Judgment likelihood

Estimation of corrosion likelihood results from consideration of the characteristics of the soils and of the installed object, which are tabulated in Table 4-1 for nonalloyed and low-alloy steel products. Rating numbers, Z, are given according to the data on individual characteristics from which a further judgment can be made using the sum of the rating numbers. 

The paired comparisons method (NUREG/CR-3688) is a structured expert judgment method in which human errors are compared in pairs. By combining the judgments of the group of experts, the errors arc arranged in order of likelihood of occurrence, of the human errors considered, they can be used as "anchor points list. Documentation requirements are given in Table 4.5-8. 

Risk analysis is an assessment of tlie likelihood (probability) of an accidental release of a hazardous material and tlie actual consequences that might occur, based on tlie estimated vulnerable zones. The risk analysis is a judgment of probability and severity of consequences based on tlie history of previous incidents, local experience, and tlie best available current technological information. It provides an estimation of ... 

Expert Judgment quantifies an expert s state of knowledge or perceptions of the likelihood of an incident. This knowledge may be based on historical data, insights gained from models, experience, or a combination of these factors. 

Cause-consequence analysis serx es to characterize tlie physical effects resulting from a specific incident and the impact of these physical effects on people, the environment, and property. Some consequence models or equations used to estimate tlie potential for damage or injury are as follows Source Models, Dispersion Models, Fire Explosion Models, and Effect Models. Likelihood estimation (frequency estimation), cliaractcrizcs the probability of occurrence for each potential incident considered in tlie analysis. The major tools used for likelihood estimation are as follows Historical Data, Failure sequence modeling techniques, and Expert Judgment. 

As discussed in Section 5.3, site-specific conditions, including previous incident history, must be considered when assigning likelihood categories. The assessment team must have a thorough working knowledge of plant systems and practices to make a reasonable judgment of event likelihood. 

Beliefs are indeterminate when the evidence is insufficient to justify a judgment about the likelihood of the various out comes of aaion. This can happen in two main ways through uncertainty, especially about the future, and through strategic interaaion. 

Many of these estimates depend on professional judgment and experience regarding the likelihood of exposures from soils in different kinds of sites. For further information on the evaluation process see ATSDR (1992), ... 

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