challenge to mission designers. Indeed, human health risks are currently the largest risk contributors to the risks of evacuation or loss of the crew on long-duration International Space Station missions. We describe a quantitative assessment of the relative probabilities of occurrence of the individual risks to human safety and efficiency during space flight to augment qualitative assessments used in this field to date. Quantitative probabilistic risk assessments will allow program managers to focus resources on those human health risks most likely to occur with undesirable consequences. Truly quantitative assessments are common, even expected, in the engineering and actuarial spheres, but that capability is just emerging in some arenas of life sciences research, such as identifying and minimize the hazards to astronauts during future space exploration missions. Our expectation is that these results can be used to inform NASA mission design trade studies in the near future with the objective of preventing the higher among the human health risks. We identify and discuss statistical techniques to provide this risk quantification based on relevant sets of astronaut biomedical data from short and long duration space flights as well as relevant analog populations. We outline critical assumptions made in the calculations and discuss the rationale for these. Our efforts to date have focussed on quantifying the probabilities of medical risks that are qualitatively perceived as relatively high risks of radiation sickness, cardiac dysrhythmias, medically significant renal stone formation due to increased calcium mobilization, decompression sickness as a result of EVA (extravehicular activity), and bone fracture due to loss of bone mineral density. We present these quantitative probabilities in order-of-magnitude comparison format so that relative risk can be gauged. We address the effects of

On the security of a novel probabilistic signature based on bilinear square Diffie-Hellman problem and its extension.

Science.gov (United States)

Zhao, Zhenguo; Shi, Wenbo

2014-01-01

Probabilistic signature scheme has been widely used in modern electronic commerce since it could provide integrity, authenticity, and nonrepudiation. Recently, Wu and Lin proposed a novel probabilistic signature (PS) scheme using the bilinear square Diffie-Hellman (BSDH) problem. They also extended it to a universal designated verifier signature (UDVS) scheme. In this paper, we analyze the security of Wu et al.'s PS scheme and UDVS scheme. Through concrete attacks, we demonstrate both of their schemes are not unforgeable. The security analysis shows that their schemes are not suitable for practical applications.

Probabilistic risk assessment (PRA) reference document. Final report

International Nuclear Information System (INIS)

Murphy, J.A.

1984-09-01

This document describes the current status of probabilistic risk assessment (PRA) as practiced in the nuclear reactor regulatory process. The PRA studies that have been completed or are under way are reviewed. The levels of maturity of the methodologies used in a PRA are discussed. Insights derived from PRAs are listed. The potential uses of PRA results for regulatory purposes are discussed. This document was issued for comment in February 1984 entitled Probabilistic Risk Assessment (PRA): Status Report and Guidance for Regulatory Application. The comments received on the draft have been considered for this final version of the report

Review of the Diablo Canyon probabilistic risk assessment

International Nuclear Information System (INIS)

Bozoki, G.E.; Fitzpatrick, R.G.; Bohn, M.P.; Sabek, M.G.; Ravindra, M.K.; Johnson, J.J.

1994-08-01

This report details the review of the Diablo Canyon Probabilistic Risk Assessment (DCPRA). The study was performed under contract from the Probabilistic Risk Analysis Branch, Office of Nuclear Reactor Research, USNRC by Brookhaven National Laboratory. The DCPRA is a full scope Level I effort and although the review touched on all aspects of the PRA, the internal events and seismic events received the vast majority of the review effort. The report includes a number of independent systems analyses sensitivity studies, importance analyses as well as conclusions on the adequacy of the DCPRA for use in the Diablo Canyon Long Term Seismic Program

Developing Probabilistic Safety Performance Margins for Unknown and Underappreciated Risks

Science.gov (United States)

Benjamin, Allan; Dezfuli, Homayoon; Everett, Chris

2015-01-01

Probabilistic safety requirements currently formulated or proposed for space systems, nuclear reactor systems, nuclear weapon systems, and other types of systems that have a low-probability potential for high-consequence accidents depend on showing that the probability of such accidents is below a specified safety threshold or goal. Verification of compliance depends heavily upon synthetic modeling techniques such as PRA. To determine whether or not a system meets its probabilistic requirements, it is necessary to consider whether there are significant risks that are not fully considered in the PRA either because they are not known at the time or because their importance is not fully understood. The ultimate objective is to establish a reasonable margin to account for the difference between known risks and actual risks in attempting to validate compliance with a probabilistic safety threshold or goal. In this paper, we examine data accumulated over the past 60 years from the space program, from nuclear reactor experience, from aircraft systems, and from human reliability experience to formulate guidelines for estimating probabilistic margins to account for risks that are initially unknown or underappreciated. The formulation includes a review of the safety literature to identify the principal causes of such risks.

Risk analysis of analytical validations by probabilistic modification of FMEA.

Science.gov (United States)

Barends, D M; Oldenhof, M T; Vredenbregt, M J; Nauta, M J

2012-05-01

Risk analysis is a valuable addition to validation of an analytical chemistry process, enabling not only detecting technical risks, but also risks related to human failures. Failure Mode and Effect Analysis (FMEA) can be applied, using a categorical risk scoring of the occurrence, detection and severity of failure modes, and calculating the Risk Priority Number (RPN) to select failure modes for correction. We propose a probabilistic modification of FMEA, replacing the categorical scoring of occurrence and detection by their estimated relative frequency and maintaining the categorical scoring of severity. In an example, the results of traditional FMEA of a Near Infrared (NIR) analytical procedure used for the screening of suspected counterfeited tablets are re-interpretated by this probabilistic modification of FMEA. Using this probabilistic modification of FMEA, the frequency of occurrence of undetected failure mode(s) can be estimated quantitatively, for each individual failure mode, for a set of failure modes, and the full analytical procedure. Copyright © 2012 Elsevier B.V. All rights reserved.

Probabilistic risk assessment: Number 219

International Nuclear Information System (INIS)

Bari, R.A.

1985-01-01

This report describes a methodology for analyzing the safety of nuclear power plants. A historical overview of plants in the US is provided, and past, present, and future nuclear safety and risk assessment are discussed. A primer on nuclear power plants is provided with a discussion of pressurized water reactors (PWR) and boiling water reactors (BWR) and their operation and containment. Probabilistic Risk Assessment (PRA), utilizing both event-tree and fault-tree analysis, is discussed as a tool in reactor safety, decision making, and communications. (FI)

Probabilistic risk analysis in chemical engineering

International Nuclear Information System (INIS)

Schmalz, F.

1991-01-01

In risk analysis in the chemical industry, recognising potential risks is considered more important than assessing their quantitative extent. Even in assessing risks, emphasis is not on the probability involved but on the possible extent. Qualitative assessment has proved valuable here. Probabilistic methods are used in individual cases where the wide implications make it essential to be able to assess the reliability of safety precautions. In this case, assessment therefore centres on the reliability of technical systems and not on the extent of a chemical risk. 7 figs

Whither probabilistic security management for real-time operation of power systems ?

OpenAIRE

Karangelos, Efthymios; Panciatici, Patrick; Wehenkel, Louis

2016-01-01

This paper investigates the stakes of introducing probabilistic approaches for the management of power system’s security. In real-time operation, the aim is to arbitrate in a rational way between preventive and corrective control, while taking into account i) the prior probabilities of contingencies, ii) the possible failure modes of corrective control actions, iii) the socio-economic consequences of service interruptions. This work is a first step towards the construction of a globally co...

Use of limited data to construct Bayesian networks for probabilistic risk assessment.

Energy Technology Data Exchange (ETDEWEB)

Groth, Katrina M.; Swiler, Laura Painton

2013-03-01

Probabilistic Risk Assessment (PRA) is a fundamental part of safety/quality assurance for nuclear power and nuclear weapons. Traditional PRA very effectively models complex hardware system risks using binary probabilistic models. However, traditional PRA models are not flexible enough to accommodate non-binary soft-causal factors, such as digital instrumentation&control, passive components, aging, common cause failure, and human errors. Bayesian Networks offer the opportunity to incorporate these risks into the PRA framework. This report describes the results of an early career LDRD project titled %E2%80%9CUse of Limited Data to Construct Bayesian Networks for Probabilistic Risk Assessment%E2%80%9D. The goal of the work was to establish the capability to develop Bayesian Networks from sparse data, and to demonstrate this capability by producing a data-informed Bayesian Network for use in Human Reliability Analysis (HRA) as part of nuclear power plant Probabilistic Risk Assessment (PRA). This report summarizes the research goal and major products of the research.

Risk management on nuclear power plant. Application of probabilistic risk assessment

International Nuclear Information System (INIS)

Kojima, Shigeo

2003-01-01

In U.S.A., nuclear safety regulation is moving to risk-informed regulation (RIR), so necessity of a standard to provide contents of probabilistic risk assessment (PRA) constructing its roots has been discussed for a long time. In 1998, the Committee on Nuclear Risk Management (CNRM) of the American Society of Mechanical Engineers (ASME) began to investigate the standard, of which last edition was published as the Standard for Probabilistic Risk Management for Nuclear Power Plant Applications: RA-S-2002 (PRMA) on April, 2002. As in the Committee, the Nuclear Regulatory Commission (NRC), electric power companies, national institutes, PRA specialists, and so on took parts to carry out many discussions with full energies of participants on risk management in U.S.A., the standard was finished after about four years' efforts. In U.S.A., risk management having already used PRA is successfully practiced, U.S.A. is at a stage with more advancing steps of the risk management than Japan is. Here was described on the standard of PRA and a concrete method of the risk management carried out at nuclear power stations. (G.K.)

Limited probabilistic risk assessment applications in plant backfitting

International Nuclear Information System (INIS)

Desaedeleer, G.

1987-01-01

Plant backfitting programs are defined on the basis of deterministic (e.g. Systematic Evaluation Program) or probabilistic (e.g. Probabilistic Risk Assessment) approaches. Each approach provides valuable assets in defining the program and has its own advantages and disadvantages. Ideally one should combine the strong points of each approach. This chapter summarizes actual experience gained from combinations of deterministic and probabilistic approaches to define and implement PWR backfitting programs. Such combinations relate to limited applications of probabilistic techniques and are illustrated for upgrading fluid systems. These evaluations allow sound and rational optimization systems upgrade. However, the boundaries of the reliability analysis need to be clearly defined and system reliability may have to go beyond classical boundaries (e.g. identification of weak links in support systems). Also the implementation of upgrade on a system per system basis is not necessarily cost-effective. (author)

Exploring the uncertainties in cancer risk assessment using the integrated probabilistic risk assessment (IPRA) approach.

Science.gov (United States)

Slob, Wout; Bakker, Martine I; Biesebeek, Jan Dirk Te; Bokkers, Bas G H

2014-08-01

Current methods for cancer risk assessment result in single values, without any quantitative information on the uncertainties in these values. Therefore, single risk values could easily be overinterpreted. In this study, we discuss a full probabilistic cancer risk assessment approach in which all the generally recognized uncertainties in both exposure and hazard assessment are quantitatively characterized and probabilistically evaluated, resulting in a confidence interval for the final risk estimate. The methodology is applied to three example chemicals (aflatoxin, N-nitrosodimethylamine, and methyleugenol). These examples illustrate that the uncertainty in a cancer risk estimate may be huge, making single value estimates of cancer risk meaningless. Further, a risk based on linear extrapolation tends to be lower than the upper 95% confidence limit of a probabilistic risk estimate, and in that sense it is not conservative. Our conceptual analysis showed that there are two possible basic approaches for cancer risk assessment, depending on the interpretation of the dose-incidence data measured in animals. However, it remains unclear which of the two interpretations is the more adequate one, adding an additional uncertainty to the already huge confidence intervals for cancer risk estimates. © 2014 Society for Risk Analysis.

Optimization (Alara) and probabilistic exposures: the application of optimization criteria to the control of risks due to exposures of a probabilistic nature

International Nuclear Information System (INIS)

Gonzalez, A.J.

1989-01-01

The paper described the application of the principles of optimization recommended by the International Commission on Radiological Protection (ICRP) to the restrain of radiation risks due to exposures that may or may not be incurred and to which a probability of occurrence can be assigned. After describing the concept of probabilistic exposures, it proposes a basis for a converging policy of control for both certain and probabilistic exposures, namely the dose-risk relationship adopted for radiation protection purposes. On that basis some coherent approaches for dealing with probabilistic exposures, such as the limitation of individual risks, are discussed. The optimization of safety for reducing all risks from probabilistic exposures to as-low-as-reasonably-achievable (ALARA) levels is reviewed in full. The principles of optimization of protection are used as a basic framework and the relevant factors to be taken into account when moving to probabilistic exposures are presented. The paper also reviews the decision-aiding techniques suitable for performing optimization with particular emphasis to the multi-attribute utility-analysis technique. Finally, there is a discussion on some practical application of decision-aiding multi-attribute utility analysis to probabilistic exposures including the use of probabilistic utilities. In its final outlook, the paper emphasizes the need for standardization and solutions to generic problems, if optimization of safety is to be successful

Bayesian probabilistic network approach for managing earthquake risks of cities

DEFF Research Database (Denmark)

Bayraktarli, Yahya; Faber, Michael

2011-01-01

This paper considers the application of Bayesian probabilistic networks (BPNs) to large-scale risk based decision making in regard to earthquake risks. A recently developed risk management framework is outlined which utilises Bayesian probabilistic modelling, generic indicator based risk models...... and a fourth module on the consequences of an earthquake. Each of these modules is integrated into a BPN. Special attention is given to aggregated risk, i.e. the risk contribution from assets at multiple locations in a city subjected to the same earthquake. The application of the methodology is illustrated...... on an example considering a portfolio of reinforced concrete structures in a city located close to the western part of the North Anatolian Fault in Turkey....

A tiered approach for probabilistic ecological risk assessment of contaminated sites

International Nuclear Information System (INIS)

Zolezzi, M.; Nicolella, C.; Tarazona, J.V.

2005-01-01

This paper presents a tiered methodology for probabilistic ecological risk assessment. The proposed approach starts from deterministic comparison (ratio) of single exposure concentration and threshold or safe level calculated from a dose-response relationship, goes through comparison of probabilistic distributions that describe exposure values and toxicological responses of organisms to the chemical of concern, and finally determines the so called distribution-based quotients (DBQs). In order to illustrate the proposed approach, soil concentrations of 1,2,4-trichlorobenzene (1,2,4- TCB) measured in an industrial contaminated site were used for site-specific probabilistic ecological risks assessment. By using probabilistic distributions, the risk, which exceeds a level of concern for soil organisms with the deterministic approach, is associated to the presence of hot spots reaching concentrations able to affect acutely more than 50% of the soil species, while the large majority of the area presents 1,2,4- TCB concentrations below those reported as toxic [it

A methodology for reviewing Probabilistic Risk Assessments

International Nuclear Information System (INIS)

Derby, S.L.

1983-01-01

The starting point for peer review of a Probabilistic Risk Assessment (PRA) is a clear understanding of how the risk estimate was prepared and of what contributions dominate the calculation. The problem facing the reviewers is how to cut through the complex details of a PRA to gain this understanding. This paper presents a structured, analytical procedure that solves this problem. The effectiveness of this solution is demonstrated by an application on the Zion Probabilistic Safety Study. The procedure found the three dominant initiating events and provided a simplified reconstruction of the calculation of the risk estimate. Significant assessments of uncertainty were also identified. If peer review disputes the accuracy of these judgments, then the revised risk estimate could significantly increase. The value of this procedure comes from having a systematic framework for the PRA review. Practical constraints limit the time and qualified people needed for an adequate review. Having the established framework from this procedure as a starting point, reviewers can focus most of their attention on the accuracy and the completeness of the calculation. Time wasted at the start of the review is reduced by first using this procedure to sort through the technical details of the PRA and to reconstruct the risk estimate from dominant contributions

Application of probabilistic risk assessment to advanced liquid metal reactor designs

International Nuclear Information System (INIS)

Carroll, W.P.; Temme, M.I.

1987-01-01

The United States Department of Energy (US DOE) has been active in the development and application of probabilistic risk assessment methods within its liquid metal breeder reactor development program for the past eleven years. These methods have been applied to comparative risk evaluations, the selection of design features for reactor concepts, the selection and emphasis of research and development programs, and regulatory discussions. The application of probabilistic methods to reactors which are in the conceptual design stage presents unique data base, modeling, and timing challenges, and excellent opportunities to improve the final design. We provide here the background and insights on the experience which the US DOE liquid metal breeder reactor program has had in its application of probabilistic methods to the Clinch River Breeder Reactor Plant project, the Conceptual Design State of the Large Development Plant, and updates on this design. Plans for future applications of probabilistic risk assessment methods are also discussed. The US DOE is embarking on an innovative design program for liquid metal reactors. (author)

Current status and future expectation concerning probabilistic risk assessment of NPPs. 1. Features and issues of probabilistic risk assessment methodology

International Nuclear Information System (INIS)

Yamashita, Masahiro

2012-01-01

Probabilistic risk assessment (PRA) of Nuclear Power Plants (NPPs) could play an important role in assuring safety of NPPs. However PRA had not always effectively used, which was indicated in Japanese government's report on Fukushima Daiichi NPP accident. At the Risk Technical Committee (RTC) of Standards Committee of Atomic Energy Society of Japan, preparation of standards (implementing criteria) focusing on PRA methodology and investigation on basic philosophy for use of PRA had been in progress. Based on activities of RTC, a serial in three articles including this described current status and future expectation concerning probabilistic risk assessment of NPPs. This article introduced features and issues of PRA methodology related to the use of PRA. Features of PRA methodology could be shown as (1) systematic and comprehensive understanding of risk, (2) support of grading approach, (3) identification of effective safety upgrade measures and (4) quantitative understanding of effects of uncertainty. Issues of PRA methodology were (1) extension of PRA application area, (2) upgrade of PRA methodology, (3) quality assurance of PRA, (4) treatment of uncertainty and (5) quantitative evaluation criteria. (T. Tanaka)

Bayesian Inference for NASA Probabilistic Risk and Reliability Analysis

Science.gov (United States)

Dezfuli, Homayoon; Kelly, Dana; Smith, Curtis; Vedros, Kurt; Galyean, William

2009-01-01

This document, Bayesian Inference for NASA Probabilistic Risk and Reliability Analysis, is intended to provide guidelines for the collection and evaluation of risk and reliability-related data. It is aimed at scientists and engineers familiar with risk and reliability methods and provides a hands-on approach to the investigation and application of a variety of risk and reliability data assessment methods, tools, and techniques. This document provides both: A broad perspective on data analysis collection and evaluation issues. A narrow focus on the methods to implement a comprehensive information repository. The topics addressed herein cover the fundamentals of how data and information are to be used in risk and reliability analysis models and their potential role in decision making. Understanding these topics is essential to attaining a risk informed decision making environment that is being sought by NASA requirements and procedures such as 8000.4 (Agency Risk Management Procedural Requirements), NPR 8705.05 (Probabilistic Risk Assessment Procedures for NASA Programs and Projects), and the System Safety requirements of NPR 8715.3 (NASA General Safety Program Requirements).

Integrated probabilistic risk assessment for nanoparticles: the case of nanosilica in food.

Science.gov (United States)

Jacobs, Rianne; van der Voet, Hilko; Ter Braak, Cajo J F

Insight into risks of nanotechnology and the use of nanoparticles is an essential condition for the social acceptance and safe use of nanotechnology. One of the problems with which the risk assessment of nanoparticles is faced is the lack of data, resulting in uncertainty in the risk assessment. We attempt to quantify some of this uncertainty by expanding a previous deterministic study on nanosilica (5-200 nm) in food into a fully integrated probabilistic risk assessment. We use the integrated probabilistic risk assessment method in which statistical distributions and bootstrap methods are used to quantify uncertainty and variability in the risk assessment. Due to the large amount of uncertainty present, this probabilistic method, which separates variability from uncertainty, contributed to a better understandable risk assessment. We found that quantifying the uncertainties did not increase the perceived risk relative to the outcome of the deterministic study. We pinpointed particular aspects of the hazard characterization that contributed most to the total uncertainty in the risk assessment, suggesting that further research would benefit most from obtaining more reliable data on those aspects.

Integrated probabilistic risk assessment for nanoparticles: the case of nanosilica in food

International Nuclear Information System (INIS)

Jacobs, Rianne; Voet, Hilko van der; Braak, Cajo J. F. ter

2015-01-01

Insight into risks of nanotechnology and the use of nanoparticles is an essential condition for the social acceptance and safe use of nanotechnology. One of the problems with which the risk assessment of nanoparticles is faced is the lack of data, resulting in uncertainty in the risk assessment. We attempt to quantify some of this uncertainty by expanding a previous deterministic study on nanosilica (5–200 nm) in food into a fully integrated probabilistic risk assessment. We use the integrated probabilistic risk assessment method in which statistical distributions and bootstrap methods are used to quantify uncertainty and variability in the risk assessment. Due to the large amount of uncertainty present, this probabilistic method, which separates variability from uncertainty, contributed to a better understandable risk assessment. We found that quantifying the uncertainties did not increase the perceived risk relative to the outcome of the deterministic study. We pinpointed particular aspects of the hazard characterization that contributed most to the total uncertainty in the risk assessment, suggesting that further research would benefit most from obtaining more reliable data on those aspects

Integrated probabilistic risk assessment for nanoparticles: the case of nanosilica in food

Energy Technology Data Exchange (ETDEWEB)

Jacobs, Rianne, E-mail: rianne.jacobs@wur.nl; Voet, Hilko van der; Braak, Cajo J. F. ter [Wageningen University and Research Centre, Biometris (Netherlands)

2015-06-15

Insight into risks of nanotechnology and the use of nanoparticles is an essential condition for the social acceptance and safe use of nanotechnology. One of the problems with which the risk assessment of nanoparticles is faced is the lack of data, resulting in uncertainty in the risk assessment. We attempt to quantify some of this uncertainty by expanding a previous deterministic study on nanosilica (5–200 nm) in food into a fully integrated probabilistic risk assessment. We use the integrated probabilistic risk assessment method in which statistical distributions and bootstrap methods are used to quantify uncertainty and variability in the risk assessment. Due to the large amount of uncertainty present, this probabilistic method, which separates variability from uncertainty, contributed to a better understandable risk assessment. We found that quantifying the uncertainties did not increase the perceived risk relative to the outcome of the deterministic study. We pinpointed particular aspects of the hazard characterization that contributed most to the total uncertainty in the risk assessment, suggesting that further research would benefit most from obtaining more reliable data on those aspects.

Probabilistic risk assessment of HTGRs

International Nuclear Information System (INIS)

Fleming, K.N.; Houghton, W.J.; Hannaman, G.W.; Joksimovic, V.

1980-08-01

Probabilistic Risk Assessment methods have been applied to gas-cooled reactors for more than a decade and to HTGRs for more than six years in the programs sponsored by the US Department of Energy. Significant advancements to the development of PRA methodology in these programs are summarized as are the specific applications of the methods to HTGRs. Emphasis here is on PRA as a tool for evaluating HTGR design options. Current work and future directions are also discussed

Risk assessment using probabilistic standards

International Nuclear Information System (INIS)

Avila, R.

2004-01-01

A core element of risk is uncertainty represented by plural outcomes and their likelihood. No risk exists if the future outcome is uniquely known and hence guaranteed. The probability that we will die some day is equal to 1, so there would be no fatal risk if sufficiently long time frame is assumed. Equally, rain risk does not exist if there was 100% assurance of rain tomorrow, although there would be other risks induced by the rain. In a formal sense, any risk exists if, and only if, more than one outcome is expected at a future time interval. In any practical risk assessment we have to deal with uncertainties associated with the possible outcomes. One way of dealing with the uncertainties is to be conservative in the assessments. For example, we may compare the maximal exposure to a radionuclide with a conservatively chosen reference value. In this case, if the exposure is below the reference value then it is possible to assure that the risk is low. Since single values are usually compared; this approach is commonly called 'deterministic'. Its main advantage lies in the simplicity and in that it requires minimum information. However, problems arise when the reference values are actually exceeded or might be exceeded, as in the case of potential exposures, and when the costs for realizing the reference values are high. In those cases, the lack of knowledge on the degree of conservatism involved impairs a rational weighing of the risks against other interests. In this presentation we will outline an approach for dealing with uncertainties that in our opinion is more consistent. We will call it a 'fully probabilistic risk assessment'. The essence of this approach consists in measuring the risk in terms of probabilities, where the later are obtained from comparison of two probabilistic distributions, one reflecting the uncertainties in the outcomes and one reflecting the uncertainties in the reference value (standard) used for defining adverse outcomes. Our first aim

Probabilistic risk assessment of HTGRs

International Nuclear Information System (INIS)

Fleming, K.N.; Houghton, W.J.; Hannaman, G.W.; Joksimovic, V.

1981-01-01

Probabilistic Risk Assessment methods have been applied to gas-cooled reactors for more than a decade and to HTGRs for more than six years in the programs sponsored by the U.S. Department of Energy. Significant advancements to the development of PRA methodology in these programs are summarized as are the specific applications of the methods to HTGRs. Emphasis here is on PRA as a tool for evaluating HTGR design options. Current work and future directions are also discussed. (author)

Probabilistic Logical Characterization

DEFF Research Database (Denmark)

Hermanns, Holger; Parma, Augusto; Segala, Roberto

2011-01-01

Probabilistic automata exhibit both probabilistic and non-deterministic choice. They are therefore a powerful semantic foundation for modeling concurrent systems with random phenomena arising in many applications ranging from artificial intelligence, security, systems biology to performance...... modeling. Several variations of bisimulation and simulation relations have proved to be useful as means to abstract and compare different automata. This paper develops a taxonomy of logical characterizations of these relations on image-finite and image-infinite probabilistic automata....

Probabilistic risk assessment of earthquakes at the Rocky Flats Plant and subsequent upgrade to reduce risk

International Nuclear Information System (INIS)

Day, S.A.

1989-01-01

An analysis to determine the risk associated with earthquakes at the Rocky Flats Plant was performed. Seismic analyses and structural evaluations were used to postulate building and equipment damage and radiological releases to the environment from various magnitudes of earthquakes. Dispersion modeling and dose assessment to the public were then calculated. The frequency of occurrence of various magnitudes of earthquakes were determined from the Department of Energy natural Phenomena Hazards Modeling Project. Risk to the public was probabilistically assessed for each magnitude of earthquake and for overall seismic risk. Based on the results of this Probabilistic Risk Assessment and a cost/benefit analysis, seismic upgrades are being implemented for several plutonium-handling facilities for the purpose of risk reduction

Probabilistic inhalation risk assessment due to radioactivity released from coal fired thermal power plants

International Nuclear Information System (INIS)

Tiwari, M.; Ajmal, P.Y.; Bhangare, R.C.; Sahu, S.K.; Pandit, G.G.

2014-01-01

This paper deals with assessment of radiological risk to the general public around in the neighborhood of a 1000 MWe coal-based thermal power plant. We have used Monte Carlo simulation for characterization of uncertainty in inhalation risk due to radionuclide escaping from the stack of thermal power plant. Monte Carlo simulation treats parameters as random variables bound to a given probabilistic distribution to evaluate the distribution of the resulting output. Risk assessment is the process that estimates the likelihood of occurrence of adverse effects to humans and ecological receptors as a result of exposure to hazardous chemical, radiation, and/or biological agents. Quantitative risk characterization involves evaluating exposure estimates against a benchmark of toxicity, such as a cancer slope factor. Risk is calculated by multiplying the carcinogenic slope factor (SF) of the radionuclide by the dose an individual receives. The collective effective doses to the population living in the neighborhood of coal-based thermal power plant were calculated using Gaussian plume dispersion model. Monte Carlo Analysis is the most widely used probabilistic method in risk assessment. The MCA technique treats any uncertain parameter as random variable that obeys a given probabilistic distribution. This technique is widely used for analyzing probabilistic uncertainty. In MCA computer simulation are used to combine multiple probability distributions associated with the dose and SF depicted in risk equation. Thus we get a probabilistic distribution for the risk

Relative risk of probabilistic category learning deficits in patients with schizophrenia and their siblings

Science.gov (United States)

Weickert, Thomas W.; Goldberg, Terry E.; Egan, Michael F.; Apud, Jose A.; Meeter, Martijn; Myers, Catherine E.; Gluck, Mark A; Weinberger, Daniel R.

2010-01-01

Background While patients with schizophrenia display an overall probabilistic category learning performance deficit, the extent to which this deficit occurs in unaffected siblings of patients with schizophrenia is unknown. There are also discrepant findings regarding probabilistic category learning acquisition rate and performance in patients with schizophrenia. Methods A probabilistic category learning test was administered to 108 patients with schizophrenia, 82 unaffected siblings, and 121 healthy participants. Results Patients with schizophrenia displayed significant differences from their unaffected siblings and healthy participants with respect to probabilistic category learning acquisition rates. Although siblings on the whole failed to differ from healthy participants on strategy and quantitative indices of overall performance and learning acquisition, application of a revised learning criterion enabling classification into good and poor learners based on individual learning curves revealed significant differences between percentages of sibling and healthy poor learners: healthy (13.2%), siblings (34.1%), patients (48.1%), yielding a moderate relative risk. Conclusions These results clarify previous discrepant findings pertaining to probabilistic category learning acquisition rate in schizophrenia and provide the first evidence for the relative risk of probabilistic category learning abnormalities in unaffected siblings of patients with schizophrenia, supporting genetic underpinnings of probabilistic category learning deficits in schizophrenia. These findings also raise questions regarding the contribution of antipsychotic medication to the probabilistic category learning deficit in schizophrenia. The distinction between good and poor learning may be used to inform genetic studies designed to detect schizophrenia risk alleles. PMID:20172502

Probabilistic Risk Assessment to Inform Decision Making: Frequently Asked Questions

Science.gov (United States)

General concepts and principles of Probabilistic Risk Assessment (PRA), describe how PRA can improve the bases of Agency decisions, and provide illustrations of how PRA has been used in risk estimation and in describing the uncertainty in decision making.

Probabilistic cumulative risk assessment of anti-androgenic pesticides in food

DEFF Research Database (Denmark)

Müller, Anne Kirstine; Nielsen, Elsa

2008-01-01

A cumulative risk assessment of three anti-androgenic pesticides vinclozolin, procymidone and prochloraz in combination has been carried out using an Integrated Probabilistic Risk Assessment (IPRA) model. In the model, variability in both exposure and sensitivity between individuals were combined...

Probabilistic cumulative risk assessment of anti-androgenic pesticides in food.

NARCIS (Netherlands)

Müller, A.K.; Bosgra, S.; Boon, P.E.; van der Voet, H.; Nielsen, E.; Ladefoged, O.

2009-01-01

In this paper, we present a cumulative risk assessment of three anti-androgenic pesticides (vinclozolin, procymidone and prochloraz) using the relative potency factor (RPF) approach and an integrated probabilistic risk assessment (IPRA) model. RPFs for each substance were estimated for three

Probabilistic cumulative risk assessment of anti-androgenic pesticides in food

NARCIS (Netherlands)

Muller, A.K.; Bosgra, S.; Boon, P.E.; Voet, van der H.; Nielsen, E.; Ladefoged, O.

2009-01-01

In this paper, we present a cumulative risk assessment of three anti-androgenic pesticides (vinclozolin, procymidone and prochloraz) using the relative potency factor (RPF) approach and an integrated probabilistic risk assessment (IPRA) model. RPFs for each substance were estimated for three

Probabilistic risk analysis for nuclear power plants

International Nuclear Information System (INIS)

Hauptmanns, U.

1988-01-01

Risk analysis is applied if the calculation of risk from observed failures is not possible, because events contributing substantially to risk are too seldom, as in the case of nuclear reactors. The process of analysis provides a number of benefits. Some of them are listed. After this by no means complete enumeration of possible benefits to be derived from a risk analysis. An outline of risk studiesd for PWR's with some comments on the models used are given. The presentation is indebted to the detailed treatment of the subject given in the PRA Procedures Guide. Thereafter some results of the German Risk Study, Phase B, which is under way are communicated. The paper concludes with some remarks on probabilistic considerations in licensing procedures. (orig./DG)

Bayesian Hierarchical Structure for Quantifying Population Variability to Inform Probabilistic Health Risk Assessments.

Science.gov (United States)

Shao, Kan; Allen, Bruce C; Wheeler, Matthew W

2017-10-01

Human variability is a very important factor considered in human health risk assessment for protecting sensitive populations from chemical exposure. Traditionally, to account for this variability, an interhuman uncertainty factor is applied to lower the exposure limit. However, using a fixed uncertainty factor rather than probabilistically accounting for human variability can hardly support probabilistic risk assessment advocated by a number of researchers; new methods are needed to probabilistically quantify human population variability. We propose a Bayesian hierarchical model to quantify variability among different populations. This approach jointly characterizes the distribution of risk at background exposure and the sensitivity of response to exposure, which are commonly represented by model parameters. We demonstrate, through both an application to real data and a simulation study, that using the proposed hierarchical structure adequately characterizes variability across different populations. © 2016 Society for Risk Analysis.

Probabilistic risk assessment in the nuclear power industry

International Nuclear Information System (INIS)

Fullwood, R.R.; Hall, R.E.

1988-01-01

This book describes the more important improvements in risk assessment methodology developed over the last decade. The book covers the following areas - a general view of risk pertaining to nuclear power, mathematics necessary to understand the text, a concise overview of the light water reactors and their features for protecting the public, probabilities and consequences calculated to form risk assessment to the plant, and 34 applications of probabilistic risk assessment (PRA) in the power generation industry. There is a glossary of acronyms and unusual words and a list of references. (author)

Security 2020 Reduce Security Risks This Decade

CERN Document Server

Howard, Doug; Schneier, Bruce

2010-01-01

Identify real security risks and skip the hype After years of focusing on IT security, we find that hackers are as active and effective as ever. This book gives application developers, networking and security professionals, those that create standards, and CIOs a straightforward look at the reality of today's IT security and a sobering forecast of what to expect in the next decade. It debunks the media hype and unnecessary concerns while focusing on the knowledge you need to combat and prioritize the actual risks of today and beyond.IT security needs are constantly evolving; this guide examine

Insights gained through probabilistic risk assessments

International Nuclear Information System (INIS)

Hitchler, M.J.; Burns, N.L.; Liparulo, N.J.; Mink, F.J.

1987-01-01

The insights gained through a comparison of seven probabilistic risk assessments (PRA) studies (Italian PUN, Sizewell B, Ringhals 2, Millstone 3, Zion 1 and 2, Oconee 3, and Seabrook) included insights regarding the adequacy of the PRA technology utilized in the studies and the potential areas for improvement and insights regarding the adequacy of plant designs and how PRA has been utilized to enhance the design and operation of nuclear power plants

Application of probabilistic risk based optimization approaches in environmental restoration

International Nuclear Information System (INIS)

Goldammer, W.

1995-01-01

The paper presents a general approach to site-specific risk assessments and optimization procedures. In order to account for uncertainties in the assessment of the current situation and future developments, optimization parameters are treated as probabilistic distributions. The assessments are performed within the framework of a cost-benefit analysis. Radiation hazards and conventional risks are treated within an integrated approach. Special consideration is given to consequences of low probability events such as, earthquakes or major floods. Risks and financial costs are combined to an overall figure of detriment allowing one to distinguish between benefits of available reclamation options. The probabilistic analysis uses a Monte Carlo simulation technique. The paper demonstrates the applicability of this approach in aiding the reclamation planning using an example from the German reclamation program for uranium mining and milling sites

Application of probabilistic risk assessment to reprocessing

International Nuclear Information System (INIS)

Perkins, W.C.

1984-01-01

The Savannah River Laboratory uses probabilistic methods of risk assessment in safety analyses of reprocessing facilities at the Savannah River Plant. This method uses both the probability of an accident and its consequence to calculate the risks from radiological, chemical, and industrial hazards. The three principal steps in such an assesment are identification of accidents, calculation of frequencies, and consequence quantification. The tools used at SRL include several databanks, logic tree methods, and computer-assisted methods for calculating both frequencies and consequences. 5 figures

Use of Probabilistic Risk Assessment in Shuttle Decision Making Process

Science.gov (United States)

Boyer, Roger L.; Hamlin, Teri, L.

2011-01-01

This slide presentation reviews the use of Probabilistic Risk Assessment (PRA) to assist in the decision making for the shuttle design and operation. Probabilistic Risk Assessment (PRA) is a comprehensive, structured, and disciplined approach to identifying and analyzing risk in complex systems and/or processes that seeks answers to three basic questions: (i.e., what can go wrong? what is the likelihood of these occurring? and what are the consequences that could result if these occur?) The purpose of the Shuttle PRA (SPRA) is to provide a useful risk management tool for the Space Shuttle Program (SSP) to identify strengths and possible weaknesses in the Shuttle design and operation. SPRA was initially developed to support upgrade decisions, but has evolved into a tool that supports Flight Readiness Reviews (FRR) and near real-time flight decisions. Examples of the use of PRA for the shuttle are reviewed.

Probabilistic relationships in acceptable risk studies

International Nuclear Information System (INIS)

Benjamin, J.R.

1977-01-01

Acceptable risk studies involve uncertainties in future events; consequences and associated values, the acceptability levels, and the future decision environment. Probabilistic procedures afford the basic analytical tool to study the influence of each of these parameters on the acceptable risk decision, including their interrelationships, and combinations. A series of examples are presented in the paper in increasing complexity to illustrate the principles involved and to quantify the relationships to the acceptable risk decision. The basic objective of such studies is to broaden the scientific basis of acceptable risk decision making. It is shown that rationality and consistency in decision making is facilitated by such studies and that rather simple relationships exist in many situations of interest. The variation in criteria associated with an increase in the state of knowledge or change in the level of acceptability is also discussed. (Auth.)

Probabilistic relationships in acceptable risk studies

International Nuclear Information System (INIS)

Benjamin, J.R.

1977-01-01

Acceptable risk studies involve uncertainties in future events: consequences and associated values, the acceptability levels, and the future decision environment. Probabilistic procedures afford the basic analytical tool to study the influence of each of these parameters on the acceptable risk decision, including their interrelationships, and combinations. A series of examples are presented in the paper in increasing complexity to illustrate the principles involved and to quantify the relationships to the acceptable risk decision. The basic objective of such studies is to broaden the scientific basis of acceptable risk decision making. It is shown that rationality and consistency in decision making is facilitated by such studies and that rather simple relationships exist in many situations of interest. The variation in criteria associated with an increase in the state of knowledge or change in the level of acceptability is also discussed

A Probabilistic Typhoon Risk Model for Vietnam

Science.gov (United States)

Haseemkunju, A.; Smith, D. F.; Brolley, J. M.

2017-12-01

Annually, the coastal Provinces of low-lying Mekong River delta region in the southwest to the Red River Delta region in Northern Vietnam is exposed to severe wind and flood risk from landfalling typhoons. On average, about two to three tropical cyclones with a maximum sustained wind speed of >=34 knots make landfall along the Vietnam coast. Recently, Typhoon Wutip (2013) crossed Central Vietnam as a category 2 typhoon causing significant damage to properties. As tropical cyclone risk is expected to increase with increase in exposure and population growth along the coastal Provinces of Vietnam, insurance/reinsurance, and capital markets need a comprehensive probabilistic model to assess typhoon risk in Vietnam. In 2017, CoreLogic has expanded the geographical coverage of its basin-wide Western North Pacific probabilistic typhoon risk model to estimate the economic and insured losses from landfalling and by-passing tropical cyclones in Vietnam. The updated model is based on 71 years (1945-2015) of typhoon best-track data and 10,000 years of a basin-wide simulated stochastic tracks covering eight countries including Vietnam. The model is capable of estimating damage from wind, storm surge and rainfall flooding using vulnerability models, which relate typhoon hazard to building damageability. The hazard and loss models are validated against past historical typhoons affecting Vietnam. Notable typhoons causing significant damage in Vietnam are Lola (1993), Frankie (1996), Xangsane (2006), and Ketsana (2009). The central and northern coastal provinces of Vietnam are more vulnerable to wind and flood hazard, while typhoon risk in the southern provinces are relatively low.

Overview of the probabilistic risk assessment approach

International Nuclear Information System (INIS)

Reed, J.W.

1985-01-01

The techniques of probabilistic risk assessment (PRA) are applicable to Department of Energy facilities. The background and techniques of PRA are given with special attention to seismic, wind and flooding external events. A specific application to seismic events is provided to demonstrate the method. However, the PRA framework is applicable also to wind and external flooding. 3 references, 8 figures, 1 table

Development of a Quantitative Framework for Regulatory Risk Assessments: Probabilistic Approaches

International Nuclear Information System (INIS)

Wilmot, R.D.

2003-11-01

The Swedish regulators have been active in the field of performance assessment for many years and have developed sophisticated approaches to the development of scenarios and other aspects of assessments. These assessments have generally used dose as the assessment end-point and have been based on deterministic calculations. Recently introduced Swedish regulations have introduced a risk criterion for radioactive waste disposal: the annual risk of harmful effects after closure of a disposal facility should not exceed 10 -6 for a representative individual in the group exposed to the greatest risk. A recent review of the overall structure of risk assessments in safety cases concluded that there are a number of decisions and assumptions in the development of a risk assessment methodology that could potentially affect the calculated results. Regulatory understanding of these issues, potentially supported by independent calculations, is important in preparing for review of a proponent's risk assessment. One approach to evaluating risk in performance assessments is to use the concept of probability to express uncertainties, and to propagate these probabilities through the analysis. This report describes the various approaches available for undertaking such probabilistic analyses, both as a means of accounting for uncertainty in the determination of risk and more generally as a means of sensitivity and uncertainty analysis. The report discusses the overall nature of probabilistic analyses and how they are applied to both the calculation of risk and sensitivity analyses. Several approaches are available, including differential analysis, response surface methods and simulation. Simulation is the approach most commonly used, both in assessments for radioactive waste disposal and in other subject areas, and the report describes the key stages of this approach in detail. Decisions relating to the development of input PDFs, sampling methods (including approaches to the treatment

The characterisation and evaluation of uncertainty in probabilistic risk analysis

International Nuclear Information System (INIS)

Parry, G.W.; Winter, P.W.

1980-10-01

The sources of uncertainty in probabilistic risk analysis are discussed using the event/fault tree methodology as an example. The role of statistics in quantifying these uncertainties is investigated. A class of uncertainties is identified which is, at present, unquantifiable, using either classical or Bayesian statistics. It is argued that Bayesian statistics is the more appropriate vehicle for the probabilistic analysis of rare events and a short review is given with some discussion on the representation of ignorance. (author)

Perception of Risk and Terrorism-Related Behavior Change: Dual Influences of Probabilistic Reasoning and Reality Testing

Science.gov (United States)

Denovan, Andrew; Dagnall, Neil; Drinkwater, Kenneth; Parker, Andrew; Clough, Peter

2017-01-01

The present study assessed the degree to which probabilistic reasoning performance and thinking style influenced perception of risk and self-reported levels of terrorism-related behavior change. A sample of 263 respondents, recruited via convenience sampling, completed a series of measures comprising probabilistic reasoning tasks (perception of randomness, base rate, probability, and conjunction fallacy), the Reality Testing subscale of the Inventory of Personality Organization (IPO-RT), the Domain-Specific Risk-Taking Scale, and a terrorism-related behavior change scale. Structural equation modeling examined three progressive models. Firstly, the Independence Model assumed that probabilistic reasoning, perception of risk and reality testing independently predicted terrorism-related behavior change. Secondly, the Mediation Model supposed that probabilistic reasoning and reality testing correlated, and indirectly predicted terrorism-related behavior change through perception of risk. Lastly, the Dual-Influence Model proposed that probabilistic reasoning indirectly predicted terrorism-related behavior change via perception of risk, independent of reality testing. Results indicated that performance on probabilistic reasoning tasks most strongly predicted perception of risk, and preference for an intuitive thinking style (measured by the IPO-RT) best explained terrorism-related behavior change. The combination of perception of risk with probabilistic reasoning ability in the Dual-Influence Model enhanced the predictive power of the analytical-rational route, with conjunction fallacy having a significant indirect effect on terrorism-related behavior change via perception of risk. The Dual-Influence Model possessed superior fit and reported similar predictive relations between intuitive-experiential and analytical-rational routes and terrorism-related behavior change. The discussion critically examines these findings in relation to dual-processing frameworks. This

Perception of Risk and Terrorism-Related Behavior Change: Dual Influences of Probabilistic Reasoning and Reality Testing.

Science.gov (United States)

Denovan, Andrew; Dagnall, Neil; Drinkwater, Kenneth; Parker, Andrew; Clough, Peter

2017-01-01

The present study assessed the degree to which probabilistic reasoning performance and thinking style influenced perception of risk and self-reported levels of terrorism-related behavior change. A sample of 263 respondents, recruited via convenience sampling, completed a series of measures comprising probabilistic reasoning tasks (perception of randomness, base rate, probability, and conjunction fallacy), the Reality Testing subscale of the Inventory of Personality Organization (IPO-RT), the Domain-Specific Risk-Taking Scale, and a terrorism-related behavior change scale. Structural equation modeling examined three progressive models. Firstly, the Independence Model assumed that probabilistic reasoning, perception of risk and reality testing independently predicted terrorism-related behavior change. Secondly, the Mediation Model supposed that probabilistic reasoning and reality testing correlated, and indirectly predicted terrorism-related behavior change through perception of risk. Lastly, the Dual-Influence Model proposed that probabilistic reasoning indirectly predicted terrorism-related behavior change via perception of risk, independent of reality testing. Results indicated that performance on probabilistic reasoning tasks most strongly predicted perception of risk, and preference for an intuitive thinking style (measured by the IPO-RT) best explained terrorism-related behavior change. The combination of perception of risk with probabilistic reasoning ability in the Dual-Influence Model enhanced the predictive power of the analytical-rational route, with conjunction fallacy having a significant indirect effect on terrorism-related behavior change via perception of risk. The Dual-Influence Model possessed superior fit and reported similar predictive relations between intuitive-experiential and analytical-rational routes and terrorism-related behavior change. The discussion critically examines these findings in relation to dual-processing frameworks. This

Perception of Risk and Terrorism-Related Behavior Change: Dual Influences of Probabilistic Reasoning and Reality Testing

Directory of Open Access Journals (Sweden)

Andrew Denovan

2017-10-01

Full Text Available The present study assessed the degree to which probabilistic reasoning performance and thinking style influenced perception of risk and self-reported levels of terrorism-related behavior change. A sample of 263 respondents, recruited via convenience sampling, completed a series of measures comprising probabilistic reasoning tasks (perception of randomness, base rate, probability, and conjunction fallacy, the Reality Testing subscale of the Inventory of Personality Organization (IPO-RT, the Domain-Specific Risk-Taking Scale, and a terrorism-related behavior change scale. Structural equation modeling examined three progressive models. Firstly, the Independence Model assumed that probabilistic reasoning, perception of risk and reality testing independently predicted terrorism-related behavior change. Secondly, the Mediation Model supposed that probabilistic reasoning and reality testing correlated, and indirectly predicted terrorism-related behavior change through perception of risk. Lastly, the Dual-Influence Model proposed that probabilistic reasoning indirectly predicted terrorism-related behavior change via perception of risk, independent of reality testing. Results indicated that performance on probabilistic reasoning tasks most strongly predicted perception of risk, and preference for an intuitive thinking style (measured by the IPO-RT best explained terrorism-related behavior change. The combination of perception of risk with probabilistic reasoning ability in the Dual-Influence Model enhanced the predictive power of the analytical-rational route, with conjunction fallacy having a significant indirect effect on terrorism-related behavior change via perception of risk. The Dual-Influence Model possessed superior fit and reported similar predictive relations between intuitive-experiential and analytical-rational routes and terrorism-related behavior change. The discussion critically examines these findings in relation to dual

Biomechanical rupture risk assessment of abdominal aortic aneurysms based on a novel probabilistic rupture risk index.

