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Lessons Learned from Guy Wire and Anchor Replacement at Sequoyah Nuclear Plant

This presentation by Doyle Pittman at the 12th NUMUG Meeting in 2008 discusses the extensive lessons learned during the replacement of guy wires and anchors for a 91-meter tower at Sequoyah Nuclear Plant. Key insights include the need for civil engineering support, the importance of a comprehensive work plan, and understanding the regulatory implications of degraded conditions. The challenges of ensuring structural integrity and compliance with safety and regulatory standards highlight the critical role of detailed planning and rigorous inspection processes.

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Lessons Learned from Guy Wire and Anchor Replacement at Sequoyah Nuclear Plant

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  1. Lessons Learned from Guy Wire and Anchor Replacement at Sequoyah Nuclear Plantby Doyle Pittman12thNUMUG Meeting - 2008

  2. Background • 91-m tower erected in 1970 • Advance 33 in. triangular, galvanized tower • Instrumented at 3 levels • 18, 3/8 in. guy wires • 6 guy anchors • 2003 and 2004 inspections: • Replace guy wires • Replace two guy anchors • Install new grounding • Work order but no $$ 12thNUMUG Meeting - 2008

  3. Background Continued • Guy wire tension checked every 3-years • Self assessment in 2006 found no tolerance limit for tension • Acceptable range = 1050 to 2250 pounds per square inch • Six wires outside range • Declared tower unsafe to climb March 2007 • Investigated alternative ways to reach instruments – mobile crane with basket 12thNUMUG Meeting - 2008

  4. Lesson 1- Need Civil Engineer Support • Maintain tower specifications • Perform structural analysis • replace or repair tower • wind load less than design • Guy anchor placement • slope • clearance • ground disturbance • Tower condition 12thNUMUG Meeting - 2008

  5. Lesson 2 – Need for Workplan • Training • Forms/approvals • crane operation • digging permit • NEPA review • job safety analysis • rigging planning • Pre-job brief • weather conditions • Contingencies • concrete drying 12thNUMUG Meeting - 2008

  6. Lesson 3 – Regulatory Implications • Degraded condition determination • Calibration due dates • Tolerance • Tracking • Data recoverability • Limiting Condition for Operation • Moved to technical requirements manual • Any two of three wind levels • One of three temperature differences 12thNUMUG Meeting - 2008

  7. Getting Closer! 12thNUMUG Meeting - 2008

  8. New Guy Wire and Anchor 12thNUMUG Meeting - 2008

  9. 12thNUMUG Meeting - 2008

  10. Success!!! 12thNUMUG Meeting - 2008

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