Risk Based

The SMS must be a risk-based system. That means it must be aligned to the risks arising in the workplace. Emphasis on certain SMS elements will be different according to the hazards associated with the work and the processes used. There is no SMS that is ideal for all mines, industries, and other workplaces therefore they should be seen as a framework on which to build a risk-specific system for the industry. The main aim of the system is to reduce risks therefore the system must be aligned to those risks. 

The key factor in safety and safety culture change is management leadership. The SMS must be initiated and supported by senior management as well as line and frontline management. Dr. Mark A. Friend (1997) says Only members of the management team can create or change the environment. (And it is, after all, their job to do so.) (p. 34). 

Safety systems that originate and are maintained in the safety department will have little effect on the organization. It is estimated that about 15% of a company s problems can be controlled by employees, but 85% can be controlled by management. This means that most safety problems are management problems. Management will 

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The project "Non-Invasive Inspection within an Asset Risk Management Strategy" is another joint industry project, funded by EC-THERMIE, representing the current trend towards onstream (non-invasive) inspection in combination with risk-based inspection philosophies to establish component condition. In this project, industry and authorities participate aiming at a beneficial use of today s NDT without sacrificing on safety. 

In plant maintenance, the availability of quantitative and non-invasive screening NDT methods will reduce the time needed for shutdowns and increase the intervals between them. Modem NDT methods will become just as important a tool for Risk Based Inspection approaches and maintenance planning as operational parameters and degradation mechanisms already are. 

Risk-Based Inspection. Inspection programs developed using risk analysis methods are becoming increasingly popular (15,16) (see Hazard ANALYSIS AND RISK ASSESSMENT). In this approach, the frequency and type of in-service inspection (IS I) is determined by the probabiUstic risk assessment (PRA) of the inspection results. Here, the results might be a false acceptance of a part that will fail as well as the false rejection of a part that will not fail. Whether a plant or a consumer product, false acceptance of a defective part could lead to catastrophic failure and considerable cost. Also, the false rejection of parts may lead to unjustified, and sometimes exorbitant, costs of operation (2). Risk is defined as follows ... 

In the simplest terms, a fault-tree for risk analysis requires the following information probabiUty of detection of a particular anomaly for an NDE system, repair or replacement decision for an item judged defective, probabiUty of failure of the anomaly, cost of failure, cost of inspection, and cost of repair. Implementation of a risk-based inspection system should lead to an overall improvement in the inspection costs as well as in the safety in operation for a plant, component, or a system. Unless the database is well estabUshed, however, costs may fluctuate considerably. 

ASME Research Task Eorce on Risk-Based Inspection Guidelines, Risk-Based Inspection—Development of Guidelines, CRTD Vol. 20-1, The American Society of Mechanical Engineers, New York, 1991. 

Consequence Phase 3 Develop Detailed Quantitative Estimate of the impacts of the Accident Scenarios. Sometimes an accident scenario is not understood enough to make risk-based decisions without having a more quantitative estimation of the effects. Quantitative consequence analysis will vary according to the hazards of interest (e.g., toxic, flammable, or reactive materials), specific accident scenarios (e.g., releases, runaway reactions, fires, or explosions), and consequence type of interest (e.g., onsite impacts, offsite impacts, environmental releases). The general technique is to model release rates/quantities, dispersion of released materials, fires, and explosions, and then estimate the effects of these events on employees, the public, the facility, neighboring facilities, and the environment. 

The development of a quantitative estimate of risk based on engineering evaluation and mathematical techniques for combining estimates of incident consequences and frequencies... 

Bohnenblust, H. and Slovic, P. 1998 Integrating Technical Analysis and Public Values in Risk-based Decision Making. Reliability Engineering and System Safety, 59, 151-159. 

Provide a reasonable risk-based framework for making decisions regarding nuclear plani design, operation, and siting. 

