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Electrical Cable Aging and Condition Monitoring Codes and Standards for Nuclear Power Plants. Electrical Cable Task Group (ECTG) Co-Chairs: Dr. Stephanie Watson, NIST Corey McDaniel, R-SCC. ECTG Scope. Objectives: Inventory of relevant standards with gaps and overlaps analysis.
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Electrical Cable Aging and Condition Monitoring Codes and Standards for Nuclear Power Plants • Electrical Cable Task Group (ECTG) • Co-Chairs: • Dr. Stephanie Watson, NIST Corey McDaniel, R-SCC
ECTG Scope Objectives: • Inventory of relevant standards with gaps and overlaps analysis. • Recommendations for revisions or new electrical cable standards. • Review of current citations of electrical cables codes and standards in NRC regulatory documents. • Recommendations for research that is needed.
Gaps in Research(Previously discussed; still relevant) • Determination of aging mechanisms • Low voltage cable under wet conditions • High voltage cables under temperature, radiation, and wet conditions • Accident condition qualification • Newly developed insulation materials • Determination of extended service life of aged cables • Determination of the effectiveness of cable splicing and aging process • Standardization of procedures for condition monitoring test methods • Calibration of equipment and optimization of test parameters • Development and optimization of acceptance criteria
Priority NRC Regulatory Documents • Recommendation: Revise RG 1.218, Condition Monitoring Techniques for Electric Cables Used in Nuclear Power Plants (Revision 0, April 2012). • Include Transmission & Distribution (T&D) Techniques, such as dielectric spectroscopy, on-line partial discharge, VLF. • Discuss caveats of Cable Indenter • Acceptable for elastomer polymers, but NOT reliable for semi-crystalline polymers like PE and XLPE • Complex results for multi-component/multi-polymer cables • Clarify DC HiPot procedure-potentially harmful influence with degree of degradation • Note that EPRI guides -1020804, 1020805, and 1021629 are being used by US NPPs for programmatic and condition monitoring techniques. • Caution about applying any single diagnostic to achieve the goal
Priority NRC Regulatory Documents • (Continued) • Recommendation: Revise RG 1.89 “Environmental Qualification of Certain Electric Equipment Important to Safety for Nuclear Power Plants” (Revision 1, June 1984) • Update reference to IEEE 323-2003. • Recommendation: Revise RG 1.189 “Fire Protection for Nuclear Power Plants (Revision 2, October 2009) • using recent versions of IEEE 323 and IEEE 1202. • Question: • Even if we determine that new or revised standards are needed, how will the changes be driven? SDOs have processes for revisions; revisions are not always from emerging technical issues or demands of users.
Gaps in Research and Standards Existing NPPs • Cable Aging Studies • Accelerated aging and extrapolation to 60 years • Thermal and radiation sequence • Diffusion limited oxidation • Water Submergence and its Effects • Medium versus low voltage • Activation Energy Determination • Adequacy of Cable Characterization Techniques • Destructive versus non-destructive • Line Resonance Analysis (LIRA) • Low voltage cable applications; SDOs need to develop a method • Currently used in NPPs (I&C, power), T&D, Wind Parks (on/offshore), Process Industry, Oil and Gas Industry (above ground, underground, submarine, umbilical cables), Cable Manufacturers (reference measurements, QC) • Joint Time and Frequency Domain Reflectometry • Cable field tests for non-shielded cables (5 kV and above) • Universal procedure for walk-downs of cable installations
Gaps in Research and Standards New NPPs • Qualification testing on low smoke zero halogen cables • Performance correlation between fast non-oxidative diffusion limited oxidation controlled exposure (IEEE 323) with oxidatively driven materials degradation for long term plant normal operation (low dose radiation and low temperature) • Commonly accepted definitions of low and medium (action for SDOs)
Status and Path Forward • July: • Added task group co-chair from industry. • Draft report submitted to Steering Committee for review and comment. • Task group co-chair facilitating review and update of draft report by industry. • Late August: • Finalization of draft final report. • Draft final report to Steering Committee and NESCC. • September: • Completion of final report. • Publication.