Science.gov (United States)

Polzer, Stanislav; Gasser, T Christian

2015-12-06

A rupture risk assessment is critical to the clinical treatment of abdominal aortic aneurysm (AAA) patients. The biomechanical AAA rupture risk assessment quantitatively integrates many known AAA rupture risk factors but the variability of risk predictions due to model input uncertainties remains a challenging limitation. This study derives a probabilistic rupture risk index (PRRI). Specifically, the uncertainties in AAA wall thickness and wall strength were considered, and wall stress was predicted with a state-of-the-art deterministic biomechanical model. The discriminative power of PRRI was tested in a diameter-matched cohort of ruptured (n = 7) and intact (n = 7) AAAs and compared to alternative risk assessment methods. Computed PRRI at 1.5 mean arterial pressure was significantly (p = 0.041) higher in ruptured AAAs (20.21(s.d. 14.15%)) than in intact AAAs (3.71(s.d. 5.77)%). PRRI showed a high sensitivity and specificity (discriminative power of 0.837) to discriminate between ruptured and intact AAA cases. The underlying statistical representation of stochastic data of wall thickness, wall strength and peak wall stress had only negligible effects on PRRI computations. Uncertainties in AAA wall stress predictions, the wide range of reported wall strength and the stochastic nature of failure motivate a probabilistic rupture risk assessment. Advanced AAA biomechanical modelling paired with a probabilistic rupture index definition as known from engineering risk assessment seems to be superior to a purely deterministic approach. © 2015 The Author(s).

Cutting costs through detailed probabilistic fire risk analysis

Energy Technology Data Exchange (ETDEWEB)

Oliveira, Luiz; Huser, Asmund; Vianna, Savio [Det Norske Veritas PRINCIPIA, Rio de Janeiro, RJ (Brazil)

2004-07-01

A new procedure for calculation of fire risks to offshore installations has been developed. The purposes of the procedure are to calculate the escalation and impairment frequencies to be applied in quantitative risk analyses, to optimize Passive Fire Protection (PFP) arrangement, and to optimize other fire mitigation means. The novelties of the procedure are that it uses state of the art Computational Fluid Dynamics (CFD) models to simulate fires and radiation, as well as the use of a probabilistic approach to decide the dimensioning fire loads. A CFD model of an actual platform was used to investigate the dynamic properties of a large set of jet fires, resulting in detailed knowledge of the important parameters that decide the severity of offshore fires. These results are applied to design the procedure. Potential increase in safety is further obtained for those conditions where simplified tools may have failed to predict abnormal heat loads due to geometrical effects. Using a field example it is indicated that the probabilistic approach can give significant reductions in PFP coverage with corresponding cost savings, still keeping the risk at acceptable level. (author)

Probabilistic Seismic Risk Assessment in Manizales, Colombia:Quantifying Losses for Insurance Purposes

Institute of Scientific and Technical Information of China (English)

Mario A.Salgado-Gálvez; Gabriel A.Bernal; Daniela Zuloaga; Mabel C.Marulanda; Omar-Darío Cardona; Sebastián Henao

2017-01-01

A fully probabilistic seismic risk assessment was developed in Manizales,Colombia,considering assets of different types.The first type includes elements that are part of the water and sewage network,and the second type includes public and private buildings.This assessment required the development of a probabilistic seismic hazard analysis that accounts for the dynamic soil response,assembling high resolution exposure databases,and the development of damage models for different types of elements.The economic appraisal of the exposed assets was developed together with specialists of the water utilities company of Manizales and the city administration.The risk assessment was performed using several Comprehensive Approach to Probabilistic Risk Assessment modules as well as the R-System,obtaining results in terms of traditional metrics such as loss exceedance curve,average annual loss,and probable maximum loss.For the case of pipelines,repair rates were also estimated.The results for the water and sewage network were used in activities related to the expansion and maintenance strategies,as well as for the exploration of financial retention and transfer alternatives using insurance schemes based on technical,probabilistic,and prospective damage and loss estimations.In the case of the buildings,the results were used in the update of the technical premium values of the existing collective insurance scheme.

Information risk and security modeling

Science.gov (United States)

Zivic, Predrag

2005-03-01

This research paper presentation will feature current frameworks to addressing risk and security modeling and metrics. The paper will analyze technical level risk and security metrics of Common Criteria/ISO15408, Centre for Internet Security guidelines, NSA configuration guidelines and metrics used at this level. Information IT operational standards view on security metrics such as GMITS/ISO13335, ITIL/ITMS and architectural guidelines such as ISO7498-2 will be explained. Business process level standards such as ISO17799, COSO and CobiT will be presented with their control approach to security metrics. Top level, the maturity standards such as SSE-CMM/ISO21827, NSA Infosec Assessment and CobiT will be explored and reviewed. For each defined level of security metrics the research presentation will explore the appropriate usage of these standards. The paper will discuss standards approaches to conducting the risk and security metrics. The research findings will demonstrate the need for common baseline for both risk and security metrics. This paper will show the relation between the attribute based common baseline and corporate assets and controls for risk and security metrics. IT will be shown that such approach spans over all mentioned standards. The proposed approach 3D visual presentation and development of the Information Security Model will be analyzed and postulated. Presentation will clearly demonstrate the benefits of proposed attributes based approach and defined risk and security space for modeling and measuring.

Probabilistic environmental risk characterization of pharmaceuticals in sewage treatment plant discharges.

Science.gov (United States)

Christensen, Anne Munch; Markussen, Bo; Baun, Anders; Halling-Sørensen, Bent

2009-10-01

The occurrence of pharmaceuticals in different water bodies and the findings of effects on aquatic organisms in ecotoxicity tests have raised concerns about environmental risks of pharmaceuticals in receiving waters. Due to the fact that the amount of ecotoxicological studies has increased significantly during the last decade, probabilistic approaches for risk characterization of these compounds may be feasible. This approach was evaluated by applying it to 22 human-used pharmaceuticals covering both pharmaceuticals with a high volume and high ecotoxicity, using ecotoxicological effect data from laboratory studies and comparing these to monitoring data on the effluents from sewage treatment plants in Europe and pharmaceutical sales quantities. We found that for 19 of the 22 selected pharmaceuticals the existing data were sufficient for probabilistic risk characterizations. The subsequently modeled ratios between monitored concentrations and low-effect concentrations were mostly above a factor of 100. Compared to the current paradigm for EU environmental risk assessment where a safety factor of 10 or 100 might have been used it seems that for the modeled compounds there's a low environmental risk. However, similarly calculated ratios for five pharmaceuticals (propranolol, ibuprofen, furosemide, ofloxacin, and ciprofloxacin) were below 100, while ibuprofen and ciprofloxacin are considered to be of high concern due to lack of ecotoxicity studies. This paper shows that by applying probabilistic approaches, existing data can be used to execute a comprehensive study on probability of impacts, thereby contributing to a more comprehensive environmental risk assessment of pharmaceuticals.

Dynamical systems probabilistic risk assessment

Energy Technology Data Exchange (ETDEWEB)

Denman, Matthew R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ames, Arlo Leroy [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2014-03-01

Probabilistic Risk Assessment (PRA) is the primary tool used to risk-inform nuclear power regulatory and licensing activities. Risk-informed regulations are intended to reduce inherent conservatism in regulatory metrics (e.g., allowable operating conditions and technical specifications) which are built into the regulatory framework by quantifying both the total risk profile as well as the change in the risk profile caused by an event or action (e.g., in-service inspection procedures or power uprates). Dynamical Systems (DS) analysis has been used to understand unintended time-dependent feedbacks in both industrial and organizational settings. In dynamical systems analysis, feedback loops can be characterized and studied as a function of time to describe the changes to the reliability of plant Structures, Systems and Components (SSCs). While DS has been used in many subject areas, some even within the PRA community, it has not been applied toward creating long-time horizon, dynamic PRAs (with time scales ranging between days and decades depending upon the analysis). Understanding slowly developing dynamic effects, such as wear-out, on SSC reliabilities may be instrumental in ensuring a safely and reliably operating nuclear fleet. Improving the estimation of a plant's continuously changing risk profile will allow for more meaningful risk insights, greater stakeholder confidence in risk insights, and increased operational flexibility.

Multi-Hazard Advanced Seismic Probabilistic Risk Assessment Tools and Applications

International Nuclear Information System (INIS)

Coleman, Justin L.; Bolisetti, Chandu; Veeraraghavan, Swetha; Parisi, Carlo; Prescott, Steven R.; Gupta, Abhinav

2016-01-01

Design of nuclear power plant (NPP) facilities to resist natural hazards has been a part of the regulatory process from the beginning of the NPP industry in the United States (US), but has evolved substantially over time. The original set of approaches and methods was entirely deterministic in nature and focused on a traditional engineering margins-based approach. However, over time probabilistic and risk-informed approaches were also developed and implemented in US Nuclear Regulatory Commission (NRC) guidance and regulation. A defense-in-depth framework has also been incorporated into US regulatory guidance over time. As a result, today, the US regulatory framework incorporates deterministic and probabilistic approaches for a range of different applications and for a range of natural hazard considerations. This framework will continue to evolve as a result of improved knowledge and newly identified regulatory needs and objectives, most notably in response to the NRC activities developed in response to the 2011 Fukushima accident in Japan. Although the US regulatory framework has continued to evolve over time, the tools, methods and data available to the US nuclear industry to meet the changing requirements have not kept pace. Notably, there is significant room for improvement in the tools and methods available for external event probabilistic risk assessment (PRA), which is the principal assessment approach used in risk-informed regulations and risk-informed decision-making applied to natural hazard assessment and design. This is particularly true if PRA is applied to natural hazards other than seismic loading. Development of a new set of tools and methods that incorporate current knowledge, modern best practice, and state-of-the-art computational resources would lead to more reliable assessment of facility risk and risk insights (e.g., the SSCs and accident sequences that are most risk-significant), with less uncertainty and reduced conservatisms.

Multi-Hazard Advanced Seismic Probabilistic Risk Assessment Tools and Applications

Energy Technology Data Exchange (ETDEWEB)

Coleman, Justin L. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Bolisetti, Chandu [Idaho National Lab. (INL), Idaho Falls, ID (United States); Veeraraghavan, Swetha [Idaho National Lab. (INL), Idaho Falls, ID (United States); Parisi, Carlo [Idaho National Lab. (INL), Idaho Falls, ID (United States); Prescott, Steven R. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Gupta, Abhinav [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2016-09-01

Design of nuclear power plant (NPP) facilities to resist natural hazards has been a part of the regulatory process from the beginning of the NPP industry in the United States (US), but has evolved substantially over time. The original set of approaches and methods was entirely deterministic in nature and focused on a traditional engineering margins-based approach. However, over time probabilistic and risk-informed approaches were also developed and implemented in US Nuclear Regulatory Commission (NRC) guidance and regulation. A defense-in-depth framework has also been incorporated into US regulatory guidance over time. As a result, today, the US regulatory framework incorporates deterministic and probabilistic approaches for a range of different applications and for a range of natural hazard considerations. This framework will continue to evolve as a result of improved knowledge and newly identified regulatory needs and objectives, most notably in response to the NRC activities developed in response to the 2011 Fukushima accident in Japan. Although the US regulatory framework has continued to evolve over time, the tools, methods and data available to the US nuclear industry to meet the changing requirements have not kept pace. Notably, there is significant room for improvement in the tools and methods available for external event probabilistic risk assessment (PRA), which is the principal assessment approach used in risk-informed regulations and risk-informed decision-making applied to natural hazard assessment and design. This is particularly true if PRA is applied to natural hazards other than seismic loading. Development of a new set of tools and methods that incorporate current knowledge, modern best practice, and state-of-the-art computational resources would lead to more reliable assessment of facility risk and risk insights (e.g., the SSCs and accident sequences that are most risk-significant), with less uncertainty and reduced conservatisms.

Significance of earthquake risk in nuclear power plant probabilistic risk assessments

International Nuclear Information System (INIS)

Sues, R.H.; Amico, P.J.; Campbell, R.D.

1990-01-01

During the last eight years, approximately 25 utility-sponsored probabilistic risk assessments (PRAs) have been conducted for US nuclear reactors. Of these, ten have been published, seven of which have included complete seismic risk assessment. The results of the seven published PRAs are reviewed here in order to ascertain the significance of the risk due to earthquake initiating events. While PRA methodology has been in a state of development over the past seven years, and the results are subject to interpretation (as discussed in the paper), from the review conducted it is clear that earthquake-induced initiating events are important risk contributors. It is concluded that earthquake initiating events should not be dismissed, a priori, in any nuclear plant risk assessment. (orig.)

Report on probabilistic safety assessment (PSA) quality assurance in utilization of risk information

International Nuclear Information System (INIS)

2006-12-01

Recently in Japan, introduction of nuclear safety regulations using risk information such as probabilistic safety assessment (PSA) has been considered and utilization of risk information in the rational and practical measures on safety assurance has made a progress to start with the operation or inspection area. The report compiled results of investigation and studies of PSA quality assurance in risk-informed activities in the USA. Relevant regulatory guide and standard review plan as well as issues and recommendations were reviewed for technical adequacy and advancement of probabilistic risk assessment technology in risk-informed decision making. Useful and important information to be referred as issues in PSA quality assurance was identified. (T. Tanaka)

77 FR 29391 - An Approach for Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific...

Science.gov (United States)

2012-05-17

... NUCLEAR REGULATORY COMMISSION [NRC-2012-0110] An Approach for Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis AGENCY: Nuclear Regulatory Commission. ACTION: Draft regulatory guide; request for comment. SUMMARY: The U.S. Nuclear Regulatory...

N reactor external events probabilistic risk assessment

International Nuclear Information System (INIS)

Baxter, J.T.

1989-01-01

An external events probabilistic risk assessment of the N Reactor has been completed. The methods used are those currently being proposed for external events analysis in NUREG-1150. Results are presented for the external hazards that survived preliminary screening. They are earthquake, fire, and external flood. Core damage frequencies for these hazards are shown to be comparable to those for commercial pressurized water reactors. Dominant fire sequences are described and related to 10 CFR 50, Appendix R design requirements. Potential remedial measures that reduce fire core damage risk are described including modifications to fire protection systems, procedure changes, and addition of new administrative controls. Dominant seismic sequences are described. The effect of non-safety support system dependencies on seismic risk is presented

Hazardous waste transportation risk assessment: Benefits of a combined deterministic and probabilistic Monte Carlo approach in expressing risk uncertainty

International Nuclear Information System (INIS)

Policastro, A.J.; Lazaro, M.A.; Cowen, M.A.; Hartmann, H.M.; Dunn, W.E.; Brown, D.F.

1995-01-01

This paper presents a combined deterministic and probabilistic methodology for modeling hazardous waste transportation risk and expressing the uncertainty in that risk. Both the deterministic and probabilistic methodologies are aimed at providing tools useful in the evaluation of alternative management scenarios for US Department of Energy (DOE) hazardous waste treatment, storage, and disposal (TSD). The probabilistic methodology can be used to provide perspective on and quantify uncertainties in deterministic predictions. The methodology developed has been applied to 63 DOE shipments made in fiscal year 1992, which contained poison by inhalation chemicals that represent an inhalation risk to the public. Models have been applied to simulate shipment routes, truck accident rates, chemical spill probabilities, spill/release rates, dispersion, population exposure, and health consequences. The simulation presented in this paper is specific to trucks traveling from DOE sites to their commercial TSD facilities, but the methodology is more general. Health consequences are presented as the number of people with potentially life-threatening health effects. Probabilistic distributions were developed (based on actual item data) for accident release amounts, time of day and season of the accident, and meteorological conditions

Risk-informed design of IRIS using a level-1 probabilistic risk assessment from its conceptual design phase

International Nuclear Information System (INIS)

Mizuno, Yuko; Ninokata, Hisashi; Finnicum, David J.

2005-01-01

In this study, a probabilistic risk assessment (PRA) for the International Reactor Innovative and Secure (IRIS) has been generated to address two key areas as a part of the effort for the pre-application licensing of the IRIS design. First, the IRIS PRA is supporting the evaluation of IRIS design by providing design insights as well as a solid risk basis for the pre-licensing evaluation of the IRIS design. Second, the current PRA task is beginning the preparation of the more complete PRA analyses and documentation that will be required for Design Certification. The initial IRIS PRA is an at-power, Level-1 PRA for internal events that focuses on the evaluation of the IRIS design features to support the risk-informed design of IRIS by application of the PRA insights and the risk information to the design. To accomplish the evaluation, a reasonably complete Level-1 PRA model has been developed. The use of PRA in the early stages of the design has allowed a selection of design and performance features and an optimization of the design of several systems to reduce the potential for events that could lead to core damage via both enhanced prevention and mitigation of challenges. As a result, the total core damage frequency for internal events for the IRIS design has been calculated as 1.2x10 -8 per year

The probabilistic approach in the licensing process and the development of probabilistic risk assessment methodology in Japan

International Nuclear Information System (INIS)

Togo, Y.; Sato, K.

1981-01-01

The probabilistic approach has long seemed to be one of the most comprehensive methods for evaluating the safety of nuclear plants. So far, most of the guidelines and criteria for licensing are based on the deterministic concept. However, there have been a few examples to which the probabilistic approach was directly applied, such as the evaluation of aircraft crashes and turbine missiles. One may find other examples of such applications. However, a much more important role is now to be played by this concept, in implementing the 52 recommendations from the lessons learned from the TMI accident. To develop the probabilistic risk assessment methodology most relevant to Japanese situations, a five-year programme plan has been adopted and is to be conducted by the Japan Atomic Research Institute from fiscal 1980. Various problems have been identified and are to be solved through this programme plan. The current status of developments is described together with activities outside the government programme. (author)

Simple probabilistic method for relative risk evaluation of nuclear terrorism events

International Nuclear Information System (INIS)

Zhang Songbai; Wu Jun

2006-01-01

On the basis of the event-tree and probability analysis methods, a probabilistic method of nuclear terrorism risk was built, and the risk of terrorism events was analyzed. With the statistical data for and hypothetical data for relative events, the relative probabilities of the four kinds of nuclear terrorism events were obtained, as well as the relative risks of these four kinds of nuclear terrorism events were calculated by using this probabilistic method. The illustrated case show that the descending sequence of damages from the four kinds of nuclear terrorism events for single event is as following: nuclear explosive and improvised nuclear explosive, nuclear facility attacked, and 'dirty bomb'. Under the hypothetical condition, the descending sequence of possibilities for the four kinds of nuclear terrorism events is as following: 'dirty bomb', nuclear facility attacked, improvised nuclear explosive and nuclear explosive, but the descending sequence of risks is as following: 'dirty bomb', improvised nuclear explosive, nuclear facility attacked, and nuclear explosive . (authors)

HTGR containment design options: an application of probabilistic risk assessment

International Nuclear Information System (INIS)

1977-08-01

Through the use of probabilistic risk assessment (PRA), it is possible to quantitatively evaluate the radiological risk associated with a given reactor design and to place such risk into perspective with alternative designs. The merits are discussed for several containment alternatives for the HTGR from the viewpoints of economics and licensability, as well as public risk. The quantification of cost savings and public risk indicates that presently acceptable public risk can be maintained and cost savings of $40 million can result from use of a vented confinement for the HTGR

Managing information technology security risk

Science.gov (United States)

Gilliam, David

2003-01-01

Information Technology (IT) Security Risk Management is a critical task for the organization to protect against the loss of confidentiality, integrity and availability of IT resources. As systems bgecome more complex and diverse and and attacks from intrusions and malicious content increase, it is becoming increasingly difficult to manage IT security risk. This paper describes a two-pronged approach in addressing IT security risk and risk management in the organization: 1) an institutional enterprise appraoch, and 2) a project life cycle approach.

Fault trees and the impact of human variability on probabilistic risk analysis

International Nuclear Information System (INIS)

1983-01-01

It has long been recognized that human reliability is an important factor in probabilistic risk analysis. In the field, this is true in a direct operational sense as well as in the areas of installation and maintenance. The interest in quantification arises from the desire to achieve optimum design in the human factors sense (operability-maintainability) and from the need to include human reliability considerations in probabilistic risk analysis to achieve complete and valid risk evaluation. In order to integrate human reliability into the system analysis, it is necessary to consider two questions. These relate to the way that human functions fit into the existing analytical models and methods as well as the nature of human failure mechanisms, modes and failure (error) rates

Probabilistic framework for product design optimization and risk management

Science.gov (United States)

Keski-Rahkonen, J. K.

2018-05-01

Probabilistic methods have gradually gained ground within engineering practices but currently it is still the industry standard to use deterministic safety margin approaches to dimensioning components and qualitative methods to manage product risks. These methods are suitable for baseline design work but quantitative risk management and product reliability optimization require more advanced predictive approaches. Ample research has been published on how to predict failure probabilities for mechanical components and furthermore to optimize reliability through life cycle cost analysis. This paper reviews the literature for existing methods and tries to harness their best features and simplify the process to be applicable in practical engineering work. Recommended process applies Monte Carlo method on top of load-resistance models to estimate failure probabilities. Furthermore, it adds on existing literature by introducing a practical framework to use probabilistic models in quantitative risk management and product life cycle costs optimization. The main focus is on mechanical failure modes due to the well-developed methods used to predict these types of failures. However, the same framework can be applied on any type of failure mode as long as predictive models can be developed.

Seismic Probabilistic Risk Assessment (SPRA), approach and results

International Nuclear Information System (INIS)

Campbell, R.D.

1995-01-01

During the past 15 years there have been over 30 Seismic Probabilistic Risk Assessments (SPRAs) and Seismic Probabilistic Safety Assessments (SPSAs) conducted of Western Nuclear Power Plants, principally of US design. In this paper PRA and PSA are used interchangeably as the overall process is essentially the same. Some similar assessments have been done for reactors in Taiwan, Korea, Japan, Switzerland and Slovenia. These plants were also principally US supplied or built under US license. Since the restructuring of the governments in former Soviet Bloc countries, there has been grave concern regarding the safety of the reactors in these countries. To date there has been considerable activity in conducting partial seismic upgrades but the overall quantification of risk has not been pursued to the depth that it has in Western countries. This paper summarizes the methodology for Seismic PRA/PSA and compares results of two partially completed and two completed PRAs of soviet designed reactors to results from earlier PRAs on US Reactors. A WWER 440 and a WWER 1000 located in low seismic activity regions have completed PRAs and results show the seismic risk to be very low for both designs. For more active regions, partially completed PRAs of a WWER 440 and WWER 1000 located at the same site show the WWER 440 to have much greater seismic risk than the WWER 1000 plant. The seismic risk from the 1000 MW plant compares with the high end of seismic risk for earlier seismic PRAs in the US. Just as for most US plants, the seismic risk appears to be less than the risk from internal events if risk is measured is terms of mean core damage frequency. However, due to the lack of containment for the earlier WWER 440s, the risk to the public may be significantly greater due to the more probable scenario of an early release. The studies reported have not taken the accident sequences beyond the stage of core damage hence the public heath risk ratios are speculative. (author)

Ecohydrology of agroecosystems: probabilistic description of yield reduction risk under limited water availability

Science.gov (United States)

Vico, Giulia; Porporato, Amilcare

2013-04-01

Supplemental irrigation represents one of the main strategies to mitigate the effects of climate variability and stabilize yields. Irrigated agriculture currently provides 40% of food production and its relevance is expected to further increase in the near future, in face of the projected alterations of rainfall patterns and increase in food, fiber, and biofuel demand. Because of the significant investments and water requirements involved in irrigation, strategic choices are needed to preserve productivity and profitability, while maintaining a sustainable water management - a nontrivial task given the unpredictability of the rainfall forcing. To facilitate decision making under uncertainty, a widely applicable probabilistic framework is proposed. The occurrence of rainfall events and irrigation applications are linked probabilistically to crop development during the growing season and yields at harvest. Based on these linkages, the probability density function of yields and corresponding probability density function of required irrigation volumes, as well as the probability density function of yields under the most common case of limited water availability are obtained analytically, as a function of irrigation strategy, climate, soil and crop parameters. The full probabilistic description of the frequency of occurrence of yields and water requirements is a crucial tool for decision making under uncertainty, e.g., via expected utility analysis. Furthermore, the knowledge of the probability density function of yield allows us to quantify the yield reduction hydrologic risk. Two risk indices are defined and quantified: the long-term risk index, suitable for long-term irrigation strategy assessment and investment planning, and the real-time risk index, providing a rigorous probabilistic quantification of the emergence of drought conditions during a single growing season in an agricultural setting. Our approach employs relatively few parameters and is thus easily and

Adolescents' Heightened Risk-Seeking in a Probabilistic Gambling Task

Science.gov (United States)

Burnett, Stephanie; Bault, Nadege; Coricelli, Giorgio; Blakemore, Sarah-Jayne

2010-01-01

This study investigated adolescent males' decision-making under risk, and the emotional response to decision outcomes, using a probabilistic gambling task designed to evoke counterfactually mediated emotions (relief and regret). Participants were 20 adolescents (aged 9-11), 26 young adolescents (aged 12-15), 20 mid-adolescents (aged 15-18) and 17…

Uncertainty analysis in the applications of nuclear probabilistic risk assessment

International Nuclear Information System (INIS)

Le Duy, T.D.

2011-01-01

The aim of this thesis is to propose an approach to model parameter and model uncertainties affecting the results of risk indicators used in the applications of nuclear Probabilistic Risk assessment (PRA). After studying the limitations of the traditional probabilistic approach to represent uncertainty in PRA model, a new approach based on the Dempster-Shafer theory has been proposed. The uncertainty analysis process of the proposed approach consists in five main steps. The first step aims to model input parameter uncertainties by belief and plausibility functions according to the data PRA model. The second step involves the propagation of parameter uncertainties through the risk model to lay out the uncertainties associated with output risk indicators. The model uncertainty is then taken into account in the third step by considering possible alternative risk models. The fourth step is intended firstly to provide decision makers with information needed for decision making under uncertainty (parametric and model) and secondly to identify the input parameters that have significant uncertainty contributions on the result. The final step allows the process to be continued in loop by studying the updating of beliefs functions given new data. The proposed methodology was implemented on a real but simplified application of PRA model. (author)

Probabilistic Risk Assessment Procedures Guide for NASA Managers and Practitioners (Second Edition)

Science.gov (United States)

Stamatelatos,Michael; Dezfuli, Homayoon; Apostolakis, George; Everline, Chester; Guarro, Sergio; Mathias, Donovan; Mosleh, Ali; Paulos, Todd; Riha, David; Smith, Curtis;

Application of probabilistic risk assessment in nuclear and environmental licensing processes of nuclear reactors in Brazil

International Nuclear Information System (INIS)

Mata, Jonatas F.C. da; Vasconcelos, Vanderley de; Mesquita, Amir Z.

2015-01-01

The nuclear accident at Fukushima Daiichi, occurred in Japan in 2011, brought reflections, worldwide, on the management of nuclear and environmental licensing processes of existing nuclear reactors. One of the key lessons learned in this matter, is that the studies of Probabilistic Safety Assessment and Severe Accidents are becoming essential, even in the early stage of a nuclear development project. In Brazil, Brazilian Nuclear Energy Commission, CNEN, conducts the nuclear licensing. The organism responsible for the environmental licensing is Brazilian Institute of Environment and Renewable Natural Resources, IBAMA. In the scope of the licensing processes of these two institutions, the safety analysis is essentially deterministic, complemented by probabilistic studies. The Probabilistic Safety Assessment (PSA) is the study performed to evaluate the behavior of the nuclear reactor in a sequence of events that may lead to the melting of its core. It includes both probability and consequence estimation of these events, which are called Severe Accidents, allowing to obtain the risk assessment of the plant. Thus, the possible shortcomings in the design of systems are identified, providing basis for safety assessment and improving safety. During the environmental licensing, a Quantitative Risk Analysis (QRA), including probabilistic evaluations, is required in order to support the development of the Risk Analysis Study, the Risk Management Program and the Emergency Plan. This article aims to provide an overview of probabilistic risk assessment methodologies and their applications in nuclear and environmental licensing processes of nuclear reactors in Brazil. (author)

Application of probabilistic risk assessment in nuclear and environmental licensing processes of nuclear reactors in Brazil

Energy Technology Data Exchange (ETDEWEB)

Mata, Jonatas F.C. da; Vasconcelos, Vanderley de; Mesquita, Amir Z., E-mail: jonatasfmata@yahoo.com.br, E-mail: vasconv@cdtn.br, E-mail: amir@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2015-07-01

The nuclear accident at Fukushima Daiichi, occurred in Japan in 2011, brought reflections, worldwide, on the management of nuclear and environmental licensing processes of existing nuclear reactors. One of the key lessons learned in this matter, is that the studies of Probabilistic Safety Assessment and Severe Accidents are becoming essential, even in the early stage of a nuclear development project. In Brazil, Brazilian Nuclear Energy Commission, CNEN, conducts the nuclear licensing. The organism responsible for the environmental licensing is Brazilian Institute of Environment and Renewable Natural Resources, IBAMA. In the scope of the licensing processes of these two institutions, the safety analysis is essentially deterministic, complemented by probabilistic studies. The Probabilistic Safety Assessment (PSA) is the study performed to evaluate the behavior of the nuclear reactor in a sequence of events that may lead to the melting of its core. It includes both probability and consequence estimation of these events, which are called Severe Accidents, allowing to obtain the risk assessment of the plant. Thus, the possible shortcomings in the design of systems are identified, providing basis for safety assessment and improving safety. During the environmental licensing, a Quantitative Risk Analysis (QRA), including probabilistic evaluations, is required in order to support the development of the Risk Analysis Study, the Risk Management Program and the Emergency Plan. This article aims to provide an overview of probabilistic risk assessment methodologies and their applications in nuclear and environmental licensing processes of nuclear reactors in Brazil. (author)

Probabilistic modeling of the flows and environmental risks of nano-silica

International Nuclear Information System (INIS)

Wang, Yan; Kalinina, Anna; Sun, Tianyin; Nowack, Bernd

2016-01-01

Nano-silica, the engineered nanomaterial with one of the largest production volumes, has a wide range of applications in consumer products and industry. This study aimed to quantify the exposure of nano-silica to the environment and to assess its risk to surface waters. Concentrations were calculated for four environmental (air, soil, surface water, sediments) and two technical compartments (wastewater, solid waste) for the EU and Switzerland using probabilistic material flow modeling. The corresponding median concentration in surface water is predicted to be 0.12 μg/l in the EU (0.053–3.3 μg/l, 15/85% quantiles). The concentrations in sediments in the complete sedimentation scenario were found to be the largest among all environmental compartments, with a median annual increase of 0.43 mg/kg·y in the EU (0.19–12 mg/kg·y, 15/85% quantiles). Moreover, probabilistic species sensitivity distributions (PSSD) were computed and the risk of nano-silica in surface waters was quantified by comparing the predicted environmental concentration (PEC) with the predicted no-effect concentration (PNEC) distribution, which was derived from the cumulative PSSD. This assessment suggests that nano-silica currently poses no risk to aquatic organisms in surface waters. Further investigations are needed to assess the risk of nano-silica in other environmental compartments, which is currently not possible due to a lack of ecotoxicological data. - Highlights: • We quantify the exposure of nano-silica to technical systems and the environment. • The median concentration in surface waters is predicted to be 0.12 μg/L in the EU. • Probabilistic species sensitivity distributions were computed for surface waters. • The risk assessment suggests that nano-silica poses no risk to aquatic organisms.

Methodology for Applying Cyber Security Risk Evaluation from BN Model to PSA Model

Energy Technology Data Exchange (ETDEWEB)

Shin, Jin Soo; Heo, Gyun Young [Kyung Hee University, Youngin (Korea, Republic of); Kang, Hyun Gook [KAIST, Dajeon (Korea, Republic of); Son, Han Seong [Joongbu University, Chubu (Korea, Republic of)

2014-08-15

There are several advantages to use digital equipment such as cost, convenience, and availability. It is inevitable to use the digital I and C equipment replaced analog. Nuclear facilities have already started applying the digital system to I and C system. However, the nuclear facilities also have to change I and C system even though it is difficult to use digital equipment due to high level of safety, irradiation embrittlement, and cyber security. A cyber security which is one of important concerns to use digital equipment can affect the whole integrity of nuclear facilities. For instance, cyber-attack occurred to nuclear facilities such as the SQL slammer worm, stuxnet, DUQU, and flame. The regulatory authorities have published many regulatory requirement documents such as U.S. NRC Regulatory Guide 5.71, 1.152, IAEA guide NSS-17, IEEE Standard, and KINS Regulatory Guide. One of the important problem of cyber security research for nuclear facilities is difficulty to obtain the data through the penetration experiments. Therefore, we make cyber security risk evaluation model with Bayesian network (BN) for nuclear reactor protection system (RPS), which is one of the safety-critical systems to trip the reactor when the accident is happened to the facilities. BN can be used for overcoming these problems. We propose a method to apply BN cyber security model to probabilistic safety assessment (PSA) model, which had been used for safety assessment of system, structure and components of facility. The proposed method will be able to provide the insight of safety as well as cyber risk to the facility.

Methodology for Applying Cyber Security Risk Evaluation from BN Model to PSA Model

International Nuclear Information System (INIS)

Shin, Jin Soo; Heo, Gyun Young; Kang, Hyun Gook; Son, Han Seong

2014-01-01

There are several advantages to use digital equipment such as cost, convenience, and availability. It is inevitable to use the digital I and C equipment replaced analog. Nuclear facilities have already started applying the digital system to I and C system. However, the nuclear facilities also have to change I and C system even though it is difficult to use digital equipment due to high level of safety, irradiation embrittlement, and cyber security. A cyber security which is one of important concerns to use digital equipment can affect the whole integrity of nuclear facilities. For instance, cyber-attack occurred to nuclear facilities such as the SQL slammer worm, stuxnet, DUQU, and flame. The regulatory authorities have published many regulatory requirement documents such as U.S. NRC Regulatory Guide 5.71, 1.152, IAEA guide NSS-17, IEEE Standard, and KINS Regulatory Guide. One of the important problem of cyber security research for nuclear facilities is difficulty to obtain the data through the penetration experiments. Therefore, we make cyber security risk evaluation model with Bayesian network (BN) for nuclear reactor protection system (RPS), which is one of the safety-critical systems to trip the reactor when the accident is happened to the facilities. BN can be used for overcoming these problems. We propose a method to apply BN cyber security model to probabilistic safety assessment (PSA) model, which had been used for safety assessment of system, structure and components of facility. The proposed method will be able to provide the insight of safety as well as cyber risk to the facility

Method and system for dynamic probabilistic risk assessment

Science.gov (United States)

Dugan, Joanne Bechta (Inventor); Xu, Hong (Inventor)

2013-01-01

The DEFT methodology, system and computer readable medium extends the applicability of the PRA (Probabilistic Risk Assessment) methodology to computer-based systems, by allowing DFT (Dynamic Fault Tree) nodes as pivot nodes in the Event Tree (ET) model. DEFT includes a mathematical model and solution algorithm, supports all common PRA analysis functions and cutsets. Additional capabilities enabled by the DFT include modularization, phased mission analysis, sequence dependencies, and imperfect coverage.

Probabilistic cumulative risk assessment of anti-androgenic pesticides in food

DEFF Research Database (Denmark)

Müller, Anne Kirstine; Bosgra, Sieto; Boon, Polly E.

2009-01-01

In this paper, we present a cumulative risk assessment of three anti-androgenic pesticides (vinclozolin, procymidone and prochloraz) using the relative potency factor (RPF) approach and an integrated probabilistic risk assessment (IPRA) model. RPFs for each substance were estimated for three......) and the fraction of individuals with IMoEs vinclozolin, procymidone and prochloraz is not likely to be of concern for the reproductive development of their male foetuses. However...

Human reliability assessment and probabilistic risk assessment

International Nuclear Information System (INIS)

Embrey, D.E.; Lucas, D.A.

1989-01-01

Human reliability assessment (HRA) is used within Probabilistic Risk Assessment (PRA) to identify the human errors (both omission and commission) which have a significant effect on the overall safety of the system and to quantify the probability of their occurrence. There exist a variey of HRA techniques and the selection of an appropriate one is often difficult. This paper reviews a number of available HRA techniques and discusses their strengths and weaknesses. The techniques reviewed include: decompositional methods, time-reliability curves and systematic expert judgement techniques. (orig.)

The importance of probabilistic evaluations in connection with risk analyses according to technical safety laws

International Nuclear Information System (INIS)

Mathiak, E.

1984-01-01

The nuclear energy sector exemplifies the essential importance to be attached to the practical application of probabilistic evaluations (e.g. probabilistic reliability analyses) in connection with the legal risk assessment of technical systems and installations. The study is making use of a triad risk analysis and tries to reconcile the natural science and legal points of view. Without changing the definitions of 'risk' and 'hazard' in the legal sense of their meaning the publication discusses their reconcilation with the laws of natural science, their interpretation and application in view of the latter. (HSCH) [de

Development of reliability databases and the particular requirements of probabilistic risk analyses

International Nuclear Information System (INIS)

Meslin, T.

1989-01-01

Nuclear utilities have an increasing need to develop reliability databases for their operating experience. The purposes of these databases are often multiple, including both equipment maintenance aspects and probabilistic risk analyses. EDF has therefore been developing experience feedback databases, including the Reliability Data Recording System (SRDF) and the Event File, as well as the history of numerous operating documents. Furthermore, since the end of 1985, EDF has been preparing a probabilistic safety analysis applied to one 1,300 MWe unit, for which a large amount of data of French origin is necessary. This data concerns both component reliability parameters and initiating event frequencies. The study has thus been an opportunity for trying out the performance databases for a specific application, as well as in-depth audits of a number of nuclear sites to make it possible to validate numerous results. Computer aided data collection is also on trial in a number of plants. After describing the EDF operating experience feedback files, we discuss the particular requirements of probabilistic risk analyses, and the resources implemented by EDF to satisfy them. (author). 5 refs

Probabilistic insurance

OpenAIRE

Wakker, P.P.; Thaler, R.H.; Tversky, A.

1997-01-01

textabstractProbabilistic insurance is an insurance policy involving a small probability that the consumer will not be reimbursed. Survey data suggest that people dislike probabilistic insurance and demand more than a 20% reduction in the premium to compensate for a 1% default risk. While these preferences are intuitively appealing they are difficult to reconcile with expected utility theory. Under highly plausible assumptions about the utility function, willingness to pay for probabilistic i...

Probabilistic Insurance

NARCIS (Netherlands)

Wakker, P.P.; Thaler, R.H.; Tversky, A.

1997-01-01

Probabilistic insurance is an insurance policy involving a small probability that the consumer will not be reimbursed. Survey data suggest that people dislike probabilistic insurance and demand more than a 20% reduction in premium to compensate for a 1% default risk. These observations cannot be

Probabilistic Insurance

NARCIS (Netherlands)

P.P. Wakker (Peter); R.H. Thaler (Richard); A. Tversky (Amos)

1997-01-01

textabstractProbabilistic insurance is an insurance policy involving a small probability that the consumer will not be reimbursed. Survey data suggest that people dislike probabilistic insurance and demand more than a 20% reduction in the premium to compensate for a 1% default risk. While these

Dealing with uncertainty arising out of probabilistic risk assessment

International Nuclear Information System (INIS)

Solomon, K.A.; Kastenberg, W.E.; Nelson, P.F.

1984-03-01

In addressing the area of safety goal implementation, the question of uncertainty arises. This report suggests that the Nuclear Regulatory Commission (NRC) should examine how other regulatory organizations have addressed the issue. Several examples are given from the chemical industry, and comparisons are made to nuclear power risks. Recommendations are made as to various considerations that the NRC should require in probabilistic risk assessments in order to properly treat uncertainties in the implementation of the safety goal policy. 40 references, 7 figures, 5 tables

Predicting the onset of psychosis in patients at clinical high risk: practical guide to probabilistic prognostic reasoning.

Science.gov (United States)

Fusar-Poli, P; Schultze-Lutter, F

2016-02-01

Prediction of psychosis in patients at clinical high risk (CHR) has become a mainstream focus of clinical and research interest worldwide. When using CHR instruments for clinical purposes, the predicted outcome is but only a probability; and, consequently, any therapeutic action following the assessment is based on probabilistic prognostic reasoning. Yet, probabilistic reasoning makes considerable demands on the clinicians. We provide here a scholarly practical guide summarising the key concepts to support clinicians with probabilistic prognostic reasoning in the CHR state. We review risk or cumulative incidence of psychosis in, person-time rate of psychosis, Kaplan-Meier estimates of psychosis risk, measures of prognostic accuracy, sensitivity and specificity in receiver operator characteristic curves, positive and negative predictive values, Bayes' theorem, likelihood ratios, potentials and limits of real-life applications of prognostic probabilistic reasoning in the CHR state. Understanding basic measures used for prognostic probabilistic reasoning is a prerequisite for successfully implementing the early detection and prevention of psychosis in clinical practice. Future refinement of these measures for CHR patients may actually influence risk management, especially as regards initiating or withholding treatment. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Performing Probabilistic Risk Assessment Through RAVEN

Energy Technology Data Exchange (ETDEWEB)

A. Alfonsi; C. Rabiti; D. Mandelli; J. Cogliati; R. Kinoshita

2013-06-01

The Reactor Analysis and Virtual control ENviroment (RAVEN) code is a software tool that acts as the control logic driver and post-processing engine for the newly developed Thermal-Hydraulic code RELAP-7. RAVEN is now a multi-purpose Probabilistic Risk Assessment (PRA) software framework that allows dispatching different functionalities: Derive and actuate the control logic required to simulate the plant control system and operator actions (guided procedures), allowing on-line monitoring/controlling in the Phase Space Perform both Monte-Carlo sampling of random distributed events and Dynamic Event Tree based analysis Facilitate the input/output handling through a Graphical User Interface (GUI) and a post-processing data mining module

2009 Space Shuttle Probabilistic Risk Assessment Overview

Science.gov (United States)

Hamlin, Teri L.; Canga, Michael A.; Boyer, Roger L.; Thigpen, Eric B.

2010-01-01

Loss of a Space Shuttle during flight has severe consequences, including loss of a significant national asset; loss of national confidence and pride; and, most importantly, loss of human life. The Shuttle Probabilistic Risk Assessment (SPRA) is used to identify risk contributors and their significance; thus, assisting management in determining how to reduce risk. In 2006, an overview of the SPRA Iteration 2.1 was presented at PSAM 8 [1]. Like all successful PRAs, the SPRA is a living PRA and has undergone revisions since PSAM 8. The latest revision to the SPRA is Iteration 3. 1, and it will not be the last as the Shuttle program progresses and more is learned. This paper discusses the SPRA scope, overall methodology, and results, as well as provides risk insights. The scope, assumptions, uncertainties, and limitations of this assessment provide risk-informed perspective to aid management s decision-making process. In addition, this paper compares the Iteration 3.1 analysis and results to the Iteration 2.1 analysis and results presented at PSAM 8.

Probabilistic disaggregation model with application to natural hazard risk assessment of portfolios

DEFF Research Database (Denmark)

Custer, Rocco; Nishijima, Kazuyoshi

In natural hazard risk assessment, a resolution mismatch between hazard data and aggregated exposure data is often observed. A possible solution to this issue is the disaggregation of exposure data to match the spatial resolution of hazard data. Disaggregation models available in literature...... disaggregation model that considers the uncertainty in the disaggregation, taking basis in the scaled Dirichlet distribution. The proposed probabilistic disaggregation model is applied to a portfolio of residential buildings in the Canton Bern, Switzerland, subject to flood risk. Thereby, the model is verified...... are usually deterministic and make use of auxiliary indicator, such as land cover, to spatially distribute exposures. As the dependence between auxiliary indicator and disaggregated number of exposures is generally imperfect, uncertainty arises in disaggregation. This paper therefore proposes a probabilistic...

Integration of Probabilistic Exposure Assessment and Probabilistic Hazard Characterization

NARCIS (Netherlands)

Voet, van der H.; Slob, W.

2007-01-01

A method is proposed for integrated probabilistic risk assessment where exposure assessment and hazard characterization are both included in a probabilistic way. The aim is to specify the probability that a random individual from a defined (sub)population will have an exposure high enough to cause a

reputation Risks through Information Security Incidents

Directory of Open Access Journals (Sweden)

Vitaly Eduardovich Dorokhov

2014-05-01

Full Text Available The article deals with accounting reputational risks arising through information security breaches in the management of a business entity. Security breach incidents which results to the loss of reputation are identified. Based on this analysis the definition of reputational risk in information security is given.

Architecture for Integrated Medical Model Dynamic Probabilistic Risk Assessment

Science.gov (United States)

Jaworske, D. A.; Myers, J. G.; Goodenow, D.; Young, M.; Arellano, J. D.

2016-01-01

Probabilistic Risk Assessment (PRA) is a modeling tool used to predict potential outcomes of a complex system based on a statistical understanding of many initiating events. Utilizing a Monte Carlo method, thousands of instances of the model are considered and outcomes are collected. PRA is considered static, utilizing probabilities alone to calculate outcomes. Dynamic Probabilistic Risk Assessment (dPRA) is an advanced concept where modeling predicts the outcomes of a complex system based not only on the probabilities of many initiating events, but also on a progression of dependencies brought about by progressing down a time line. Events are placed in a single time line, adding each event to a queue, as managed by a planner. Progression down the time line is guided by rules, as managed by a scheduler. The recently developed Integrated Medical Model (IMM) summarizes astronaut health as governed by the probabilities of medical events and mitigation strategies. Managing the software architecture process provides a systematic means of creating, documenting, and communicating a software design early in the development process. The software architecture process begins with establishing requirements and the design is then derived from the requirements.

