ASME PCC-3–2017 pdf download.Inspection Planning Using Risk-Based Methods.
1 SCOPE, INTRODUCTION, AND PURPOSE 1.1 Scope The risk analysis principles, guidance, and implemen- tation strategies presented in this Standard are broadly applicable; however, this Standard has been specifically developed for applications involving fixed pressure- containing equipment and components. This Standard is not intended to be used for nuclear power plant com- ponents; see ASME BPV, Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components. It pro- vides guidance to owners, operators, and designers of pressure-containing equipment for developing and implementing an inspection program. These guidelines include means for assessing an inspection program and its plan. The approach emphasizes safe and reliable operation through cost-effective inspection. A spectrum of complementary risk analysis approaches (qualitative through fully quantitative) should be considered as part of the inspection planning process.
1.2 Introduction This Standard provides information on using risk analysis to develop and plan an effective inspection strategy. Inspection planning is a systematic process that begins with identification of facilities or equipment and culminates in an inspection plan. Both the probability 1 offailure andthe consequence offailure should be evalu- ated by considering all credible damage mechanisms that could be expected to affect the facilities or equip- ment. In addition, failure scenarios based on each credi- ble damage mechanism should be developed and considered. The output of the inspection planning process con- ducted according to these guidelines should be an inspection plan for each equipment item analyzed that includes (a) inspection methods that should be used (b) extent of inspection (percent of total area to be examined or specific locations) (c) inspection interval (timing) (d) other risk mitigation activities (e) the residual level of risk after inspection and other mitigation actions have been implemented
2.2 Overview of Risk Analysis The complexity of a risk analysis is a function of the number of factors that can affect the risk and there is a continuous spectrum of methods available to assess risk. The methods range from a strictly relative ranking to rigorous calculation. The methods generally represent a range of precision for the resulting risk analysis (see para. 3.3.6). Any particular analysis may not yield usable results due to a lack of data, low-quality data, or the use of an approach that does not adequately differentiate the risks represented by the equipment items. Therefore, the risk analysis should be validated before decisions are made based on the analysis results. A logical progression for a risk analysis is (a) collect and validate the necessary data and infor- mation (see section 5) (b) identify damage mechanisms and, optionally, determine the damage mode(s) for each mechanism (e.g., general metal loss, local metal loss, and pitting) (see section 6) (c) determine the probability of failure over a defined time frame for each damage mechanism (see section 7) (d) determine credible failure mode(s) (e.g., small leak, large leak, and rupture) (see section 7) (e) identify credible consequence scenarios that will result from the failure mode(s) (see section 8)ASME PCC-3 pdf download.