The confluence of sharply rising Operations and Maintenance (O M) costs. NRC requested Individual Plant Examinations (IPEs) and increased personal computer capabilities gave rise to the R R Workstation. Its uses and maintains-current PSA models and databases for individual plants to perform O M planning and scheduling, and uses the PSA in IPE models to identify plant design, procedure and operational vulnerabilities. The Risk and Reliability Workstation Alliance was organized by EPRI to support the R R Workshop in order to achieve O M cost reduction, plant productivity and safety enhancement through risk-based, user-friendly, windowed software louls (Table 3.6 8). The Alliance, initiated in 1992, includes 25 U.S. utilities and four international partners from Spain, France, Korea, and Mexico. SAIC is the prime contractor for the R R Workstation, with participation of five other PSA vendors. 

Risk-Based Categorization of NRC Technical and Generic Issues... 

Plant-specific features and modeling assumptions affecting risk, and Use of IPEs for risk-based regulation. 

Risk-based information provides a foundation for regulation of severe accidents. Early PRAs, with large uncertainties, indicated risk that was above or below the Safety Goals depending on containment performance. Consequently the NRC developed an Integration Plan for Closure of Severe Accident Issues (SECY-88-47) with six main elements to this plan 1) individual plant examinations (IPE), 2) containment performance improvements, 3) improved plant oper itions, 4) severe accident research, 5) external event considerations, and 6) accident management. 

Murphy, J. A., 1996, Risk-Based Regulation Practical Experience in Using Risk-Related Insights to Solve Regulatory Issues, PSA 96, pp 945-948. 

In order to assess the target concentrations of air contaminants both human risk-based and technology-based approaches can be used (Fig. 6.7). The various approaches are dealt with in more detail elsewhere. F" ... 

Section 13.2 Qualitative Risk Scenarios Section 13.3 Quantitative Risk Non-carcinogens Section 13.4 Quantitative Risk Carcinogens Section 13.5 Risk Uncertainties/Liinitations Section 13.6 Risk-Based Decision Making Section 13.7 Public Perception of Risk... 

The use of the risk-based decision making process allows for efficient allocation of limited resources, such as time, money, regulatory oversight, and qualified professionals. Advantages of using tliis process include ... 

Site assessment activities are focused on collecting only tliat iiifomiatioii that is necessary to make risk-based corrective action decisions... 

By using risk-based decision making, decisions are made in a consistent maimer. Protection of both human healtli and the enviromiient can be accounted for. ... 

Risk-based decision making and risk-based corrective action arc decision making processes for assessing and responding to a health hazard. The processes take into account effects on human healdi and the enviroiunent, inasmuch as chemical releases vaiy greatly in terms of complexity, physical and chemical characteristics, and in the risk that they may pose. Risk-based corrective action (RBCA) was initially designed by the American Society for Testing and Materials (ASTM) to assess petroleum releases, but tlie process may be tailored for use with any hazard. 

Hazardous uasie sites, inaeiive Canocr inoidenoc of 1000 annually from 6 ehemieals assessed. Considerable unocrtainly sinoe risk based on cxlnipolation from 35 sites lo about 25,000 sites. 

Definition of a medicai device Risk-based classification of devices Essential principles of safety and performance Labelling... 

To encourage the implementation of risk-based approaches that focus both industry and Agency attention on critical areas. 

Risk Management Ecological Risk-Based Decision-Making Stahl, Bachman, Barton, Clark, deFur, Ells, Pittinger, Slimak, Wentsel, editors... 

The Leggett (1992) model was developed to predict tissue doses and whole-body dose to people who may be exposed to americium. The model is considered an updated version of the ICRP (1989) model for americium, which has been used to establish risk-based limits of intake of241 Am (ICRP 1989). The Leggett (1992) and ICRP (1989) models predict similar long-term average doses of americium to the liver and skeleton for an injection exposure and would be expected to predict similar radiation risks and risk-based intake limits (Leggett 1992). Descriptions of applications of the Leggett (1992) model in risk assessment have not been reported. 

In using any risk measure, it should be remembered that risk measures, at best, are only estimates of possible event frequency and consequences All risk measurements have uncertainties. In some situations, the uncertainties can be highly significant. The fact that risk measurement is imprecise should be a consideration in any risk-based decision-making process. Chapter 5 of Reference 4 provides further discussion of uncertainty in risk decision making. 

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