A framework to integrate software behavior into dynamic probabilistic risk assessment

International Nuclear Information System (INIS)

Zhu Dongfeng; Mosleh, Ali; Smidts, Carol

2007-01-01

Software plays an increasingly important role in modern safety-critical systems. Although, research has been done to integrate software into the classical probabilistic risk assessment (PRA) framework, current PRA practice overwhelmingly neglects the contribution of software to system risk. Dynamic probabilistic risk assessment (DPRA) is considered to be the next generation of PRA techniques. DPRA is a set of methods and techniques in which simulation models that represent the behavior of the elements of a system are exercised in order to identify risks and vulnerabilities of the system. The fact remains, however, that modeling software for use in the DPRA framework is also quite complex and very little has been done to address the question directly and comprehensively. This paper develops a methodology to integrate software contributions in the DPRA environment. The framework includes a software representation, and an approach to incorporate the software representation into the DPRA environment SimPRA. The software representation is based on multi-level objects and the paper also proposes a framework to simulate the multi-level objects in the simulation-based DPRA environment. This is a new methodology to address the state explosion problem in the DPRA environment. This study is the first systematic effort to integrate software risk contributions into DPRA environments

Probabilistic risk analysis for the NASA space shuttle: a brief history and current work

International Nuclear Information System (INIS)

Pate-Cornell, Elisabeth; Dillon, Robin

2001-01-01

While NASA managers have always relied on risk analysis tools for the development and maintenance of space projects, quantitative and especially probabilistic techniques have been gaining acceptance in recent years. In some cases, the studies have been required, for example, to launch the Galileo spacecraft with plutonium fuel, but these successful applications have helped to demonstrate the benefits of these tools. This paper reviews the history of probabilistic risk analysis (PRA) by NASA for the space shuttle program and discusses the status of the on-going development of the Quantitative Risk Assessment System (QRAS) software that performs PRA. The goal is to have within NASA a tool that can be used when needed to update previous risk estimates and to assess the benefits of possible upgrades to the system

A probabilistic assessment of health risks associated with short-term exposure to tropospheric ozone

Energy Technology Data Exchange (ETDEWEB)

Whitfield, R.G; Biller, W.F.; Jusko, M.J.; Keisler, J.M.

1996-06-01

The work described in this report is part of a larger risk assessment sponsored by the U.S. Environmental Protection Agency. Earlier efforts developed exposure-response relationships for acute health effects among populations engaged in heavy exertion. Those efforts also developed a probabilistic national ambient air quality standards exposure model and a general methodology for integrating probabilistic exposure-response relation- ships and exposure estimates to calculate overall risk results. Recently published data make it possible to model additional health endpoints (for exposure at moderate exertion), including hospital admissions. New air quality and exposure estimates for alternative national ambient air quality standards for ozone are combined with exposure-response models to produce the risk results for hospital admissions and acute health effects. Sample results explain the methodology and introduce risk output formats.

Risk Management Technologies With Logic and Probabilistic Models

CERN Document Server

Solozhentsev, E D

2012-01-01

This book presents intellectual, innovative, information technologies (I3-technologies) based on logical and probabilistic (LP) risk models. The technologies presented here consider such models for structurally complex systems and processes with logical links and with random events in economics and technology.  The volume describes the following components of risk management technologies: LP-calculus; classes of LP-models of risk and efficiency; procedures for different classes; special software for different classes; examples of applications; methods for the estimation of probabilities of events based on expert information. Also described are a variety of training courses in these topics. The classes of risk models treated here are: LP-modeling, LP-classification, LP-efficiency, and LP-forecasting. Particular attention is paid to LP-models of risk of failure to resolve difficult economic and technical problems. Amongst the  discussed  procedures of I3-technologies  are the construction of  LP-models,...

Use of risk assessment methods for security design and analysis of nuclear and radioactive facilities

International Nuclear Information System (INIS)

Vasconcelos, Vanderley de; Andrade, Marcos C.; Jordao, Elizabete

2011-01-01

The objective of this work is to evaluate the applicability of risk assessment methods for analyzing the physical protection of nuclear and radioactive facilities. One of the important processes for physical protection in nuclear and radioactive facilities is the identifying of areas containing nuclear materials, structures, systems or components to be protected from sabotage, which could directly or indirectly lead to unacceptable radiological consequences. A survey of the international guidelines and recommendations about vital area identification, design basis threat (DBT), and the security of nuclear and radioactive facilities was carried out. The traditional methods used for quantitative risk assessment, like FMEA (Failure Mode and Effect Analysis), Event and Decision Trees, Fault and Success Trees, Vulnerability Assessment, Monte Carlo Simulation, Probabilistic Safety Assessment, Scenario Analysis, and Game Theory, among others, are highlighted. The applicability of such techniques to security issues, their pros and cons, the general resources needed to implement them, as data or support software, are analyzed. Finally, an approach to security design and analysis, beginning with a qualitative and preliminary examination to determine the range of possible scenarios, outcomes, and the systems to be included in the analyses, and proceeding to a progressively use of more quantitative techniques is presented. (author)

Probabilistic risk analysis and its role in regulatory activity in a developing country

International Nuclear Information System (INIS)

Arredondo-Sanchez, C.

1985-01-01

The author discusses the criterion adopted for regulatory activity in a developing country with a nuclear power plant. He describes the problems that have to be overcome as a result of changes in the regulations during construction of the plant. There is discussion of the action taken by the regulatory body when introducing the method of probabilistic risk analysis. The part played by this form of analysis in quantifying the safety objectives proposed in the USA together with its limitations and the problems involved in this methodology are examined. Lastly, the author gives an opinion on the use that probabilistic risk analysis should be put to in developing countries such as Mexico. (author)

PRA (Probabilistic Risk Assessments) Participation versus Validation

Science.gov (United States)

DeMott, Diana; Banke, Richard

2013-01-01

Probabilistic Risk Assessments (PRAs) are performed for projects or programs where the consequences of failure are highly undesirable. PRAs primarily address the level of risk those projects or programs posed during operations. PRAs are often developed after the design has been completed. Design and operational details used to develop models include approved and accepted design information regarding equipment, components, systems and failure data. This methodology basically validates the risk parameters of the project or system design. For high risk or high dollar projects, using PRA methodologies during the design process provides new opportunities to influence the design early in the project life cycle to identify, eliminate or mitigate potential risks. Identifying risk drivers before the design has been set allows the design engineers to understand the inherent risk of their current design and consider potential risk mitigation changes. This can become an iterative process where the PRA model can be used to determine if the mitigation technique is effective in reducing risk. This can result in more efficient and cost effective design changes. PRA methodology can be used to assess the risk of design alternatives and can demonstrate how major design changes or program modifications impact the overall program or project risk. PRA has been used for the last two decades to validate risk predictions and acceptability. Providing risk information which can positively influence final system and equipment design the PRA tool can also participate in design development, providing a safe and cost effective product.

Application of Bayesian network to the probabilistic risk assessment of nuclear waste disposal

International Nuclear Information System (INIS)

Lee, Chang-Ju; Lee, Kun Jai

2006-01-01

The scenario in a risk analysis can be defined as the propagating feature of specific initiating event which can go to a wide range of undesirable consequences. If we take various scenarios into consideration, the risk analysis becomes more complex than do without them. A lot of risk analyses have been performed to actually estimate a risk profile under both uncertain future states of hazard sources and undesirable scenarios. Unfortunately, in case of considering specific systems such as a radioactive waste disposal facility, since the behaviour of future scenarios is hardly predicted without special reasoning process, we cannot estimate their risk only with a traditional risk analysis methodology. Moreover, we believe that the sources of uncertainty at future states can be reduced pertinently by setting up dependency relationships interrelating geological, hydrological, and ecological aspects of the site with all the scenarios. It is then required current methodology of uncertainty analysis of the waste disposal facility be revisited under this belief. In order to consider the effects predicting from an evolution of environmental conditions of waste disposal facilities, this paper proposes a quantitative assessment framework integrating the inference process of Bayesian network to the traditional probabilistic risk analysis. We developed and verified an approximate probabilistic inference program for the specific Bayesian network using a bounded-variance likelihood weighting algorithm. Ultimately, specific models, including a model for uncertainty propagation of relevant parameters were developed with a comparison of variable-specific effects due to the occurrence of diverse altered evolution scenarios (AESs). After providing supporting information to get a variety of quantitative expectations about the dependency relationship between domain variables and AESs, we could connect the results of probabilistic inference from the Bayesian network with the consequence

A Probabilistic Analysis of Surface Water Flood Risk in London.

Science.gov (United States)

Jenkins, Katie; Hall, Jim; Glenis, Vassilis; Kilsby, Chris

2017-10-30

Flooding in urban areas during heavy rainfall, often characterized by short duration and high-intensity events, is known as "surface water flooding." Analyzing surface water flood risk is complex as it requires understanding of biophysical and human factors, such as the localized scale and nature of heavy precipitation events, characteristics of the urban area affected (including detailed topography and drainage networks), and the spatial distribution of economic and social vulnerability. Climate change is recognized as having the potential to enhance the intensity and frequency of heavy rainfall events. This study develops a methodology to link high spatial resolution probabilistic projections of hourly precipitation with detailed surface water flood depth maps and characterization of urban vulnerability to estimate surface water flood risk. It incorporates probabilistic information on the range of uncertainties in future precipitation in a changing climate. The method is applied to a case study of Greater London and highlights that both the frequency and spatial extent of surface water flood events are set to increase under future climate change. The expected annual damage from surface water flooding is estimated to be to be £171 million, £343 million, and £390 million/year under the baseline, 2030 high, and 2050 high climate change scenarios, respectively. © 2017 Society for Risk Analysis.

Future trends in flood risk in Indonesia - A probabilistic approach

Science.gov (United States)

Muis, Sanne; Guneralp, Burak; Jongman, Brenden; Ward, Philip

2014-05-01

Indonesia is one of the 10 most populous countries in the world and is highly vulnerable to (river) flooding. Catastrophic floods occur on a regular basis; total estimated damages were US 0.8 bn in 2010 and US 3 bn in 2013. Large parts of Greater Jakarta, the capital city, are annually subject to flooding. Flood risks (i.e. the product of hazard, exposure and vulnerability) are increasing due to rapid increases in exposure, such as strong population growth and ongoing economic development. The increase in risk may also be amplified by increasing flood hazards, such as increasing flood frequency and intensity due to climate change and land subsidence. The implementation of adaptation measures, such as the construction of dykes and strategic urban planning, may counteract these increasing trends. However, despite its importance for adaptation planning, a comprehensive assessment of current and future flood risk in Indonesia is lacking. This contribution addresses this issue and aims to provide insight into how socio-economic trends and climate change projections may shape future flood risks in Indonesia. Flood risk were calculated using an adapted version of the GLOFRIS global flood risk assessment model. Using this approach, we produced probabilistic maps of flood risks (i.e. annual expected damage) at a resolution of 30"x30" (ca. 1km x 1km at the equator). To represent flood exposure, we produced probabilistic projections of urban growth in a Monte-Carlo fashion based on probability density functions of projected population and GDP values for 2030. To represent flood hazard, inundation maps were computed using the hydrological-hydraulic component of GLOFRIS. These maps show flood inundation extent and depth for several return periods and were produced for several combinations of GCMs and future socioeconomic scenarios. Finally, the implementation of different adaptation strategies was incorporated into the model to explore to what extent adaptation may be able to

Transmission grid security

CERN Document Server

Haarla, Liisa; Hirvonen, Ritva; Labeau, Pierre-Etienne

2011-01-01

In response to the growing importance of power system security and reliability, ""Transmission Grid Security"" proposes a systematic and probabilistic approach for transmission grid security analysis. The analysis presented uses probabilistic safety assessment (PSA) and takes into account the power system dynamics after severe faults. In the method shown in this book the power system states (stable, not stable, system breakdown, etc.) are connected with the substation reliability model. In this way it is possible to: estimate the system-wide consequences of grid faults; identify a chain of eve

Advanced Small Modular Reactor (SMR) Probabilistic Risk Assessment (PRA) Technical Exchange Meeting

Energy Technology Data Exchange (ETDEWEB)

Smith, Curtis [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2013-09-01

During FY13, the INL developed an advanced SMR PRA framework which has been described in the report Small Modular Reactor (SMR) Probabilistic Risk Assessment (PRA) Detailed Technical Framework Specification, INL/EXT-13-28974 (April 2013). In this framework, the various areas are considered: Probabilistic models to provide information specific to advanced SMRs Representation of specific SMR design issues such as having co-located modules and passive safety features Use of modern open-source and readily available analysis methods Internal and external events resulting in impacts to safety All-hazards considerations Methods to support the identification of design vulnerabilities Mechanistic and probabilistic data needs to support modeling and tools In order to describe this framework more fully and obtain feedback on the proposed approaches, the INL hosted a technical exchange meeting during August 2013. This report describes the outcomes of that meeting.

Site-specific probabilistic ecological risk assessment of a volatile chlorinated hydrocarbon-contaminated tidal estuary.

Science.gov (United States)

Hunt, James; Birch, Gavin; Warne, Michael St J

2010-05-01

Groundwater contaminated with volatile chlorinated hydrocarbons (VCHs) was identified as discharging to Penrhyn Estuary, an intertidal embayment of Botany Bay, New South Wales, Australia. A screening-level hazard assessment of surface water in Penrhyn Estuary identified an unacceptable hazard to marine organisms posed by VCHs. Given the limitations of hazard assessments, the present study conducted a higher-tier, quantitative probabilistic risk assessment using the joint probability curve (JPC) method that accounted for variability in exposure and toxicity profiles to quantify risk (delta). Risk was assessed for 24 scenarios, including four areas of the estuary based on three exposure scenarios (low tide, high tide, and both low and high tides) and two toxicity scenarios (chronic no-observed-effect concentrations [NOEC] and 50% effect concentrations [EC50]). Risk (delta) was greater at low tide than at high tide and varied throughout the tidal cycle. Spatial distributions of risk in the estuary were similar using both NOEC and EC50 data. The exposure scenario including data combined from both tides was considered the most accurate representation of the ecological risk in the estuary. When assessing risk using data across both tides, the greatest risk was identified in the Springvale tributary (delta=25%)-closest to the source area-followed by the inner estuary (delta=4%) and the Floodvale tributary (delta=2%), with the lowest risk in the outer estuary (delta=0.1%), farthest from the source area. Going from the screening level ecological risk assessment (ERA) to the probabilistic ERA changed the risk from unacceptable to acceptable in 50% of exposure scenarios in two of the four areas within the estuary. The probabilistic ERA provided a more realistic assessment of risk than the screening-level hazard assessment. Copyright (c) 2010 SETAC.

A perspective of PC-based probabilistic risk assessment

International Nuclear Information System (INIS)

Sattison, M.B.; Rasmuson, D.M.; Robinson, R.C.; Russell, K.D.; Van Siclen, V.S.

1987-01-01

Probabilistic risk assessment (PRA) information has been under-utilized in the past due to the large effort required to input the PRA data and the large expense of the computers needed to run PRA codes. The microcomputer-based Integrated Reliability and Risk Analysis System (IRRAS) and the System Analysis and Risk Assessment (SARA) System, under development at the Idaho National Engineering Laboratory, have greatly enhanced the ability of managers to use PRA techniques in their decision-making. IRRAS is a tool that allows an analyst to create, modify, update, and reanalyze a plant PRA to keep the risk assessment current with the plant's configuration and operation. The SARA system is used to perform sensitivity studies on the results of a PRA. This type of analysis can be used to evaluate proposed changes to a plant or its operation. The success of these two software projects demonstrate that risk information can be made readily available to those that need it. This is the first step in the development of a true risk management capability

Risk assessment techniques for civil aviation security

Energy Technology Data Exchange (ETDEWEB)

Tamasi, Galileo, E-mail: g.tamasi@enac.rupa.i [Ente Nazionale per l' Aviazione Civile-Direzione Progetti, Studi e Ricerche, Via di Villa Ricotti, 42, 00161 Roma (Italy); Demichela, Micaela, E-mail: micaela.demichela@polito.i [SAfeR-Centro Studi su Sicurezza, Affidabilita e Rischi, Dipartimento di Scienza dei Materiali e Ingegneria Chimica, Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129 Torino (Italy)

2011-08-15

Following the 9/11 terrorists attacks in New York a strong economical effort was made to improve and adapt aviation security, both in infrastructures as in airplanes. National and international guidelines were promptly developed with the objective of creating a security management system able to supervise the identification of risks and the definition and optimization of control measures. Risk assessment techniques are thus crucial in the above process, since an incorrect risk identification and quantification can strongly affect both the security level as the investments needed to reach it. The paper proposes a set of methodologies to qualitatively and quantitatively assess the risk in the security of civil aviation and the risk assessment process based on the threats, criticality and vulnerabilities concepts, highlighting their correlation in determining the level of risk. RAMS techniques are applied to the airport security system in order to analyze the protection equipment for critical facilities located in air-side, allowing also the estimation of the importance of the security improving measures vs. their effectiveness.

Risk assessment techniques for civil aviation security

International Nuclear Information System (INIS)

Tamasi, Galileo; Demichela, Micaela

2011-01-01

Following the 9/11 terrorists attacks in New York a strong economical effort was made to improve and adapt aviation security, both in infrastructures as in airplanes. National and international guidelines were promptly developed with the objective of creating a security management system able to supervise the identification of risks and the definition and optimization of control measures. Risk assessment techniques are thus crucial in the above process, since an incorrect risk identification and quantification can strongly affect both the security level as the investments needed to reach it. The paper proposes a set of methodologies to qualitatively and quantitatively assess the risk in the security of civil aviation and the risk assessment process based on the threats, criticality and vulnerabilities concepts, highlighting their correlation in determining the level of risk. RAMS techniques are applied to the airport security system in order to analyze the protection equipment for critical facilities located in air-side, allowing also the estimation of the importance of the security improving measures vs. their effectiveness.

Using Probabilistic Models to Appraise and Decide on Sovereign Disaster Risk Financing and Insurance

OpenAIRE

Ley-Borrás, Roberto; Fox, Benjamin D.

2015-01-01

This paper presents an overview of the structure of probabilistic catastrophe risk models, discusses their importance for appraising sovereign disaster risk financing and insurance instruments and strategy, and puts forward a model and a process for improving decision making on the linked disaster risk management strategy and sovereign disaster risk financing and insurance strategy. The pa...

Insights from Guideline for Performance of Internal Flooding Probabilistic Risk Assessment (IFPRA)

International Nuclear Information System (INIS)

Choi, Sun Yeong; Yang, Joo Eon

2009-01-01

An internal flooding (IF) risk assessment refers to the quantitative probabilistic safety assessment (PSA) treatment of flooding as a result of pipe and tank breaks inside the plants, as well as from other recognized flood sources. The industry consensus standard for Internal Events Probabilistic Risk Assessment (ASME-RA-Sb-2005) includes high-level and supporting technical requirements for developing internal flooding probabilistic risk assessment (IFPRA). This industry standard is endorsed in Regulatory Guide 1.200, Revision 1 as an acceptable approach for addressing the risk contribution from IF events for risk informed applications that require U.S. Nuclear Regulatory commission (NRC) approval. In 2006, EPRI published a draft report for IFPRA that addresses the requirements of the ASME PRA consensus standard and have made efforts to refine and update the final EPRI IFPRA guideline. Westinghouse has performed an IFPRA analysis for several nuclear power plants (NPPs), such as Watts Bar and Fort Calhoun, using the draft EPRI guidelines for development of an IFPRA. Proprietary methodologies have been developed to apply the EPRI guidelines. The objectives of the draft report for IFPRA guideline are to: · Provide guidance for PSA practitioners in the performance of the elements of a PRA associated with internal flooding events consistent with the current state of the art for internal flooding PRA · Provide guidance regarding acceptable approaches that is sufficient to meeting the requirements of the ASME PRA Standard associated with internal flooding · Incorporate lessons learned in the performance of internal flooding PRAs including those identified as pilot applications of earlier drafts of this procedures guide The purpose of this paper is to present a vision for domestic nuclear power plants' IFPRA by comparing the method of the draft EPRI guidelines with the existing IFPRA method for domestic NPPs

Insights from Guideline for Performance of Internal Flooding Probabilistic Risk Assessment (IFPRA)

Energy Technology Data Exchange (ETDEWEB)

Choi, Sun Yeong; Yang, Joo Eon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2009-10-15

An internal flooding (IF) risk assessment refers to the quantitative probabilistic safety assessment (PSA) treatment of flooding as a result of pipe and tank breaks inside the plants, as well as from other recognized flood sources. The industry consensus standard for Internal Events Probabilistic Risk Assessment (ASME-RA-Sb-2005) includes high-level and supporting technical requirements for developing internal flooding probabilistic risk assessment (IFPRA). This industry standard is endorsed in Regulatory Guide 1.200, Revision 1 as an acceptable approach for addressing the risk contribution from IF events for risk informed applications that require U.S. Nuclear Regulatory commission (NRC) approval. In 2006, EPRI published a draft report for IFPRA that addresses the requirements of the ASME PRA consensus standard and have made efforts to refine and update the final EPRI IFPRA guideline. Westinghouse has performed an IFPRA analysis for several nuclear power plants (NPPs), such as Watts Bar and Fort Calhoun, using the draft EPRI guidelines for development of an IFPRA. Proprietary methodologies have been developed to apply the EPRI guidelines. The objectives of the draft report for IFPRA guideline are to: {center_dot} Provide guidance for PSA practitioners in the performance of the elements of a PRA associated with internal flooding events consistent with the current state of the art for internal flooding PRA {center_dot} Provide guidance regarding acceptable approaches that is sufficient to meeting the requirements of the ASME PRA Standard associated with internal flooding {center_dot} Incorporate lessons learned in the performance of internal flooding PRAs including those identified as pilot applications of earlier drafts of this procedures guide The purpose of this paper is to present a vision for domestic nuclear power plants' IFPRA by comparing the method of the draft EPRI guidelines with the existing IFPRA method for domestic NPPs.

Integrated probabilistic risk assessment for nanoparticles: the case of nanosilica in food

OpenAIRE

Jacobs, R.; Voet, van der, H.; Braak, ter, C.J.F.

2015-01-01

Insight into risks of nanotechnology and the use of nanoparticles is an essential condition for the social acceptance and safe use of nanotechnology. One of the problems with which the risk assessment of nanoparticles is faced is the lack of data, resulting in uncertainty in the risk assessment. We attempt to quantify some of this uncertainty by expanding a previous deterministic study on nanosilica (5?200?nm) in food into a fully integrated probabilistic risk assessment. We use the integrate...

Probabilistic risk assessment of abalone Haliotis diversicolor supertexta exposed to waterborne zinc

International Nuclear Information System (INIS)

Liao Chungmin; Ling Minpei

2004-01-01

This paper describes a risk assessment approach that integrates predicted tissue concentrations of zinc (Zn) with a concentration-response relationship and leads to predictions of survival risk for pond abalone Haliotis diversicolor supertexta as well as to the uncertainties associated with these predictions. The models implemented include a probabilistic bioaccumulation model, which linking biokinetic and consumer-resource models, accounts for Zn exposure profile and a modified Hill model for reconstructing a dose-response profile for abalone exposed to waterborne Zn. The growth risk is assessed by hazard quotients characterized by measured water level and chronic no-observed effect concentration. Our risk analyses for H. diversicolor supertexta reared near Toucheng, Kouhu, and Anping, respectively, in north, central, and south Taiwan region indicate a relatively low likelihood that survival is being affected by waterborne Zn. Expected risks of mortality for abalone were estimated as 0.46 (Toucheng), 0.36 (Kouhu), and 0.29 (Anping). The predicted 90th-percentiles of hazard quotient for potential growth risk were estimated as 1.94 (Toucheng), 0.47 (Kouhu), and 0.51 (Anping). These findings indicate that waterborne Zn exposure poses no significant risk to pond abalone in Kouhu and Anping, yet a relative high growth risk in Toucheng is alarming. Because of a scarcity of toxicity and exposure data, the probabilistic risk assessment was based on very conservative assumptions. - A novel risk assessment method was developed for abalone

Probabilistic risk assessment of abalone Haliotis diversicolor supertexta exposed to waterborne zinc

Energy Technology Data Exchange (ETDEWEB)

Liao Chungmin; Ling Minpei

2004-01-01

This paper describes a risk assessment approach that integrates predicted tissue concentrations of zinc (Zn) with a concentration-response relationship and leads to predictions of survival risk for pond abalone Haliotis diversicolor supertexta as well as to the uncertainties associated with these predictions. The models implemented include a probabilistic bioaccumulation model, which linking biokinetic and consumer-resource models, accounts for Zn exposure profile and a modified Hill model for reconstructing a dose-response profile for abalone exposed to waterborne Zn. The growth risk is assessed by hazard quotients characterized by measured water level and chronic no-observed effect concentration. Our risk analyses for H. diversicolor supertexta reared near Toucheng, Kouhu, and Anping, respectively, in north, central, and south Taiwan region indicate a relatively low likelihood that survival is being affected by waterborne Zn. Expected risks of mortality for abalone were estimated as 0.46 (Toucheng), 0.36 (Kouhu), and 0.29 (Anping). The predicted 90th-percentiles of hazard quotient for potential growth risk were estimated as 1.94 (Toucheng), 0.47 (Kouhu), and 0.51 (Anping). These findings indicate that waterborne Zn exposure poses no significant risk to pond abalone in Kouhu and Anping, yet a relative high growth risk in Toucheng is alarming. Because of a scarcity of toxicity and exposure data, the probabilistic risk assessment was based on very conservative assumptions. - A novel risk assessment method was developed for abalone.

Risk-informed approach for safety, safeguards, and security (3S) by design

International Nuclear Information System (INIS)

Suzuki, Mitsutoshi; Burr, Tom; Howell, John

2011-01-01

Over several decades the nuclear energy society worldwide has developed safety assessment methodology based on probabilistic risk analysis for incorporating its benefit into design and accident prevention for nuclear reactors. Although safeguards and security communities have different histories and technical aspects compared to safety, risk assessment as a supplement to their current requirements could be developed to promote synergism between Safety, Safeguards, and Security (3S) and to install effective countermeasures in the design of complex nuclear fuel cycle facilities. Since the 3S initiative was raised by G8 countries at Hokkaido Toyako-Summit in 2008, one approach to developing synergism in a 3S By Design (3SBD) process has been the application of risk-oriented assessment methodology. In the existing regulations of safeguards and security, a risk notion has already been considered for inherent threat and hazard recognition. To integrate existing metrics into a risk-oriented approach, several mathematical methods have already been surveyed, with attention to the scarcity of intentional acts in the case of safeguards and the sparseness of actual event data. A two-dimensional probability distribution composed of measurement error and incidence probabilities has been proposed to formalize inherent difficulties in the International Atomic Energy Agency (IAEA) safeguards criteria. In particular, the incidence probability that is difficult to estimate has been explained using a Markov model and game theory. In this work, a feasibility study of 3SBD is performed for an aqueous reprocessing process, and synergetic countermeasures are presented for preliminary demonstration of 3SBD. Although differences and conflicts between individual 'S' communities exist, the integrated approach would be valuable for optimization and balance between the 3S design features as well as for effective and efficient implementation under existing regulation frameworks. In addition

Probabilistic risk assessment in the CPI

International Nuclear Information System (INIS)

Guymer, P.; Kaiser, G.D.; Mc Kelvey, T.C.; Hannaman, G.W.

1987-01-01

Probabilistic Risk Assessment (PRA) is a method of quantifying the frequency of occurrence and magnitude of the consequences of accidents in systems that contain hazardous materials such as toxic, flammable or explosive chemicals. The frequency and magnitude of the consequences are the basic elements in the definition of risk, often simply expressed as the product of frequency and magnitude, summed over all accident sequences. PRA is a mature technique that has been used to estimate risk for a number of industrial facilities: for example, the Canvey Island Petrochemical complex; the Port of Rotterdam; the Reactor Safety Study, the first study to put the risks associated with nuclear power into perspective; and the transportation of chlorine. PRA has been developed to a greater level of sophistication in the nuclear industry than in the chemical industry. In the nuclear area, its usefulness has been demonstrated by increased plant safety, engineering insights, and cost-saving recommendations. Data and methods have been developed to increase the level of realism of the treatment of operator actions in PRA studies. It can be stated generally that the same methods can be applied with equal success in the chemical industry. However, there are pitfalls into which the unwary nuclear-oriented PRA analyst may stumble if he does not bear in mind that there are significant differences between nuclear plants and chemical plants

Comparison between Canadian probabilistic safety assessment methods formulated by Atomic Energy of Canada limited and probabilistic risk assessment methods

International Nuclear Information System (INIS)

Shapiro, H.S.; Smith, J.E.

1989-01-01

The procedures used by Atomic Energy of Canada Limited (AECL) to perform probabilistic safety assessments (PRAs) differ somewhat from conventionally accepted probabilistic risk assessment (PRA) procedures used elsewhere. In Canada, PSA is used by AECL as an audit tool for an evolving design. The purpose is to assess the safety of the plant in engineering terms. Thus, the PSA procedures are geared toward providing engineering feedback so that necessary changes can be made to the design at an early stage, input can be made to operating procedures, and test and maintenance programs can be optimized in terms of costs. Most PRAs, by contrast, are performed in plants that are already built. Their main purpose is to establish the core melt frequency and the risk to the public due to core melt. Also, any design modification is very expensive. The differences in purpose and timing between PSA and PRA have resulted in differences in methodology and scope. The PSA procedures are used on all plants being designed by AECL

Bayesian parameter estimation in probabilistic risk assessment

International Nuclear Information System (INIS)

Siu, Nathan O.; Kelly, Dana L.

1998-01-01

Bayesian statistical methods are widely used in probabilistic risk assessment (PRA) because of their ability to provide useful estimates of model parameters when data are sparse and because the subjective probability framework, from which these methods are derived, is a natural framework to address the decision problems motivating PRA. This paper presents a tutorial on Bayesian parameter estimation especially relevant to PRA. It summarizes the philosophy behind these methods, approaches for constructing likelihood functions and prior distributions, some simple but realistic examples, and a variety of cautions and lessons regarding practical applications. References are also provided for more in-depth coverage of various topics

Information Security Risk Assessment in Hospitals.

Science.gov (United States)

Ayatollahi, Haleh; Shagerdi, Ghazal

2017-01-01

To date, many efforts have been made to classify information security threats, especially in the healthcare area. However, there are still many unknown risks which may threat the security of health information and their resources especially in the hospitals. The aim of this study was to assess the risks threatening information security in the hospitals located in one of the northwest cities of Iran. This study was completed in 2014. The participants were information technology managers who worked in the hospitals (n=27). The research instrument was a questionnaire composed of a number of open and closed questions. The content validity of the questionnaire was confirmed, and the reliability of the closed questions was measured by using the test-retest method (r =0.78). The results showed that among the information security risks, fire found to be a high probability/high impact risk factor. Human and physical/environmental threats were among the low probability risk factors. Regarding the information security safeguards used in the hospitals, the results showed that the use of the technical safeguards was the most frequent one (n =22, 91.7%) compared to the administrative (n =21, 87.5%) and the physical safeguards (n =16, 66.7%). The high probability risk factors require quick corrective actions to be taken. Therefore, the underlying causes of such threats should be identified and controlled before experiencing adverse effects. It is also important to note that information security in health care systems needs to be considered at a macro level with respect to the national interests and policies.

A probabilistic topic model for clinical risk stratification from electronic health records.

Science.gov (United States)

Huang, Zhengxing; Dong, Wei; Duan, Huilong

2015-12-01

Risk stratification aims to provide physicians with the accurate assessment of a patient's clinical risk such that an individualized prevention or management strategy can be developed and delivered. Existing risk stratification techniques mainly focus on predicting the overall risk of an individual patient in a supervised manner, and, at the cohort level, often offer little insight beyond a flat score-based segmentation from the labeled clinical dataset. To this end, in this paper, we propose a new approach for risk stratification by exploring a large volume of electronic health records (EHRs) in an unsupervised fashion. Along this line, this paper proposes a novel probabilistic topic modeling framework called probabilistic risk stratification model (PRSM) based on Latent Dirichlet Allocation (LDA). The proposed PRSM recognizes a patient clinical state as a probabilistic combination of latent sub-profiles, and generates sub-profile-specific risk tiers of patients from their EHRs in a fully unsupervised fashion. The achieved stratification results can be easily recognized as high-, medium- and low-risk, respectively. In addition, we present an extension of PRSM, called weakly supervised PRSM (WS-PRSM) by incorporating minimum prior information into the model, in order to improve the risk stratification accuracy, and to make our models highly portable to risk stratification tasks of various diseases. We verify the effectiveness of the proposed approach on a clinical dataset containing 3463 coronary heart disease (CHD) patient instances. Both PRSM and WS-PRSM were compared with two established supervised risk stratification algorithms, i.e., logistic regression and support vector machine, and showed the effectiveness of our models in risk stratification of CHD in terms of the Area Under the receiver operating characteristic Curve (AUC) analysis. As well, in comparison with PRSM, WS-PRSM has over 2% performance gain, on the experimental dataset, demonstrating that

Improving organisational resilience through enterprise security risk management.

Science.gov (United States)

Petruzzi, John; Loyear, Rachelle

Enterprise Security Risk Management (ESRM) is a new philosophy and method of managing security programmes through the use of traditional risk principles. As a philosophy and life cycle, ESRM is focused on creating a business partnership between security practitioners and business leaders to more effectively provide protection against security risks in line with acceptable risk tolerances as defined by business asset owners and stakeholders. This paper explores the basics of the ESRM philosophy and life cycle and also shows how embracing the ESRM philosophy and implementing a risk-based security management model in the business organisation can lead to higher levels of organisational resilience as desired by organisation leaders, executives and the board of directors.

Probabilistic risk analysis and fault trees: Initial discussion of application to identification of risk at a wellhead

Science.gov (United States)

Rodak, C.; Silliman, S.

2012-02-01

Wellhead protection is of critical importance for managing groundwater resources. While a number of previous authors have addressed questions related to uncertainties in advective capture zones, methods for addressing wellhead protection in the presence of uncertainty in the chemistry of groundwater contaminants, the relationship between land-use and contaminant sources, and the impact on health of the receiving population are limited. It is herein suggested that probabilistic risk analysis (PRA) combined with fault trees (FT) provides a structure whereby chemical transport can be combined with uncertainties in source, chemistry, and health impact to assess the probability of negative health outcomes in the population. As such, PRA-FT provides a new strategy for the identification of areas of probabilistically high human health risk. Application of this approach is demonstrated through a simplified case study involving flow to a well in an unconfined aquifer with heterogeneity in aquifer properties and contaminant sources.

A probabilistic risk assessment for field radiography based on expert judgment and opinion

International Nuclear Information System (INIS)

Jang, Han-Ki; Ryu, Hyung-Joon; Kim, Ji-Young; Lee, Jai-Ki; Cho, Kun-Woo

2011-01-01

A probabilistic approach was applied to assess radiation risk associated with the field radiography using gamma sources. The Delphi method based on the expert judgments and opinions was used in the process of characterization of parameters affecting risk, which are inevitably subject to large uncertainties. A mathematical approach applying the Bayesian inferences was employed for data processing to improve the Delphi results. This process consists of three phases: (1) setting prior distributions, (2) constructing the likelihood functions and (3) deriving the posterior distributions based on the likelihood functions. The approach for characterizing input parameters using the Bayesian inference is provided for improved risk estimates without intentional rejection of part of the data, which demonstrated utility of Bayesian updating of distributions of uncertain input parameters in PRA (Probabilistic Risk Assessment). The data analysis portion for PRA in field radiography is addressed for estimates of the parameters used to determine the frequencies and consequences of the various events modeled. In this study, radiological risks for the worker and the public member in the vicinity of the work place are estimated for field radiography system in Korea based on two-dimensional Monte Carlo Analysis (2D MCA). (author)

Probabilistic risk criteria and their application to nuclear chemical plant design

International Nuclear Information System (INIS)

Arthur, T.; Barnes, D.S.; Brown, M.L.; Taig, A.R.; Johnston, B.D.; Hayns, M.

1989-01-01

A nuclear chemical plant safety strategy is presented. The use of risk criteria in design is demonstrated by reference to a particular area of the plant. This involves the application of Probabilistic Risk Assessment (PRA) techniques. Computer programs developed by the UK Atomic Energy Authority (UKAEA) at its Safety and Reliability Directorate (SRD) are used toe valuate and analyze the resultant fault trees. the magnitude of releases are estimated and individual and societal risks determined. The paper concludes that the application of PRA to a nuclear chemical plant can be structured in such a way as to allow a designer to work to quantitative risk targets

Assessment and presentation of uncertainties in probabilistic risk assessment: how should this be done

International Nuclear Information System (INIS)

Garlick, A.R.; Holloway, N.J.

1987-01-01

Despite continuing improvements in probabilistic risk assessment (PRA) techniques, PRA results, particularly those including degraded core analysis, will have maximum uncertainties of several orders of magnitude. This makes the expression of results, a matter no less important than their estimation. We put forward some ideas on the assessment and expression of highly uncertain quantities, such as probabilities of outcomes of a severe accident. These do not form a consistent set, but rather a number of alternative approaches aimed at stimulating discussion. These include non-probability expressions, such as fuzzy logic or Schafer's support and plausibility which abandon the purely probabilistic expression of risk for a more flexible type of expression, in which other types of measure are possible. The 'risk equivalent plant' concepts represent the opposite approach. Since uncertainty in a risk measure is in itself a form of risk, an attempt is made to define a 'risk equivalent' which is a risk with perfectly defined parameters, regarded (by means of suitable methods of judgement) as 'equally undesirable' with the actual plant. Some guidelines are given on the use of Bayesian methods in data-free or limited data situations. (author)

Security risks arising from portable storage devices

CSIR Research Space (South Africa)

Molotsi, K

2012-10-01

Full Text Available of the security risks arising from the use of PSDs, and further provides possible security countermeasures to help organisations and users to protect their digital assets. APPROACH Literature review: ? To investigate security risks posed by PSDs... technology in the workplace. International Journal of Electronic Security and Digital Forensics. 3(1): 73?81 [3] Kim, K., Kim, E. & Hong S. (2009). Privacy information protection in portable device. Proceedings of International Conference on Convergence...

Asset backed securities : risks, ratings and quantitative modelling

NARCIS (Netherlands)

Jönsson, B.H.B.; Schoutens, W.

2009-01-01

Asset backed securities (ABSs) are structured finance products backed by pools of assets and are created through a securitisation process. The risks in asset backed securities, such as, credit risk, prepayment risk, market risks, operational risk, and legal risks, are directly connected with the

Information security risk assessment, aggregation, and mitigation

NARCIS (Netherlands)

Lenstra, A.K.; Voss, T.; Wang, H.; Pieprzyk, J.; Varadharajan, V.

2004-01-01

As part of their compliance process with the Basel 2 operational risk management requirements, banks must define how they deal with information security risk management. In this paper we describe work in progress on a new quantitative model to assess and aggregate information security risks that is

Uncertainty propagation in probabilistic risk assessment: A comparative study

International Nuclear Information System (INIS)

Ahmed, S.; Metcalf, D.R.; Pegram, J.W.

1982-01-01

Three uncertainty propagation techniques, namely method of moments, discrete probability distribution (DPD), and Monte Carlo simulation, generally used in probabilistic risk assessment, are compared and conclusions drawn in terms of the accuracy of the results. For small uncertainty in the basic event unavailabilities, the three methods give similar results. For large uncertainty, the method of moments is in error, and the appropriate method is to propagate uncertainty in the discrete form either by DPD method without sampling or by Monte Carlo. (orig.)

PRA (probabilistic risk analysis) in the nuclear sector. Quantifying human error and human malice

International Nuclear Information System (INIS)

Heyes, A.G.

1995-01-01

Regardless of the regulatory style chosen ('command and control' or 'functional') a vital prerequisite for coherent safety regulations in the nuclear power industry is the ability to assess accident risk. In this paper we present a critical analysis of current techniques of probabilistic risk analysis applied in the industry, with particular regard to the problems of quantifying risks arising from, or exacerbated by, human risk and/or human error. (Author)

Tolerability of risk, safety assessment principles and their implications for probabilistic safety analysis

International Nuclear Information System (INIS)

Ewing, D.J.F.; Campbell, J.F.

1994-01-01

This paper gives a regulatory view of probabilistic safety assessment as seen by the Nuclear Installations Inspectorate (NII) and in the light of the general regulatory risk aims set out in the Health and Safety Executive's (HSE) The tolerability of risk from nuclear power stations (TOR) and in Safety assessment principles for nuclear plants (SAPs), prepared by NII on behalf of the HSE. Both of these publications were revised and republished in 1992. This paper describes the SAPs, together with the historical background, the motivation for review, the effects of the Sizewell and Hinkley Point C public inquiries, changes since the original versions, comparison with international standards and use in assessment. For new plant, probabilistic safety analysis (PSA) is seen as an essential tool in balancing the safety of the design and in demonstrating compliance with TOR and the SAPs. (Author)

Critical infrastructure cyber-security risk management

OpenAIRE

Spyridopoulos, T.; Maraslis, K.; Tryfonas, T.; Oikonomou, G.

2017-01-01

Traditional IT cyber-security risk management methods are based on the evaluation of risks calculated as the likelihood of cyber-security incidents occurring. However, these probabilities are usually estimations or guesses based on past experience and incomplete data. Incorrect estimations can lead to errors in the evaluation of risks that can ultimately affect the protection of the system. This issue is also transferred to methods used in Industrial Control Systems (ICSs), as they are mainly...

Probabilistic Modeling of Seismic Risk Based Design for a Dual System Structure

OpenAIRE

Sidi, Indra Djati

2017-01-01

The dual system structure concept has gained popularity in the construction of high-rise buildings over the last decades. Meanwhile, earthquake engineering design provisions for buildings have moved from the uniform hazard concept to the uniform risk concept upon recognizing the uncertainties involved in the earthquake resistance of concrete structures. In this study, a probabilistic model for the evaluation of such risk is proposed for a dual system structure consisting of shear walls or cor...

Advanced Seismic Probabilistic Risk Assessment Demonstration Project Plan

Energy Technology Data Exchange (ETDEWEB)

Coleman, Justin [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2014-09-01

Idaho National Laboratories (INL) has an ongoing research and development (R&D) project to remove excess conservatism from seismic probabilistic risk assessments (SPRA) calculations. These risk calculations should focus on providing best estimate results, and associated insights, for evaluation and decision-making. This report presents a plan for improving our current traditional SPRA process using a seismic event recorded at a nuclear power plant site, with known outcomes, to improve the decision making process. SPRAs are intended to provide best estimates of the various combinations of structural and equipment failures that can lead to a seismic induced core damage event. However, in general this approach has been conservative, and potentially masks other important events (for instance, it was not the seismic motions that caused the Fukushima core melt events, but the tsunami ingress into the facility).

Flood Risk and Probabilistic Benefit Assessment to Support Management of Flood-Prone Lands: Evidence From Candaba Floodplains, Philippines

Science.gov (United States)

Juarez, A. M.; Kibler, K. M.; Sayama, T.; Ohara, M.

2016-12-01

Flood management decision-making is often supported by risk assessment, which may overlook the role of coping capacity and the potential benefits derived from direct use of flood-prone land. Alternatively, risk-benefit analysis can support floodplain management to yield maximum socio-ecological benefits for the minimum flood risk. We evaluate flood risk-probabilistic benefit tradeoffs of livelihood practices compatible with direct human use of flood-prone land (agriculture/wild fisheries) and nature conservation (wild fisheries only) in Candaba, Philippines. Located north-west to Metro Manila, Candaba area is a multi-functional landscape that provides a temporally-variable mix of possible land uses, benefits and ecosystem services of local and regional value. To characterize inundation from 1.3- to 100-year recurrence intervals we couple frequency analysis with rainfall-runoff-inundation modelling and remotely-sensed data. By combining simulated probabilistic floods with both damage and benefit functions (e.g. fish capture and rice yield with flood intensity) we estimate potential damages and benefits over varying probabilistic flood hazards. We find that although direct human uses of flood-prone land are associated with damages, for all the investigated magnitudes of flood events with different frequencies, the probabilistic benefits ( 91 million) exceed risks by a large margin ( 33 million). Even considering risk, probabilistic livelihood benefits of direct human uses far exceed benefits provided by scenarios that exclude direct "risky" human uses (difference of 85 million). In addition, we find that individual coping strategies, such as adapting crop planting periods to the flood pulse or fishing rather than cultivating rice in the wet season, minimize flood losses ( 6 million) while allowing for valuable livelihood benefits ($ 125 million) in flood-prone land. Analysis of societal benefits and local capacities to cope with regular floods demonstrate the

Probabilistic Risk Assessment (PRA): A Practical and Cost Effective Approach

Science.gov (United States)

Lee, Lydia L.; Ingegneri, Antonino J.; Djam, Melody

2006-01-01

The Lunar Reconnaissance Orbiter (LRO) is the first mission of the Robotic Lunar Exploration Program (RLEP), a space exploration venture to the Moon, Mars and beyond. The LRO mission includes spacecraft developed by NASA Goddard Space Flight Center (GSFC) and seven instruments built by GSFC, Russia, and contractors across the nation. LRO is defined as a measurement mission, not a science mission. It emphasizes the overall objectives of obtaining data to facilitate returning mankind safely to the Moon in preparation for an eventual manned mission to Mars. As the first mission in response to the President's commitment of the journey of exploring the solar system and beyond: returning to the Moon in the next decade, then venturing further into the solar system, ultimately sending humans to Mars and beyond, LRO has high-visibility to the public but limited resources and a tight schedule. This paper demonstrates how NASA's Lunar Reconnaissance Orbiter Mission project office incorporated reliability analyses in assessing risks and performing design tradeoffs to ensure mission success. Risk assessment is performed using NASA Procedural Requirements (NPR) 8705.5 - Probabilistic Risk Assessment (PRA) Procedures for NASA Programs and Projects to formulate probabilistic risk assessment (PRA). As required, a limited scope PRA is being performed for the LRO project. The PRA is used to optimize the mission design within mandated budget, manpower, and schedule constraints. The technique that LRO project office uses to perform PRA relies on the application of a component failure database to quantify the potential mission success risks. To ensure mission success in an efficient manner, low cost and tight schedule, the traditional reliability analyses, such as reliability predictions, Failure Modes and Effects Analysis (FMEA), and Fault Tree Analysis (FTA), are used to perform PRA for the large system of LRO with more than 14,000 piece parts and over 120 purchased or contractor

National security risks? Uncertainty, austerity and other logics of risk in the UK government’s National Security Strategy

NARCIS (Netherlands)

Hammerstad, A.; Boas, I.J.C.

