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Risk Ranking : An Example Process and Method. Shane A. McManus Senior Engineer, SI. Nuclear Cable Workshop August 6-7, 2012 Richmond, VA. www.STRUCTINT.com 877-4SI-POWER. Objectives. Project Basis Cable Aging Management Tools Yard Cable Assessment Data Handling Risk Ranking
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Risk Ranking : An Example Process and Method Shane A. McManus Senior Engineer, SI Nuclear Cable Workshop August 6-7, 2012 Richmond, VA www.STRUCTINT.com 877-4SI-POWER
Objectives • Project Basis • Cable Aging Management Tools • Yard Cable Assessment • Data Handling • Risk Ranking • Inspection Prioritization • Concepts within a Building
Baseline Phase – Scoping & Prioritization Determine Scope Inspection Planning Data Collection and Integration Risk Ranking Determine Scope – Define which cable / connector components (MV, LV, Instrument, EQ and/or non-EQ, splices, etc.) are within the scope of the program at each plant. Data Collection/Integration – Relevant data, whether from existing databases (e.g., cable, operating experience, corrective action) or other sources are collected and organized. Risk Ranking – A risk assessment is performed to gain insights that best focus station resources in a way that mitigates the likelihood of failure and potential consequences of failure. Inspection Planning – Develop risk prioritized inspection walkdown scope and most appropriate tests based on environment, service conditions and materials of construction.
Project Basis • NUREG/CR-7000 • Select cables to be monitored. • Develop database for monitored cables. • Characterize and monitor service environments. • Identify stressors and expected aging mechanisms. • Select condition monitoring techniques suitable to monitored cables. • Establish baseline condition of monitored cables. • Identify cable characteristics and aging effects being monitored by each selected condition monitoring technique. • Perform test and inspection activities for periodic condition monitoring of cables. • Periodically review and incorporate plant and industry experience. • Periodically review, assess, and trend the condition of monitored cables. • Identify degraded conditions and take prompt corrective actions.
Visualization of Cable Information A visual representation of cable database information (inspection & risk results, drawings, PDF or pictures) through a GIS interface can offer the following benefits. • Visual review and analysis of data allows for multi-variant analysis and the recognition of patterns not possible with tabular information. • Combinations of cable information (layers) can be selectively ‘turned on’ by user. Simply ‘clicking’ on a feature reveals a table of information relevant to the cables in that area. • View assets associated with a specific cable or other information near cables (pipes, equipment, tanks, etc.) that may potentially contribute to degradation, such as from leakage. • Data can help facilitate inspection planning. • For underground cable, the risk associated with accidental contact during excavations (associated with fencing installation, buried pipe excavations, monitoring wells and other modifications) can be minimized.
CAM Foundation and Design Inputs • Raceway • Cable Type • Equipment
Walkdowns, Inspections, and Testing • Based on the raw risk data derived from the CAM Algorithms and the IsoRisk graphs a few observations were made: • MV submerged cables selected for testing and inspections per GALL AMP X1.E3. • Cables with the highest ROF values selected for walkdowns. Walkdown results dictated further inspections and testing. • Cables with the highest LOD selected for inspections. • Overall COF was low. • Did not impact plant operability. • Located in more adverse environments. • Sentinel concept implemented and results extrapolated.
Conclusions • NUREG/CR-7000 CAM Program Elements Addressed • Select cables to be monitored. • Develop database for monitored cables. • Characterize and monitor service environments. • Identify stressors and expected aging mechanisms. • Select condition monitoring techniques suitable to monitored cables. • Establish baseline condition of monitored cables. • Identify cable characteristics and aging effects being monitored by each selected condition monitoring technique. • Perform test and inspection activities for periodic condition monitoring of cables. • Incorporate plant and industry experience. • Periodically review, assess, and trend the condition of monitored cables. • Identify degraded conditions and take prompt corrective actions.