IN-LINE INSPECTION PERFORMANCE, II VALIDATION SAMPLING

摘要

The performance of in-line inspection tools employed for integrity assessments has significant impact on the reliability of assessment results, the extent of required remediation, and justification of inspection intervals. A previous paper by the authors established criteria for determining the number of "successful" measurements for establishing whether a tool's performance should be accepted or rejected. The previous paper has also identified a "gray area" between these two limits, where it is not possible to either accept or reject the tool's performance. In practice, the number of "successful" measurements usually falls in this "gray" area. This paper addresses how to assess tool performance in this "gray" area in terms of sizing tolerance, certainty, and confidence level. A sampling scheme related to the gray area is discussed. Examples are given for illustration.