2015-01-01

Risk scholars within Security Studies have argued that the concept of security has gone through a fundamental transformation away from a threat-based conceptualisation of defence, urgency
and exceptionality to one of preparedness, precautions and prevention of future risks, some of which are

Probabilistic modeling of the flows and environmental risks of nano-silica.

Science.gov (United States)

Wang, Yan; Kalinina, Anna; Sun, Tianyin; Nowack, Bernd

2016-03-01

Nano-silica, the engineered nanomaterial with one of the largest production volumes, has a wide range of applications in consumer products and industry. This study aimed to quantify the exposure of nano-silica to the environment and to assess its risk to surface waters. Concentrations were calculated for four environmental (air, soil, surface water, sediments) and two technical compartments (wastewater, solid waste) for the EU and Switzerland using probabilistic material flow modeling. The corresponding median concentration in surface water is predicted to be 0.12 μg/l in the EU (0.053-3.3 μg/l, 15/85% quantiles). The concentrations in sediments in the complete sedimentation scenario were found to be the largest among all environmental compartments, with a median annual increase of 0.43 mg/kg · y in the EU (0.19-12 mg/kg · y, 15/85% quantiles). Moreover, probabilistic species sensitivity distributions (PSSD) were computed and the risk of nano-silica in surface waters was quantified by comparing the predicted environmental concentration (PEC) with the predicted no-effect concentration (PNEC) distribution, which was derived from the cumulative PSSD. This assessment suggests that nano-silica currently poses no risk to aquatic organisms in surface waters. Further investigations are needed to assess the risk of nano-silica in other environmental compartments, which is currently not possible due to a lack of ecotoxicological data. Copyright © 2015 Elsevier B.V. All rights reserved.

Probabilistic disaggregation of a spatial portfolio of exposure for natural hazard risk assessment

DEFF Research Database (Denmark)

Custer, Rocco; Nishijima, Kazuyoshi

2018-01-01

In natural hazard risk assessment situations are encountered where information on the portfolio of exposure is only available in a spatially aggregated form, hindering a precise risk assessment. Recourse might be found in the spatial disaggregation of the portfolio of exposure to the resolution...... of a portfolio of buildings in two communes in Switzerland and the results are compared to sample observations. The relevance of probabilistic disaggregation uncertainty in natural hazard risk assessment is illustrated with the example of a simple flood risk assessment....

Improving Information Security Risk Management

Science.gov (United States)

Singh, Anand

2009-01-01

manaOptimizing risk to information to protect the enterprise as well as to satisfy government and industry mandates is a core function of most information security departments. Risk management is the discipline that is focused on assessing, mitigating, monitoring and optimizing risks to information. Risk assessments and analyses are critical…

Probabilistic risk assessment for the Sandia National Laboratories Technical Area V Liquid Waste Disposal System surface impoundments

International Nuclear Information System (INIS)

Dawson, L.A.; Eidson, A.F.

1996-01-01

A probabilistic risk assessment was completed for a former radioactive waste disposal site. The site, two unlined surface impoundment, was designed as part of the Liquid Waste Disposal System (LWDS) to receive radioactive effluent from nuclear reactors in Technical Area-V (TA-V) at Sandia National Laboratories/New Mexico (SNL/NM). First, a statistical comparison of site sampling results to natural background, using EPA methods, and a spatial distribution analysis were performed. Risk assessment was conducted with SNL/NM's Probabilistic Risk Evaluation and Characterization Investigation System model. The risk assessment indicated that contamination from several constituents might have been high enough to require remediation. However, further analysis based on expected site closure activities and recent EPA guidance indicated that No Further Action was acceptable

Risk-Informed Safety Assurance and Probabilistic Assessment of Mission-Critical Software-Intensive Systems

Science.gov (United States)

Guarro, Sergio B.

2010-01-01

This report validates and documents the detailed features and practical application of the framework for software intensive digital systems risk assessment and risk-informed safety assurance presented in the NASA PRA Procedures Guide for Managers and Practitioner. This framework, called herein the "Context-based Software Risk Model" (CSRM), enables the assessment of the contribution of software and software-intensive digital systems to overall system risk, in a manner which is entirely compatible and integrated with the format of a "standard" Probabilistic Risk Assessment (PRA), as currently documented and applied for NASA missions and applications. The CSRM also provides a risk-informed path and criteria for conducting organized and systematic digital system and software testing so that, within this risk-informed paradigm, the achievement of a quantitatively defined level of safety and mission success assurance may be targeted and demonstrated. The framework is based on the concept of context-dependent software risk scenarios and on the modeling of such scenarios via the use of traditional PRA techniques - i.e., event trees and fault trees - in combination with more advanced modeling devices such as the Dynamic Flowgraph Methodology (DFM) or other dynamic logic-modeling representations. The scenarios can be synthesized and quantified in a conditional logic and probabilistic formulation. The application of the CSRM method documented in this report refers to the MiniAERCam system designed and developed by the NASA Johnson Space Center.

Recent case studies and advancements in probabilistic risk assessment

International Nuclear Information System (INIS)

Garrick, B.J.

1985-01-01

During the period from 1977 to 1984, Pickard, Lowe and Garrick, Inc., had the lead in preparing several full scope probabilistic risk assessments for electric utilities. Five of those studies are discussed from the point of view of advancements and lessons learned. The objective and trend of these studies is toward utilization of the risk models by the plant owners as risk management tools. Advancements that have been made are in presentation ad documentation of the PRAs, generation of more understandable plant level information, and improvements in methodology to facilitate technology transfer. Specific areas of advancement are in the treatment of such issues as dependent failures, human interaction, and the uncertainty in the source term. Lessons learned cover a wide spectrum and include the importance of plant specific models for meaningful risk management, the role of external events in risk, the sensitivity of contributors to choice of risk index, and the very important finding that the public risk is extremely small. The future direction of PRA is to establish less dependence on experts for in-plant application. Computerizing the PRAs such that they can be accessed on line and interactively is the key

Implementation of condition-dependent probabilistic risk assessment using surveillance data on passive components

International Nuclear Information System (INIS)

Lewandowski, Radoslaw; Denning, Richard; Aldemir, Tunc; Zhang, Jinsuo

2016-01-01

Highlights: • Condition-dependent probabilistic risk assessment (PRA). • Time-dependent characterization of plant-specific risk. • Containment bypass involving in secondary system piping and SCC in SG tubes. - Abstract: A great deal of surveillance data are collected for a nuclear power plant that reflect the changing condition of the plant as it ages. Although surveillance data are used to determine failure probabilities of active components for the plant’s probabilistic risk assessment (PRA) and to indicate the need for maintenance activities, they are not used in a structured manner to characterize the evolving risk of the plant. The present study explores the feasibility of using a condition-dependent PRA framework that takes a first principles approach to modeling the progression of degradation mechanisms to characterize evolving risk, periodically adapting the model to account for surveillance results. A case study is described involving a potential containment bypass accident sequence due to the progression of flow-accelerated corrosion in secondary system piping and stress corrosion cracking of steam generator tubes. In this sequence, a steam line break accompanied by failure to close of a main steam isolation valve results in depressurization of the steam generator and induces the rupture of one or more faulted steam generator tubes. The case study indicates that a condition-dependent PRA framework might be capable of providing early identification of degradation mechanisms important to plant risk.

Climate Change and Risks to National Security

Science.gov (United States)

Titley, D.

2017-12-01

Climate change impacts national security in three ways: through changes in the operating environments of the military; by increasing risks to security infrastructure, specifically bases and training ranges; and by exacerbating and accelerating the risks of state collapse and conflict in regions that are already fragile and unstable. Additionally there will be unique security challenges in the Arctic as sea-ice melts out and human activities increase across multiple dimensions. Military forces will also likely see increased demand for Humanitarian Assistance and Disaster Relief resulting from a combination of increased human population, rising sea-level, and potentially stronger and wetter storms. The talk will explore some of the lesser known aspects of these changes, examine selected climate-driven 'wild cards' that have the potential to disrupt regional and global security, and explore how migration in the face of a changing climate may heighten security issues. I will assess the positions U.S. executive and legislative branches with respect to climate & security, and how those positions have evolved since the November 2016 election, sometimes in counter-intuitive ways. The talk will close with some recommended courses of action the security enterprise can take to manage this climate risk.

Audit Teknologiinformasiatas Physical Security Control Dan Logical Security Control Serta Penentuan Kondisi Security Risk Studi Kasus: PT Talc Indonesia

OpenAIRE

Inggrid; Arfianti, Rizka I; Utami, Viany

2009-01-01

Abstract The fast growth of technology has an impact to the accounting field. This relates to the term of information technology (17) auditing. One of the risI6 of using information technology in business which can be fatal enough i fignored is security risk Security risk can be reduced by security controls which include physical security control and logical security contra Information technology auditing is the process of collecting and evaluating evidence to determine whether or not a co...

Risk to Water Security on Small Islands

Science.gov (United States)

Holding, S. T.; Allen, D. M.

2013-12-01

The majority of fresh water available on small islands is shallow groundwater that forms a freshwater lens. Freshwater lenses are generally limited in extent and as such are vulnerable to many stressors that impact water security. These include stressors related to climate change, such as sea level rise, as well as those related to human impacts, such as contamination. Traditionally, water security assessments have focussed on indicators that provide a snapshot of the current condition. However, recent work suggests that in order to effectively manage the water system, it is also important to consider uncertain future impacts to the system by evaluating how different stressors might impact water security. In this study, a framework for assessing risk to water security was developed and tested on Andros Island in The Bahamas. The assessment comprises two main components that characterise the water system: numerical modelling studies and a hazard survey. A baseline numerical model of the freshwater lens throughout Andros Island was developed to simulate the morphology of the freshwater lens and estimate the freshwater resources currently available. The model was prepared using SEAWAT, a density-dependent flow and solute transport code. Various stressors were simulated in the model to evaluate the response of the freshwater lens to predicted future shifts in climate patterns, sea level rise, and changes in water use. A hazard survey was also conducted on the island to collect information related to the storage of contaminants, sanitation infrastructure, waste disposal practices and groundwater abstraction rates. The results of the survey form a geo-spatial database of the location and associated hazards to the freshwater lens. The resulting risk framework provides a ranking of overall risk to water security based on information from the numerical modelling and hazard survey. The risk framework is implemented in a Geographic Information System (GIS) and provides a map

RiskREP: Risk-Based Security Requirements Elicitation and Prioritization (extended version)

NARCIS (Netherlands)

Herrmann, Andrea; Morali, A.

2010-01-01

Today, companies are required to be in control of the security of their IT assets. This is especially challenging in the presence of limited budgets and conflicting requirements. Here, we present Risk-Based Requirements Elicitation and Prioritization (RiskREP), a method for managing IT security

Seismic risk maps of Switzerland; description of the probabilistic method and discussion of some input parameters

International Nuclear Information System (INIS)

Mayer-Rosa, D.; Merz, H.A.

1976-01-01

The probabilistic model used in a seismic risk mapping project for Switzerland is presented. Some of its advantages and limitations are spelled out. In addition some earthquake parameters which should be carefully investigated before using them in a seismic risk analysis are discussed

Towards Agile Security Risk Management in RE and Beyond

NARCIS (Netherlands)

Nunes Leal Franqueira, V.; Bakalova, Z.; Tun, Thein Tan; Daneva, Maia

Little attention has been given so far to the process of security risk management at the early stages of system development. Security has been addressed by isolated security assurance practices, some of which consider risks and mitigations but they do not provide an overview of the overall security

Security Risk Assessment in Software Development Projects

OpenAIRE

Svendsen, Heidi

2017-01-01

Software security is increasing in importance, linearly with vulnerabilities caused by software flaws. It is not possible to spend all the project s resources on software security. To spend the resources given to security in an effective way, one should know what is most important to protect. By performing a risk analysis the project know which vulnerabilities they face. A risk analysis will prioritise the vulnerabilities, and when the vulnerabilities are prioritised the project know where th...

Probabilistic assessment of roadway departure risk in a curve

Science.gov (United States)

Rey, G.; Clair, D.; Fogli, M.; Bernardin, F.

2011-10-01

Roadway departure while cornering constitutes a major part of car accidents and casualties in France. Even though drastic policy about overspeeding contributes to reduce accidents, there obviously exist other factors. This article presents the construction of a probabilistic strategy for the roadway departure risk assessment. A specific vehicle dynamic model is developed in which some parameters are modelled by random variables. These parameters are deduced from a sensitivity analysis to ensure an efficient representation of the inherent uncertainties of the system. Then, structural reliability methods are employed to assess the roadway departure risk in function of the initial conditions measured at the entrance of the curve. This study is conducted within the French national road safety project SARI that aims to implement a warning systems alerting the driver in case of dangerous situation.

Probabilistic risk assessment of aircraft impact on a spent nuclear fuel dry storage

Energy Technology Data Exchange (ETDEWEB)

Almomani, Belal, E-mail: balmomani@kaist.ac.kr [Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Lee, Sanghoon, E-mail: shlee1222@kmu.ac.kr [Department of Mechanical and Automotive Engineering, Keimyung University, Dalgubeol-daero 1095, Dalseo-gu, Daegu (Korea, Republic of); Jang, Dongchan, E-mail: dongchan.jang@kaist.ac.kr [Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Kang, Hyun Gook, E-mail: kangh6@rpi.edu [Department of Mechanical, Aerospace and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180 (United States)

2017-01-15

Highlights: • A new risk assessment frame is proposed for aircraft impact into an interim dry storage. • It uses event tree analysis, response-structural analysis, consequence analysis, and Monte Carlo simulation. • A case study of the proposed procedure is presented to illustrate the methodology’s application. - Abstract: This paper proposes a systematic risk evaluation framework for one of the most significant impact events on an interim dry storage facility, an aircraft crash, by using a probabilistic approach. A realistic case study that includes a specific cask model and selected impact conditions is performed to demonstrate the practical applicability of the proposed framework. An event tree analysis of an occurred aircraft crash that defines a set of impact conditions and storage cask response is constructed. The Monte-Carlo simulation is employed for the probabilistic approach in consideration of sources of uncertainty associated with the impact loads onto the internal storage casks. The parameters for representing uncertainties that are managed probabilistically include the aircraft impact velocity, the compressive strength of the reinforced concrete wall, the missile shape factor, and the facility wall thickness. Failure probabilities of the impacted wall and a single storage cask under direct mechanical impact load caused by the aircraft crash are estimated. A finite element analysis is applied to simulate the postulated direct engine impact load onto the cask body, and a source term analysis for associated releases of radioactive materials as well as an off-site consequence analysis are performed. Finally, conditional risk contribution calculations are represented by an event tree model. Case study results indicate that no severe risk is presented, as the radiological consequences do not exceed regulatory exposure limits to the public. This risk model can be used with any other representative detailed parameters and reference design concepts for

Development of reliability and probabilistic safety assessment program RiskA

International Nuclear Information System (INIS)

Wu, Yican

2015-01-01

Highlights: • There are four parts in the structure of RiskA. User input part lets users input the PSA model and some necessary data by GUI or model transformation tool. In calculation engine part, fault tree analysis, event tree analysis, uncertainty analysis, sensitivity analysis, importance analysis and failure mode and effects analysis are supplied. User output part outputs the analysis results, user customized reports and some other data. The last part includes reliability database, some other common tools and help documents. • RiskA has several advanced features. Extensible framework makes it easy to add any new functions, making RiskA to be a large platform of reliability and probabilistic safety assessment. It is very fast to analysis fault tree in RiskA because many advanced algorithm improvement were made. Many model formats can be imported and exported, which made the PSA model in the commercial software can be easily transformed to adapt RiskA platform. Web-based co-modeling let several users in different places work together whenever they are online. • The comparison between RiskA and other mature PSA codes (e.g. CAFTA, RiskSpectrum, XFTA) has demonstrated that the calculation and analysis of RiskA is correct and efficient. Based on the development of this code package, many applications of safety and reliability analysis of some research reactors and nuclear power plants were performed. The development of RiskA appears to be of realistic and potential value for academic research and practical operation safety management of nuclear power plants in China and abroad. - Abstract: PSA (probabilistic safety assessment) software, the indispensable tool in nuclear safety assessment, has been widely used. An integrated reliability and PSA program named RiskA has been developed by FDS Team. RiskA supplies several standard PSA modules including fault tree analysis, event tree analysis, uncertainty analysis, failure mode and effect analysis and reliability

Development of probabilistic risk analysis library

International Nuclear Information System (INIS)

Soga, Shota; Kirimoto, Yukihiro; Kanda, Kenichi

2015-01-01

We developed a library that is designed to perform level 1 Probabilistic Risk Analysis using Binary Decision Diagram (BDD). In particular, our goal is to develop a library that will allow Japanese electric utilities to take the advantages of BDD that can solve Event Tree (ET) and Fault Tree (FT) models analytically. Using BDD, the library supports negation in FT which allows more flexible modeling of ET/FT. The library is written by C++ within an object-oriented framework using open source software. The library itself is a header-only library so that Japanese electric utilities can take advantages of its transparency to speed up development and to build their own software for their specific needs. In this report, the basic capabilities of the library is briefly described. In addition, several applications of the library are demonstrated including validation of MCS evaluation of PRA model and evaluation of corrective and preventive maintenance considering common cause failure. (author)

Security engineering: systems engineering of security through the adaptation and application of risk management

Science.gov (United States)

Gilliam, David P.; Feather, Martin S.

2004-01-01

Information Technology (IT) Security Risk Management is a critical task in the organization, which must protect its resources and data against the loss of confidentiality, integrity, and availability. As systems become more complex and diverse, and more vulnerabilities are discovered while attacks from intrusions and malicious content increase, it is becoming increasingly difficult to manage IT security. This paper describes an approach to address IT security risk through risk management and mitigation in both the institution and in the project life cycle.

Probabilistic seasonal Forecasts to deterministic Farm Leve Decisions: Innovative Approach

Science.gov (United States)

Mwangi, M. W.

2015-12-01

Climate change and vulnerability are major challenges in ensuring household food security. Climate information services have the potential to cushion rural households from extreme climate risks. However, most the probabilistic nature of climate information products is not easily understood by majority of smallholder farmers. Despite the probabilistic nature, climate information have proved to be a valuable climate risk adaptation strategy at the farm level. This calls for innovative ways to help farmers understand and apply climate information services to inform their farm level decisions. The study endeavored to co-design and test appropriate innovation systems for climate information services uptake and scale up necessary for achieving climate risk development. In addition it also determined the conditions necessary to support the effective performance of the proposed innovation system. Data and information sources included systematic literature review, secondary sources, government statistics, focused group discussions, household surveys and semi-structured interviews. Data wasanalyzed using both quantitative and qualitative data analysis techniques. Quantitative data was analyzed using the Statistical Package for Social Sciences (SPSS) software. Qualitative data was analyzed using qualitative techniques, which involved establishing the categories and themes, relationships/patterns and conclusions in line with the study objectives. Sustainable livelihood, reduced household poverty and climate change resilience were the impact that resulted from the study.

A probabilistic quantitative risk assessment model for the long-term work zone crashes.

Science.gov (United States)

Meng, Qiang; Weng, Jinxian; Qu, Xiaobo

2010-11-01

Work zones especially long-term work zones increase traffic conflicts and cause safety problems. Proper casualty risk assessment for a work zone is of importance for both traffic safety engineers and travelers. This paper develops a novel probabilistic quantitative risk assessment (QRA) model to evaluate the casualty risk combining frequency and consequence of all accident scenarios triggered by long-term work zone crashes. The casualty risk is measured by the individual risk and societal risk. The individual risk can be interpreted as the frequency of a driver/passenger being killed or injured, and the societal risk describes the relation between frequency and the number of casualties. The proposed probabilistic QRA model consists of the estimation of work zone crash frequency, an event tree and consequence estimation models. There are seven intermediate events--age (A), crash unit (CU), vehicle type (VT), alcohol (AL), light condition (LC), crash type (CT) and severity (S)--in the event tree. Since the estimated value of probability for some intermediate event may have large uncertainty, the uncertainty can thus be characterized by a random variable. The consequence estimation model takes into account the combination effects of speed and emergency medical service response time (ERT) on the consequence of work zone crash. Finally, a numerical example based on the Southeast Michigan work zone crash data is carried out. The numerical results show that there will be a 62% decrease of individual fatality risk and 44% reduction of individual injury risk if the mean travel speed is slowed down by 20%. In addition, there will be a 5% reduction of individual fatality risk and 0.05% reduction of individual injury risk if ERT is reduced by 20%. In other words, slowing down speed is more effective than reducing ERT in the casualty risk mitigation. 2010 Elsevier Ltd. All rights reserved.

Application of probabilistic risk assessment methodology to fusion

International Nuclear Information System (INIS)

Piet, S.J.

1985-07-01

Probabilistic Risk Assessment (PRA) tools are applied to general fusion issues in a systematic way, generally qualitatively. The potential value of PRA to general fusion safety and economic issues is discussed. Several important design insights result: possible fault interactions must be minimized (decouple fault conditions), inherently safe designs must include provision for passively handling loss of site power and loss of coolant conditions, the reliability of the vacuum boundary appears vital to maximizing facility availabilty and minimizing safety risk, and economic analyses appear to be incomplete without consideration of potential availability loss from forced outrages. A modification to PRA formalism is introduced, called the fault interaction matrix. The fault interaction matrix contains information concerning what initial fault condition could lead to other fault conditions and with what frequency. Thus, the fault interaction matrix represents a way to present and measure the degree to which a designer has decoupled possible fault conditions in his design

Applications of the EBR-II Probabilistic Risk Assessment

International Nuclear Information System (INIS)

Roglans, J.: Ragland, W.A.; Hill, D.J.

1993-01-01

A Probabilistic Risk Assessment (PRA) of the Experimental Breeder Reactor 11 (EBR-11), a Department of Energy (DOE) Category A research reactor, has recently been completed at Argonne National Laboratory (ANL), and has been performed with close collaboration between PRA analysts and engineering and operations staff. A product of this Involvement of plant personnel has been a excellent acceptance of the PRA as a tool, which has already resulted In a variety of applications of the EBR-11 PRA. The EBR-11 has been used in support of plant hardware and procedure modifications and In new system design work. A new application in support of the refueling safety analysis will be completed in the near future

Are engineered nano iron oxide particles safe? an environmental risk assessment by probabilistic exposure, effects and risk modeling.

Science.gov (United States)

Wang, Yan; Deng, Lei; Caballero-Guzman, Alejandro; Nowack, Bernd

2016-12-01

Nano iron oxide particles are beneficial to our daily lives through their use in paints, construction materials, biomedical imaging and other industrial fields. However, little is known about the possible risks associated with the current exposure level of engineered nano iron oxides (nano-FeOX) to organisms in the environment. The goal of this study was to predict the release of nano-FeOX to the environment and assess their risks for surface waters in the EU and Switzerland. The material flows of nano-FeOX to technical compartments (waste incineration and waste water treatment plants) and to the environment were calculated with a probabilistic modeling approach. The mean value of the predicted environmental concentrations (PECs) of nano-FeOX in surface waters in the EU for a worst-case scenario (no particle sedimentation) was estimated to be 28 ng/l. Using a probabilistic species sensitivity distribution, the predicted no-effect concentration (PNEC) was determined from ecotoxicological data. The risk characterization ratio, calculated by dividing the PEC by PNEC values, was used to characterize the risks. The mean risk characterization ratio was predicted to be several orders of magnitude smaller than 1 (1.4 × 10 - 4 ). Therefore, this modeling effort indicates that only a very limited risk is posed by the current release level of nano-FeOX to organisms in surface waters. However, a better understanding of the hazards of nano-FeOX to the organisms in other ecosystems (such as sediment) needs to be assessed to determine the overall risk of these particles to the environment.

Health Security and Risk Aversion.

Science.gov (United States)

Herington, Jonathan

2016-09-01

Health security has become a popular way of justifying efforts to control catastrophic threats to public health. Unfortunately, there has been little analysis of the concept of health security, nor the relationship between health security and other potential aims of public health policy. In this paper I develop an account of health security as an aversion to risky policy options. I explore three reasons for thinking risk avoidance is a distinctly worthwhile aim of public health policy: (i) that security is intrinsically valuable, (ii) that it is necessary for social planning and (iii) that it is an appropriate response to decision-making in contexts of very limited information. Striking the right balance between securing and maximizing population health thus requires a substantive, and hitherto unrecognized, value judgment. Finally, I critically evaluate the current health security agenda in light of this new account of the concept and its relationship to the other aims of public health policy. © 2016 John Wiley & Sons Ltd.

Some probabilistic aspects of fracture

International Nuclear Information System (INIS)

Thomas, J.M.

1982-01-01

Some probabilistic aspects of fracture in structural and mechanical components are examined. The principles of fracture mechanics, material quality and inspection uncertainty are formulated into a conceptual and analytical framework for prediction of failure probability. The role of probabilistic fracture mechanics in a more global context of risk and optimization of decisions is illustrated. An example, where Monte Carlo simulation was used to implement a probabilistic fracture mechanics analysis, is discussed. (orig.)

Safety and security risk assessments--now demystified!

Science.gov (United States)

White, Donald E

2011-01-01

Safety/security risk assessments no longer need to spook nor baffle healthcare safety/security managers. This grid template provides at-at-glance quick lookup of the possible threats, the affected people and things, a priority ranking of these risks, and a workable solution for each risk. Using the standard document, spreadsheet, or graphics software already available on your computer, you can easily use a scientific method to produce professional looking risk assessments that get quickly understood by both senior managers and first responders alike!

The Terrestrial Investigation Model: A probabilistic risk assessment model for birds exposed to pesticides

Science.gov (United States)

One of the major recommendations of the National Academy of Science to the USEPA, NMFS and USFWS was to utilize probabilistic methods when assessing the risks of pesticides to federally listed endangered and threatened species. The Terrestrial Investigation Model (TIM, version 3....

Applications of probabilistic risk analysis in nuclear criticality safety design

International Nuclear Information System (INIS)

Chang, J.K.

1992-01-01

Many documents have been prepared that try to define the scope of the criticality analysis and that suggest adding probabilistic risk analysis (PRA) to the deterministic safety analysis. The report of the US Department of Energy (DOE) AL 5481.1B suggested that an accident is credible if the occurrence probability is >1 x 10 -6 /yr. The draft DOE 5480 safety analysis report suggested that safety analyses should include the application of methods such as deterministic safety analysis, risk assessment, reliability engineering, common-cause failure analysis, human reliability analysis, and human factor safety analysis techniques. The US Nuclear Regulatory Commission (NRC) report NRC SG830.110 suggested that major safety analysis methods should include but not be limited to risk assessment, reliability engineering, and human factor safety analysis. All of these suggestions have recommended including PRA in the traditional criticality analysis

Flood risk and adaptation strategies under climate change and urban expansion: A probabilistic analysis using global data.

Science.gov (United States)

Muis, Sanne; Güneralp, Burak; Jongman, Brenden; Aerts, Jeroen C J H; Ward, Philip J

2015-12-15

An accurate understanding of flood risk and its drivers is crucial for effective risk management. Detailed risk projections, including uncertainties, are however rarely available, particularly in developing countries. This paper presents a method that integrates recent advances in global-scale modeling of flood hazard and land change, which enables the probabilistic analysis of future trends in national-scale flood risk. We demonstrate its application to Indonesia. We develop 1000 spatially-explicit projections of urban expansion from 2000 to 2030 that account for uncertainty associated with population and economic growth projections, as well as uncertainty in where urban land change may occur. The projections show that the urban extent increases by 215%-357% (5th and 95th percentiles). Urban expansion is particularly rapid on Java, which accounts for 79% of the national increase. From 2000 to 2030, increases in exposure will elevate flood risk by, on average, 76% and 120% for river and coastal floods. While sea level rise will further increase the exposure-induced trend by 19%-37%, the response of river floods to climate change is highly uncertain. However, as urban expansion is the main driver of future risk, the implementation of adaptation measures is increasingly urgent, regardless of the wide uncertainty in climate projections. Using probabilistic urban projections, we show that spatial planning can be a very effective adaptation strategy. Our study emphasizes that global data can be used successfully for probabilistic risk assessment in data-scarce countries. Copyright © 2015 Elsevier B.V. All rights reserved.

Spatial interactions database development for effective probabilistic risk assessment

International Nuclear Information System (INIS)

Liming, J. K.; Dunn, R. F.

2008-01-01

In preparation for a subsequent probabilistic risk assessment (PRA) fire risk analysis update, the STP Nuclear Operating Company (STPNOC) is updating its spatial interactions database (SID). This work is being performed to support updating the spatial interactions analysis (SIA) initially performed for the original South Texas Project Electric Generating Station (STPEGS) probabilistic safely assessment (PSA) and updated in the STPEGS Level 2 PSA and IPE Report. S/A is a large-scope screening analysis performed for nuclear power plant PRA that serves as a prerequisite basis for more detailed location-dependent, hazard-spec analyses in the PRA, such as fire risk analysis, flooding risk analysis, etc. SIA is required to support the 'completeness' argument for the PRA scope. The objectives of the current SID development effort are to update the spatial interactions analysis data, to the greatest degree practical, to be consistent with the following: the as-built plant as of December 31, 2007 the in-effect STPNOC STPEGS Units 1 and 2 PRA the current technology and intent of NUREG/CR-6850 guidance for lire risk analysis database support the requirements for PRA SIA, including fire and flooding risk analysis, established by NRC Regulatory Guide 1.200 and the ASME PRA Standard (ASME RA-S-2002 updated through ASME RA-Sc-2007,) This paper presents the approach and methodology for state-of-the-art SID development and applications, including an overview of the SIA process for nuclear power plant PRA. The paper shows how current relational database technology and existing, conventional station information sources can be employed to collect, process, and analyze spatial interactions data for the plant in an effective and efficient manner to meet the often challenging requirements of industry guidelines and standards such as NUREG/CR-6850, NRC Regulatory Guide 1.200, and ASME RA-S-2002 (updated through ASME RA-Sc 2007). This paper includes tables and figures illustrating how SIA

Seismic qualification of equipment by means of probabilistic risk assessment

International Nuclear Information System (INIS)

Azarm, M.A.; Farahzad, P.; Boccio, J.L.

1982-01-01

Upon the sponsorship of the Equipment Qualification Branch (EQB) of NRC, Brookhaven National Laboratory (BNL) has utilized a risk-based approach for identifying, in a generic fashion, seismically risk-sensitive equipment. It is anticipated that the conclusions drawn therefrom and the methodology employed will, in part, reconcile some of the concerns dealing with the seismic qualification of equipment in operating plants. The approach taken augments an existing sensitivity analysis, based upon the WASH-1400 Reactor Safety Study (RSS), by accounting for seismicity and component fragility with the Kennedy model and by essentially including the requisite seismic data presented in the Zion Probabilistic Safety Study (ZPSS). Parametrically adjusting the seismic-related variables and ascertaining their effects on overall plant risk, core-melt probability, accident sequence probability, etc., allows one to identify those seismically risk-sensitive systems and equipment. This paper describes the approach taken and highlights the results obtained thus far for a hypothetical pressurized water reactor

A Probabilistic Asteroid Impact Risk Model

Science.gov (United States)

Mathias, Donovan L.; Wheeler, Lorien F.; Dotson, Jessie L.

2016-01-01

Asteroid threat assessment requires the quantification of both the impact likelihood and resulting consequence across the range of possible events. This paper presents a probabilistic asteroid impact risk (PAIR) assessment model developed for this purpose. The model incorporates published impact frequency rates with state-of-the-art consequence assessment tools, applied within a Monte Carlo framework that generates sets of impact scenarios from uncertain parameter distributions. Explicit treatment of atmospheric entry is included to produce energy deposition rates that account for the effects of thermal ablation and object fragmentation. These energy deposition rates are used to model the resulting ground damage, and affected populations are computed for the sampled impact locations. The results for each scenario are aggregated into a distribution of potential outcomes that reflect the range of uncertain impact parameters, population densities, and strike probabilities. As an illustration of the utility of the PAIR model, the results are used to address the question of what minimum size asteroid constitutes a threat to the population. To answer this question, complete distributions of results are combined with a hypothetical risk tolerance posture to provide the minimum size, given sets of initial assumptions. Model outputs demonstrate how such questions can be answered and provide a means for interpreting the effect that input assumptions and uncertainty can have on final risk-based decisions. Model results can be used to prioritize investments to gain knowledge in critical areas or, conversely, to identify areas where additional data has little effect on the metrics of interest.

THE MODEL FOR RISK ASSESSMENT ERP-SYSTEMS INFORMATION SECURITY

Directory of Open Access Journals (Sweden)

V. S. Oladko

2016-12-01

Full Text Available The article deals with the problem assessment of information security risks in the ERP-system. ERP-system functions and architecture are studied. The model malicious impacts on levels of ERP-system architecture are composed. Model-based risk assessment, which is the quantitative and qualitative approach to risk assessment, built on the partial unification 3 methods for studying the risks of information security - security models with full overlapping technique CRAMM and FRAP techniques developed.

Survey of probabilistic methods in safety and risk assessment for nuclear power plant licensing

International Nuclear Information System (INIS)

1984-04-01

After an overview about the goals and general methods of probabilistic approaches in nuclear safety the main features of probabilistic safety or risk assessment (PRA) methods are discussed. Mostly in practical applications not a full-fledged PRA is applied but rather various levels of analysis leading from unavailability assessment of systems over the more complex analysis of the probable core damage stages up to the assessment of the overall health effects on the total population from a certain practice. The various types of application are discussed in relation to their limitation and benefits for different stages of design or operation of nuclear power plants. This gives guidance for licensing staff to judge the usefulness of the various methods for their licensing decisions. Examples of the application of probabilistic methods in several countries are given. Two appendices on reliability analysis and on containment and consequence analysis provide some more details on these subjects. (author)

Security Risks: Management and Mitigation in the Software Life Cycle

Science.gov (United States)

Gilliam, David P.

2004-01-01

A formal approach to managing and mitigating security risks in the software life cycle is requisite to developing software that has a higher degree of assurance that it is free of security defects which pose risk to the computing environment and the organization. Due to its criticality, security should be integrated as a formal approach in the software life cycle. Both a software security checklist and assessment tools should be incorporated into this life cycle process and integrated with a security risk assessment and mitigation tool. The current research at JPL addresses these areas through the development of a Sotfware Security Assessment Instrument (SSAI) and integrating it with a Defect Detection and Prevention (DDP) risk management tool.

Potential for the adoption of probabilistic risk assessments by end-users and decision-makers

DEFF Research Database (Denmark)

Frewer, Lynn J.; Fischer, Arnout R. H.; van den Brink, Paul J.

2008-01-01

-user and regulatory uptake has not been, to date, extensive. A case study, utilizing the Theory of Planned Behavior, was conducted in order to identify potential determinants of end-user adoption of probabilistic risk assessments associated with the ecotoxicological impact of pesticides. Seventy potential end...

Optimal Portfolio Allocation under a Probabilistic Risk Constraint and the Incentives for Financial Innovation

NARCIS (Netherlands)

J. Daníelsson (Jón); B.N. Jorgensen (Bjørn); C.G. de Vries (Casper); X. Yang (Xiaoguang)

2001-01-01

textabstractWe derive, in a complete markets environment, an investor's optimal portfolio allocation subject to both a budget constraint and a probabilistic risk constraint. We demonstrate that the set of feasible portfolios need not be connected or convex, while the number of local optima increases

Simplified probabilistic risk assessment in fuel reprocessing

International Nuclear Information System (INIS)

Solbrig, C.W.

1993-01-01

An evaluation was made to determine if a backup mass tracking computer would significantly reduce the probability of criticality in the fuel reprocessing of the Integral Fast Reactor. Often tradeoff studies, such as this, must be made that would greatly benefit from a Probably Risk Assessment (PRA). The major benefits of a complete PRA can often be accrued with a Simplified Probabilistic Risk Assessment (SPRA). An SPRA was performed by selecting a representative fuel reprocessing operation (moving a piece of fuel) for analysis. It showed that the benefit of adding parallel computers was small compared to the benefit which could be obtained by adding parallelism to two computer input steps and two of the weighing operations. The probability of an incorrect material moves with the basic process is estimated to be 4 out of 100 moves. The actual values of the probability numbers are considered accurate to within an order of magnitude. The most useful result of developing the fault trees accrue from the ability to determine where significant improvements in the process can be made. By including the above mentioned parallelism, the error move rate can be reduced to 1 out of 1000

Scenario logic and probabilistic management of risk in business and engineering

CERN Document Server

Solojentsev, Evgueni D

2009-01-01

The book proposes a uniform logic and probabilistic (LP) approach to risk estimation and analysis in engineering and economics. It covers the methodological and theoretical basis of risk management at the design, test, and operation stages of economic, banking, and engineering systems with groups of incompatible events (GIE). It considers the risk LP-models in classification, investment, management of companies, bribes and corruption, analysis of risk and efficiency of social and economical processes, and management of development. Key features of this Second Edition: -Five new chapters -Treatment of the basic principles of the modern risk LP theory (the LP-calculus, the LP-methods and the risk LP-theory with GIE) using uniform methodology and terminology with a practical orientation towards both engineering and economics, for the first time in book form -Clear definitions and notations, revised sections and chapters, an extended list of references, and a new subject index -More than a hundred illustrations a...

A probabilistic approach for debris impact risk with numerical simulations of debris behaviors

International Nuclear Information System (INIS)

Kihara, Naoto; Matsuyama, Masafumi; Fujii, Naoki

2013-01-01

We propose a probabilistic approach for evaluating the impact risk of tsunami debris through Monte Carlo simulations with a combined system comprising a depth-averaged two-dimensional shallow water model and a discrete element model customized to simulate the motions of floating objects such as vessels. In the proposed method, first, probabilistic tsunami hazard analysis is carried out, and the exceedance probability of tsunami height and numerous tsunami time series for various hazard levels on the offshore side of a target site are estimated. Second, a characteristic tsunami time series for each hazard level is created by cluster analysis. Third, using the Monte Carlo simulation model the debris impact probability with the buildings of interest and the exceedance probability of debris impact speed are evaluated. (author)

Optimal security investments and extreme risk.

Science.gov (United States)

Mohtadi, Hamid; Agiwal, Swati

2012-08-01

In the aftermath of 9/11, concern over security increased dramatically in both the public and the private sector. Yet, no clear algorithm exists to inform firms on the amount and the timing of security investments to mitigate the impact of catastrophic risks. The goal of this article is to devise an optimum investment strategy for firms to mitigate exposure to catastrophic risks, focusing on how much to invest and when to invest. The latter question addresses the issue of whether postponing a risk mitigating decision is an optimal strategy or not. Accordingly, we develop and estimate both a one-period model and a multiperiod model within the framework of extreme value theory (EVT). We calibrate these models using probability measures for catastrophic terrorism risks associated with attacks on the food sector. We then compare our findings with the purchase of catastrophic risk insurance. © 2012 Society for Risk Analysis.

Advanced Test Reactor probabilistic risk assessment methodology and results summary

International Nuclear Information System (INIS)

Eide, S.A.; Atkinson, S.A.; Thatcher, T.A.

1992-01-01

The Advanced Test Reactor (ATR) probabilistic risk assessment (PRA) Level 1 report documents a comprehensive and state-of-the-art study to establish and reduce the risk associated with operation of the ATR, expressed as a mean frequency of fuel damage. The ATR Level 1 PRA effort is unique and outstanding because of its consistent and state-of-the-art treatment of all facets of the risk study, its comprehensive and cost-effective risk reduction effort while the risk baseline was being established, and its thorough and comprehensive documentation. The PRA includes many improvements to the state-of-the-art, including the following: establishment of a comprehensive generic data base for component failures, treatment of initiating event frequencies given significant plant improvements in recent years, performance of efficient identification and screening of fire and flood events using code-assisted vital area analysis, identification and treatment of significant seismic-fire-flood-wind interactions, and modeling of large loss-of-coolant accidents (LOCAs) and experiment loop ruptures leading to direct damage of the ATR core. 18 refs

RiskREP : risk-based security requirements elicitation and prioritization

NARCIS (Netherlands)

Herrmann, A.; Morali, A.; Etalle, S.; Wieringa, R.J.

2011-01-01

Companies are under pressure to be in control of their assets but at the same time they must operate as efficiently as possible. This means that they aim to implement "good-enough security" but need to be able to justify their security investment plans. In this paper, we present a Risk-Based

Notes for a workshop on risk analysis and decision under uncertainty. The practical use of probabilistic and Bayesian methodology inreal life risk assessment and decision problems

Energy Technology Data Exchange (ETDEWEB)

1979-01-01

The use of probabilistic, and especially Bayesian, methods is explained. The concepts of risk and decision, and probability and frequency are elucidated. The mechanics of probability and probabilistic calculations is discussed. The use of the method for particular problems, such as the frequency of aircraft crashes at a specified nuclear reactor site, is illustrated. 64 figures, 20 tables. (RWR)

Notes for a workshop on risk analysis and decision under uncertainty. The practical use of probabilistic and Bayesian methodology inreal life risk assessment and decision problems

International Nuclear Information System (INIS)

1979-01-01

The use of probabilistic, and especially Bayesian, methods is explained. The concepts of risk and decision, and probability and frequency are elucidated. The mechanics of probability and probabilistic calculations is discussed. The use of the method for particular problems, such as the frequency of aircraft crashes at a specified nuclear reactor site, is illustrated. 64 figures, 20 tables

Development and Application of a Probabilistic Risk-Benefit Assessment Model for Infant Feeding Integrating Microbiological, Nutritional, and Chemical Components.

Science.gov (United States)

Boué, Géraldine; Cummins, Enda; Guillou, Sandrine; Antignac, Jean-Philippe; Le Bizec, Bruno; Membré, Jeanne-Marie

2017-12-01

A probabilistic and interdisciplinary risk-benefit assessment (RBA) model integrating microbiological, nutritional, and chemical components was developed for infant milk, with the objective of predicting the health impact of different scenarios of consumption. Infant feeding is a particular concern of interest in RBA as breast milk and powder infant formula have both been associated with risks and benefits related to chemicals, bacteria, and nutrients, hence the model considers these three facets. Cronobacter sakazakii, dioxin-like polychlorinated biphenyls (dl-PCB), and docosahexaenoic acid (DHA) were three risk/benefit factors selected as key issues in microbiology, chemistry, and nutrition, respectively. The present model was probabilistic with variability and uncertainty separated using a second-order Monte Carlo simulation process. In this study, advantages and limitations of undertaking probabilistic and interdisciplinary RBA are discussed. In particular, the probabilistic technique was found to be powerful in dealing with missing data and to translate assumptions into quantitative inputs while taking uncertainty into account. In addition, separation of variability and uncertainty strengthened the interpretation of the model outputs by enabling better consideration and distinction of natural heterogeneity from lack of knowledge. Interdisciplinary RBA is necessary to give more structured conclusions and avoid contradictory messages to policymakers and also to consumers, leading to more decisive food recommendations. This assessment provides a conceptual development of the RBA methodology and is a robust basis on which to build upon. © 2017 Society for Risk Analysis.

Probabilistic environmental risk assessment of five nanomaterials (nano-TiO2, nano-Ag, nano-ZnO, CNT, and fullerenes).

Science.gov (United States)

Coll, Claudia; Notter, Dominic; Gottschalk, Fadri; Sun, Tianyin; Som, Claudia; Nowack, Bernd

2016-01-01

The environmental risks of five engineered nanomaterials (nano-TiO2, nano-Ag, nano-ZnO, CNT, and fullerenes) were quantified in water, soils, and sediments using probabilistic Species Sensitivity Distributions (pSSDs) and probabilistic predicted environmental concentrations (PECs). For water and soil, enough ecotoxicological endpoints were found for a full risk characterization (between 17 and 73 data points per nanomaterial for water and between 4 and 20 for soil) whereas for sediments, the data availability was not sufficient. Predicted No Effect Concentrations (PNECs) were obtained from the pSSD and used to calculate risk characterization ratios (PEC/PNEC). For most materials and environmental compartments, exposure and effect concentrations were separated by several orders of magnitude. Nano-ZnO in freshwaters and nano-TiO2 in soils were the combinations where the risk characterization ratio was closest to one, meaning that these are compartment/ENM combinations to be studied in more depth with the highest priority. The probabilistic risk quantification allows us to consider the large variability of observed effects in different ecotoxicological studies and the uncertainty in modeled exposure concentrations. The risk characterization results presented in this work allows for a more focused investigation of environmental risks of nanomaterials by consideration of material/compartment combinations where the highest probability for effects with predicted environmental concentrations is likely.

Innovative probabilistic risk assessment applications: barrier impairments and fracture toughness. Panel Discussion

International Nuclear Information System (INIS)

Osterman, Michael; Root, Steven; Li, F.; Modarres, Mohammad; Reinhart, F. Mark; Bradley, Biff; Calhoun, David J.

2001-01-01

Full text of publication follows: New probabilistic risk assessment (PRA) applications promise to improve the overall safety and efficiency of nuclear plant operations. This discussion will explore the use of PRA in evaluating barrier integrity with respect to the consequences of natural phenomena such as tornadoes, floods, and harsh environments. Additionally, the session will explore proposals to improve fracture toughness techniques using PRA. (authors)

Forecasting risk along a river basin using a probabilistic and deterministic model for environmental risk assessment of effluents through ecotoxicological evaluation and GIS.

Science.gov (United States)

Gutiérrez, Simón; Fernandez, Carlos; Barata, Carlos; Tarazona, José Vicente

2009-12-20

This work presents a computer model for Risk Assessment of Basins by Ecotoxicological Evaluation (RABETOX). The model is based on whole effluent toxicity testing and water flows along a specific river basin. It is capable of estimating the risk along a river segment using deterministic and probabilistic approaches. The Henares River Basin was selected as a case study to demonstrate the importance of seasonal hydrological variations in Mediterranean regions. As model inputs, two different ecotoxicity tests (the miniaturized Daphnia magna acute test and the D.magna feeding test) were performed on grab samples from 5 waste water treatment plant effluents. Also used as model inputs were flow data from the past 25 years, water velocity measurements and precise distance measurements using Geographical Information Systems (GIS). The model was implemented into a spreadsheet and the results were interpreted and represented using GIS in order to facilitate risk communication. To better understand the bioassays results, the effluents were screened through SPME-GC/MS analysis. The deterministic model, performed each month during one calendar year, showed a significant seasonal variation of risk while revealing that September represents the worst-case scenario with values up to 950 Risk Units. This classifies the entire area of study for the month of September as "sublethal significant risk for standard species". The probabilistic approach using Monte Carlo analysis was performed on 7 different forecast points distributed along the Henares River. A 0% probability of finding "low risk" was found at all forecast points with a more than 50% probability of finding "potential risk for sensitive species". The values obtained through both the deterministic and probabilistic approximations reveal the presence of certain substances, which might be causing sublethal effects in the aquatic species present in the Henares River.

