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Lessons Learned from Guy Wire and Anchor Replacement at Sequoyah Nuclear Plant by Doyle Pittman 12th NUMUG Meeting - 2008. 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

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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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