Scenario-based approach to risk analysis in support of cyber security

Energy Technology Data Exchange (ETDEWEB)

Gertman, D. I.; Folkers, R.; Roberts, J. [Idaho National Laboratory, Roberts and Folkers Associates, LLC, Idaho Falls, ID 83404 (United States)

2006-07-01

The US infrastructure is continually challenged by hostile nation states and others who would do us harm. Cyber vulnerabilities and weaknesses are potential targets and are the result of years of construction and technological improvement in a world less concerned with security than is currently the case. As a result, cyber attack presents a class of challenges for which we are just beginning to prepare. What has been done in the nuclear, chemical and energy sectors as a means of anticipating and preparing for randomly occurring accidents and off-normal events is to develop scenarios as a means by which to prioritize and quantify risk and to take action. However, the number of scenarios risk analysts can develop is almost limitless. How do we ascertain which scenario has the greatest merit? One of the more important contributions of probabilistic risk analysis (PRA) has been to quantify the initiating event probability associated with various classes of accidents; and to quantify the occurrence of various conditions, i.e., end-states, as a function of these important accident sequences. Typically, various classes of conditions are represented by scenarios and are quantified in terms of cut sets and binned into end states. For example, the nuclear industry has a well-defined set of initiating events that are studied in assessing risk. The maturation of risk analysis for cyber security from accounting for barriers or looking at conditions statically to one of ascertaining the probability associated with certain events is, in part, dependent upon the adoption of a scenario-based approach. For example, scenarios take into account threats to personnel and public safety; economic damage, and compromises to major operational and safety functions. Scenarios reflect system, equipment, and component configurations as well as key human-system interactions related to event detection, diagnosis, mitigation and restoration of systems. As part of a cyber attack directed toward

Scenario-based approach to risk analysis in support of cyber security

International Nuclear Information System (INIS)

Gertman, D. I.; Folkers, R.; Roberts, J.

2006-01-01

The US infrastructure is continually challenged by hostile nation states and others who would do us harm. Cyber vulnerabilities and weaknesses are potential targets and are the result of years of construction and technological improvement in a world less concerned with security than is currently the case. As a result, cyber attack presents a class of challenges for which we are just beginning to prepare. What has been done in the nuclear, chemical and energy sectors as a means of anticipating and preparing for randomly occurring accidents and off-normal events is to develop scenarios as a means by which to prioritize and quantify risk and to take action. However, the number of scenarios risk analysts can develop is almost limitless. How do we ascertain which scenario has the greatest merit? One of the more important contributions of probabilistic risk analysis (PRA) has been to quantify the initiating event probability associated with various classes of accidents; and to quantify the occurrence of various conditions, i.e., end-states, as a function of these important accident sequences. Typically, various classes of conditions are represented by scenarios and are quantified in terms of cut sets and binned into end states. For example, the nuclear industry has a well-defined set of initiating events that are studied in assessing risk. The maturation of risk analysis for cyber security from accounting for barriers or looking at conditions statically to one of ascertaining the probability associated with certain events is, in part, dependent upon the adoption of a scenario-based approach. For example, scenarios take into account threats to personnel and public safety; economic damage, and compromises to major operational and safety functions. Scenarios reflect system, equipment, and component configurations as well as key human-system interactions related to event detection, diagnosis, mitigation and restoration of systems. As part of a cyber attack directed toward

Probabilistic Design of Coastal Flood Defences in Vietnam

NARCIS (Netherlands)

Mai Van, C.

2010-01-01

This study further develops the method of probabilistic design and to address a knowledge gap in its application regarding safety and reliability, risk assessment and risk evaluation to the fields of flood defences. The thesis discusses: - a generic probabilistic design framework for assessing flood

Probabilistic Risk Assessment of Cancer from Exposure Inorganic Arsenic in Duplicate Food by Villagers in Ronphibun, Thailand

Directory of Open Access Journals (Sweden)

Piyawat Saipan

2010-07-01

Full Text Available Ronphibun district is a district in Nakorn Si Thammarat province, within southern Thailand. This district is the site of several former tin mines that were in operation 100 years ago. Arsenic contamination caused by past mining activities remains in the area. The specific purpose of this study was conducted to assess cancer risk in people living within Ronphibun district from exposure to inorganic arsenic via duplicate food using probabilistic risk assessment. A hundred and fifty duplicate food samples were collected from participants. Inorganic arsenic concentrations are determined by hydride generation atomic absorption spectrometry. Inorganic arsenic concentrations in duplicate food ranged from 0.16 to 0.42 μg/g dry weight. The probabilistic carcinogenic risk levels were 6.76 x 10-4 and 1.74 x 10-3 based on the 50th and 95th percentile, respectively. Risk values for people in Ronphibun from exposure to inorganic arsenic remained higher than the acceptable target risk. Sensitivity analysis indicted that exposure duration and concentrations of arsenic in food were the two most influential of cancer risk estimates.

Probabilistic health risk assessment for arsenic intake through drinking groundwater in Taiwan's Pingtung Plain

Science.gov (United States)

Liang, C. P.; Chen, J. S.

2017-12-01

An abundant and inexpensive supply of groundwater is used to meet drinking, agriculture and aquaculture requirements of the residents in the Pingtung Plain. Long-term groundwater quality monitoring data indicate that the As content in groundwater in the Pingtung Plain exceeds the maximum level of 10 g/L recommended by the World Health Organization (WHO). The situation is further complicated by the fact that only 46.89% of population in the Pingtung Plain has been served with tap water, far below the national average of 92.93%. Considering there is a considerable variation in the measured concentrations, from below the detection limit (consumption rate and body weight of the individual, the conventional approach to conducting a human health risk assessment may be insufficient for health risk management. This study presents a probabilistic risk assessment for inorganic As intake through the consumption of the drinking groundwater by local residents in the Pingtung Plain. The probabilistic risk assessment for inorganic As intake through the consumption of the drinking groundwater is achieved using Monte Carlo simulation technique based on the hazard quotient (HQ) and target cancer risk (TR) established by the U.S. Environmental Protection Agency. This study demonstrates the importance of the individual variability of inorganic As intake through drinking groundwater consumption when evaluating a high exposure sub-group of the population who drink high As content groundwater.

Probabilistic risk models for multiple disturbances: an example of forest insects and wildfires

Science.gov (United States)

Haiganoush K. Preisler; Alan A. Ager; Jane L. Hayes

2010-01-01

Building probabilistic risk models for highly random forest disturbances like wildfire and forest insect outbreaks is a challenging. Modeling the interactions among natural disturbances is even more difficult. In the case of wildfire and forest insects, we looked at the probability of a large fire given an insect outbreak and also the incidence of insect outbreaks...

Incorporating linguistic, probabilistic, and possibilistic information in a risk-based approach for ranking contaminated sites.

Science.gov (United States)

Zhang, Kejiang; Achari, Gopal; Pei, Yuansheng

2010-10-01

Different types of uncertain information-linguistic, probabilistic, and possibilistic-exist in site characterization. Their representation and propagation significantly influence the management of contaminated sites. In the absence of a framework with which to properly represent and integrate these quantitative and qualitative inputs together, decision makers cannot fully take advantage of the available and necessary information to identify all the plausible alternatives. A systematic methodology was developed in the present work to incorporate linguistic, probabilistic, and possibilistic information into the Preference Ranking Organization METHod for Enrichment Evaluation (PROMETHEE), a subgroup of Multi-Criteria Decision Analysis (MCDA) methods for ranking contaminated sites. The identification of criteria based on the paradigm of comparative risk assessment provides a rationale for risk-based prioritization. Uncertain linguistic, probabilistic, and possibilistic information identified in characterizing contaminated sites can be properly represented as numerical values, intervals, probability distributions, and fuzzy sets or possibility distributions, and linguistic variables according to their nature. These different kinds of representation are first transformed into a 2-tuple linguistic representation domain. The propagation of hybrid uncertainties is then carried out in the same domain. This methodology can use the original site information directly as much as possible. The case study shows that this systematic methodology provides more reasonable results. © 2010 SETAC.

77 FR 61446 - Proposed Revision Probabilistic Risk Assessment and Severe Accident Evaluation for New Reactors

Science.gov (United States)

2012-10-09

... Severe Accident Evaluation for New Reactors AGENCY: Nuclear Regulatory Commission. ACTION: Standard... its Standard Review Plan (SRP), Section 19.0, ``Probabilistic Risk Assessment and Severe Accident... assessment (PRA) information and severe accident assessments for new reactors submitted to support design...

Risk-informed, performance-based safety-security interface

International Nuclear Information System (INIS)

Mrowca, B.; Eltawila, F.

2012-01-01

Safety-security interface is a term that is used as part of the commercial nuclear power security framework to promote coordination of the many potentially adverse interactions between plant security and plant safety. Its object is to prevent the compromise of either. It is also used to describe the concept of building security into a plant's design similar to the long standing practices used for safety therefore reducing the complexity of the operational security while maintaining or enhancing overall security. With this in mind, the concept of safety-security interface, when fully implemented, can influence a plant's design, operation and maintenance. It brings the approach use for plant security to one that is similar to that used for safety. Also, as with safety, the application of risk-informed techniques to fully implement and integrate safety and security is important. Just as designers and operators have applied these techniques to enhance and focus safety, these same techniques can be applied to security to not only enhance and focus the security but also to aid in the implementation of effective techniques to address the safety-security interfaces. Implementing this safety-security concept early within the design process can prevent or reduce security vulnerabilities through low cost solutions that often become difficult and expensive to retrofit later in the design and/or post construction period. These security considerations address many of the same issues as safety in ensuring that the response of equipment and plant personnel are adequate. That is, both safety and security are focused on reaching safe shutdown and preventing radiological release. However, the initiation of challenges and the progression of actions in response these challenges and even the definitions of safe shutdown can be considerably different. This paper explores the techniques and limitations that are employed to fully implement a risk-informed, safety-security interface

Using Financial Instruments to Transfer the Information Security Risks

Directory of Open Access Journals (Sweden)

Pankaj Pandey

2016-05-01

Full Text Available For many individuals and organizations, cyber-insurance is the most practical and only way of handling a major financial impact of an information security event. However, the cyber-insurance market suffers from the problem of information asymmetry, lack of product diversity, illiquidity, high transaction cost, and so on. On the other hand, in theory, capital market-based financial instruments can provide a risk transfer mechanism with the ability to absorb the adverse impact of an information security event. Thus, this article addresses the limitations in the cyber-(reinsurance markets with a set of capital market-based financial instruments. This article presents a set of information security derivatives, namely options, vanilla options, swap, and futures that can be traded at an information security prediction market. Furthermore, this article demonstrates the usefulness of information security derivatives in a given scenario and presents an evaluation of the same in comparison with cyber-insurance. In our analysis, we found that the information security derivatives can at least be a partial solution to the problems in the cyber-insurance markets. The information security derivatives can be used as an effective tool for information elicitation and aggregation, cyber risk pricing, risk hedging, and strategic decision making for information security risk management.

Exploring probabilistic tools for the development of a platform for Quantitative Risk Assessment (QRA) of hydro-meteorological hazards in Europe

Science.gov (United States)

Zumpano, V.; Hussin, H. Y.; Breinl, K.

2012-04-01

Mass-movements and floods are hydro-meteorological hazards that can have catastrophic effects on communities living in mountainous areas prone to these disastrous events. Environmental, climate and socio-economic changes are expected to affect the tempo-spatial patterns of hydro-meteorological hazards and associated risks in Europe. These changes and their effects on the occurrence of future hazards need to be analyzed and modeled using probabilistic hazard and risk assessment methods in order to assist stakeholders in disaster management strategies and policy making. Quantitative Risk Assessment (QRA) using probabilistic methods can further calculate damage and losses to multi-hazards and determine the uncertainties related to all the probabilistic components of the hazard and the vulnerability of the elements at risk. Therefore, in order to develop an effective platform that can quantitatively calculate the risk of mass-movements and floods in several European test sites, an extensive inventory and analysis has been carried out of the available tools and software related to the probabilistic risk assessment of single and multi-hazards. The tools have been reviewed based on whether they are open source and freely available, their required input data, the availability and type of hazard and vulnerability modules, transparency of methods used, their validation and calibration techniques, the inclusion of uncertainties and their state of the art. The analysis also specially focused on the applicability of the tools to European study areas. The findings showed that assumptions and simplifications are made when assessing and quantifying the hazards. The interaction between multiple hazards, like cascading effects are not assessed in most tools and some consider the hazard and vulnerability as qualitative components, rather than quantitative ones. This analysis of hazard and risk assessment tools and software will give future developers and experts a better overview of

Bayesian inference in probabilistic risk assessment-The current state of the art

International Nuclear Information System (INIS)

Kelly, Dana L.; Smith, Curtis L.

2009-01-01

Markov chain Monte Carlo (MCMC) approaches to sampling directly from the joint posterior distribution of aleatory model parameters have led to tremendous advances in Bayesian inference capability in a wide variety of fields, including probabilistic risk analysis. The advent of freely available software coupled with inexpensive computing power has catalyzed this advance. This paper examines where the risk assessment community is with respect to implementing modern computational-based Bayesian approaches to inference. Through a series of examples in different topical areas, it introduces salient concepts and illustrates the practical application of Bayesian inference via MCMC sampling to a variety of important problems

Development of a cyber security risk model using Bayesian networks

International Nuclear Information System (INIS)

Shin, Jinsoo; Son, Hanseong; Khalil ur, Rahman; Heo, Gyunyoung

2015-01-01

Cyber security is an emerging safety issue in the nuclear industry, especially in the instrumentation and control (I and C) field. To address the cyber security issue systematically, a model that can be used for cyber security evaluation is required. In this work, a cyber security risk model based on a Bayesian network is suggested for evaluating cyber security for nuclear facilities in an integrated manner. The suggested model enables the evaluation of both the procedural and technical aspects of cyber security, which are related to compliance with regulatory guides and system architectures, respectively. The activity-quality analysis model was developed to evaluate how well people and/or organizations comply with the regulatory guidance associated with cyber security. The architecture analysis model was created to evaluate vulnerabilities and mitigation measures with respect to their effect on cyber security. The two models are integrated into a single model, which is called the cyber security risk model, so that cyber security can be evaluated from procedural and technical viewpoints at the same time. The model was applied to evaluate the cyber security risk of the reactor protection system (RPS) of a research reactor and to demonstrate its usefulness and feasibility. - Highlights: • We developed the cyber security risk model can be find the weak point of cyber security integrated two cyber analysis models by using Bayesian Network. • One is the activity-quality model signifies how people and/or organization comply with the cyber security regulatory guide. • Other is the architecture model represents the probability of cyber-attack on RPS architecture. • The cyber security risk model can provide evidence that is able to determine the key element for cyber security for RPS of a research reactor

Sound Probabilistic #SAT with Projection

Directory of Open Access Journals (Sweden)

Vladimir Klebanov

2016-10-01

Full Text Available We present an improved method for a sound probabilistic estimation of the model count of a boolean formula under projection. The problem solved can be used to encode a variety of quantitative program analyses, such as concerning security of resource consumption. We implement the technique and discuss its application to quantifying information flow in programs.

Risk assessment for sustainable food security in China according to integrated food security--taking Dongting Lake area for example.

Science.gov (United States)

Qi, Xiaoxing; Liu, Liming; Liu, Yabin; Yao, Lan

2013-06-01

Integrated food security covers three aspects: food quantity security, food quality security, and sustainable food security. Because sustainable food security requires that food security must be compatible with sustainable development, the risk assessment of sustainable food security is becoming one of the most important issues. This paper mainly focuses on the characteristics of sustainable food security problems in the major grain-producing areas in China. We establish an index system based on land resources and eco-environmental conditions and apply a dynamic assessment method based on status assessments and trend analysis models to overcome the shortcomings of the static evaluation method. Using fuzzy mathematics, the risks are categorized into four grades: negligible risk, low risk, medium risk, and high risk. A case study was conducted in one of China's major grain-producing areas: Dongting Lake area. The results predict that the status of the sustainable food security in the Dongting Lake area is unsatisfactory for the foreseeable future. The number of districts at the medium-risk range will increase from six to ten by 2015 due to increasing population pressure, a decrease in the cultivated area, and a decrease in the effective irrigation area. Therefore, appropriate policies and measures should be put forward to improve it. The results could also provide direct support for an early warning system-which could be used to monitor food security trends or nutritional status so to inform policy makers of impending food shortages-to prevent sustainable food security risk based on some classical systematic methods. This is the first research of sustainable food security in terms of risk assessment, from the perspective of resources and the environment, at the regional scale.

Probabilistic safety analysis vs probabilistic fracture mechanics -relation and necessary merging

International Nuclear Information System (INIS)

Nilsson, Fred

1997-01-01

A comparison is made between some general features of probabilistic fracture mechanics (PFM) and probabilistic safety assessment (PSA) in its standard form. We conclude that: Result from PSA is a numerically expressed level of confidence in the system based on the state of current knowledge. It is thus not any objective measure of risk. It is important to carefully define the precise nature of the probabilistic statement and relate it to a well defined situation. Standardisation of PFM methods is necessary. PFM seems to be the only way to obtain estimates of the pipe break probability. Service statistics are of doubtful value because of scarcity of data and statistical inhomogeneity. Collection of service data should be directed towards the occurrence of growing cracks

Integration of Probabilistic and Multi-Hazard Risk Assessment Within Urban Development Planning and Emergency Preparedness and Response:Application to Manizales, Colombia

Institute of Scientific and Technical Information of China (English)

Gabriel A.Bernal; Mario A.Salgado-Gálvez; Daniela Zuloaga; Julián Tristancho; Diana González; Omar-Dar(i)o Cardona

2017-01-01

The details of a multi-hazard and probabilistic risk assessment,developed for urban planning and emergency response activities in Manizales,Colombia,are presented in this article.This risk assessment effort was developed under the framework of an integral disaster risk management project whose goal was to connect risk reduction activities by using open access and state-of-theart risk models.A probabilistic approach was used for the analysis of seismic,landslide,and volcanic hazards to obtain stochastic event sets suitable for probabilistic loss estimation and to generate risk results in different metrics after aggregating in a rigorous way the losses associated to the different hazards.Detailed and high resolution exposure databases were used for the building stock and infrastructure of the city together with a set of vulnerability functions for each of the perils considered.The urban and territorial ordering plan of the city was updated for socioeconomic development and land use using the hazard and risk inputs and determinants,which cover not only the current urban area but also those adjacent areas where the expansion of Manizales is expected to occur.The emergency response capabilities of the city were improved by taking into account risk scenarios and after updating an automatic and real-time post-earthquake damage assessment.

A probabilistic risk assessment of Oconee Unit 3. Executive highlights 60

International Nuclear Information System (INIS)

1984-04-01

In 1980 the Nuclear Safety Analysis Center and Duke Power Co. joined in a project to provide the utility industry with a practical, useful example of the application of probabilistic risk assessment (PRA) methods. PRA is a structured analysis technique that accounts for all the failure possibilities that might conceivably lead to core damage. The technique uses probabilities as discriminators to determine which are most significant. The following were project objectives: to provide the host utility with an analytic model of the plant that describes and estimates the likelihood of failure combinations that could lead to core melt; to evaluate the risks to the plant and to the public; to improve utility capabilities in PRA methods and applications

Agent of opportunity risk mitigation: people, engineering, and security efficacy.

Science.gov (United States)

Graham, Margaret E; Tunik, Michael G; Farmer, Brenna M; Bendzans, Carly; McCrillis, Aileen M; Nelson, Lewis S; Portelli, Ian; Smith, Silas; Goldberg, Judith D; Zhang, Meng; Rosenberg, Sheldon D; Goldfrank, Lewis R

2010-12-01

Agents of opportunity (AO) are potentially harmful biological, chemical, radiological, and pharmaceutical substances commonly used for health care delivery and research. AOs are present in all academic medical centers (AMC), creating vulnerability in the health care sector; AO attributes and dissemination methods likely predict risk; and AMCs are inadequately secured against a purposeful AO dissemination, with limited budgets and competing priorities. We explored health care workers' perceptions of AMC security and the impact of those perceptions on AO risk. Qualitative methods (survey, interviews, and workshops) were used to collect opinions from staff working in a medical school and 4 AMC-affiliated hospitals concerning AOs and the risk to hospital infrastructure associated with their uncontrolled presence. Secondary to this goal, staff perception concerning security, or opinions about security behaviors of others, were extracted, analyzed, and grouped into themes. We provide a framework for depicting the interaction of staff behavior and access control engineering, including the tendency of staff to "defeat" inconvenient access controls. In addition, 8 security themes emerged: staff security behavior is a significant source of AO risk; the wide range of opinions about "open" front-door policies among AMC staff illustrates a disparity of perceptions about the need for security; interviewees expressed profound skepticism concerning the effectiveness of front-door access controls; an AO risk assessment requires reconsideration of the security levels historically assigned to areas such as the loading dock and central distribution sites, where many AOs are delivered and may remain unattended for substantial periods of time; researchers' view of AMC security is influenced by the ongoing debate within the scientific community about the wisdom of engaging in bioterrorism research; there was no agreement about which areas of the AMC should be subject to stronger access

Probabilistic modeling of dietary intake of substances - The risk management question governs the method

NARCIS (Netherlands)

Pieters MN; Ossendorp BC; Bakker MI; Slob W; SIR

2005-01-01

In this report the discussion on the use of probabilistic modeling in relation to pesticide use in food crops is analyzed. Due to different policy questions the current discussion is complex and considers safety of an MRL as well as probability of a health risk. The question regarding the use of

INFORMATION SECURITY IN MOBILE MODULAR MEASURING SYSTEMS

Directory of Open Access Journals (Sweden)

A. N. Tkhishev

2017-01-01

Full Text Available A special aspect of aircraft test is carrying out both flight evaluation and ground operation evaluation in a structure of flying aids and special tools equipment. The specific of flight and sea tests involve metering in offshore zone, which excludes the possibility of fixed geodetically related measuring tools. In this regard, the specific role is acquired by shipbased measurement systems, in particular the mobile modular measuring systems. Information processed in the mobile modular measurement systems is a critical resource having a high level of confidentiality. When carrying out their functions, it should be implemented a proper information control of the mobile modular measurement systems to ensure their protection from the risk of data leakage, modification or loss, i.e. to ensure a certain level of information security. Due to the specific of their application it is difficult to solve the problems of information security in such complexes. The intruder model, the threat model, the security requirements generated for fixed informatization objects are not applicable to mobile systems. It was concluded that the advanced mobile modular measuring systems designed for flight experiments monitoring and control should be created due to necessary information protection measures and means. The article contains a diagram of security requirements formation, starting with the data envelopment analysis and ending with the practical implementation. The information security probabilistic model applied to mobile modular measurement systems is developed. The list of current security threats based on the environment and specific of the mobile measurement system functioning is examined. The probabilistic model of the information security evaluation is given. The problems of vulnerabilities transformation of designed information system into the security targets with the subsequent formation of the functional and trust requirements list are examined.

The NUREG-1150 probabilistic risk assessment for the Grand Gulf nuclear station

International Nuclear Information System (INIS)

Brown, T.D.; Breeding, R.J.; Jow, H.N.; Higgins, S.J.; Shiver, A.W.; Helton, J.C.

1992-01-01

This paper summarizes the findings of the probabilistic risk assessment (PRA) for Unit 1 of the Grand Gulf Nuclear Station performed in support of NUREG-1150. The emphasis is on the 'back-end' analyses, that is, the acident progression, source term, consequence analsyes, and risk results obtained when the results of these analyses are combined with the accident frequency analysis. The offsite risk from internal initiating events was found to be quite low, both with respect to the safety goals and to the other plants analyzed in NUREG-1150. The offsite risk is dominated by short-term station blackout plant damage states. The long-term blackout group and the anticiptated transients without scram (ATWS) group contribute considerably less to risk. Transients in which the power conversion system is unavailable are very minor contributors to risk. The low values for risk can be attributed to low core damage frequency, good emergency response, and plant features that reduce the potential source term. (orig.)

Application of Bayesian network methodology to the probabilistic risk assessment of nuclear waste disposal facility

International Nuclear Information System (INIS)

Lee, Chang Ju

2006-02-01

The scenario in a risk analysis can be defined as the propagating feature of specific initiating event which can go to a wide range of undesirable consequences. If one takes various scenarios into consideration, the risk analysis becomes more complex than do without them. A lot of risk analyses have been performed to actually estimate a risk profile under both uncertain future states of hazard sources and undesirable scenarios. Unfortunately, in case of considering some stochastic passive systems such as a radioactive waste disposal facility, since the behaviour of future scenarios is hardly predicted without special reasoning process, we cannot estimate their risk only with a traditional risk analysis methodology. Moreover, it is believed that the sources of uncertainty at future states can be reduced pertinently by setting up dependency relationships interrelating geological, hydrological, and ecological aspects of the site with all the scenarios. It is then required current methodology of uncertainty analysis of the waste disposal facility be revisited under this belief. In order to consider the effects predicting from an evolution of environmental conditions of waste disposal facilities, this study proposes a quantitative assessment framework integrating the inference process of Bayesian network to the traditional probabilistic risk analysis. In this study an approximate probabilistic inference program for the specific Bayesian network developed and verified using a bounded-variance likelihood weighting algorithm. Ultimately, specific models, including a Monte-Carlo model for uncertainty propagation of relevant parameters, were developed with a comparison of variable-specific effects due to the occurrence of diverse altered evolution scenarios (AESs). After providing supporting information to get a variety of quantitative expectations about the dependency relationship between domain variables and AESs, this study could connect the results of probabilistic

OVERVIEW OF THE SAPHIRE PROBABILISTIC RISK ANALYSIS SOFTWARE

Energy Technology Data Exchange (ETDEWEB)

Smith, Curtis L.; Wood, Ted; Knudsen, James; Ma, Zhegang

2016-10-01

The Systems Analysis Programs for Hands-on Integrated Reliability Evaluations (SAPHIRE) is a software application developed for performing a complete probabilistic risk assessment (PRA) using a personal computer (PC) running the Microsoft Windows operating system. SAPHIRE Version 8 is funded by the U.S. Nuclear Regulatory Commission (NRC) and developed by the Idaho National Laboratory (INL). INL's primary role in this project is that of software developer and tester. However, INL also plays an important role in technology transfer by interfacing and supporting SAPHIRE users, who constitute a wide range of PRA practitioners from the NRC, national laboratories, the private sector, and foreign countries. In this paper, we provide an overview of the current technical capabilities found in SAPHIRE Version 8, including the user interface and enhanced solving algorithms.

EVALUATION OF MILITARY ACTIVITY IMPACT ON HUMANS THROUGH A PROBABILISTIC ECOLOGICAL RISK ASSESSMENT. EXAMPLE OF A FORMER MISSILE BASE.

Directory of Open Access Journals (Sweden)

Sergiy ОREL

2015-10-01

Full Text Available The current article provides a methodology focused on the assessment of environmental factors after termination of military activity and uses a former missile base as an example. The assessment of environmental conditions is performed through an evaluation of the risks posed by the hazardous chemicals contained by underground and surface water sources and soil to human health . Moreover, by conducting deterministic and probabilistic risk assessments, the article determines that the probabilistic assessment provides more accurate and qualitative information for decision-making on the use of environmental protection measures, which often saves financial and material resources needed for their implementation.

Dynamic Positioning System (DPS) Risk Analysis Using Probabilistic Risk Assessment (PRA)

Science.gov (United States)

Thigpen, Eric B.; Boyer, Roger L.; Stewart, Michael A.; Fougere, Pete

2017-01-01

The National Aeronautics and Space Administration (NASA) Safety & Mission Assurance (S&MA) directorate at the Johnson Space Center (JSC) has applied its knowledge and experience with Probabilistic Risk Assessment (PRA) to projects in industries ranging from spacecraft to nuclear power plants. PRA is a comprehensive and structured process for analyzing risk in complex engineered systems and/or processes. The PRA process enables the user to identify potential risk contributors such as, hardware and software failure, human error, and external events. Recent developments in the oil and gas industry have presented opportunities for NASA to lend their PRA expertise to both ongoing and developmental projects within the industry. This paper provides an overview of the PRA process and demonstrates how this process was applied in estimating the probability that a Mobile Offshore Drilling Unit (MODU) operating in the Gulf of Mexico and equipped with a generically configured Dynamic Positioning System (DPS) loses location and needs to initiate an emergency disconnect. The PRA described in this paper is intended to be generic such that the vessel meets the general requirements of an International Maritime Organization (IMO) Maritime Safety Committee (MSC)/Circ. 645 Class 3 dynamically positioned vessel. The results of this analysis are not intended to be applied to any specific drilling vessel, although provisions were made to allow the analysis to be configured to a specific vessel if required.

Probabilistic pattern of risks in company’s Quality management system

Directory of Open Access Journals (Sweden)

Mager Vladimir

2017-01-01

Full Text Available One possible approach for calculation of probabilistic rate of risks in Quality management system (QMS, which is prescribed by requirements of International Standard ISO 9001:2015, is proposed in this article. Aspects of the theory of dependability and Markov techniques are used, which are applied for evaluation of probability of failures in complicated technical systems. Representation of QMS processes as a graph with controlled discrete Markov chains is suggested, which allows to evaluate a probability of customer requirements non-fulfillment as a function of an intensity of mistakes that bring to non-conformities in QMS.

Probabilistic risk assessment framework for structural systems under multiple hazards using Bayesian statistics

Energy Technology Data Exchange (ETDEWEB)

Kwag, Shinyoung [North Carolina State University, Raleigh, NC 27695 (United States); Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of); Gupta, Abhinav, E-mail: agupta1@ncsu.edu [North Carolina State University, Raleigh, NC 27695 (United States)

2017-04-15

Highlights: • This study presents the development of Bayesian framework for probabilistic risk assessment (PRA) of structural systems under multiple hazards. • The concepts of Bayesian network and Bayesian inference are combined by mapping the traditionally used fault trees into a Bayesian network. • The proposed mapping allows for consideration of dependencies as well as correlations between events. • Incorporation of Bayesian inference permits a novel way for exploration of a scenario that is likely to result in a system level “vulnerability.” - Abstract: Conventional probabilistic risk assessment (PRA) methodologies (USNRC, 1983; IAEA, 1992; EPRI, 1994; Ellingwood, 2001) conduct risk assessment for different external hazards by considering each hazard separately and independent of each other. The risk metric for a specific hazard is evaluated by a convolution of the fragility and the hazard curves. The fragility curve for basic event is obtained by using empirical, experimental, and/or numerical simulation data for a particular hazard. Treating each hazard as an independently can be inappropriate in some cases as certain hazards are statistically correlated or dependent. Examples of such correlated events include but are not limited to flooding induced fire, seismically induced internal or external flooding, or even seismically induced fire. In the current practice, system level risk and consequence sequences are typically calculated using logic trees to express the causative relationship between events. In this paper, we present the results from a study on multi-hazard risk assessment that is conducted using a Bayesian network (BN) with Bayesian inference. The framework can consider statistical dependencies among risks from multiple hazards, allows updating by considering the newly available data/information at any level, and provide a novel way to explore alternative failure scenarios that may exist due to vulnerabilities.

Probabilistic risk assessment framework for structural systems under multiple hazards using Bayesian statistics

International Nuclear Information System (INIS)

Kwag, Shinyoung; Gupta, Abhinav

2017-01-01

Highlights: • This study presents the development of Bayesian framework for probabilistic risk assessment (PRA) of structural systems under multiple hazards. • The concepts of Bayesian network and Bayesian inference are combined by mapping the traditionally used fault trees into a Bayesian network. • The proposed mapping allows for consideration of dependencies as well as correlations between events. • Incorporation of Bayesian inference permits a novel way for exploration of a scenario that is likely to result in a system level “vulnerability.” - Abstract: Conventional probabilistic risk assessment (PRA) methodologies (USNRC, 1983; IAEA, 1992; EPRI, 1994; Ellingwood, 2001) conduct risk assessment for different external hazards by considering each hazard separately and independent of each other. The risk metric for a specific hazard is evaluated by a convolution of the fragility and the hazard curves. The fragility curve for basic event is obtained by using empirical, experimental, and/or numerical simulation data for a particular hazard. Treating each hazard as an independently can be inappropriate in some cases as certain hazards are statistically correlated or dependent. Examples of such correlated events include but are not limited to flooding induced fire, seismically induced internal or external flooding, or even seismically induced fire. In the current practice, system level risk and consequence sequences are typically calculated using logic trees to express the causative relationship between events. In this paper, we present the results from a study on multi-hazard risk assessment that is conducted using a Bayesian network (BN) with Bayesian inference. The framework can consider statistical dependencies among risks from multiple hazards, allows updating by considering the newly available data/information at any level, and provide a novel way to explore alternative failure scenarios that may exist due to vulnerabilities.

Probabilistic risk assessment and its role in plant modifications

International Nuclear Information System (INIS)

Diederich, A.R.; McElroy, W.F.

1986-01-01

Electric Utilities today have a tool available to improve management's ability to evaluate nuclear power plant modifications (MODS). Probabilistic Risk Assessment (PRA), is a tool of choice since it can be applied to a specific situation such as MOD request review, bringing the perspectives of reliability, financial risk and consequences to the public in addition to the more rigid requirements like those associated with Quality Assurance or licensing criteria. The techniques used in the PRA process revolve about the creation and manipulation of Fault Trees and Event Trees, which are used to quantify the event sequences and reliability of plant systems in a logical framework. It is through these methods that chains of sequences, or events, are understood. The degree to which plant systems are modelled in the PRA can vary depending on resources and purpose. Philadelphia Elecrtric Company's PRA modelled ten (10) major systems but this number may increase during the application and updating process

Approach to modeling of human performance for purposes of probabilistic risk assessment

International Nuclear Information System (INIS)

Swain, A.D.

1983-01-01

This paper describes the general approach taken in NUREG/CR-1278 to model human performance in sufficienct detail to permit probabilistic risk assessments of nuclear power plant operations. To show the basis for the more specific models in the above NUREG, a simplified model of the human component in man-machine systems is presented, the role of performance shaping factors is discussed, and special problems in modeling the cognitive aspect of behavior are described

An integral approach to the use of probabilistic risk assessment methods

International Nuclear Information System (INIS)

Schwarzblat, M.; Arellano, J.

1987-01-01

In this chapter some of the work developed at the Instituto de Investigaciones Electricas in the area of probabilistic risk analysis are presented. In this area, work has been basically focused in the following directions: development and implementation of methods, and applications to real systems. The first part of this paper describes the area of methods development and implementation, presenting an integrated package of computer programs for fault tree analysis. In the second part some of the most important applications developed for real systems are presented. (author)

Issues related to structural aging in probabilistic risk assessment of nuclear power plants

International Nuclear Information System (INIS)

Ellingwood, Bruce R.

1998-01-01

Structural components and systems have an important safety function in nuclear power plants. Although they are essentially passive under normal operating conditions, they play a key role in mitigating the impact of extreme environmental events such as earthquakes, winds, fire and floods on plant safety. Moreover, the importance of structural components and systems in accident mitigation is amplified by common-cause effects. Reinforced concrete structural components and systems in NPPs are subject to a phenomenon known as aging, leading to time-dependent changes in strength and stiffness that may impact their ability to withstand various challenges during their service lives from operation, the environment and accidents. Time-dependent changes in structural properties as well as challenges to the system are random in nature. Accordingly, condition assessment of existing structures should be performed within a probabilistic framework. The mathematical formalism of a probabilistic risk assessment (PRA) provides a means for identifying aging structural components that may play a significant role in mitigating plant risk. Structural condition assessments supporting a decision regarding continued service can be rendered more efficient if guided by the logic of a PRA

Probabilistic Structural Analysis Program

Science.gov (United States)

Pai, Shantaram S.; Chamis, Christos C.; Murthy, Pappu L. N.; Stefko, George L.; Riha, David S.; Thacker, Ben H.; Nagpal, Vinod K.; Mital, Subodh K.

2010-01-01

NASA/NESSUS 6.2c is a general-purpose, probabilistic analysis program that computes probability of failure and probabilistic sensitivity measures of engineered systems. Because NASA/NESSUS uses highly computationally efficient and accurate analysis techniques, probabilistic solutions can be obtained even for extremely large and complex models. Once the probabilistic response is quantified, the results can be used to support risk-informed decisions regarding reliability for safety-critical and one-of-a-kind systems, as well as for maintaining a level of quality while reducing manufacturing costs for larger-quantity products. NASA/NESSUS has been successfully applied to a diverse range of problems in aerospace, gas turbine engines, biomechanics, pipelines, defense, weaponry, and infrastructure. This program combines state-of-the-art probabilistic algorithms with general-purpose structural analysis and lifting methods to compute the probabilistic response and reliability of engineered structures. Uncertainties in load, material properties, geometry, boundary conditions, and initial conditions can be simulated. The structural analysis methods include non-linear finite-element methods, heat-transfer analysis, polymer/ceramic matrix composite analysis, monolithic (conventional metallic) materials life-prediction methodologies, boundary element methods, and user-written subroutines. Several probabilistic algorithms are available such as the advanced mean value method and the adaptive importance sampling method. NASA/NESSUS 6.2c is structured in a modular format with 15 elements.

The Concepts of Risk, Safety, and Security: Applications in Everyday Language.

Science.gov (United States)

Boholm, Max; Möller, Niklas; Hansson, Sven Ove

2016-02-01

The concepts of risk, safety, and security have received substantial academic interest. Several assumptions exist about their nature and relation. Besides academic use, the words risk, safety, and security are frequent in ordinary language, for example, in media reporting. In this article, we analyze the concepts of risk, safety, and security, and their relation, based on empirical observation of their actual everyday use. The "behavioral profiles" of the nouns risk, safety, and security and the adjectives risky, safe, and secure are coded and compared regarding lexical and grammatical contexts. The main findings are: (1) the three nouns risk, safety, and security, and the two adjectives safe and secure, have widespread use in different senses, which will make any attempt to define them in a single unified manner extremely difficult; (2) the relationship between the central risk terms is complex and only partially confirms the distinctions commonly made between the terms in specialized terminology; (3) whereas most attempts to define risk in specialized terminology have taken the term to have a quantitative meaning, nonquantitative meanings dominate in everyday language, and numerical meanings are rare; and (4) the three adjectives safe, secure, and risky are frequently used in comparative form. This speaks against interpretations that would take them as absolute, all-or-nothing concepts. © 2015 Society for Risk Analysis.

Study on structural seismic margin and probabilistic seismic risk. Development of a structural capacity-seismic risk diagram

International Nuclear Information System (INIS)

Nakajima, Masato; Ohtori, Yasuki; Hirata, Kazuta

2010-01-01

Seismic margin is extremely important index and information when we evaluate and account seismic safety of critical structures, systems and components quantitatively. Therefore, it is required that electric power companies evaluate the seismic margin of each plant in back-check of nuclear power plants in Japan. The seismic margin of structures is usually defined as a structural capacity margin corresponding to design earthquake ground motion. However, there is little agreement as to the definition of the seismic margin and we have no knowledge about a relationship between the seismic margin and seismic risk (annual failure probability) which is obtained in PSA (Probabilistic Safety Assessment). The purpose of this report is to discuss a definition of structural seismic margin and to develop a diagram which can identify a relation between seismic margin and seismic risk. The main results of this paper are described as follows: (1) We develop seismic margin which is defined based on the fact that intensity of earthquake ground motion is more appropriate than the conventional definition (i.e., the response-based seismic margin) for the following reasons: -seismic margin based on earthquake ground motion is invariant where different typed structures are considered, -stakeholders can understand the seismic margin based on the earthquake ground motion better than the response-based one. (2) The developed seismic margin-risk diagram facilitates us to judge easily whether we need to perform detailed probabilistic risk analysis or only deterministic analysis, given that the reference risk level although information on the uncertainty parameter beta is not obtained. (3) We have performed numerical simulations based on the developed method for four sites in Japan. The structural capacity-risk diagram differs depending on each location because the diagram is greatly influenced by seismic hazard information for a target site. Furthermore, the required structural capacity

The NUREG-1150 probabilistic risk assessment for the Sequoyah nuclear plant

International Nuclear Information System (INIS)

Gregory, J.J.; Breeding, R.J.; Higgins, S.J.; Shiver, A.W.; Helton, J.C.; Murfin, W.B.

1992-01-01

This paper summarizes the findings of the probabilistic risk assessment (PRA) for Unit 1 of the Sequoyah Nuclear Plant performed in support of NUREG-1150. The emphasis is on the 'back-end' analyses, the accident progression, source term, and consequence analyses, and the risk results obtained when the results of these analyses are combined with the accident frequency analysis. The results of this PRA indicate that the offsite risk from internal initiating events at Sequoyah are quite low with respect to the safety goals. The containment appears likely to withstand the loads that might be placed upon it if the reactor vessel fails. A good portion of the risk, in this analysis, comes from initiating events which bypass the containment. These events are estimated to have a relatively low frequency of occurrence, but their consequences are quite large. Other events that contribute to offsite risk involve early containment failures that occur during degradation of the core or near the time of vessel breach. Considerable uncertainty is associated with the risk estimates produced in this analysis. Offsite risk from external initiating events was not included in this analysis. (orig.)

Development of probabilistic risk assessment methodology against extreme snow for sodium-cooled fast reactor

Energy Technology Data Exchange (ETDEWEB)

Yamano, Hidemasa, E-mail: yamano.hidemasa@jaea.go.jp; Nishino, Hiroyuki; Kurisaka, Kenichi

2016-11-15

Highlights: • Snow PRA methodology was developed. • Snow hazard category was defined as the combination of daily snowfall depth (speed) and snowfall duration. • Failure probability models of snow removal action, manual operation of the air cooler dampers and the access route were developed. • Snow PRA showed less than 10{sup −6}/reactor-year of core damage frequency. - Abstract: This paper describes snow probabilistic risk assessment (PRA) methodology development through external hazard and event sequence evaluations mainly in terms of decay heat removal (DHR) function of a sodium-cooled fast reactor (SFR). Using recent 50-year weather data at a typical Japanese SFR site, snow hazard categories were set for the combination of daily snowfall depth (snowfall speed) and snowfall duration which can be calculated by dividing the snow depth by the snowfall speed. For each snow hazard category, the event sequence was evaluated by event trees which consist of several headings representing the loss of DHR. Snow removal action and manual operation of the air cooler dampers were introduced into the event trees as accident managements. Access route failure probability model was also developed for the quantification of the event tree. In this paper, the snow PRA showed less than 10{sup −6}/reactor-year of core damage frequency. The dominant snow hazard category was the combination of 1–2 m/day of snowfall speed and 0.5–0.75 day of snowfall duration. Importance and sensitivity analyses indicated a high risk contribution of the securing of the access routes.

Development of probabilistic risk assessment methodology against extreme snow for sodium-cooled fast reactor

International Nuclear Information System (INIS)

Yamano, Hidemasa; Nishino, Hiroyuki; Kurisaka, Kenichi

2016-01-01

Highlights: • Snow PRA methodology was developed. • Snow hazard category was defined as the combination of daily snowfall depth (speed) and snowfall duration. • Failure probability models of snow removal action, manual operation of the air cooler dampers and the access route were developed. • Snow PRA showed less than 10"−"6/reactor-year of core damage frequency. - Abstract: This paper describes snow probabilistic risk assessment (PRA) methodology development through external hazard and event sequence evaluations mainly in terms of decay heat removal (DHR) function of a sodium-cooled fast reactor (SFR). Using recent 50-year weather data at a typical Japanese SFR site, snow hazard categories were set for the combination of daily snowfall depth (snowfall speed) and snowfall duration which can be calculated by dividing the snow depth by the snowfall speed. For each snow hazard category, the event sequence was evaluated by event trees which consist of several headings representing the loss of DHR. Snow removal action and manual operation of the air cooler dampers were introduced into the event trees as accident managements. Access route failure probability model was also developed for the quantification of the event tree. In this paper, the snow PRA showed less than 10"−"6/reactor-year of core damage frequency. The dominant snow hazard category was the combination of 1–2 m/day of snowfall speed and 0.5–0.75 day of snowfall duration. Importance and sensitivity analyses indicated a high risk contribution of the securing of the access routes.

Probabilistic fire risk assessment for Koeberg Nuclear Power Station Unit 1

International Nuclear Information System (INIS)

Grobbelaar, J.F.; Foster, N.A.S.; Luesse, L.J.

1995-01-01

A probabilistic fire risk assessment was done for Koeberg Nuclear Power Station Unit 1. Areas where fires are likely to start were identified. Equipment important to safety, as well as their power and/or control cable routes were identified in each fire confinement sector. Fire confinement sectors where internal initiating events could be caused by fire were identified. Detection failure and suppression failure fault trees and event trees were constructed. The core damage frequency associated with each fire confinement sector was calculated, and important fire confinement sectors were identified. (author)

Transmission capacity assessment by probabilistic planning. An approach

International Nuclear Information System (INIS)

Lammintausta, M.

2002-01-01

The Finnish electricity markets participate in the Scandinavian markets, Nord-Pool. The Finnish market is free for marketers, producers and consumers. All these participants can be seen as customers of the transmission network, which in turn can be considered to be a market place in which electricity can be sold and bought. The Finnish transmission network is owned and operated by an independent company, Fingrid that has the full responsibility of the Finnish transmission system. The available transfer capacity of a transmission route is traditionally limited by deterministic security constraints. More efficient and flexible network utilisation could be achieved with probabilistic planning methods. This report introduces a simple and practical probabilistic approach for transfer limit and risk assessment. The method is based on the economical benefit and risk predictions. It uses also the existing results of deterministic data and it could be used side by side with the deterministic method. The basic concept and necessary equations for expected risks of various market players have been derived for further developments. The outage costs and thereby the risks of the market participants depend on how the system operator reacts to the faults. In the Finnish power system consumers will usually experience no costs due to the faults because of meshed network and counter trade method preferred by the system operator. The costs to the producers and dealers are also low because of the counter trade method. The network company will lose the cost of reparation, additional losses and cost of regulation power because of counter trades. In case power flows will be rearranged drastically because of aggressive strategies used in the electricity markets, the only way to fulfil the needs of free markets is that the network operator buys regulation power for short-term problems and reinforces the network in the long-term situations. The reinforcement is done if the network can not be

Potential for accidents in a nuclear power plant: probabilistic risk assessment, applied statistical decision theory, and implications of such considerations to mathematics education

International Nuclear Information System (INIS)

Dios, R.A.

1984-01-01

This dissertation focuses upon the field of probabilistic risk assessment and its development. It investigates the development of probabilistic risk assessment in nuclear engineering. To provide background for its development, the related areas of population dynamics (demography), epidemiology and actuarial science are studied by presenting information upon how risk has been viewed in these areas over the years. A second major problem involves presenting an overview of the mathematical models related to risk analysis to mathematics educators and making recommendations for presenting this theory in classes of probability and statistics for mathematics and engineering majors at the undergraduate and graduate levels

A mediation model to explain decision making under conditions of risk among adolescents: the role of fluid intelligence and probabilistic reasoning.

Science.gov (United States)

Donati, Maria Anna; Panno, Angelo; Chiesi, Francesca; Primi, Caterina

2014-01-01

This study tested the mediating role of probabilistic reasoning ability in the relationship between fluid intelligence and advantageous decision making among adolescents in explicit situations of risk--that is, in contexts in which information on the choice options (gains, losses, and probabilities) were explicitly presented at the beginning of the task. Participants were 282 adolescents attending high school (77% males, mean age = 17.3 years). We first measured fluid intelligence and probabilistic reasoning ability. Then, to measure decision making under explicit conditions of risk, participants performed the Game of Dice Task, in which they have to decide among different alternatives that are explicitly linked to a specific amount of gain or loss and have obvious winning probabilities that are stable over time. Analyses showed a significant positive indirect effect of fluid intelligence on advantageous decision making through probabilistic reasoning ability that acted as a mediator. Specifically, fluid intelligence may enhance ability to reason in probabilistic terms, which in turn increases the likelihood of advantageous choices when adolescents are confronted with an explicit decisional context. Findings show that in experimental paradigm settings, adolescents are able to make advantageous decisions using cognitive abilities when faced with decisions under explicit risky conditions. This study suggests that interventions designed to promote probabilistic reasoning, for example by incrementing the mathematical prerequisites necessary to reason in probabilistic terms, may have a positive effect on adolescents' decision-making abilities.

Probabilistic logics and probabilistic networks

CERN Document Server

Haenni, Rolf; Wheeler, Gregory; Williamson, Jon; Andrews, Jill

2014-01-01

Probabilistic Logic and Probabilistic Networks presents a groundbreaking framework within which various approaches to probabilistic logic naturally fit. Additionally, the text shows how to develop computationally feasible methods to mesh with this framework.

Risk-Based Predictive Maintenance for Safety-Critical Systems by Using Probabilistic Inference

Directory of Open Access Journals (Sweden)

Tianhua Xu

2013-01-01

Full Text Available Risk-based maintenance (RBM aims to improve maintenance planning and decision making by reducing the probability and consequences of failure of equipment. A new predictive maintenance strategy that integrates dynamic evolution model and risk assessment is proposed which can be used to calculate the optimal maintenance time with minimal cost and safety constraints. The dynamic evolution model provides qualified risks by using probabilistic inference with bucket elimination and gives the prospective degradation trend of a complex system. Based on the degradation trend, an optimal maintenance time can be determined by minimizing the expected maintenance cost per time unit. The effectiveness of the proposed method is validated and demonstrated by a collision accident of high-speed trains with obstacles in the presence of safety and cost constrains.

Securing the energy industry : perspectives in security risk management

Energy Technology Data Exchange (ETDEWEB)

Hurd, G.L. [Anadarko Canada Corp., Calgary, AB (Canada)

2003-07-01

This presentation offered some perspectives in security risk management as it relates to the energy sector. Since the events of September 11, 2001 much attention has been given to terrorism and the business is reviewing protection strategies. The paper made reference to each of the following vulnerabilities in the energy sector: information technology, globalization, business restructuring, interdependencies, political/regulatory change, and physical/human factors. The vulnerability of information technology is that it can be subject to cyber and virus attacks. Dangers of globalization lie in privacy and information security, forced nationalization, organized crime, and anti-globalization efforts. It was noted that the Y2K phenomenon provided valuable lessons regarding interdependencies and the effects of power outages, water availability, transportation disruption, common utility corridor accidents, and compounding incidents. The paper also noted the conflict between the government's desire to have a resilient infrastructure that can withstand and recover from attacks versus a company's ability to afford this capability. The physical/human factors that need to be considered in risk management include crime, domestic terrorism, and disasters such as natural disasters, industrial disasters and crisis. The energy industry has geographically dispersed vulnerable systems. It has done a fair job of physical security and has good emergency management practices, but it was noted that the industry cannot protect against all threats. A strategy of vigilance and awareness is needed to deal with threats. Other strategies include contingency planning, physical security, employee communication, and emergency response plans. tabs., figs.

A cooperative model for IS security risk management in distributed environment.

Science.gov (United States)

Feng, Nan; Zheng, Chundong

2014-01-01

Given the increasing cooperation between organizations, the flexible exchange of security information across the allied organizations is critical to effectively manage information systems (IS) security in a distributed environment. In this paper, we develop a cooperative model for IS security risk management in a distributed environment. In the proposed model, the exchange of security information among the interconnected IS under distributed environment is supported by Bayesian networks (BNs). In addition, for an organization's IS, a BN is utilized to represent its security environment and dynamically predict its security risk level, by which the security manager can select an optimal action to safeguard the firm's information resources. The actual case studied illustrates the cooperative model presented in this paper and how it can be exploited to manage the distributed IS security risk effectively.

Incorporating organizational factors into Probabilistic Risk Assessment (PRA) of complex socio-technical systems: A hybrid technique formalization

International Nuclear Information System (INIS)

Mohaghegh, Zahra; Kazemi, Reza; Mosleh, Ali

2009-01-01

This paper is a result of a research with the primary purpose of extending Probabilistic Risk Assessment (PRA) modeling frameworks to include the effects of organizational factors as the deeper, more fundamental causes of accidents and incidents. There have been significant improvements in the sophistication of quantitative methods of safety and risk assessment, but the progress on techniques most suitable for organizational safety risk frameworks has been limited. The focus of this paper is on the choice of 'representational schemes' and 'techniques.' A methodology for selecting appropriate candidate techniques and their integration in the form of a 'hybrid' approach is proposed. Then an example is given through an integration of System Dynamics (SD), Bayesian Belief Network (BBN), Event Sequence Diagram (ESD), and Fault Tree (FT) in order to demonstrate the feasibility and value of hybrid techniques. The proposed hybrid approach integrates deterministic and probabilistic modeling perspectives, and provides a flexible risk management tool for complex socio-technical systems. An application of the hybrid technique is provided in the aviation safety domain, focusing on airline maintenance systems. The example demonstrates how the hybrid method can be used to analyze the dynamic effects of organizational factors on system risk

Use and Communication of Probabilistic Forecasts.

Science.gov (United States)

Raftery, Adrian E

2016-12-01

Probabilistic forecasts are becoming more and more available. How should they be used and communicated? What are the obstacles to their use in practice? I review experience with five problems where probabilistic forecasting played an important role. This leads me to identify five types of potential users: Low Stakes Users, who don't need probabilistic forecasts; General Assessors, who need an overall idea of the uncertainty in the forecast; Change Assessors, who need to know if a change is out of line with expectatations; Risk Avoiders, who wish to limit the risk of an adverse outcome; and Decision Theorists, who quantify their loss function and perform the decision-theoretic calculations. This suggests that it is important to interact with users and to consider their goals. The cognitive research tells us that calibration is important for trust in probability forecasts, and that it is important to match the verbal expression with the task. The cognitive load should be minimized, reducing the probabilistic forecast to a single percentile if appropriate. Probabilities of adverse events and percentiles of the predictive distribution of quantities of interest seem often to be the best way to summarize probabilistic forecasts. Formal decision theory has an important role, but in a limited range of applications.

Use and Communication of Probabilistic Forecasts

Science.gov (United States)

Raftery, Adrian E.

2015-01-01

Probabilistic forecasts are becoming more and more available. How should they be used and communicated? What are the obstacles to their use in practice? I review experience with five problems where probabilistic forecasting played an important role. This leads me to identify five types of potential users: Low Stakes Users, who don’t need probabilistic forecasts; General Assessors, who need an overall idea of the uncertainty in the forecast; Change Assessors, who need to know if a change is out of line with expectatations; Risk Avoiders, who wish to limit the risk of an adverse outcome; and Decision Theorists, who quantify their loss function and perform the decision-theoretic calculations. This suggests that it is important to interact with users and to consider their goals. The cognitive research tells us that calibration is important for trust in probability forecasts, and that it is important to match the verbal expression with the task. The cognitive load should be minimized, reducing the probabilistic forecast to a single percentile if appropriate. Probabilities of adverse events and percentiles of the predictive distribution of quantities of interest seem often to be the best way to summarize probabilistic forecasts. Formal decision theory has an important role, but in a limited range of applications. PMID:28446941

Probabilistic assessment of dry transport with burnup credit

International Nuclear Information System (INIS)

Lake, W.H.

2003-01-01

The general concept of probabilistic analysis and its application to the use of burnup credit in spent fuel transport is explored. Discussion of the probabilistic analysis method is presented. The concepts of risk and its perception are introduced, and models are suggested for performing probability and risk estimates. The general probabilistic models are used for evaluating the application of burnup credit for dry spent nuclear fuel transport. Two basic cases are considered. The first addresses the question of the relative likelihood of exceeding an established criticality safety limit with and without burnup credit. The second examines the effect of using burnup credit on the overall risk for dry spent fuel transport. Using reasoned arguments and related failure probability and consequence data analysis is performed to estimate the risks of using burnup credit for dry transport of spent nuclear fuel. (author)

TWO-PARAMETER IRT MODEL APPLICATION TO ASSESS PROBABILISTIC CHARACTERISTICS OF PROHIBITED ITEMS DETECTION BY AVIATION SECURITY SCREENERS

Directory of Open Access Journals (Sweden)

Alexander K. Volkov

2017-01-01

Full Text Available The modern approaches to the aviation security screeners’ efficiency have been analyzedand, certain drawbacks have been considered. The main drawback is the complexity of ICAO recommendations implementation concerning taking into account of shadow x-ray image complexity factors during preparation and evaluation of prohibited items detection efficiency by aviation security screeners. Х-ray image based factors are the specific properties of the x-ray image that in- fluence the ability to detect prohibited items by aviation security screeners. The most important complexity factors are: geometric characteristics of a prohibited item; view difficulty of prohibited items; superposition of prohibited items byother objects in the bag; bag content complexity; the color similarity of prohibited and usual items in the luggage.The one-dimensional two-parameter IRT model and the related criterion of aviation security screeners’ qualification have been suggested. Within the suggested model the probabilistic detection characteristics of aviation security screeners are considered as functions of such parameters as the difference between level of qualification and level of x-ray images com- plexity, and also between the aviation security screeners’ responsibility and structure of their professional knowledge. On the basis of the given model it is possible to consider two characteristic functions: first of all, characteristic function of qualifica- tion level which describes multi-complexity level of x-ray image interpretation competency of the aviation security screener; secondly, characteristic function of the x-ray image complexity which describes the range of x-ray image interpretation com- petency of the aviation security screeners having various training levels to interpret the x-ray image of a certain level of com- plexity. The suggested complex criterion to assess the level of the aviation security screener qualification allows to evaluate his or

Innovative real time simulation training and nuclear probabilistic risk assessment

International Nuclear Information System (INIS)

Reisinger, M.F.

1991-01-01

Operator errors have been an area of public concern for the safe operation of nuclear power plants since the TMI2 incident. Simply stated, nuclear plants are very complex systems and the public is skeptical of the operators' ability to comprehend and deal with the vast indications and complexities of potential nuclear power plant events. Prior to the TMI2 incident, operator errors and human factors were not included as contributing factors in the Probabilistic Risk Assessment (PRA) studies of nuclear power plant accidents. More recent efforts in nuclear risk assessment have addressed some of the human factors affecting safe nuclear plant operations. One study found four major factors having significant impact on operator effectiveness. This paper discusses human factor PRAs, new applications in simulation training and the specific potential benefits from simulation in promoting safer operation of future power plants as well as current operating power plants

6 CFR 27.200 - Information regarding security risk for a chemical facility.

Science.gov (United States)

2010-01-01

... chemical facility. 27.200 Section 27.200 Domestic Security DEPARTMENT OF HOMELAND SECURITY, OFFICE OF THE SECRETARY CHEMICAL FACILITY ANTI-TERRORISM STANDARDS Chemical Facility Security Program § 27.200 Information regarding security risk for a chemical facility. (a) Information to determine security risk. In order to...

RiskREP: Risk-Based Security Requirements Elicitation and Prioritization

OpenAIRE

Herrmann, Andrea; Morali, A.; Etalle, Sandro; Wieringa, Roelf J.; Niedrite, Laila; Strazdina, Renate; Wangler, Benkt

2011-01-01

Companies are under pressure to be in control of their assets but at the same time they must operate as efficiently as possible. This means that they aim to implement “good-enough security‿ but need to be able to justify their security investment plans. In this paper, we present a Risk-Based Requirements Prioritization method (RiskREP) that extends misuse case-based methods with IT architecture based risk assessment and countermeasure definition and prioritization. Countermeasure prioritizati...

Evaluation of structural fragilities for an IPEEE seismic probabilistic risk assessment study

International Nuclear Information System (INIS)

Ghiocel, D.M.; Wilson, P.R.; Stevenson, J.D.

1995-01-01

The paper presents the main issues and results of a structural fragility analysis for a Seismic Probabilistic Risk Assessment (SPRA) study of a nuclear power plant (NPP) in the Eastern US. The fragility evaluations were performed for the Reactor Building, Auxiliary Building, Intake Structure and Diesel Generator Building. The random seismic input is defined in terms of the Uniform Hazard Spectrum (UHS) earthquake on the NPP site anchored to a reference level of 0.40 g Zero Period Ground Acceleration (ZPGA). Because of the soft soil conditions new Soil-Structure Interaction (SSI) analyses were performed using the original finite element (stick) structural models and the complex frequency approach. The soil deposit randomness was described by the variations in both the low strain soil shear modules and in its dependence with the shear strain. The probabilistic SSI analyses were performed using digital simulation techniques. The critical failure modes for each structure are investigated and the fragility evaluations are discussed. Concluding remarks and recommendations for improving the quality of the structural fragility analyses are included

Comparison of a Traditional Probabilistic Risk Assessment Approach with Advanced Safety Analysis

Energy Technology Data Exchange (ETDEWEB)

Smith, Curtis L; Mandelli, Diego; Zhegang Ma

2014-11-01

As part of the Light Water Sustainability Program (LWRS) [1], the purpose of the Risk Informed Safety Margin Characterization (RISMC) [2] Pathway research and development (R&D) is to support plant decisions for risk-informed margin management with the aim to improve economics, reliability, and sustain safety of current NPPs. In this paper, we describe the RISMC analysis process illustrating how mechanistic and probabilistic approaches are combined in order to estimate a safety margin. We use the scenario of a “station blackout” (SBO) wherein offsite power and onsite power is lost, thereby causing a challenge to plant safety systems. We describe the RISMC approach, illustrate the station blackout modeling, and contrast this with traditional risk analysis modeling for this type of accident scenario. We also describe our approach we are using to represent advanced flooding analysis.

An integrated approach to validation of safeguards and security program performance

International Nuclear Information System (INIS)

Altman, W.D.; Hunt, J.S.; Hockert, J.W.

1988-01-01

Department of Energy (DOE) requirements for safeguards and security programs are becoming increasingly performance oriented. Master Safeguards and Security Agreemtns specify performance levels for systems protecting DOE security interests. In order to measure and validate security system performance, Lawrence Livermore National Laboratory (LLNL) has developed cost effective validation tools and a comprehensive validation approach that synthesizes information gained from different activities such as force on force exercises, limited scope performance tests, equipment testing, vulnerability analyses, and computer modeling; into an overall assessment of the performance of the protection system. The analytic approach employs logic diagrams adapted from the fault and event trees used in probabilistic risk assessment. The synthesis of the results from the various validation activities is accomplished using a method developed by LLNL, based upon Bayes' theorem

Lung cancer risk in relation to traffic-related nano/ultrafine particle-bound PAHs exposure: a preliminary probabilistic assessment.

Science.gov (United States)

Liao, Chung-Min; Chio, Chia-Pin; Chen, Wei-Yu; Ju, Yun-Ru; Li, Wen-Hsuan; Cheng, Yi-Hsien; Liao, Vivian Hsiu-Chuan; Chen, Szu-Chieh; Ling, Min-Pei

2011-06-15

Exposures to carcinogenic polycyclic aromatic hydrocarbons (PAHs) have been linked to human lung cancer. The purpose of this study was to assess lung cancer risk caused by inhalation exposure to nano/ultrafine particle-bound PAHs at the population level in Taiwan appraised with recent published data. A human respiratory tract model was linked with a physiologically based pharmacokinetic model to estimate deposition fraction and internal organic-specific PAHs doses. A probabilistic risk assessment framework was developed to estimate potential lung cancer risk. We reanalyzed particle size distribution, total-PAHs, particle-bound benzo(a)pyrene (B[a]P) and PM concentrations. A dose-response profile describing the relationships between external B[a]P concentration and lung cancer risk response was constructed based on population attributable fraction (PAF). We found that 90% probability lung cancer risks ranged from 10(-5) to 10(-4) for traffic-related nano and ultrafine particle-bound PAHs, indicating a potential lung cancer risk. The particle size-specific PAF-based excess annual lung cancer incidence rate due to PAHs exposure was estimated to be less than 1 per 100,000 population, indicating a mild risk factor for lung cancer. We concluded that probabilistic risk assessment linked PAF for limiting cumulative PAHs emissions to reduce lung cancer risk plays a prominent role in future government risk assessment program. Copyright © 2011 Elsevier B.V. All rights reserved.

Marked point process framework for living probabilistic safety assessment and risk follow-up

International Nuclear Information System (INIS)

Arjas, Elja; Holmberg, Jan

1995-01-01

We construct a model for living probabilistic safety assessment (PSA) by applying the general framework of marked point processes. The framework provides a theoretically rigorous approach for considering risk follow-up of posterior hazards. In risk follow-up, the hazard of core damage is evaluated synthetically at time points in the past, by using some observed events as logged history and combining it with re-evaluated potential hazards. There are several alternatives for doing this, of which we consider three here, calling them initiating event approach, hazard rate approach, and safety system approach. In addition, for a comparison, we consider a core damage hazard arising in risk monitoring. Each of these four definitions draws attention to a particular aspect in risk assessment, and this is reflected in the behaviour of the consequent risk importance measures. Several alternative measures are again considered. The concepts and definitions are illustrated by a numerical example

Expert elicitation for deriving input data for probabilistic risk assessment of shipwrecks.

Science.gov (United States)

Landquist, H; Norrman, J; Lindhe, A; Norberg, T; Hassellöv, I-M; Lindgren, J F; Rosén, L

2017-12-15

The necessity of having a process in place for adequate risk assessment of shipwrecks that pose a threat to the marine environment is today internationally acknowledged. However, retrieving the desired data for such a risk assessment can prove challenging. One means of addressing this problem is to make use of experts' knowledge and experience. The purpose of this paper is therefore to present and analyse data for risk assessment of shipwrecks derived by expert elicitation. The main outcome is the experts' estimations of (i) the generic probability of an opening in a shipwreck due to the occurrence of a number of activities and (ii) estimations of the degree to which site-specific and wreck-specific indicators affect the probability of opening. Results show that the derived information is applicable in probabilistic shipwreck risk assessment and that the VRAKA framework now contains needed information for integrating generic and site-specific information using Bayesian updating. Copyright © 2017 Elsevier Ltd. All rights reserved.

Advances in multi-unit nuclear power plant probabilistic risk assessment

International Nuclear Information System (INIS)

Modarres, Mohammad; Zhou, Taotao; Massoud, Mahmoud

2017-01-01

The Fukushima Dai-ichi accident highlighted the importance of risks from multiple nuclear reactor unit accidents at a site. As a result, there has been considerable interest in Multi-Unit Probabilistic Risk Assessment (MUPRA) in the past few years. For considerations in nuclear safety, the MUPRA estimates measures of risk and identifies contributors to risk representing the entire site rather than the individual units in the site. In doing so, possible unit-to-unit interactions and dependencies should be modeled and accounted for in the MUPRA. In order to effectively account for these risks, six main commonality classifications—initiating events, shared connections, identical components, proximity dependencies, human dependencies, and organizational dependencies—may be used. This paper examines advances in MUPRA, offers formal definitions of multi-unit site risk measures and proposes quantitative approaches and data to account for unit-to-unit dependencies. Finally, a parametric approach for the multi-unit dependencies has been discussed and a simple example illustrates application of the proposed methodology. - Highlights: • This paper will discuss the technical aspects of an integrated MUPRA, including consideration of dependencies and assessment of the multi-unit dependency data and models for quantifying such dependencies. • The paper also provides discussions on formal definitions and metrics for multi-unit site risks. • The parametric methods are used to address multi-unit dependency situations. • A conceptual two-unit logic example is used to demonstrate the application of proposed methodology.

Probabilistic methods in fire-risk analysis

International Nuclear Information System (INIS)

Brandyberry, M.D.

1989-01-01

The first part of this work outlines a method for assessing the frequency of ignition of a consumer product in a building and shows how the method would be used in an example scenario utilizing upholstered furniture as the product and radiant auxiliary heating devices (electric heaters, wood stoves) as the ignition source. Deterministic thermal models of the heat-transport processes are coupled with parameter uncertainty analysis of the models and with a probabilistic analysis of the events involved in a typical scenario. This leads to a distribution for the frequency of ignition for the product. In second part, fire-risk analysis as currently used in nuclear plants is outlines along with a discussion of the relevant uncertainties. The use of the computer code COMPBRN is discussed for use in the fire-growth analysis along with the use of response-surface methodology to quantify uncertainties in the code's use. Generalized response surfaces are developed for temperature versus time for a cable tray, as well as a surface for the hot gas layer temperature and depth for a room of arbitrary geometry within a typical nuclear power plant compartment. These surfaces are then used to simulate the cable tray damage time in a compartment fire experiment

Development of an Automated Security Risk Assessment Methodology Tool for Critical Infrastructures.

Energy Technology Data Exchange (ETDEWEB)

Jaeger, Calvin Dell; Roehrig, Nathaniel S.; Torres, Teresa M.

2008-12-01

This document presents the security automated Risk Assessment Methodology (RAM) prototype tool developed by Sandia National Laboratories (SNL). This work leverages SNL's capabilities and skills in security risk analysis and the development of vulnerability assessment/risk assessment methodologies to develop an automated prototype security RAM tool for critical infrastructures (RAM-CITM). The prototype automated RAM tool provides a user-friendly, systematic, and comprehensive risk-based tool to assist CI sector and security professionals in assessing and managing security risk from malevolent threats. The current tool is structured on the basic RAM framework developed by SNL. It is envisioned that this prototype tool will be adapted to meet the requirements of different CI sectors and thereby provide additional capabilities.

Hydrocomplexity: Addressing water security and emergent environmental risks

Science.gov (United States)

Kumar, Praveen

2015-07-01

Water security and emergent environmental risks are among the most significant societal concerns. They are highly interlinked to other global risks such as those related to climate, human health, food, human migration, biodiversity loss, urban sustainability, etc. Emergent risks result from the confluence of unanticipated interactions from evolving interdependencies between complex systems, such as those embedded in the water cycle. They are associated with the novelty of dynamical possibilities that have significant potential consequences to human and ecological systems, and not with probabilities based on historical precedence. To ensure water security we need to be able to anticipate the likelihood of risk possibilities as they present the prospect of the most impact through cascade of vulnerabilities. They arise due to a confluence of nonstationary drivers that include growing population, climate change, demographic shifts, urban growth, and economic expansion, among others, which create novel interdependencies leading to a potential of cascading network effects. Hydrocomplexity aims to address water security and emergent risks through the development of science, methods, and practices with the potential to foster a "Blue Revolution" akin to the Green revolution for food security. It blends both hard infrastructure based solution with soft knowledge driven solutions to increase the range of planning and design, management, mitigation and adaptation strategies. It provides a conceptual and synthetic framework to enable us to integrate discovery science and engineering, observational and information science, computational and communication systems, and social and institutional approaches to address consequential water and environmental challenges.

Deterministic and probabilistic approach to determine seismic risk of nuclear power plants; a practical example

International Nuclear Information System (INIS)

Soriano Pena, A.; Lopez Arroyo, A.; Roesset, J.M.

1976-01-01

The probabilistic and deterministic approaches for calculating the seismic risk of nuclear power plants are both applied to a particular case in Southern Spain. The results obtained by both methods, when varying the input data, are presented and some conclusions drawn in relation to the applicability of the methods, their reliability and their sensitivity to change

Incorporating organizational factors into Probabilistic Risk Assessment (PRA) of complex socio-technical systems: A hybrid technique formalization

Energy Technology Data Exchange (ETDEWEB)

Mohaghegh, Zahra [Center for Risk and Reliability, University of Maryland, College Park, MD 20742 (United States)], E-mail: mohagheg@umd.edu; Kazemi, Reza; Mosleh, Ali [Center for Risk and Reliability, University of Maryland, College Park, MD 20742 (United States)

2009-05-15

This paper is a result of a research with the primary purpose of extending Probabilistic Risk Assessment (PRA) modeling frameworks to include the effects of organizational factors as the deeper, more fundamental causes of accidents and incidents. There have been significant improvements in the sophistication of quantitative methods of safety and risk assessment, but the progress on techniques most suitable for organizational safety risk frameworks has been limited. The focus of this paper is on the choice of 'representational schemes' and 'techniques.' A methodology for selecting appropriate candidate techniques and their integration in the form of a 'hybrid' approach is proposed. Then an example is given through an integration of System Dynamics (SD), Bayesian Belief Network (BBN), Event Sequence Diagram (ESD), and Fault Tree (FT) in order to demonstrate the feasibility and value of hybrid techniques. The proposed hybrid approach integrates deterministic and probabilistic modeling perspectives, and provides a flexible risk management tool for complex socio-technical systems. An application of the hybrid technique is provided in the aviation safety domain, focusing on airline maintenance systems. The example demonstrates how the hybrid method can be used to analyze the dynamic effects of organizational factors on system risk.

Key attributes of the SAPHIRE risk and reliability analysis software for risk-informed probabilistic applications

International Nuclear Information System (INIS)

Smith, Curtis; Knudsen, James; Kvarfordt, Kellie; Wood, Ted

2008-01-01

The Idaho National Laboratory is a primary developer of probabilistic risk and reliability analysis (PRRA) tools, dating back over 35 years. Evolving from mainframe-based software, the current state-of-the-practice has led to the creation of the SAPHIRE software. Currently, agencies such as the Nuclear Regulatory Commission, the National Aeronautics and Aerospace Agency, the Department of Energy, and the Department of Defense use version 7 of the SAPHIRE software for many of their risk-informed activities. In order to better understand and appreciate the power of software as part of risk-informed applications, we need to recall that our current analysis methods and solution methods have built upon pioneering work done 30-40 years ago. We contrast this work with the current capabilities in the SAPHIRE analysis package. As part of this discussion, we provide information for both the typical features and special analysis capabilities, which are available. We also present the application and results typically found with state-of-the-practice PRRA models. By providing both a high-level and detailed look at the SAPHIRE software, we give a snapshot in time for the current use of software tools in a risk-informed decision arena

A Novel TRM Calculation Method by Probabilistic Concept

Science.gov (United States)

Audomvongseree, Kulyos; Yokoyama, Akihiko; Verma, Suresh Chand; Nakachi, Yoshiki

In a new competitive environment, it becomes possible for the third party to access a transmission facility. From this structure, to efficiently manage the utilization of the transmission network, a new definition about Available Transfer Capability (ATC) has been proposed. According to the North American ElectricReliability Council (NERC)’s definition, ATC depends on several parameters, i. e. Total Transfer Capability (TTC), Transmission Reliability Margin (TRM), and Capacity Benefit Margin (CBM). This paper is focused on the calculation of TRM which is one of the security margin reserved for any uncertainty of system conditions. The TRM calculation by probabilistic method is proposed in this paper. Based on the modeling of load forecast error and error in transmission line limitation, various cases of transmission transfer capability and its related probabilistic nature can be calculated. By consideration of the proposed concept of risk analysis, the appropriate required amount of TRM can be obtained. The objective of this research is to provide realistic information on the actual ability of the network which may be an alternative choice for system operators to make an appropriate decision in the competitive market. The advantages of the proposed method are illustrated by application to the IEEJ-WEST10 model system.

Interdependent Risk and Cyber Security: An Analysis of Security Investment and Cyber Insurance

Science.gov (United States)

Shim, Woohyun

2010-01-01

An increasing number of firms rely on highly interconnected information networks. In such environments, defense against cyber attacks is complicated by residual risks caused by the interdependence of information security decisions of firms. IT security is affected not only by a firm's own management strategies but also by those of others. This…

Security breaches: tips for assessing and limiting your risks.

Science.gov (United States)

Coons, Leeanne R

2011-01-01

As part of their compliance planning, medical practices should undergo a risk assessment to determine any vulnerability within the practice relative to security breaches. Practices should also implement safeguards to limit their risks. Such safeguards include facility access controls, information and electronic media management, use of business associate agreements, and education and enforcement. Implementation of specific policies and procedures to address security incidents is another critical step that medical practices should take as part of their security incident prevention plan. Medical practices should not only develop policies and procedures to prevent, detect, contain, and correct security violations, but should make sure that such policies and procedures are actually implemented in their everyday operations.

Nuclear Regulatory Commission probabilistic risk assessment implementation program: A status report

International Nuclear Information System (INIS)

Rubin, M.P.; Caruso, M.A.

1996-01-01

The US Nuclear Regulatory Commission (NRC) is undertaking a number of activities intended to increase the consideration of risk significance in its decision processes and the effective use of risk-based technologies in its regulatory activities. Although the NRC is moving toward risk-informed regulation throughout its areas of responsibilities, this paper focuses primarily on those issues associated with reactor regulation. As the NRC completed significant milestones in its development of probabilistic risk assessment (PRA) methodology and gained considerable experience in the limited application of risk assessment to selected regulatory activities, it became evident that a much broader use of risk informed approaches offered advantages to both the NRC and the US commercial nuclear industry. This desire to enhance the use of risk assessment is driven by the clear belief that application of PRA methods will result in direct improvements in nuclear power plant operational safety from the perspective of both the regulator and the plant operator. The NRC believed that an overall policy on the use of PRA methods in nuclear regulatory activities should be established so that the many potential applications of PRA could be implemented in a consistent and predictable manner that would promote regulatory stability and efficiency. This paper describes the key activities that the NRC has undertaken to implement the initial stages of an integrated risk-informed regulatory framework

Probabilistic risk assessment on maritime spent nuclear fuel transportation (Part II: Ship collision probability)

International Nuclear Information System (INIS)

Christian, Robby; Kang, Hyun Gook

2017-01-01

This paper proposes a methodology to assess and reduce risks of maritime spent nuclear fuel transportation with a probabilistic approach. Event trees detailing the progression of collisions leading to transport casks’ damage were constructed. Parallel and crossing collision probabilities were formulated based on the Poisson distribution. Automatic Identification System (AIS) data were processed with the Hough Transform algorithm to estimate possible intersections between the shipment route and the marine traffic. Monte Carlo simulations were done to compute collision probabilities and impact energies at each intersection. Possible safety improvement measures through a proper selection of operational transport parameters were investigated. These parameters include shipment routes, ship's cruise velocity, number of transport casks carried in a shipment, the casks’ stowage configuration and loading order on board the ship. A shipment case study is presented. Waters with high collision probabilities were identified. Effective range of cruising velocity to reduce collision risks were discovered. The number of casks in a shipment and their stowage method which gave low cask damage frequencies were obtained. The proposed methodology was successful in quantifying ship collision and cask damage frequency. It was effective in assisting decision making processes to minimize risks in maritime spent nuclear fuel transportation. - Highlights: • Proposes a probabilistic framework on the safety of spent nuclear fuel transportation by sea. • Developed a marine traffic simulation model using Generalized Hough Transform (GHT) algorithm. • A transportation case study on South Korean waters is presented. • Single-vessel risk reduction method is outlined by optimizing transport parameters.

HERMES probabilistic risk assessment. Pilot study

International Nuclear Information System (INIS)

Parisot, F.; Munoz, J.

1993-01-01

The study was performed in 1989 of the contribution of probabilistic analysis for the optimal construction of system safety status in aeronautical and European nuclear industries, shows the growing trends towards incorporation of quantitative safety assessment and lead to an agreement to undertake a prototype proof study on Hermes. The main steps of the study and results are presented in the paper

Probabilistic migration modelling focused on functional barrier efficiency and low migration concepts in support of risk assessment.

Science.gov (United States)

Brandsch, Rainer

2017-10-01

Migration modelling provides reliable migration estimates from food-contact materials (FCM) to food or food simulants based on mass-transfer parameters like diffusion and partition coefficients related to individual materials. In most cases, mass-transfer parameters are not readily available from the literature and for this reason are estimated with a given uncertainty. Historically, uncertainty was accounted for by introducing upper limit concepts first, turning out to be of limited applicability due to highly overestimated migration results. Probabilistic migration modelling gives the possibility to consider uncertainty of the mass-transfer parameters as well as other model inputs. With respect to a functional barrier, the most important parameters among others are the diffusion properties of the functional barrier and its thickness. A software tool that accepts distribution as inputs and is capable of applying Monte Carlo methods, i.e., random sampling from the input distributions of the relevant parameters (i.e., diffusion coefficient and layer thickness), predicts migration results with related uncertainty and confidence intervals. The capabilities of probabilistic migration modelling are presented in the view of three case studies (1) sensitivity analysis, (2) functional barrier efficiency and (3) validation by experimental testing. Based on the predicted migration by probabilistic migration modelling and related exposure estimates, safety evaluation of new materials in the context of existing or new packaging concepts is possible. Identifying associated migration risk and potential safety concerns in the early stage of packaging development is possible. Furthermore, dedicated material selection exhibiting required functional barrier efficiency under application conditions becomes feasible. Validation of the migration risk assessment by probabilistic migration modelling through a minimum of dedicated experimental testing is strongly recommended.

Overview of seismic probabilistic risk assessment for structural analysis in nuclear facilities

International Nuclear Information System (INIS)

Reed, J.W.

1989-01-01

Probabilistic Risk Assessment (PRA) for seismic events is currently being performed for nuclear and DOE facilities. The background on seismic PRA is presented along with a basic description of the method. The seismic PRA technique is applicable to other critical facilities besides nuclear plants. The different approaches for obtained structure fragility curves are discussed and their applications to structures and equipment, in general, are addressed. It is concluded that seismic PRA is a useful technique for conducting probability analysis for a wide range of classes of structures and equipment

Use of the Safety probabilistic analysis for the risk monitor before maintenance

International Nuclear Information System (INIS)

Gonzalez C, M.

2004-01-01

In this work the use of the Safety Probabilistic Analysis (APS) of the Laguna Verde Power plant to quantify the risk before maintenance is presented. Beginning to describe the nature of the Rule of Maintenance and their risk evaluations, it is planned about the paper of the APS for that purpose, and a systematic form to establish the reaches for this use open of the model is delineated. The work provides some technique details of the implantation methods of the APS like risk monitor, including the form of introducing the systems, trains and components to the user, as well as the fitness to the models and improvements to the used platform. There are covered some of the measures taken to achieve the objectives of preserving the base model approved, to facilitate the periodic realize, and to achieve acceptable times of execution for their efficient use. (Author)

Probabilistic Causal Analysis for System Safety Risk Assessments in Commercial Air Transport

Science.gov (United States)

Luxhoj, James T.

2003-01-01

Aviation is one of the critical modes of our national transportation system. As such, it is essential that new technologies be continually developed to ensure that a safe mode of transportation becomes even safer in the future. The NASA Aviation Safety Program (AvSP) is managing the development of new technologies and interventions aimed at reducing the fatal aviation accident rate by a factor of 5 by year 2007 and by a factor of 10 by year 2022. A portfolio assessment is currently being conducted to determine the projected impact that the new technologies and/or interventions may have on reducing aviation safety system risk. This paper reports on advanced risk analytics that combine the use of a human error taxonomy, probabilistic Bayesian Belief Networks, and case-based scenarios to assess a relative risk intensity metric. A sample case is used for illustrative purposes.

Security Risks Management in Selected Academic Libraries in Osun ...

African Journals Online (AJOL)

The survival of a library depends to a large extent on how secured its collections are. Security of collections constitutes a critical challenge facing academic libraries in Nigeria. It is against this background that this study investigated the security risks management in selected academic libraries in Osun State, Nigeria.

Risk management for buildings -- Has the time come?

Energy Technology Data Exchange (ETDEWEB)

Berry, D.L.; Hunter, R.L.

1997-08-01

There are both incentives and challenges for applying formal risk management processes to buildings and other structures, including bridges, highways, dams, stadiums, shopping centers, and private dwellings. Based on an assessment of several issues, the authors conclude that for certain types of buildings and structures the time has come for the use of a formal risk-management approach, including probabilistic risk assessment methods, to help identify dominant risks to public health, safety, and security and to help manage these risks in a cost-effective manner.

The new risk paradigm for chemical process security and safety.

Science.gov (United States)

Moore, David A

2004-11-11

The world of safety and security in the chemical process industries has certainly changed since 11 September, but the biggest challenges may be yet to come. This paper will explain that there is a new risk management paradigm for chemical security, discuss the differences in interpreting this risk versus accidental risk, and identify the challenges we can anticipate will occur in the future on this issue. Companies need to be ready to manage the new chemical security responsibilities and to exceed the expectations of the public and regulators. This paper will outline the challenge and a suggested course of action.

Seismic, high wind, tornado, and probabilistic risk assessment of the high flux isotope reactor

International Nuclear Information System (INIS)

Harris, S.P.; Hashimoto, P.S.; Dizon, J.O.; Hashimoto, P.S.

1989-01-01

Natural phenomena analyses were performed on the High Flux Isotope Reactor (HFIR). Deterministic and probabilistic evaluations were made to determine the risks resulting from earthquakes, high winds, and tornadoes. Analytic methods in conjunction with field evaluations and an earthquake experience data base evaluation methods were used to provide more realistic results in a shorter amount of time. Plant modifications completed in preparation for HFIR restart and potential future enhancements are discussed

Probabilistic structural analysis of aerospace components using NESSUS

Science.gov (United States)

Shiao, Michael C.; Nagpal, Vinod K.; Chamis, Christos C.

1988-01-01

Probabilistic structural analysis of a Space Shuttle main engine turbopump blade is conducted using the computer code NESSUS (numerical evaluation of stochastic structures under stress). The goal of the analysis is to derive probabilistic characteristics of blade response given probabilistic descriptions of uncertainties in blade geometry, material properties, and temperature and pressure distributions. Probability densities are derived for critical blade responses. Risk assessment and failure life analysis is conducted assuming different failure models.

Information Uncertainty to Compare Qualitative Reasoning Security Risk Assessment Results

Energy Technology Data Exchange (ETDEWEB)

Chavez, Gregory M [Los Alamos National Laboratory; Key, Brian P [Los Alamos National Laboratory; Zerkle, David K [Los Alamos National Laboratory; Shevitz, Daniel W [Los Alamos National Laboratory

2009-01-01

The security risk associated with malevolent acts such as those of terrorism are often void of the historical data required for a traditional PRA. Most information available to conduct security risk assessments for these malevolent acts is obtained from subject matter experts as subjective judgements. Qualitative reasoning approaches such as approximate reasoning and evidential reasoning are useful for modeling the predicted risk from information provided by subject matter experts. Absent from these approaches is a consistent means to compare the security risk assessment results. Associated with each predicted risk reasoning result is a quantifiable amount of information uncertainty which can be measured and used to compare the results. This paper explores using entropy measures to quantify the information uncertainty associated with conflict and non-specificity in the predicted reasoning results. The measured quantities of conflict and non-specificity can ultimately be used to compare qualitative reasoning results which are important in triage studies and ultimately resource allocation. Straight forward extensions of previous entropy measures are presented here to quantify the non-specificity and conflict associated with security risk assessment results obtained from qualitative reasoning models.

Health risk characterization of chlorpyrifos using epidemiological dose-response data and probabilistic techniques: a case study with rice farmers in Vietnam.

Science.gov (United States)

Phung, Dung Tri; Connell, Des; Yu, Qiming; Chu, Cordia

2013-09-01

Various methods for risk characterization have been developed using probabilistic approaches. Data on Vietnamese farmers are available for the comparison of outcomes for risk characterization using different probabilistic methods. This article addresses the health risk characterization of chlorpyrifos using epidemiological dose-response data and probabilistic techniques obtained from a case study with rice farmers in Vietnam. Urine samples were collected from farmers and analyzed for trichloropyridinol (TCP), which was converted into absorbed daily dose of chlorpyrifos. Adverse health response doses due to chlorpyrifos exposure were collected from epidemiological studies to develop dose-adverse health response relationships. The health risk of chlorpyrifos was quantified using hazard quotient (HQ), Monte Carlo simulation (MCS), and overall risk probability (ORP) methods. With baseline (prior to pesticide spraying) and lifetime exposure levels (over a lifetime of pesticide spraying events), the HQ ranged from 0.06 to 7.1. The MCS method indicated less than 0.05% of the population would be affected while the ORP method indicated that less than 1.5% of the population would be adversely affected. With postapplication exposure levels, the HQ ranged from 1 to 32.5. The risk calculated by the MCS method was that 29% of the population would be affected, and the risk calculated by ORP method was 33%. The MCS and ORP methods have advantages in risk characterization due to use of the full distribution of data exposure as well as dose response, whereas HQ methods only used the exposure data distribution. These evaluations indicated that single-event spraying is likely to have adverse effects on Vietnamese rice farmers. © 2013 Society for Risk Analysis.

Probabilistic, meso-scale flood loss modelling

Science.gov (United States)

Kreibich, Heidi; Botto, Anna; Schröter, Kai; Merz, Bruno

2016-04-01

Flood risk analyses are an important basis for decisions on flood risk management and adaptation. However, such analyses are associated with significant uncertainty, even more if changes in risk due to global change are expected. Although uncertainty analysis and probabilistic approaches have received increased attention during the last years, they are still not standard practice for flood risk assessments and even more for flood loss modelling. State of the art in flood loss modelling is still the use of simple, deterministic approaches like stage-damage functions. Novel probabilistic, multi-variate flood loss models have been developed and validated on the micro-scale using a data-mining approach, namely bagging decision trees (Merz et al. 2013). In this presentation we demonstrate and evaluate the upscaling of the approach to the meso-scale, namely on the basis of land-use units. The model is applied in 19 municipalities which were affected during the 2002 flood by the River Mulde in Saxony, Germany (Botto et al. submitted). The application of bagging decision tree based loss models provide a probability distribution of estimated loss per municipality. Validation is undertaken on the one hand via a comparison with eight deterministic loss models including stage-damage functions as well as multi-variate models. On the other hand the results are compared with official loss data provided by the Saxon Relief Bank (SAB). The results show, that uncertainties of loss estimation remain high. Thus, the significant advantage of this probabilistic flood loss estimation approach is that it inherently provides quantitative information about the uncertainty of the prediction. References: Merz, B.; Kreibich, H.; Lall, U. (2013): Multi-variate flood damage assessment: a tree-based data-mining approach. NHESS, 13(1), 53-64. Botto A, Kreibich H, Merz B, Schröter K (submitted) Probabilistic, multi-variable flood loss modelling on the meso-scale with BT-FLEMO. Risk Analysis.

A review of the report ''IAEA safety targets and probabilistic risk assessment'' prepared for Greenpeace International

International Nuclear Information System (INIS)

1991-01-01

At the request of the Director General, INSAG reviewed the report ''IAEA Safety Targets and Probabilistic Risk Assessment'' prepared for Greenpeace International by the Gesellschaft fuer Oekologische Forschung und Beratung mbH, Hannover, Germany. The conclusions of the report as well as the review results of INSAG experts are reproduced in this document

Physical security and IT convergence: Managing the cyber-related risks.

Science.gov (United States)

McCreight, Tim; Leece, Doug

The convergence of physical security devices into the corporate network is increasing, due to the perceived economic benefits and efficiencies gained from using one enterprise network. Bringing these two networks together is not without risk. Physical devices like closed circuit television cameras (CCTV), card access readers, and heating, ventilation and air conditioning controllers (HVAC) are typically not secured to the standards we expect for corporate computer networks. These devices can pose significant risks to the corporate network by creating new avenues to exploit vulnerabilities in less-than-secure implementations of physical systems. The ASIS Information Technology Security Council (ITSC) developed a white paper describing steps organisations can take to reduce the risks this convergence can pose, and presented these concepts at the 2015 ASIS/ISC2 Congress in Anaheim, California. 1 This paper expands upon the six characteristics described by ITSC, and provides business continuity planners with information on how to apply these recommendations to physical security devices that use the corporate network.

Risks and threats of tax state security and methods of their neutralization

Directory of Open Access Journals (Sweden)

Y.V. Lebedzevych

2016-12-01

Full Text Available The article substantiates the relevance of the study to ensure security of the state tax. Scientists studied different approaches to defining the essence of the concept of "security tax" on the key features that would satisfy the interests of all subjects of tax relations and the necessity of legal consolidation of this concept. Analyzed the economic, social and legal nature of the existence of the security tax, identified key indicators of fiscal security of Ukraine. To determine the effectiveness of the tax administration in the interests of the tax security highlights the main threats, tax security risks caused by external and internal factors, and propose measures for their elimination and prevent the possibility of their occurrence. The stages of tax risk management with effective building security tax, designed structurally-logic of the tax risk management security.

MATILDA Version-2: Rough Earth TIALD Model for Laser Probabilistic Risk Assessment in Hilly Terrain - Part II

Science.gov (United States)

2017-07-28

risk assessment for “unsafe” scenarios. Recently, attention in the DoD has turned to Probabilistic Risk Assessment (PRA) models [5,6] as an...corresponding to the CRA undershoot boundary. The magenta- coloured line represents the portion of the C-RX(U) circle that would contribute to the...Tertiary Precaution Surface. Undershoot related laser firing restrictions within the green- coloured C-RX(U) can be ignored. Figure 34

International Space Station End-of-Life Probabilistic Risk Assessment

Science.gov (United States)

Duncan, Gary W.

2014-01-01

The International Space Station (ISS) end-of-life (EOL) cycle is currently scheduled for 2020, although there are ongoing efforts to extend ISS life cycle through 2028. The EOL for the ISS will require deorbiting the ISS. This will be the largest manmade object ever to be de-orbited therefore safely deorbiting the station will be a very complex problem. This process is being planned by NASA and its international partners. Numerous factors will need to be considered to accomplish this such as target corridors, orbits, altitude, drag, maneuvering capabilities etc. The ISS EOL Probabilistic Risk Assessment (PRA) will play a part in this process by estimating the reliability of the hardware supplying the maneuvering capabilities. The PRA will model the probability of failure of the systems supplying and controlling the thrust needed to aid in the de-orbit maneuvering.

Probabilistic risk assessment: A look at the role of artificial intelligence

International Nuclear Information System (INIS)

Wang, J.; Modarres, M.; Hunt, R.N.M.

1988-01-01

A review of traditional Probabilistic Risk Assessment (PRA) methods used in the nuclear power industry is presented. The shortcomings of the current PRA methods are pointed out. A method of performing a PRA is proposed and is computerized. The role of artificial intelligence in developing and performing the proposed PRA approach is discussed. The proposed PRA approach is verified by comparing the results to previously performed PRAs. The comparisons have supported the adequacy and completeness of the results of the proposed model. A discussion of how the proposed method can be used as an expert system to verify plant status following loss of plant hardware is also presented. (orig.)

Global water risks and national security: Building resilience (Invited)

Science.gov (United States)

Pulwarty, R. S.

2013-12-01

The UN defines water security as the capacity of a population to safeguard sustainable access to adequate quantities of acceptable quality water for sustaining livelihoods, human well-being, and socio-economic development, for ensuring protection against water-borne pollution and water-related disasters, and for preserving ecosystems in a climate of peace and political stability. This definition highlights complex and interconnected challenges and underscores the centrality of water for environmental services and human aactivities. Global risks are expressed at the national level. The 2010 Quadrennial Defense Review and the 2010 National Security Strategy identify climate change as likely to trigger outcomes that will threaten U.S. security including how freshwater resources can become a security issue. Impacts will be felt on the National Security interest through water, food and energy security, and critical infrastructure. This recognition focuses the need to consider the rates of change in climate extremes, in the context of more traditional political, economic, and social indicators that inform security analyses. There is a long-standing academic debate over the extent to which resource constraints and environmental challenges lead to inter-state conflict. It is generally recognized that water resources as a security issue to date exists mainly at the substate level and has not led to physical conflict between nation states. In conflict and disaster zones, threats to water security increase through inequitable and difficult access to water supply and related services, which may aggravate existing social fragility, tensions, violence, and conflict. This paper will (1) Outline the dimensions of water security and its links to national security (2) Analyze water footprints and management risks for key basins in the US and around the world, (3) map the link between global water security and national concerns, drawing lessons from the drought of 2012 and elsewhere

The EBR-II Probabilistic Risk Assessment: Results and insights

International Nuclear Information System (INIS)

Hill, D.J.; Ragland, W.A.; Roglans, J.

1993-01-01

This paper summarizes the results from the recently completed EBR-II Probabilistic Risk Assessment (PRA) and provides an analysis of the source of risk of the operation of EBR-II from both internal and external initiating events. The EBR-II PRA explicitly accounts for the role of reactivity feedbacks in reducing fuel damage. The results show that the expected core damage frequency from internal initiating events at EBR-II is very low, 1. 6 10 -6 yr -1 , even with a wide definition of core damage (essentially that of exceeding Technical Specification limits). The probability of damage, primarily due to liquid metal fires, from externally initiated events (excluding earthquake) is 3.6 10 -6 yr -1 . overall these results are considerably better than results for other research reactors and the nuclear industry in general and stem from three main sources: low likelihood of loss of coolant due to low system pressure and top entry double, vessels; low likelihood of loss of decay heat removal due to reliance on passive means; and low likelihood of power/flow mismatch due to both passive feedbacks and reliability of rod scram capability

ArgueSecure: Out-of-the-box Risk Assessment

NARCIS (Netherlands)

Ionita, Dan; Kegel, Roeland Hendrik,Pieter; Wieringa, Roelf J.; Baltuta, Andrei

Most established security risk assessment methodologies aim to produce ranked lists of risks. But ranking requires quantification of risks, which in turn relies on data which may not be available or estimations which might not be accurate. As an alternative, we have previously proposed

Advances in Probabilistic Risk Assessment (PRA): a look into practitioners toolbox

International Nuclear Information System (INIS)

Mok, J.; Kaasalainen, S.; Donnelly, K.

2007-01-01

The ever-increasing emphasis on the use of Probabilistic Risk Assessment (PRA) in risk-informed decision making translates into increased expectations relating to PRA applications for the groups tasked with developing and maintaining the facility PRAs. In order to succeed in meeting the demand for PRA work, it is essential to develop methodologies and tools (or utilities) that improve the efficiency with which the PRAs are processed and manipulated to obtain a solution. Examples from the Nuclear Safety Solutions (NSS) PRA Practitioners tool box include utilities for cutting logical loops, optimizing fault trees (to decrease run-times), modularizing fault trees, and converting event trees into high level fault tree logic (an important element if the PRA study is to be used to support a risk monitor such as an Equipment Out-of-Service (EOOS) Monitor). The objective of this paper is be to briefly describe the main features of these utilities, and to illustrate the value they have in terms of improving the efficiency and effectiveness of PRA development and maintenance at NSS. (author)

Use of cut-off values as meaningfulness limits in probabilistic studies and its effect on NPPs risk assessment and safety improvement

International Nuclear Information System (INIS)

Petrangeli, G.; Valeri, A.; Zaffiro, C.

1991-01-01

This paper discusses the use of cut-off values in probabilistic risk assessment/probabilistic safety assessment (PRA/PSA) of nuclear power plants (NPPs), in order to explore under which conditions this practice may help improve the meaningfulness of the results of the analyses and safety of plants, and how it may affect the assessment of risk. Reference is made, in particular, to some past practical applications, also taken from the experience of the authors within the frame of the Italian licensing process. The paper describes the Italian probabilistic criteria which use probabilistic targets and cut-off values to assess safety and identify plant safety improvements. The rationale of the approach is also discussed in the paper and results of sample applications are illustrated. The paper concludes that the use of cut-off values, if properly implemented, could be productive to improve the plant safety as it helps the analyst to focus on a restricted field of analysis, ignoring lower probability and less known events. It also points out that cut-off values should be considered as living numbers to be lowered and even eliminated as soon as significant advancements are made, through research and operational experience, in the knowledge of the pertinent events

Use of probabilistic risk assessment in maintenance activities at Palo Verde

International Nuclear Information System (INIS)

Lindquist, R.C.; Pobst, D.S.

1993-01-01

Probabilistic risk assessment (PRA) is an important tool in addressing various maintenance activities. At the Palo Verde nuclear generating station (PVNGS), the PRA has been used in a variety of ways to support a wide and diverse selection of maintenance-related activities. For on-line or at-power maintenance, the PRA was used to evaluate combinations of maintenance activities possible with the 12-week or floating maintenance schedule. The maintenance schedule was evaluated to identify any higher risk, undesirable combinations of equipment outages, such as the sole steam-driven auxiliary feedwater pump and the same train emergency diesel generator. Table I is a sampling of the results from the maintenance schedule evaluation in terms of increase in conditional core damage frequency (CDF) above the base- line value due to maintenance on some important key safety systems and combinations thereof. The baseline CDF is 7.4 x 10 -7 per 72 h

Probabilistic safety assessment as a standpoint for decision making

International Nuclear Information System (INIS)

Cepin, M.

2001-01-01

This paper focuses on the role of probabilistic safety assessment in decision-making. The prerequisites for use of the results of probabilistic safety assessment and the criteria for the decision-making based on probabilistic safety assessment are discussed. The decision-making process is described. It provides a risk evaluation of impact of the issue under investigation. Selected examples are discussed, which highlight the described process. (authors)

Integrated Deterministic-Probabilistic Safety Assessment Methodologies

Energy Technology Data Exchange (ETDEWEB)

Kudinov, P.; Vorobyev, Y.; Sanchez-Perea, M.; Queral, C.; Jimenez Varas, G.; Rebollo, M. J.; Mena, L.; Gomez-Magin, J.

2014-02-01

IDPSA (Integrated Deterministic-Probabilistic Safety Assessment) is a family of methods which use tightly coupled probabilistic and deterministic approaches to address respective sources of uncertainties, enabling Risk informed decision making in a consistent manner. The starting point of the IDPSA framework is that safety justification must be based on the coupling of deterministic (consequences) and probabilistic (frequency) considerations to address the mutual interactions between stochastic disturbances (e.g. failures of the equipment, human actions, stochastic physical phenomena) and deterministic response of the plant (i.e. transients). This paper gives a general overview of some IDPSA methods as well as some possible applications to PWR safety analyses. (Author)

A Security Risk Measurement for the RAdAC Model

National Research Council Canada - National Science Library

Britton, David W; Brown, Ian A

2007-01-01

.... The intent is to quantify the risk involved in a single information transaction. Additionally, this thesis will attempt to identify the risk factors involved when calculating the total security risk measurement...

Risk assessment of security systems based on entropy theory and the Neyman–Pearson criterion

International Nuclear Information System (INIS)

Lv, Haitao; Yin, Chao; Cui, Zongmin; Zhan, Qin; Zhou, Hongbo

2015-01-01

For a security system, the risk assessment is an important method to verdict whether its protection effectiveness is good or not. In this paper, a security system is regarded abstractly as a network by the name of a security network. A security network is made up of security nodes that are abstract functional units with the ability of detecting, delaying and responding. By the use of risk entropy and the Neyman–Pearson criterion, we construct a model to computer the protection probability of any position in the area where a security network is deployed. We provide a solution to find the most vulnerable path of a security network and the protection probability on the path is considered as the risk measure. Finally, we study the effect of some parameters on the risk and the breach protection probability of a security network. Ultimately, we can gain insight about the risk assessment of a security system. - Highlights: • A security system is regarded abstractly as a network made up of security nodes. • We construct a model to computer the protection probability provided by a security network. • We provide a better solution to find the most vulnerable path of a security network. • We build a risk assessment model for a security network based on the most vulnerable path

Seismic, high wind, tornado, and probabilistic risk assessments of the High Flux Isotope Reactor

International Nuclear Information System (INIS)

Harris, S.P.; Stover, R.L.; Hashimoto, P.S.; Dizon, J.O.

1989-01-01

Natural phenomena analyses were performed on the High Flux Isotope Reactor (HFIR) Deterministic and probabilistic evaluations were made to determine the risks resulting from earthquakes, high winds, and tornadoes. Analytic methods in conjunction with field evaluations and an earthquake experience data base evaluation methods were used to provide more realistic results in a shorter amount of time. Plant modifications completed in preparation for HFIR restart and potential future enhancements are discussed. 5 figs

Guidelines for developing NASA (National Aeronautics and Space Administration) ADP security risk management plans

Science.gov (United States)

Tompkins, F. G.

1983-01-01

This report presents guidance to NASA Computer security officials for developing ADP security risk management plans. The six components of the risk management process are identified and discussed. Guidance is presented on how to manage security risks that have been identified during a risk analysis performed at a data processing facility or during the security evaluation of an application system.

A review of game theory approach to cyber security risk management

African Journals Online (AJOL)

A review of game theory approach to cyber security risk management. ... This paper presents a review of game theoretic-based model for cyber security risk management. Specifically, issues on ... AJOL African Journals Online. HOW TO USE ...

Review insights on the probabilistic risk assessment for the Limerick Generating Station

International Nuclear Information System (INIS)

1984-08-01

In recognition of the high population density around the Limerick Generating Station site and the proposed power level, the Philadelphia Electric Company, in response to NRC staff requests, conducted and submitted between March 1981 and November 1983 a probabilistic risk assessment (PRA) on internal event contributors and a severe accident risk assessment on external event contributors to assess risks posed by operation of the plant. The applicant has developed perspectives using PRA models on the safety profile of the Limerick plant and has altered the plant design to reduce accident vulnerabilities identified in these PRAs. The staff's review of the Limerick PRA has particularly emphasized the dominant accident sequences and the resulting insights into demonstration of compliance with regulatory requirments, unique design features and major plant vulnerabilities to assess the need for any additional measures to further improve the safety of the LGS. The staff's review insights and PRA safety review conclusions are presented in this report

Probabilistic risk assessment modeling of digital instrumentation and control systems using two dynamic methodologies

Energy Technology Data Exchange (ETDEWEB)

Aldemir, T., E-mail: aldemir.1@osu.ed [Ohio State University, Nuclear Engineering Program, Columbus, OH 43210 (United States); Guarro, S. [ASCA, Inc., 1720 S. Catalina Avenue, Suite 220, Redondo Beach, CA 90277-5501 (United States); Mandelli, D. [Ohio State University, Nuclear Engineering Program, Columbus, OH 43210 (United States); Kirschenbaum, J. [Ohio State University, Department of Computer Science and Engineering, Columbus, OH 43210 (United States); Mangan, L.A. [Ohio State University, Nuclear Engineering Program, Columbus, OH 43210 (United States); Bucci, P. [Ohio State University, Department of Computer Science and Engineering, Columbus, OH 43210 (United States); Yau, M. [ASCA, Inc., 1720 S. Catalina Avenue, Suite 220, Redondo Beach, CA 90277-5501 (United States); Ekici, E. [Ohio State University, Department of Electrical and Computer Engineering, Columbus, OH 43210 (United States); Miller, D.W.; Sun, X. [Ohio State University, Nuclear Engineering Program, Columbus, OH 43210 (United States); Arndt, S.A. [U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001 (United States)

2010-10-15

The Markov/cell-to-cell mapping technique (CCMT) and the dynamic flowgraph methodology (DFM) are two system logic modeling methodologies that have been proposed to address the dynamic characteristics of digital instrumentation and control (I and C) systems and provide risk-analytical capabilities that supplement those provided by traditional probabilistic risk assessment (PRA) techniques for nuclear power plants. Both methodologies utilize a discrete state, multi-valued logic representation of the digital I and C system. For probabilistic quantification purposes, both techniques require the estimation of the probabilities of basic system failure modes, including digital I and C software failure modes, that appear in the prime implicants identified as contributors to a given system event of interest. As in any other system modeling process, the accuracy and predictive value of the models produced by the two techniques, depend not only on the intrinsic features of the modeling paradigm, but also and to a considerable extent on information and knowledge available to the analyst, concerning the system behavior and operation rules under normal and off-nominal conditions, and the associated controlled/monitored process dynamics. The application of the two methodologies is illustrated using a digital feedwater control system (DFWCS) similar to that of an operating pressurized water reactor. This application was carried out to demonstrate how the use of either technique, or both, can facilitate the updating of an existing nuclear power plant PRA model following an upgrade of the instrumentation and control system from analog to digital. Because of scope limitations, the focus of the demonstration of the methodologies was intentionally limited to aspects of digital I and C system behavior for which probabilistic data was on hand or could be generated within the existing project bounds of time and resources. The data used in the probabilistic quantification portion of the

Vulnerability Identification Errors in Security Risk Assessments

OpenAIRE

Taubenberger, Stefan

2014-01-01

At present, companies rely on information technology systems to achieve their business objectives, making them vulnerable to cybersecurity threats. Information security risk assessments help organisations to identify their risks and vulnerabilities. An accurate identification of risks and vulnerabilities is a challenge, because the input data is uncertain. So-called ’vulnerability identification errors‘ can occur if false positive vulnerabilities are identified, or if vulnerabilities remain u...

International status of application of probabilistic risk analysis

International Nuclear Information System (INIS)

Cullingford, M.C.

1984-01-01

Probabilistic Risk Assessment (PRA) having been practised for about ten years and with more than twenty studies completed has reached a level of maturity such that the insights and other products derived from specific studies may be assessed. The first full-scale PRA studies were designed to develop the methodology and assess the overall risk from nuclear power. At present PRA is performed mostly for individual plants to identify core damage accident sequences and significant contributors to such sequences. More than 25 countries are utilizing insights from PRA, some from full-scale PRA studies and other countries by performing reliability analyses on safety systems identified as important contributors to one or more core melt sequences. Many Member States of the IAEA fall into one of three groups: those having (a) a large, (b) a medium number of reactor-years of operating experience and (c) those countries in the planning or feasibility study stages of a nuclear power programme. Of the many potential uses of PRA the decision areas of safety improvement by backfitting, development of operating procedures and as the basis of standards are felt to be important by countries of all three groups. The use of PRA in showing compliance with safety goals and for plant availability studies is held to be important only by those countries which have operating experience. The evolution of the PRA methodology has led to increased attention to quantification of uncertainties both in the probabilities and consequences. Although many products from performing a PRA do not rely upon overall risk numbers, increasing emphasis is being placed on the interpretation of uncertainties in risk numbers for use in decisions. International co-operation through exchange of information regarding experience with PRA methodology and its application to nuclear safety decisions will greatly enhance the widespread use of PRA. (author)

Risk assessment of climate systems for national security.

Energy Technology Data Exchange (ETDEWEB)

Backus, George A.; Boslough, Mark Bruce Elrick; Brown, Theresa Jean; Cai, Ximing; Conrad, Stephen Hamilton; Constantine, Paul G; Dalbey, Keith R.; Debusschere, Bert J.; Fields, Richard; Hart, David Blaine; Kalinina, Elena Arkadievna; Kerstein, Alan R.; Levy, Michael; Lowry, Thomas Stephen; Malczynski, Leonard A.; Najm, Habib N.; Overfelt, James Robert; Parks, Mancel Jordan; Peplinski, William J.; Safta, Cosmin; Sargsyan, Khachik; Stubblefield, William Anthony; Taylor, Mark A.; Tidwell, Vincent Carroll; Trucano, Timothy Guy; Villa, Daniel L.

2012-10-01

Climate change, through drought, flooding, storms, heat waves, and melting Arctic ice, affects the production and flow of resource within and among geographical regions. The interactions among governments, populations, and sectors of the economy require integrated assessment based on risk, through uncertainty quantification (UQ). This project evaluated the capabilities with Sandia National Laboratories to perform such integrated analyses, as they relate to (inter)national security. The combining of the UQ results from climate models with hydrological and economic/infrastructure impact modeling appears to offer the best capability for national security risk assessments.

Probabilistic safety and risk assessments in the field of nuclear technology - Mode of operation, possibilities and limits

International Nuclear Information System (INIS)

Mertens, J.

1993-01-01

In this study probabilistic safety and risk assessments in the field of nuclear energy are explained. Mainly qualitative results and conclusions are presented. Explanations for often discussed aspects of such analysis reveal the procedure and reasonable limits of application. The mentioned literature contains detailed results. (orig./DG) [de

Protecting intellectual property in space; Proceedings of the Aerospace Computer Security Conference, McLean, VA, March 20, 1985

Science.gov (United States)

1985-01-01

The primary purpose of the Aerospace Computer Security Conference was to bring together people and organizations which have a common interest in protecting intellectual property generated in space. Operational concerns are discussed, taking into account security implications of the space station information system, Space Shuttle security policies and programs, potential uses of probabilistic risk assessment techniques for space station development, key considerations in contingency planning for secure space flight ground control centers, a systematic method for evaluating security requirements compliance, and security engineering of secure ground stations. Subjects related to security technologies are also explored, giving attention to processing requirements of secure C3/I and battle management systems and the development of the Gemini trusted multiple microcomputer base, the Restricted Access Processor system as a security guard designed to protect classified information, and observations on local area network security.

Assessing Probabilistic Risk Assessment Approaches for Insect Biological Control Introductions.

Science.gov (United States)

Kaufman, Leyla V; Wright, Mark G

2017-07-07

The introduction of biological control agents to new environments requires host specificity tests to estimate potential non-target impacts of a prospective agent. Currently, the approach is conservative, and is based on physiological host ranges determined under captive rearing conditions, without consideration for ecological factors that may influence realized host range. We use historical data and current field data from introduced parasitoids that attack an endemic Lepidoptera species in Hawaii to validate a probabilistic risk assessment (PRA) procedure for non-target impacts. We use data on known host range and habitat use in the place of origin of the parasitoids to determine whether contemporary levels of non-target parasitism could have been predicted using PRA. Our results show that reasonable predictions of potential non-target impacts may be made if comprehensive data are available from places of origin of biological control agents, but scant data produce poor predictions. Using apparent mortality data rather than marginal attack rate estimates in PRA resulted in over-estimates of predicted non-target impact. Incorporating ecological data into PRA models improved the predictive power of the risk assessments.

Probabilistic earthquake risk assessment as a tool to improve safety and explanatory adequacy

International Nuclear Information System (INIS)

Itoi, Tatsuya

2015-01-01

This paper explains the concept of probabilistic earthquake risk assessment, mainly from the viewpoint as a tool to improve safety and explanatory adequacy. The definition of risk is the expected value of undesirable effect in an engineering meaning that is likely to occur in the future, and it is defined in risk management as the triplet of scenario (what can happen), frequency, and impact. As for the earthquake risk assessment of a nuclear power plant, the fragility of structure / system / component (SSC) against earthquake (so-called earthquake fragility) is assessed, and by combining with the earthquake hazard that has been separately obtained, the occurrence frequency and impact of the accident are obtained. From the view of the authors, earthquake risk assessment is for the purpose of decision-making, and is not intended to calculate the probability in a scientifically rigorous manner. For ensuring the quality of risk assessment, the table of 'Expert utilization standards for the evaluation of epistemological uncertainty' is used. Sole quantitative risk assessment is not necessarily sufficient for risk management. It would be important to find how to build the 'framework for comprehensive decision-making.' (A.O.)

Geothermal probabilistic cost study

Energy Technology Data Exchange (ETDEWEB)

Orren, L.H.; Ziman, G.M.; Jones, S.C.; Lee, T.K.; Noll, R.; Wilde, L.; Sadanand, V.

1981-08-01

A tool is presented to quantify the risks of geothermal projects, the Geothermal Probabilistic Cost Model (GPCM). The GPCM model is used to evaluate a geothermal reservoir for a binary-cycle electric plant at Heber, California. Three institutional aspects of the geothermal risk which can shift the risk among different agents are analyzed. The leasing of geothermal land, contracting between the producer and the user of the geothermal heat, and insurance against faulty performance are examined. (MHR)

Use of probabilistic risk assessment in fuel cycle facilities

International Nuclear Information System (INIS)

Gonzalez, Felix; Gonzalez, Michelle; Wagner, Brian

2013-01-01

As expressed in its Policy Statement on the Use of Probabilistic Risk Assessment (PRA) Methods in Nuclear Regulatory Activities, the U.S Nuclear Regulatory Commission has been working for decades to increase the use of PRA technology in its regulatory activities. Since the policy statement was issued in 1995, PRA has become a core component of the nuclear power plant (NPP) licensing and oversight processes. In the last several years, interest has increased in PRA technologies and their possible application to other areas including, but not limited to, spent fuel handling, fuel cycle facilities, reprocessing facilities, and advanced reactors. This paper describes the application of PRA technology currently used in NPPs and its application in other areas such as fuel cycle facilities and advanced reactors. It describes major challenges that are being faced in the application of PRA into new technical areas and possible ways to resolve them. (authors)

Network Security Risk Assessment System Based on Attack Graph and Markov Chain

Science.gov (United States)

Sun, Fuxiong; Pi, Juntao; Lv, Jin; Cao, Tian

2017-10-01

Network security risk assessment technology can be found in advance of the network problems and related vulnerabilities, it has become an important means to solve the problem of network security. Based on attack graph and Markov chain, this paper provides a Network Security Risk Assessment Model (NSRAM). Based on the network infiltration tests, NSRAM generates the attack graph by the breadth traversal algorithm. Combines with the international standard CVSS, the attack probability of atomic nodes are counted, and then the attack transition probabilities of ones are calculated by Markov chain. NSRAM selects the optimal attack path after comprehensive measurement to assessment network security risk. The simulation results show that NSRAM can reflect the actual situation of network security objectively.

Framework for probabilistic flood risk assessment in an Alpine region

Science.gov (United States)

Schneeberger, Klaus; Huttenlau, Matthias; Steinberger, Thomas; Achleitner, Stefan; Stötter, Johann

2014-05-01

Flooding is among the natural hazards that regularly cause significant losses to property and human lives. The assessment of flood risk delivers crucial information for all participants involved in flood risk management and especially for local authorities and insurance companies in order to estimate the possible flood losses. Therefore a framework for assessing flood risk has been developed and is introduced with the presented contribution. Flood risk is thereby defined as combination of the probability of flood events and of potential flood damages. The probability of occurrence is described through the spatial and temporal characterisation of flood. The potential flood damages are determined in the course of vulnerability assessment, whereas, the exposure and the vulnerability of the elements at risks are considered. Direct costs caused by flooding with the focus on residential building are analysed. The innovative part of this contribution lies on the development of a framework which takes the probability of flood events and their spatio-temporal characteristic into account. Usually the probability of flooding will be determined by means of recurrence intervals for an entire catchment without any spatial variation. This may lead to a misinterpretation of the flood risk. Within the presented framework the probabilistic flood risk assessment is based on analysis of a large number of spatial correlated flood events. Since the number of historic flood events is relatively small additional events have to be generated synthetically. This temporal extrapolation is realised by means of the method proposed by Heffernan and Tawn (2004). It is used to generate a large number of possible spatial correlated flood events within a larger catchment. The approach is based on the modelling of multivariate extremes considering the spatial dependence structure of flood events. The input for this approach are time series derived from river gauging stations. In a next step the

FlySec: a risk-based airport security management system based on security as a service concept

Science.gov (United States)

Kyriazanos, Dimitris M.; Segou, Olga E.; Zalonis, Andreas; Thomopoulos, Stelios C. A.

2016-05-01

Complementing the ACI/IATA efforts, the FLYSEC European H2020 Research and Innovation project (http://www.fly-sec.eu/) aims to develop and demonstrate an innovative, integrated and end-to-end airport security process for passengers, enabling a guided and streamlined procedure from the landside to airside and into the boarding gates, and offering for an operationally validated innovative concept for end-to-end aviation security. FLYSEC ambition turns through a well-structured work plan into: (i) innovative processes facilitating risk-based screening; (ii) deployment and integration of new technologies and repurposing existing solutions towards a risk-based Security paradigm shift; (iii) improvement of passenger facilitation and customer service, bringing security as a real service in the airport of tomorrow;(iv) achievement of measurable throughput improvement and a whole new level of Quality of Service; and (v) validation of the results through advanced "in-vitro" simulation and "in-vivo" pilots. On the technical side, FLYSEC achieves its ambitious goals by integrating new technologies on video surveillance, intelligent remote image processing and biometrics combined with big data analysis, open-source intelligence and crowdsourcing. Repurposing existing technologies is also in the FLYSEC objectives, such as mobile application technologies for improved passenger experience and positive boarding applications (i.e. services to facilitate boarding and landside/airside way finding) as well as RFID for carry-on luggage tracking and quick unattended luggage handling. In this paper, the authors will describe the risk based airport security management system which powers FLYSEC intelligence and serves as the backend on top of which FLYSEC's front end technologies reside for security services management, behaviour and risk analysis.

Regional probabilistic nuclear risk and vulnerability assessment by integration of mathematical modelling land GIS-analysis

International Nuclear Information System (INIS)

Rigina, O.; Baklanov, A.

2002-01-01

The Kola Peninsula, Russian Arctic exceeds all other regions in the world in the number of nuclear reactors. The study was aimed at estimating possible radiation risks to the population in the Nordic countries in case of a severe accident in the Kola Peninsula. A new approach based on probabilistic analysis of modelled possible pathways of radionuclide transport and precipitation was developed. For the general population, Finland is at most risk with respect to the Kola NPP, because of: high population density or proximity to the radiation-risk sites and relatively high probability of an airflow trajectory there, and precipitation. After considering the critical group, northern counties in Norway, Finland and Sweden appear to be most vulnerable. (au)

Probabilistic risk assessment model for allergens in food: sensitivity analysis of the minimum eliciting dose and food consumption

NARCIS (Netherlands)

Kruizinga, A.G.; Briggs, D.; Crevel, R.W.R.; Knulst, A.C.; Bosch, L.M.C.v.d.; Houben, G.F.

2008-01-01

Previously, TNO developed a probabilistic model to predict the likelihood of an allergic reaction, resulting in a quantitative assessment of the risk associated with unintended exposure to food allergens. The likelihood is estimated by including in the model the proportion of the population who is

Probabilistic Modeling and Risk Assessment of Cable Icing

DEFF Research Database (Denmark)

Roldsgaard, Joan Hee

This dissertation addresses the issues related to icing of structures with special emphasis on bridge cables. Cable supported bridges in cold climate suffers for ice accreting on the cables, this poses three different undesirable situations. Firstly the changed shape of the cable due to ice...... preliminary framework is modified for assessing the probability of occurrence of in-cloud and precipitation icing and its duration. Different probabilistic models are utilized for the representation of the meteorological variables and their appropriateness is evaluated both through goodness-of-fit tests...... are influencing the two icing mechanisms and their duration. The model is found to be more sensitive to changes in the discretization levels of the input variables. Thirdly the developed operational probabilistic framework for the assessment of the expected number of occurrences of ice/snow accretion on bridge...

Probabilistic risk assessment from potential exposures to the public applied for innovative nuclear installations

International Nuclear Information System (INIS)

Dvorzhak, Alla; Mora, Juan C.; Robles, Beatriz

2016-01-01

Potential exposures are those that may occur as a result of unanticipated operational performance or accidents. Potential exposure situations are probabilistic in nature because they depend on uncertain events such as equipment failure, operator errors or external initiators beyond the control of the operator. Consequently, there may exist a range of possible radiological impacts that need to be considered. In this paper a Level 3 Probabilistic Safety Assessment (PSA) for a hypothetical scenario relevant to Innovative Nuclear Energy Systems (INS) was conducted using computer code MACCS (MELCOR Accident Consequence Code Systems). The acceptability of an INS was analyzed taking into account the general requirement that relocation or evacuation measures must not be necessary beyond the site boundary. In addition, deterministic modeling of the accident consequences for the critical meteorological conditions was carried out using the JRODOS decision support system (Real-time On-line Decision Support system for off-site emergency management in Europe). The approach used for dose and risk assessment from potential exposure of accidental releases and their comparison with acceptance criteria are presented. The methodology described can be used as input to the licensing procedure and engineering design considerations to help satisfy relevant health and environmental impact criteria for fission or fusion nuclear installations. - Highlights: • PSA Level-3 based on WinMACCS code is carried out for accidental release. • Family curves of percentiles for radiation exposure doses are constructed. • Risk indicators for potential exposure are defined. • Using of risk acceptance curve criteria is proposed for decision making process.

A probabilistic method for species sensitivity distributions taking into account the inherent uncertainty and variability of effects to estimate environmental risk.

Science.gov (United States)

Gottschalk, Fadri; Nowack, Bernd

2013-01-01

This article presents a method of probabilistically computing species sensitivity distributions (SSD) that is well-suited to cope with distinct data scarcity and variability. First, a probability distribution that reflects the uncertainty and variability of sensitivity is modeled for each species considered. These single species sensitivity distributions are then combined to create an SSD for a particular ecosystem. A probabilistic estimation of the risk is carried out by combining the probability of critical environmental concentrations with the probability of organisms being impacted negatively by these concentrations. To evaluate the performance of the method, we developed SSD and risk calculations for the aquatic environment exposed to triclosan. The case studies showed that the probabilistic results reflect the empirical information well, and the method provides a valuable alternative or supplement to more traditional methods for calculating SSDs based on averaging raw data and/or on using theoretical distributional forms. A comparison and evaluation with single SSD values (5th-percentile [HC5]) revealed the robustness of the proposed method. Copyright © 2012 SETAC.

Probabilistic meta-analysis of risk from the exposure to Hg in artisanal gold mining communities in Colombia

OpenAIRE

Miguel García, Eduardo de; Ortega Romero, Marcelo; Gómez San Martín, Amaia; Clavijo, Diana

2014-01-01

Colombia is one of the largest per capita mercury polluters in the world as a consequence of its artisanal gold mining activities. The severity of this problem in terms of potential health effects was evaluated by means of a probabilistic risk assessment carried out in the twelve departments (or provinces) in Colombia with the largest gold production. The two exposure pathways included in the risk assessment were inhalation of elemental Hg vapors and ingestion of fish contaminated with methyl...

Probabilistic Risk Assessment of Cancer from Exposure Inorganic Arsenic in Duplicate Food by Villagers in Ronphibun, Thailand

OpenAIRE

Piyawat Saipan

2010-01-01

Ronphibun district is a district in Nakorn Si Thammarat province, within southern Thailand. This district is the site of several former tin mines that were in operation 100 years ago. Arsenic contamination caused by past mining activities remains in the area. The specific purpose of this study was conducted to assess cancer risk in people living within Ronphibun district from exposure to inorganic arsenic via duplicate food using probabilistic risk assessment. A hundred and fifty duplicate fo...

TREATING UNCERTAINTIES IN A NUCLEAR SEISMIC PROBABILISTIC RISK ASSESSMENT BY MEANS OF THE DEMPSTER-SHAFER THEORY OF EVIDENCE

OpenAIRE

Lo , Chung-Kung; Pedroni , N.; Zio , Enrico

2014-01-01

International audience; The analyses carried out within the Seismic Probabilistic Risk Assessments (SPRAs) of Nuclear Power Plants (NPPs) are affected by significant aleatory and epistemic uncertainties. These uncertainties have to be represented and quantified coherently with the data, information and knowledge available, to provide reasonable assurance that related decisions can be taken robustly and with confidence. The amount of data, information and knowledge available for seismic risk a...

Data security and risk assessment in cloud computing

Directory of Open Access Journals (Sweden)

Li Jing

2018-01-01

Full Text Available Cloud computing has attracted more and more attention as it reduces the cost of IT infrastructure of organizations. In our country, business Cloud services, such as Alibaba Cloud, Huawei Cloud, QingCloud, UCloud and so on are gaining more and more uses, especially small or median organizations. In the cloud service scenario, the program and data are migrating into cloud, resulting the lack of trust between customers and cloud service providers. However, the recent study on Cloud computing is mainly focused on the service side, while the data security and trust have not been sufficiently studied yet. This paper investigates into the data security issues from data life cycle which includes five steps when an organization uses Cloud computing. A data management framework is given out, including not only the data classification but also the risk management framework. Concretely, the data is divided into two varieties, business and personal information. And then, four classification levels (high, medium, low, normal according to the different extent of the potential adverse effect is introduced. With the help of classification, the administrators can identify the application or data to implement corresponding security controls. At last, the administrators conduct the risk assessment to alleviate the risk of data security. The trust between customers and cloud service providers will be strengthen through this way.

Novel Threat-risk Index Using Probabilistic Risk Assessment and Human Reliability Analysis - Final Report

Energy Technology Data Exchange (ETDEWEB)

George A. Beitel

2004-02-01

In support of a national need to improve the current state-of-the-art in alerting decision makers to the risk of terrorist attack, a quantitative approach employing scientific and engineering concepts to develop a threat-risk index was undertaken at the Idaho National Engineering and Environmental Laboratory (INEEL). As a result of this effort, a set of models has been successfully integrated into a single comprehensive model known as Quantitative Threat-Risk Index Model (QTRIM), with the capability of computing a quantitative threat-risk index on a system level, as well as for the major components of the system. Such a threat-risk index could provide a quantitative variant or basis for either prioritizing security upgrades or updating the current qualitative national color-coded terrorist threat alert.

On the use of data and judgment in probabilistic risk and safety analysis

International Nuclear Information System (INIS)

Kaplan, S.

1986-01-01

This paper reviews the line of thought of a nuclear plant probabilistic risk analysis (PRA) identifying the points where data and judgement enter. At the ''bottom'' of the process, data and judgment are combined, using one and two stage Bayesian methods, to express what is known about the element of variables. Higher in the process, we see the use of judgment in identifying scenarios and developing almost models and specifying initiating event categories. Finally, we discuss the judgments involved in deciding to do a PRA and in applying the results. (orig.)

Space shuttle main propulsion pressurization system probabilistic risk assessment

International Nuclear Information System (INIS)

Plastiras, J.K.

1989-01-01

This paper reports that, in post-Challenger discussions with Congressional Committees and the National Research Council Risk Management Oversight Panel, criticism was levied against NASA because of the inability to prioritize the 1300+ single point failures. In the absence of a ranking it was difficult to determine where special effort was needed in failure evaluation, in design improvement, in management review of problems, and in flight readiness reviews. The belief was that the management system was overwhelmed by the quantity of critical hardware items that were on the Critical Items List (CIL) and that insufficient attention was paid to the items that required it. Congressional staff members from Congressman Markey's committee who have oversight responsibilities in the nuclear industry, and specifically over the nuclear power supplies for NASA's Galileo and Ulysses missions, felt very strongly that the addition of Probabilistic Risk Assessment (PRA) to the existing Failure Mode Effects Analysis/Hazard Analysis (FMEA/HA) methods was exceedingly important. Specifically, the Markey committee recognized that the inductive, qualitative component-oriented FMEA could be supplemented by the deductive, quantitative systems-oriented PRA. Furthermore, they felt that the PRA approach had matured to the extent that it could be used to assess risk, even with limited shuttle-specific failure data. NASA responded with arguments that the FMEA/HA had illuminated all significant failure modes satisfactorily and that no failure rate data base was available to support the PRA approach

Risk Analysis and Security Countermeasure Selection

CERN Document Server

Norman, Thomas L

2009-01-01

Explains how to evaluate the appropriateness of security countermeasures, from a cost-effectiveness perspective. This title guides readers from basic principles to complex processes in a step-by-step fashion, evaluating DHS-approved risk assessment methods, including CARVER, API/NPRA, RAMCAP, and various Sandia methodologies

INFORMATION SECURITY RISK ASSESSMENT USING EXISTING LEGAL AND METHODOLOGICAL BASE

Directory of Open Access Journals (Sweden)

A. I. Trubei

2015-01-01

Full Text Available The article provides a survey of the existing regulatory framework for information security riskmanagement. Practical methods for information security risk and vulnerability assessment are proposed.

Predicting Rib Fracture Risk With Whole-Body Finite Element Models: Development and Preliminary Evaluation of a Probabilistic Analytical Framework

Science.gov (United States)

Forman, Jason L.; Kent, Richard W.; Mroz, Krystoffer; Pipkorn, Bengt; Bostrom, Ola; Segui-Gomez, Maria

2012-01-01

This study sought to develop a strain-based probabilistic method to predict rib fracture risk with whole-body finite element (FE) models, and to describe a method to combine the results with collision exposure information to predict injury risk and potential intervention effectiveness in the field. An age-adjusted ultimate strain distribution was used to estimate local rib fracture probabilities within an FE model. These local probabilities were combined to predict injury risk and severity within the whole ribcage. The ultimate strain distribution was developed from a literature dataset of 133 tests. Frontal collision simulations were performed with the THUMS (Total HUman Model for Safety) model with four levels of delta-V and two restraints: a standard 3-point belt and a progressive 3.5–7 kN force-limited, pretensioned (FL+PT) belt. The results of three simulations (29 km/h standard, 48 km/h standard, and 48 km/h FL+PT) were compared to matched cadaver sled tests. The numbers of fractures predicted for the comparison cases were consistent with those observed experimentally. Combining these results with field exposure informantion (ΔV, NASS-CDS 1992–2002) suggests a 8.9% probability of incurring AIS3+ rib fractures for a 60 year-old restrained by a standard belt in a tow-away frontal collision with this restraint, vehicle, and occupant configuration, compared to 4.6% for the FL+PT belt. This is the first study to describe a probabilistic framework to predict rib fracture risk based on strains observed in human-body FE models. Using this analytical framework, future efforts may incorporate additional subject or collision factors for multi-variable probabilistic injury prediction. PMID:23169122

Competition, Speculative Risks, and IT Security Outsourcing

Science.gov (United States)

Cezar, Asunur; Cavusoglu, Huseyin; Raghunathan, Srinivasan

Information security management is becoming a more critical and, simultaneously, a challenging function for many firms. Even though many security managers are skeptical about outsourcing of IT security, others have cited reasons that are used for outsourcing of traditional IT functions for why security outsourcing is likely to increase. Our research offers a novel explanation, based on competitive externalities associated with IT security, for firms' decisions to outsource IT security. We show that if competitive externalities are ignored, then a firm will outsource security if and only if the MSSP offers a quality (or a cost) advantage over in-house operations, which is consistent with the traditional explanation for security outsourcing. However, a higher quality is neither a prerequisite nor a guarantee for a firm to outsource security. The competitive risk environment and the nature of the security function outsourced, in addition to quality, determine firms' outsourcing decisions. If the reward from the competitor's breach is higher than the loss from own breach, then even if the likelihood of a breach is higher under the MSSP the expected benefit from the competitive demand externality may offset the loss from the higher likelihood of breaches, resulting in one or both firms outsourcing security. The incentive to outsource security monitoring is higher than that of infrastructure management because the MSSP can reduce the likelihood of breach on both firms and thus enhance the demand externality effect. The incentive to outsource security monitoring (infrastructure management) is higher (lower) if either the likelihood of breach on both firms is lower (higher) when security is outsourced or the benefit (relative to loss) from the externality is higher (lower). The benefit from the demand externality arising out of a security breach is higher when more of the customers that leave the breached firm switch to the non-breached firm.

Practical Methods for Information Security Risk Management

Directory of Open Access Journals (Sweden)

Cristian AMANCEI

2011-01-01

Full Text Available The purpose of this paper is to present some directions to perform the risk man-agement for information security. The article follows to practical methods through question-naire that asses the internal control, and through evaluation based on existing controls as part of vulnerability assessment. The methods presented contains all the key elements that concurs in risk management, through the elements proposed for evaluation questionnaire, list of threats, resource classification and evaluation, correlation between risks and controls and residual risk computation.

Probabilistic Risk Assessment for Astronaut Post Flight Bone Fracture

Science.gov (United States)

Lewandowski, Beth; Myers, Jerry; Licata, Angelo

2015-01-01

Introduction: Space flight potentially reduces the loading that bone can resist before fracture. This reduction in bone integrity may result from a combination of factors, the most common reported as reduction in astronaut BMD. Although evaluating the condition of bones continues to be a critical aspect of understanding space flight fracture risk, defining the loading regime, whether on earth, in microgravity, or in reduced gravity on a planetary surface, remains a significant component of estimating the fracture risks to astronauts. This presentation summarizes the concepts, development, and application of NASA's Bone Fracture Risk Module (BFxRM) to understanding pre-, post, and in mission astronaut bone fracture risk. The overview includes an assessment of contributing factors utilized in the BFxRM and illustrates how new information, such as biomechanics of space suit design or better understanding of post flight activities may influence astronaut fracture risk. Opportunities for the bone mineral research community to contribute to future model development are also discussed. Methods: To investigate the conditions in which spaceflight induced changes to bone plays a critical role in post-flight fracture probability, we implement a modified version of the NASA Bone Fracture Risk Model (BFxRM). Modifications included incorporation of variations in physiological characteristics, post-flight recovery rate, and variations in lateral fall conditions within the probabilistic simulation parameter space. The modeled fracture probability estimates for different loading scenarios at preflight and at 0 and 365 days post-flight time periods are compared. Results: For simple lateral side falls, mean post-flight fracture probability is elevated over mean preflight fracture probability due to spaceflight induced BMD loss and is not fully recovered at 365 days post-flight. In the case of more energetic falls, such as from elevated heights or with the addition of lateral movement

Information Security Risks on a University Campus

Directory of Open Access Journals (Sweden)

Amer A. Al-Rawas

2002-06-01

Full Text Available This paper is concerned with issues relating to security in the provision of information systems (IS services within a campus environment. It is based on experiences with a specific known environment; namely Sultan Qaboos University. In considering the risks and challenges that face us in the provision of IS services we need to consider a number of interwoven subject areas.  These are: the importance of information to campus communities, the types of information utilised, and the risk factors that relate to the provision of IS services. Based on our discussion of the risk factors identified within this paper, we make a number of recommendations for improving security within any environment that wishes to take the matter seriously. These recommendations are classified into three main groups: general, which are applicable to the entire institution; social, aimed at the work attitudes of staff and students; and technical, addressing the skills and technologies required.

Application of probabilistic fracture mechanics to estimate the risk of rupture of PWR steam generator tubes

International Nuclear Information System (INIS)

Pitner, P.; Riffard, T.; Granger, B.

1992-01-01

This paper describes the COMPROMIS code developed by Electricite de France (EDF) to optimize the tube bundle maintenance of steam generators. The model, based on probabilistic fracture mechanics, makes it possible to quantify the influence of in-service inspections and maintenance work on the risk of an SG tube rupture, taking all significant parameters into account as random variables (initial defect size distribution, reliability of non-destructive detection and sizing, crack initiation and propagation, critical sizes, leak before risk of break, etc.). (authors). 5 refs., 8 figs., 3 tabs

Probabilistic economic frameworks for disaster risk management

Science.gov (United States)

Dulac, Guillaume; Forni, Marc

2013-04-01

range from simple elicitation of data from a subject matter expert to calibrate a probability distribution to more advanced stochastic modelling. This approach can be referred to more as a proficiency in the language of uncertainty rather than modelling per se in the sense that it allows for greater flexibility to adapt a given context. In a real decision making context, one seldom has neither time nor budget resources to investigate all of these variables thoroughly, hence the importance of being able to prioritize the level of effort among them. Under the proposed framework, this can be done in an optimised fashion. The point here consists in applying probabilistic sensitivity analysis together with the fundamentals of the economic value of information; the framework as built is well suited to such considerations, and variables can be ranked according to their contribution to risk understanding. Efforts to deal with second order uncertainties on variables prove to be valuable when dealing with the economic value of sample information.

Context-sensitive Information security Risk identification and evaluation techniques

NARCIS (Netherlands)

Ionita, Dan

2014-01-01

The objective of my research is to improve and support the process of Information security Risk Assessment by designing a scalable Risk argumentation framework for socio-digital-technical Risk. Due to the various types of IT systems, diversity of architectures and dynamic nature of Risk, there is no

ISSUES ASSOCIATED WITH PROBABILISTIC FAILURE MODELING OF DIGITAL SYSTEMS

International Nuclear Information System (INIS)

CHU, T.L.; MARTINEZ-GURIDI, G.; LIHNER, J.; OVERLAND, D.

2004-01-01

The current U.S. Nuclear Regulatory Commission (NRC) licensing process of instrumentation and control (I and C) systems is based on deterministic requirements, e.g., single failure criteria, and defense in depth and diversity. Probabilistic considerations can be used as supplements to the deterministic process. The National Research Council has recommended development of methods for estimating failure probabilities of digital systems, including commercial off-the-shelf (COTS) equipment, for use in probabilistic risk assessment (PRA). NRC staff has developed informal qualitative and quantitative requirements for PRA modeling of digital systems. Brookhaven National Laboratory (BNL) has performed a review of the-state-of-the-art of the methods and tools that can potentially be used to model digital systems. The objectives of this paper are to summarize the review, discuss the issues associated with probabilistic modeling of digital systems, and identify potential areas of research that would enhance the state of the art toward a satisfactory modeling method that could be integrated with a typical probabilistic risk assessment

RiskREP: Risk-Based Security Requirements Elicitation and Prioritization

NARCIS (Netherlands)

Herrmann, Andrea; Morali, A.; Etalle, Sandro; Wieringa, Roelf J.; Niedrite, Laila; Strazdina, Renate; Wangler, Benkt

2011-01-01

Companies are under pressure to be in control of their assets but at the same time they must operate as efficiently as possible. This means that they aim to implement “good-enough security‿ but need to be able to justify their security investment plans. In this paper, we present a Risk-Based

Level-1 seismic probabilistic risk assessment for a PWR plant

International Nuclear Information System (INIS)

Kondo, Keisuke; Nishio, Masahide; Fujimoto, Haruo; Ichitsuka, Akihiro

2014-01-01

In Japan, revised Seismic Design Guidelines for the domestic light water reactors was published on September 19, 2006. These new guidelines have introduced the purpose to confirm that residual risk resulting from earthquake that exceeds the design limit seismic ground motion (Ss) is sufficiently small, based on the probabilistic risk assessment (PRA) method, in addition to conventional deterministic design base methodology. In response to this situation, JNES had been working to improve seismic PRA (SPRA) models for individual domestic light water reactors. In case of PWR in Japan, total of 24 plants were grouped into 11 categories to develop individual SPRA model. The new regulatory rules against the Fukushima dai-ichi nuclear power plants' severe accidents occurred on March 11, 2011, are going to be enforced in July 2013 and utilities are necessary to implement additional safety measures to avoid and mitigate severe accident occurrence due to external events such as earthquake and tsunami, by referring to the results of severe accident study including SPRA. In this paper a SPRA model development for a domestic 3-loop PWR plant as part of the above-mentioned 11 categories is described. We paid special attention to how to categorize initiating events that are specific to seismic phenomena and how to confirm the effect of the simultaneous failure probability calculation model for the multiple components on the result of core damage frequency evaluation. Simultaneous failure probability for multiple components has been evaluated by power multiplier method. Then tentative level-1 seismic probabilistic risk assessment (SPRA) has been performed by the developed SPSA model with seismic hazard and fragility data. The base case was evaluated under the condition with calculated fragility data and conventional power multiplier. The difference in CDF between the case of conventional power multiplier and that of power multiplier=1 (complete dependence) was estimated to be

Nuclear and isotopic techniques underpinning probabilistic ecological risk analysis in coastal marine systems

International Nuclear Information System (INIS)

Szymczak, R.; Twining, J.; Hollins, S.; Hughes, C.; Mazumder, D.; Alquezar, R.

2006-01-01

Full text: The historical operation of manufacturing, chemical and other industries in the Sydney Harbour catchment over many decades has left a legacy of high chemical contamination in the surrounding catchment, such that a recent report describes Port Jackson as one of the most contaminated harbours in the world (Birch and Taylor, 2005). The legacy in Homebush Bay is amongst the worst in the harbour and presents a considerable management problem. Elucidation of environmental processes is the key to effective ecosystem management, however few tools are available to determine their inter-relationships, rates and directions. This study has four components: (1) determination of linkages between high trophic order species and different habitats resources using stable isotopic analyses of carbon and nitrogen. These studies identify trophic cascades forming the basis for selection of biota for contaminant transfer experiments; (2) short-term (weeks - months) chronology and geochemistry of sediment cores and traps in Homebush Bay to determine rates of sedimentation and resuspension (using environmental/cosmogenic Be). Models derived from these studies provide the contaminants levels against which risk is assessed; (3) biokinetic studies using proxy radiotracer isotopes (eg. 75 Se and 109 Cd for analogous stable metals) of the uptake and trophic transfer of contaminants by specific estaurine biota. Here we identify the rates and extent to which contaminants accumulated and transferred to predators/seafoods; and (4) application of a probabilistic ecological risk assessment model (AQUARISK) set to criteria determined by stakeholder consensus. In this study we analysed the distribution of natural isotopes and redistribution of artificial isotopes injected into ecological compartments to determine the key trophic linkages and contaminant pathways in an estuarine system and contribute to improving the accuracy and specificity of a probabilistic ecological risk assessment

A probabilistic model for hydrokinetic turbine collision risks: exploring impacts on fish.

Science.gov (United States)

Hammar, Linus; Eggertsen, Linda; Andersson, Sandra; Ehnberg, Jimmy; Arvidsson, Rickard; Gullström, Martin; Molander, Sverker

2015-01-01

A variety of hydrokinetic turbines are currently under development for power generation in rivers, tidal straits and ocean currents. Because some of these turbines are large, with rapidly moving rotor blades, the risk of collision with aquatic animals has been brought to attention. The behavior and fate of animals that approach such large hydrokinetic turbines have not yet been monitored at any detail. In this paper, we conduct a synthesis of the current knowledge and understanding of hydrokinetic turbine collision risks. The outcome is a generic fault tree based probabilistic model suitable for estimating population-level ecological risks. New video-based data on fish behavior in strong currents are provided and models describing fish avoidance behaviors are presented. The findings indicate low risk for small-sized fish. However, at large turbines (≥5 m), bigger fish seem to have high probability of collision, mostly because rotor detection and avoidance is difficult in low visibility. Risks can therefore be substantial for vulnerable populations of large-sized fish, which thrive in strong currents. The suggested collision risk model can be applied to different turbine designs and at a variety of locations as basis for case-specific risk assessments. The structure of the model facilitates successive model validation, refinement and application to other organism groups such as marine mammals.

A probabilistic model for hydrokinetic turbine collision risks: exploring impacts on fish.

Directory of Open Access Journals (Sweden)

Linus Hammar

Full Text Available A variety of hydrokinetic turbines are currently under development for power generation in rivers, tidal straits and ocean currents. Because some of these turbines are large, with rapidly moving rotor blades, the risk of collision with aquatic animals has been brought to attention. The behavior and fate of animals that approach such large hydrokinetic turbines have not yet been monitored at any detail. In this paper, we conduct a synthesis of the current knowledge and understanding of hydrokinetic turbine collision risks. The outcome is a generic fault tree based probabilistic model suitable for estimating population-level ecological risks. New video-based data on fish behavior in strong currents are provided and models describing fish avoidance behaviors are presented. The findings indicate low risk for small-sized fish. However, at large turbines (≥5 m, bigger fish seem to have high probability of collision, mostly because rotor detection and avoidance is difficult in low visibility. Risks can therefore be substantial for vulnerable populations of large-sized fish, which thrive in strong currents. The suggested collision risk model can be applied to different turbine designs and at a variety of locations as basis for case-specific risk assessments. The structure of the model facilitates successive model validation, refinement and application to other organism groups such as marine mammals.

Work-related violence against security guards--who is most at risk?

Science.gov (United States)

Leino, Tuula; Selin, Risto; Summala, Heikki; Virtanen, Marianna

2011-01-01

Studies on violence in the work of security guards are largely lacking. This study is unique in that it focuses on security guards (n=1,010) in Finland, and assesses the different forms, prevalence, and risk factors of the work-related violence they often face. Information to a survey instrument was obtained by first interviewing 30 volunteers. Then we made a cross-sectional mailed survey that was sent to a randomized group of 2,000 security guards. The response rate was 52. We found the prevalence of verbal aggression, threats of assault, and physical acts against security guards at least once a month to be 39%, 19%, and 15% respectively. As regards risk factors and who is most at risk, our results show that male gender, young age, low work experience, late working hours, and time pressure were associated with all three forms of work-related violence. Unlike other forms of violence, verbal aggression was highly prevalent outside the metropolitan area and directed towards both more and less experienced security guards. In prevention policies for violence, it is important to identify high-risk groups such as those who have less work experience.

Video calls from lay bystanders to dispatch centers - risk assessment of information security.

Science.gov (United States)

Bolle, Stein R; Hasvold, Per; Henriksen, Eva

2011-09-30

Video calls from mobile phones can improve communication during medical emergencies. Lay bystanders can be instructed and supervised by health professionals at Emergency Medical Communication Centers. Before implementation of video mobile calls in emergencies, issues of information security should be addressed. Information security was assessed for risk, based on the information security standard ISO/IEC 27005:2008. A multi-professional team used structured brainstorming to find threats to the information security aspects confidentiality, quality, integrity, and availability. Twenty security threats of different risk levels were identified and analyzed. Solutions were proposed to reduce the risk level. Given proper implementation, we found no risks to information security that would advocate against the use of video calls between lay bystanders and Emergency Medical Communication Centers. The identified threats should be used as input to formal requirements when planning and implementing video calls from mobile phones for these call centers.

Probabilistic risk assessment for six vapour intrusion algorithms

NARCIS (Netherlands)

Provoost, J.; Reijnders, L.; Bronders, J.; Van Keer, I.; Govaerts, S.

2014-01-01

A probabilistic assessment with sensitivity analysis using Monte Carlo simulation for six vapour intrusion algorithms, used in various regulatory frameworks for contaminated land management, is presented here. In addition a deterministic approach with default parameter sets is evaluated against

A technique of including the effect of aging of passive components in probabilistic risk assessments

International Nuclear Information System (INIS)

Phillips, J.H.; Weidenhamer, G.H.

1992-01-01

The probabilistic risk assessments (PRAS) being developed at most nuclear power plants to calculate the risk of core damage generally focus on the possible failure of active components. The possible failure of passive components is given little consideration. We are developing methods for selecting risk-significant passive components and including them in PRAS. These methods provide effective ways to prioritize passive components for inspection, and where inspection reveals aging damage, mitigation or repair can be employed to reduce the likelihood of component failure. We demonstrated a method by selecting a weld in the auxiliary feedwater (AFW) system, basing our selection on expert judgement of the likelihood of failure and on an estimate of the consequence of component failure to plant safety. We then modified and used the Piping Reliability Analysis Including Seismic Events (PRAISE) computer code to perform a probabilistic structural analysis to calculate the probability that crack growth due to aging would cause the weld to fail. The PRAISE code was modified to include the effects of changing design material properties with age and changing stress cycles. The calculation included the effects of mechanical loads and thermal transients typical of the service loads for this piping design and the effects of thermal cycling caused by a leaking check valve. However, this particular calculation showed little change in low component failure probability and plant risk for 48 years of service. However, sensitivity studies showed that if the probability of component failure is high, the effect on plant risk is significant. The success of this demonstration shows that this method could be applied to nuclear power plants. The demonstration showed the method is too involved (PRAISE takes a long time to perform the calculation and the input information is extensive) for handling a large number of passive components and therefore simpler methods are needed

28 CFR 105.11 - Individuals not requiring a security risk assessment.

Science.gov (United States)

2010-07-01

... requiring a security risk assessment. (a) Citizens and nationals of the United States. A citizen or national... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Individuals not requiring a security risk assessment. 105.11 Section 105.11 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) CRIMINAL HISTORY...

Review process and quality assurance in the EBR-II probabilistic risk assessment

International Nuclear Information System (INIS)

Roglans, J.; Hill, D.J.; Ragland, W.A.

1992-01-01

A Probabilistic Risk Assessment (PRA) of the Experimental Breeder Reactor II (EBR-II), a Department of Energy (DOE) Category A reactor, has recently been completed at Argonne National Laboratory (ANL). Within the scope of the ANL QA Programs, a QA Plan specifically for the EBR-II PRA was developed. The QA Plan covered all aspects of the PRA development, with emphasis on the procedures for document and software control, and the internal and external review process. The effort spent in the quality assurance tasks for the EBR-II PRA has reciprocated by providing acceptance of the work and confidence in the quality of the results

Probabilistic risk assessment (PRA): status report and guidance for regulatory application. Draft report for comment

International Nuclear Information System (INIS)

1984-02-01

This document describes the current status of the methodologies used in probabilistic risk assessment (PRA) and provides guidance for the application of the results of PRAs to the nuclear reactor regulatory process. The PRA studies that have been completed or are underway are reviewed. The levels of maturity of the methodologies used in a PRA are discussed. Insights derived from PRAs are listed. The potential uses of PRA results for regulatory purposes are discussed

Uses of human reliability analysis probabilistic risk assessment results to resolve personnel performance issues that could affect safety

International Nuclear Information System (INIS)

O'Brien, J.N.; Spettell, C.M.

1985-10-01

This report is the first in a series which documents research aimed at improving the usefulness of Probabilistic Risk Assessment (PRA) results in addressing human risk issues. This first report describes the results of an assessment of how well currently available PRA data addresses human risk issues of current concern to NRC. Findings indicate that PRA data could be far more useful in addressing human risk issues with modification of the development process and documentation structure of PRAs. In addition, information from non-PRA sources could be integrated with PRA data to address many other issues. 12 tabs

Use of probabilistic risk assessments to define areas of possible exemption from regulatory requirements

International Nuclear Information System (INIS)

Thompson, C.A.; Carlson, D.; Kolaczkowski, A.; LaChance, J.

1988-01-01

The Risk-Based Licensing Program (RBLP) was sponsored by the Department of Energy for the purpose of establishing and demonstrating an approach for identifying potential areas for exemption from current regulatory requirements in the licensing of nuclear power plants. Such an approach could assist in the improvement of the regulatory process for both current and future nuclear plant designs. Use of the methodology could result in streamlining the regulatory process by eliminating unnecessarily detailed reviews of portions of a plant design not important to risk. The RBLP methodology utilizes probabilistic risk assessments, (PRAs), which are required of all future applicants for nuclear power plant licenses. PRA results are used as a screening tool to determine the risk significance of various plant features which are correlated to the risk importance of regulations to identify potential areas for regulatory exemption. Additional consideration is then given to non-risk factors in the final determination of exemption candidates. The RBLP methodology was demonstrated using an existing PRA. The results of the demonstration are highlighted. 10 refs

An integrated probabilistic risk analysis decision support methodology for systems with multiple state variables

International Nuclear Information System (INIS)

Sen, P.; Tan, John K.G.; Spencer, David

1999-01-01

Probabilistic risk analysis (PRA) methods have been proven to be valuable in risk and reliability analysis. However, a weak link seems to exist between methods for analysing risks and those for making rational decisions. The integrated decision support system (IDSS) methodology presented in this paper attempts to address this issue in a practical manner. In consists of three phases: a PRA phase, a risk sensitivity analysis (SA) phase and an optimisation phase, which are implemented through an integrated computer software system. In the risk analysis phase the problem is analysed by the Boolean representation method (BRM), a PRA method that can deal with systems with multiple state variables and feedback loops. In the second phase the results obtained from the BRM are utilised directly to perform importance and risk SA. In the third phase, the problem is formulated as a multiple objective decision making problem in the form of multiple objective reliability optimisation. An industrial example is included. The resultant solutions of a five objective reliability optimisation are presented, on the basis of which rational decision making can be explored

Safety evaluation for the LMFBR plant using probabilistic risk assessment techniques

International Nuclear Information System (INIS)

Kani, Y.; Aizawa, K.

1987-01-01

This paper presents an application of probabilistic risk assessment techniques to a typical loop-type liquid metal fast breeder reactor (LMFBR) plant in the detailed design stage. A comprehensive systems analysis has been performed to identify event sequences leading to core damage and provide insights into the importance of accident contributors. While traditional event tree/fault tree modeling was used for the analysis, this study involved a thorough investigation of initiating events and of support system faults. The qualification of accident sequences has been conducted by combining the fault trees based on the event trees and obtaining sequence cut sets with the use of the SETS code. This study also attempted to quantify the potential for operator recovery actions in the course of each accident sequence. (author)

A review of NRC staff uses of probabilistic risk assessment

Energy Technology Data Exchange (ETDEWEB)

1994-03-01

The NRC staff uses probabilistic risk assessment (PRA) and risk management as important elements its licensing and regulatory processes. In October 1991, the NRC`s Executive Director for Operations established the PRA Working Group to address concerns identified by the Advisory Committee on Reactor Safeguards with respect to unevenness and inconsistency in the staff`s current uses of PRA. After surveying current staff uses of PRA and identifying needed improvements, the Working Group defined a set of basic principles for staff PRA use and identified three areas for improvements: guidance development, training enhancements, and PRA methods development. For each area of improvement, the Working Group took certain actions and recommended additional work. The Working Group recommended integrating its work with other recent PRA-related activities the staff completed and improving staff interactions with PRA users in the nuclear industry. The Working Group took two key actions by developing general guidance for two uses of PRA within the NRC (that is, screening or prioritizing reactor safety issues and analyzing such issues in detail) and developing guidance on basic terms and methods important to the staff`s uses of PRA.

A review of NRC staff uses of probabilistic risk assessment

International Nuclear Information System (INIS)

1994-03-01

The NRC staff uses probabilistic risk assessment (PRA) and risk management as important elements its licensing and regulatory processes. In October 1991, the NRC's Executive Director for Operations established the PRA Working Group to address concerns identified by the Advisory Committee on Reactor Safeguards with respect to unevenness and inconsistency in the staff's current uses of PRA. After surveying current staff uses of PRA and identifying needed improvements, the Working Group defined a set of basic principles for staff PRA use and identified three areas for improvements: guidance development, training enhancements, and PRA methods development. For each area of improvement, the Working Group took certain actions and recommended additional work. The Working Group recommended integrating its work with other recent PRA-related activities the staff completed and improving staff interactions with PRA users in the nuclear industry. The Working Group took two key actions by developing general guidance for two uses of PRA within the NRC (that is, screening or prioritizing reactor safety issues and analyzing such issues in detail) and developing guidance on basic terms and methods important to the staff's uses of PRA

Assessing Probabilistic Risk Assessment Approaches for Insect Biological Control Introductions

Directory of Open Access Journals (Sweden)

Leyla V. Kaufman

2017-07-01

Full Text Available The introduction of biological control agents to new environments requires host specificity tests to estimate potential non-target impacts of a prospective agent. Currently, the approach is conservative, and is based on physiological host ranges determined under captive rearing conditions, without consideration for ecological factors that may influence realized host range. We use historical data and current field data from introduced parasitoids that attack an endemic Lepidoptera species in Hawaii to validate a probabilistic risk assessment (PRA procedure for non-target impacts. We use data on known host range and habitat use in the place of origin of the parasitoids to determine whether contemporary levels of non-target parasitism could have been predicted using PRA. Our results show that reasonable predictions of potential non-target impacts may be made if comprehensive data are available from places of origin of biological control agents, but scant data produce poor predictions. Using apparent mortality data rather than marginal attack rate estimates in PRA resulted in over-estimates of predicted non-target impact. Incorporating ecological data into PRA models improved the predictive power of the risk assessments.

Probabilistic assessment of erosion and flooding risk in the northern Gulf of Mexico

Science.gov (United States)

Wahl, Thomas; Plant, Nathaniel G.; Long, Joseph W.

2016-05-01

We assess erosion and flooding risk in the northern Gulf of Mexico by identifying interdependencies among oceanographic drivers and probabilistically modeling the resulting potential for coastal change. Wave and water level observations are used to determine relationships between six hydrodynamic parameters that influence total water level and therefore erosion and flooding, through consideration of a wide range of univariate distribution functions and multivariate elliptical copulas. Using these relationships, we explore how different our interpretation of the present-day erosion/flooding risk could be if we had seen more or fewer extreme realizations of individual and combinations of parameters in the past by simulating 10,000 physically and statistically consistent sea-storm time series. We find that seasonal total water levels associated with the 100 year return period could be up to 3 m higher in summer and 0.6 m higher in winter relative to our best estimate based on the observational records. Impact hours of collision and overwash—where total water levels exceed the dune toe or dune crest elevations—could be on average 70% (collision) and 100% (overwash) larger than inferred from the observations. Our model accounts for non-stationarity in a straightforward, non-parametric way that can be applied (with little adjustments) to many other coastlines. The probabilistic model presented here, which accounts for observational uncertainty, can be applied to other coastlines where short record lengths limit the ability to identify the full range of possible wave and water level conditions that coastal mangers and planners must consider to develop sustainable management strategies.

Probabilistic assessment of erosion and flooding risk in the northern Gulf of Mexico

Science.gov (United States)

Plant, Nathaniel G.; Wahl, Thomas; Long, Joseph W.

2016-01-01

We assess erosion and flooding risk in the northern Gulf of Mexico by identifying interdependencies among oceanographic drivers and probabilistically modeling the resulting potential for coastal change. Wave and water level observations are used to determine relationships between six hydrodynamic parameters that influence total water level and therefore erosion and flooding, through consideration of a wide range of univariate distribution functions and multivariate elliptical copulas. Using these relationships, we explore how different our interpretation of the present-day erosion/flooding risk could be if we had seen more or fewer extreme realizations of individual and combinations of parameters in the past by simulating 10,000 physically and statistically consistent sea-storm time series. We find that seasonal total water levels associated with the 100 year return period could be up to 3 m higher in summer and 0.6 m higher in winter relative to our best estimate based on the observational records. Impact hours of collision and overwash—where total water levels exceed the dune toe or dune crest elevations—could be on average 70% (collision) and 100% (overwash) larger than inferred from the observations. Our model accounts for non-stationarity in a straightforward, non-parametric way that can be applied (with little adjustments) to many other coastlines. The probabilistic model presented here, which accounts for observational uncertainty, can be applied to other coastlines where short record lengths limit the ability to identify the full range of possible wave and water level conditions that coastal mangers and planners must consider to develop sustainable management strategies.

Probabilistic Analysis of Failures Mechanisms of Large Dams

NARCIS (Netherlands)

Shams Ghahfarokhi, G.

2014-01-01

Risk and reliability analysis is presently being performed in almost all fields of engineering depending upon the specific field and its particular area. Probabilistic risk analysis (PRA), also called quantitative risk analysis (QRA) is a central feature of hydraulic engineering structural design.

Probabilistic framework for assessing the arsenic exposure risk from cooked fish consumption.

Science.gov (United States)

Ling, Min-Pei; Wu, Chiu-Hua; Chen, Szu-Chieh; Chen, Wei-Yu; Chio, Chia-Pin; Cheng, Yi-Hsien; Liao, Chung-Min

2014-12-01

Geogenic arsenic (As) contamination of groundwater is a major ecological and human health problem in southwestern and northeastern coastal areas of Taiwan. Here, we present a probabilistic framework for assessing the human health risks from consuming raw and cooked fish that were cultured in groundwater As-contaminated ponds in Taiwan by linking a physiologically based pharmacokinetics model and a Weibull dose-response model. Results indicate that As levels in baked, fried, and grilled fish were higher than those of raw fish. Frying resulted in the greatest increase in As concentration, followed by grilling, with baking affecting the As concentration the least. Simulation results show that, following consumption of baked As-contaminated fish, the health risk to humans is fish is unlikely to pose a significant risk to human health. However, contaminated fish cooked by frying resulted in significant health risks, showing the highest cumulative incidence ratios of liver cancer. We also show that males have higher cumulative incidence ratio of liver cancer than females. We found that although cooking resulted in an increase for As levels in As-contaminated fish, the risk to human health of consuming baked fish is nevertheless acceptable. We suggest the adoption of baking as a cooking method and warn against frying As-contaminated fish. We conclude that the concentration of contaminants after cooking should be taken into consideration when assessing the risk to human health.

Lethal stakes: rig-hand killings show rising security risks abroad

Energy Technology Data Exchange (ETDEWEB)

Lorenz, A

1999-05-03

The increasing demands for protection money from foreign exploration and pipeline construction companies by left-wing guerrilla groups in various South American countries led to greater attention being focused on security services. This paper discusses the various alternatives to consider when choosing a security service. The experience of a Canadian pipeline company with projects in South America, and in need of security services, is described. The company felt that it was important that the security firm have a Calgary presence. It ended up hiring Calgary Protection Concepts Corporation, which is run by former Canadian police and intelligence officers, who provide a wide range of security services. Staff spend time in the country involved to look over the local security situation, develop contacts with local intelligence officers, and contract overseas agents who arrange for bodyguards, escorts and armored cars. ProCon also helps companies develop crisis management plans, guiding senior personnel through scenarios such as kidnapping, extortion and civil strife. ProCon also has a 24-hour emergency assistance call centre to provide immediate advice, to notify personnel and family members and to monitor the situation. Trust is key to hiring an outside security service since the security firm becomes party to extremely confidential information. Top security firms usually specialize in either security work or political risk analysis, but not both. The reason for this is that there are big differences in mentality, training and capabilities between studying risks and actively guarding against hazards.

Lethal stakes: rig-hand killings show rising security risks abroad

International Nuclear Information System (INIS)

Lorenz, A.

1999-01-01

The increasing demands for protection money from foreign exploration and pipeline construction companies by left-wing guerrilla groups in various South American countries led to greater attention being focused on security services. This paper discusses the various alternatives to consider when choosing a security service. The experience of a Canadian pipeline company with projects in South America, and in need of security services, is described. The company felt that it was important that the security firm have a Calgary presence. It ended up hiring Calgary Protection Concepts Corporation, which is run by former Canadian police and intelligence officers, who provide a wide range of security services. Staff spend time in the country involved to look over the local security situation, develop contacts with local intelligence officers, and contract overseas agents who arrange for bodyguards, escorts and armored cars. ProCon also helps companies develop crisis management plans, guiding senior personnel through scenarios such as kidnapping, extortion and civil strife. ProCon also has a 24-hour emergency assistance call centre to provide immediate advice, to notify personnel and family members and to monitor the situation. Trust is key to hiring an outside security service since the security firm becomes party to extremely confidential information. Top security firms usually specialize in either security work or political risk analysis, but not both. The reason for this is that there are big differences in mentality, training and capabilities between studying risks and actively guarding against hazards

Standardized approach for developing probabilistic exposure factor distributions

Energy Technology Data Exchange (ETDEWEB)

Maddalena, Randy L.; McKone, Thomas E.; Sohn, Michael D.

2003-03-01

The effectiveness of a probabilistic risk assessment (PRA) depends critically on the quality of input information that is available to the risk assessor and specifically on the probabilistic exposure factor distributions that are developed and used in the exposure and risk models. Deriving probabilistic distributions for model inputs can be time consuming and subjective. The absence of a standard approach for developing these distributions can result in PRAs that are inconsistent and difficult to review by regulatory agencies. We present an approach that reduces subjectivity in the distribution development process without limiting the flexibility needed to prepare relevant PRAs. The approach requires two steps. First, we analyze data pooled at a population scale to (1) identify the most robust demographic variables within the population for a given exposure factor, (2) partition the population data into subsets based on these variables, and (3) construct archetypal distributions for each subpopulation. Second, we sample from these archetypal distributions according to site- or scenario-specific conditions to simulate exposure factor values and use these values to construct the scenario-specific input distribution. It is envisaged that the archetypal distributions from step 1 will be generally applicable so risk assessors will not have to repeatedly collect and analyze raw data for each new assessment. We demonstrate the approach for two commonly used exposure factors--body weight (BW) and exposure duration (ED)--using data for the U.S. population. For these factors we provide a first set of subpopulation based archetypal distributions along with methodology for using these distributions to construct relevant scenario-specific probabilistic exposure factor distributions.

An evaluation of the reliability and usefulness of external-initiator PRA (probabilistic risk analysis) methodologies

Energy Technology Data Exchange (ETDEWEB)

Budnitz, R.J.; Lambert, H.E. (Future Resources Associates, Inc., Berkeley, CA (USA))

1990-01-01

The discipline of probabilistic risk analysis (PRA) has become so mature in recent years that it is now being used routinely to assist decision-making throughout the nuclear industry. This includes decision-making that affects design, construction, operation, maintenance, and regulation. Unfortunately, not all sub-areas within the larger discipline of PRA are equally mature,'' and therefore the many different types of engineering insights from PRA are not all equally reliable. 93 refs., 4 figs., 1 tab.

An evaluation of the reliability and usefulness of external-initiator PRA [probabilistic risk analysis] methodologies

International Nuclear Information System (INIS)

Budnitz, R.J.; Lambert, H.E.

1990-01-01

The discipline of probabilistic risk analysis (PRA) has become so mature in recent years that it is now being used routinely to assist decision-making throughout the nuclear industry. This includes decision-making that affects design, construction, operation, maintenance, and regulation. Unfortunately, not all sub-areas within the larger discipline of PRA are equally ''mature,'' and therefore the many different types of engineering insights from PRA are not all equally reliable. 93 refs., 4 figs., 1 tab

Probabilistic Decision Graphs - Combining Verification and AI Techniques for Probabilistic Inference

DEFF Research Database (Denmark)

Jaeger, Manfred

2004-01-01

We adopt probabilistic decision graphs developed in the field of automated verification as a tool for probabilistic model representation and inference. We show that probabilistic inference has linear time complexity in the size of the probabilistic decision graph, that the smallest probabilistic ...

Probabilistic Flood Defence Assessment Tools

Directory of Open Access Journals (Sweden)

Slomp Robert

2016-01-01

Full Text Available The WTI2017 project is responsible for the development of flood defence assessment tools for the 3600 km of Dutch primary flood defences, dikes/levees, dunes and hydraulic structures. These tools are necessary, as per January 1st 2017, the new flood risk management policy for the Netherlands will be implemented. Then, the seven decades old design practice (maximum water level methodology of 1958 and two decades old safety standards (and maximum hydraulic load methodology of 1996 will formally be replaced by a more risked based approach for the national policy in flood risk management. The formal flood defence assessment is an important part of this new policy, especially for flood defence managers, since national and regional funding for reinforcement is based on this assessment. This new flood defence policy is based on a maximum allowable probability of flooding. For this, a maximum acceptable individual risk was determined at 1/100 000 per year, this is the probability of life loss of for every protected area in the Netherlands. Safety standards of flood defences were then determined based on this acceptable individual risk. The results were adjusted based on information from cost -benefit analysis, societal risk and large scale societal disruption due to the failure of critical infrastructure e.g. power stations. The resulting riskbased flood defence safety standards range from a 300 to a 100 000 year return period for failure. Two policy studies, WV21 (Safety from floods in the 21st century and VNK-2 (the National Flood Risk in 2010 provided the essential information to determine the new risk based safety standards for flood defences. The WTI2017 project will provide the safety assessment tools based on these new standards and is thus an essential element for the implementation of this policy change. A major issue to be tackled was the development of user-friendly tools, as the new assessment is to be carried out by personnel of the

Flood Risk Assessment Based On Security Deficit Analysis

Science.gov (United States)

Beck, J.; Metzger, R.; Hingray, B.; Musy, A.

Risk is a human perception: a given risk may be considered as acceptable or unac- ceptable depending on the group that has to face that risk. Flood risk analysis of- ten estimates economic losses from damages, but neglects the question of accept- able/unacceptable risk. With input from land use managers, politicians and other stakeholders, risk assessment based on security deficit analysis determines objects with unacceptable risk and their degree of security deficit. Such a risk assessment methodology, initially developed by the Swiss federal authorities, is illustrated by its application on a reach of the Alzette River (Luxembourg) in the framework of the IRMA-SPONGE FRHYMAP project. Flood risk assessment always involves a flood hazard analysis, an exposed object vulnerability analysis, and an analysis combing the results of these two previous analyses. The flood hazard analysis was done with the quasi-2D hydraulic model FldPln to produce flood intensity maps. Flood intensity was determined by the water height and velocity. Object data for the vulnerability analysis, provided by the Luxembourg government, were classified according to their potential damage. Potential damage is expressed in terms of direct, human life and secondary losses. A thematic map was produced to show the object classification. Protection goals were then attributed to the object classes. Protection goals are assigned in terms of an acceptable flood intensity for a certain flood frequency. This is where input from land use managers and politicians comes into play. The perception of risk in the re- gion or country influences the protection goal assignment. Protection goals as used in Switzerland were used in this project. Thematic maps showing the protection goals of each object in the case study area for a given flood frequency were produced. Com- parison between an object's protection goal and the intensity of the flood that touched the object determine the acceptability of the risk and the

Fuzzy-probabilistic multi agent system for breast cancer risk assessment and insurance premium assignment.

Science.gov (United States)

Tatari, Farzaneh; Akbarzadeh-T, Mohammad-R; Sabahi, Ahmad

2012-12-01

In this paper, we present an agent-based system for distributed risk assessment of breast cancer development employing fuzzy and probabilistic computing. The proposed fuzzy multi agent system consists of multiple fuzzy agents that benefit from fuzzy set theory to demonstrate their soft information (linguistic information). Fuzzy risk assessment is quantified by two linguistic variables of high and low. Through fuzzy computations, the multi agent system computes the fuzzy probabilities of breast cancer development based on various risk factors. By such ranking of high risk and low risk fuzzy probabilities, the multi agent system (MAS) decides whether the risk of breast cancer development is high or low. This information is then fed into an insurance premium adjuster in order to provide preventive decision making as well as to make appropriate adjustment of insurance premium and risk. This final step of insurance analysis also provides a numeric measure to demonstrate the utility of the approach. Furthermore, actual data are gathered from two hospitals in Mashhad during 1 year. The results are then compared with a fuzzy distributed approach. Copyright © 2012 Elsevier Inc. All rights reserved.

Learning Probabilistic Logic Models from Probabilistic Examples.

Science.gov (United States)

Chen, Jianzhong; Muggleton, Stephen; Santos, José

2008-10-01

We revisit an application developed originally using abductive Inductive Logic Programming (ILP) for modeling inhibition in metabolic networks. The example data was derived from studies of the effects of toxins on rats using Nuclear Magnetic Resonance (NMR) time-trace analysis of their biofluids together with background knowledge representing a subset of the Kyoto Encyclopedia of Genes and Genomes (KEGG). We now apply two Probabilistic ILP (PILP) approaches - abductive Stochastic Logic Programs (SLPs) and PRogramming In Statistical modeling (PRISM) to the application. Both approaches support abductive learning and probability predictions. Abductive SLPs are a PILP framework that provides possible worlds semantics to SLPs through abduction. Instead of learning logic models from non-probabilistic examples as done in ILP, the PILP approach applied in this paper is based on a general technique for introducing probability labels within a standard scientific experimental setting involving control and treated data. Our results demonstrate that the PILP approach provides a way of learning probabilistic logic models from probabilistic examples, and the PILP models learned from probabilistic examples lead to a significant decrease in error accompanied by improved insight from the learned results compared with the PILP models learned from non-probabilistic examples.

Cyber Risk Management for Critical Infrastructure: A Risk Analysis Model and Three Case Studies.

Science.gov (United States)

Paté-Cornell, M-Elisabeth; Kuypers, Marshall; Smith, Matthew; Keller, Philip

2018-02-01

Managing cyber security in an organization involves allocating the protection budget across a spectrum of possible options. This requires assessing the benefits and the costs of these options. The risk analyses presented here are statistical when relevant data are available, and system-based for high-consequence events that have not happened yet. This article presents, first, a general probabilistic risk analysis framework for cyber security in an organization to be specified. It then describes three examples of forward-looking analyses motivated by recent cyber attacks. The first one is the statistical analysis of an actual database, extended at the upper end of the loss distribution by a Bayesian analysis of possible, high-consequence attack scenarios that may happen in the future. The second is a systems analysis of cyber risks for a smart, connected electric grid, showing that there is an optimal level of connectivity. The third is an analysis of sequential decisions to upgrade the software of an existing cyber security system or to adopt a new one to stay ahead of adversaries trying to find their way in. The results are distributions of losses to cyber attacks, with and without some considered countermeasures in support of risk management decisions based both on past data and anticipated incidents. © 2017 Society for Risk Analysis.

Probabilistic health risk assessment of carcinogenic emissions from a MSW gasification plant.

Science.gov (United States)

Lonati, Giovanni; Zanoni, Francesca

2012-09-01

Health risk assessment due to the atmospheric emissions of carcinogenic pollutants (PCDD/Fs and Cd) from a waste gasification plant is performed by means of a probabilistic approach based on probability density functions for the description of the input data of the model parameters involved in the assessment. These functions incorporate both the epistemic and stochastic uncertainty of the input data (namely, the emission rate of the pollutants) and of all the parameters used for individual exposure assessment through the pathways of inhalation, soil ingestion and dermal contact, and diet. The uncertainty is propagated throughout the evaluation by Monte Carlo technique, resulting in the probability distribution of the individual risk. The median risk levels nearby the plant are in the 10(-8)-10(-10) range, ten-fold lower than the deterministic estimate based on precautionary values for the input data; however, the very upper percentiles (>95th) of the risk distribution can exceed the conventional 10(-6) reference value. The estimated risk is almost entirely determined by the Cd exposure through the diet; the pathways arising from PCDD/Fs exposure are without any practical significance, suggesting that the emission control should focus on Cd in order to reduce the carcinogenic risk. Risk variance decomposition shows the prevailing influence on the estimated risk of the Cd concentration at the emission stack: thus, for a more accurate risk assessment the efforts should focus primarily on the definition of its probability density function. Copyright © 2012 Elsevier Ltd. All rights reserved.

Applications of probabilistic techniques at NRC

International Nuclear Information System (INIS)

Thadani, A.; Rowsome, F.; Speis, T.

1984-01-01

The NRC is currently making extensive use of probabilistic safety assessment in the reactor regulation. Most of these applications have been introduced in the regulatory activities in the past few years. Plant Probabilistic Safety Studies are being utilized as a design tool for applications for standard designs and for assessment of plants located in regions of particularly high population density. There is considerable motivation for licenses to perform plant-specific probabilistic studies for many, if not all, of the existing operating nuclear power plants as a tool for prioritizing the implementation of the many outstanding licensing actions of these plants as well as recommending the elimination of a number of these issues which are judged to be insignificant in terms of their contribution to safety and risk. Risk assessment perspectives are being used in the priorization of generic safety issues, development of technical resolution of unresolved safety issues, assessing safety significance of proposed new regulatory requirements, assessment of safety significance of some of the occurrences at operating facilities and in environmental impact analyses of license applicants as required by the National Environmental Policy Act. (orig.)

Probabilistic commentary: the rise and fall, and rise again, of risk assessment

International Nuclear Information System (INIS)

Hendrie, J.M.

1985-02-01

Probabilistic risk assessment is mainly concerned with assessing the risks of nuclear power plants. Historically, the field of PRA began with a Senate request for a report on the safety of nuclear reactors in 1972. A quantitative report called WASH-1400 was eventually prepared and published in 1975, and in summary, it stated that nuclear reactors warranted only a low-grade concern in modern society. Criticism of this report and public perception of its results were highly visible subjects in the media, and the criticism led to the fact that PRA fell into disfavor. After Three Mile Island, it was recognized that PRA was a valuable tool for understanding such accidents, and PRA became a bit more popular again by the end of 1979. The usefulness of PRA was also supported by a German study in 1979. PRA played a significant role in the hearings on the Indian Point reactor. The present NRC regards PRA as an important tool in regulatory practice

A probabilistic seismic risk assessment procedure for nuclear power plants: (I) Methodology

Science.gov (United States)

Huang, Y.-N.; Whittaker, A.S.; Luco, N.

2011-01-01

A new procedure for probabilistic seismic risk assessment of nuclear power plants (NPPs) is proposed. This procedure modifies the current procedures using tools developed recently for performance-based earthquake engineering of buildings. The proposed procedure uses (a) response-based fragility curves to represent the capacity of structural and nonstructural components of NPPs, (b) nonlinear response-history analysis to characterize the demands on those components, and (c) Monte Carlo simulations to determine the damage state of the components. The use of response-rather than ground-motion-based fragility curves enables the curves to be independent of seismic hazard and closely related to component capacity. The use of Monte Carlo procedure enables the correlation in the responses of components to be directly included in the risk assessment. An example of the methodology is presented in a companion paper to demonstrate its use and provide the technical basis for aspects of the methodology. ?? 2011 Published by Elsevier B.V.

Dynamic modeling of physical phenomena for probabilistic risk assessments using artificial neural networks

International Nuclear Information System (INIS)

Benjamin, A.S.; Paez, T.L.; Brown, N.N.

1998-01-01

In most probabilistic risk assessments, there is a subset of accident scenarios that involves physical challenges to the system, such as high heat rates and/or accelerations. The system's responses to these challenges may be complicated, and their prediction may require the use of long-running computer codes. To deal with the many scenarios demanded by a risk assessment, the authors have been investigating the use of artificial neural networks (ANNs) as a fast-running estimation tool. They have developed a multivariate linear spline algorithm by extending previous ANN methods that use radial basis functions. They have applied the algorithm to problems involving fires, shocks, and vibrations. They have found that within the parameter range for which it is trained, the algorithm can simulate the nonlinear responses of complex systems with high accuracy. Running times per case are less than one second

Combination of the deterministic and probabilistic approaches for risk-informed decision-making in US NRC regulatory guides

International Nuclear Information System (INIS)

Patrik, M.; Babic, P.

2001-06-01

The report responds to the trend where probabilistic safety analyses are attached, on a voluntary basis (as yet), to the mandatory deterministic assessment of modifications of NPP systems or operating procedures, resulting in risk-informed type documents. It contains a nearly complete Czech translation of US NRC Regulatory Guide 1.177 and presents some suggestions for improving a) PSA study applications; b) the development of NPP documents for the regulatory body; and c) the interconnection between PSA and traditional deterministic analyses as contained in the risk-informed approach. (P.A.)

INFORMATION SECURITY RISKS OPTIMIZATION IN CLOUDY SERVICES ON THE BASIS OF LINEAR PROGRAMMING

Directory of Open Access Journals (Sweden)

I. A. Zikratov

2013-01-01

Full Text Available The paper discusses theoretical aspects of secure cloud services creation for information processing of various confidentiality degrees. A new approach to the reasoning of information security composition in distributed computing structures is suggested, presenting the problem of risk assessment as an extreme problem of decisionmaking. Linear programming method application is proved to minimize the risk of information security for given performance security in compliance with the economic balance for the maintenance of security facilities and cost of services. An example is given to illustrate the obtained theoretical results.

The application of probabilistic risk assessment to a LLW incinerator

International Nuclear Information System (INIS)

Li, K.K.; Huang, F.T.

1993-01-01

The 100 Kg/hr low-level radioactive waste (LLW) incinerator and the 1,500 ton supercompactor are two main vehicles in the Taiwan Power Company's Volume Reduction Center. Since the hot test of the incinerator in mid 1990, various problems associated with the original design and operating procedures were encountered. During the early stages of putting an incinerator in service, the modification and fine-tuning of the system would help future reliable operations. The probabilistic risk assessment (PRA) method was introduced to evaluate the interaction between potential system failure and its environmental impact and further help diagnose the system defects initially. The draft Level 1 system analysis was completed and the event and fault trees were constructed. Qualitatively, this approach is useful for preventing the system failure from occurring. However, Levels 2 and 3 analysis can only be done when sufficient data become available in the future

On the progress towards probabilistic basis for deterministic codes

International Nuclear Information System (INIS)

Ellyin, F.

1975-01-01

Fundamentals arguments for a probabilistic basis of codes are presented. A class of code formats is outlined in which explicit statistical measures of uncertainty of design variables are incorporated. The format looks very much like present codes (deterministic) except for having probabilistic background. An example is provided whereby the design factors are plotted against the safety index, the probability of failure, and the risk of mortality. The safety level of the present codes is also indicated. A decision regarding the new probabilistically based code parameters thus could be made with full knowledge of implied consequences

Managing the risks of legacy radioactive sources from a security perspective

International Nuclear Information System (INIS)

Alexander, Mark; Murray, Allan

2008-01-01

The safety and security risk posed by highly radioactive, long-lived sources at the end of their normal use has not been consistently well-managed in previous decades. The Brazilian Cs-137 accident in 1986 and the Thailand Co-60 accident in 2000 are prime examples of the consequences that ensue from the loss of control of highly dangerous sources after their normal use. With the new international emphasis on security of radioactive sources throughout their life cycle, there is now further incentive to address the management of risks posed by legacy, highly dangerous radioactive sources. The ANSTO South-East Asia Regional Security of Radioactive Sources (RSRS) Project has identified, and is addressing, a number of legacy situations that have arisen as a result of inadequate management practices in the past. Specific examples are provided of these legacy situations and the lessons learned for managing the consequent safety and security risk, and for future complete life-cycle management of highly radioactive sources. (author)

Mixture Of Probabilistic Factor Analyzers For Market Risk Measurement: Empirical Evidence From The Tunisian Foreign Exchange Market

Directory of Open Access Journals (Sweden)

Mohamed Nidhal Mosbahi

2017-05-01

Full Text Available In this paper, we propose a new approach for Basel-Compliant Value-at-Risk (VaR estimation in financial portfolio risk management, which combines Gaussian Mixture Models with probabilistic factor analysis models. This new mixed specification provides an alternative, compact, model to handle co-movements, heterogeneity and intra-frame correlations in financial data. This results in a model which concurrently performs clustering and dimensionality reduction, and can be considered as a reduced dimension mixture of probabilistic factor analyzers. For maximum likelihood estimation we have used an iterative approach based on the Alternating Expectation Conditional Maximization (AECM algorithm. Using a set of historical data in a rolling time window, from the Tunisian foreign exchange market, the model structure as well as its parameters are determined and estimated. Then, the fitted model combined with a modified Monte-Carlo simulation algorithm was used to predict the VaR. Through a Backtesting analysis, we found that this new specification exhibits a good fit to the data compared to other competing approaches, improves the accuracy of VaR prediction, possesses more flexibility, and can avoid serious violations when a financial crisis occurs.

Cyber Security Risk Evaluation of a Nuclear I&C Using BN and ET

OpenAIRE

Jinsoo Shin; Hanseong Son; Gyunyoung Heo

2017-01-01

Cyber security is an important issue in the field of nuclear engineering because nuclear facilities use digital equipment and digital systems that can lead to serious hazards in the event of an accident. Regulatory agencies worldwide have announced guidelines for cyber security related to nuclear issues, including U.S. NRC Regulatory Guide 5.71. It is important to evaluate cyber security risk in accordance with these regulatory guides. In this study, we propose a cyber security risk evaluatio...

Reliability and Probabilistic Risk Assessment - How They Play Together