Checklist of Steam Generator Repair Safety Issues at Maine Yankee

1. Circumferential cracking in the steam generator.
2. Ongoing corrosion and deformation processes.
3. Accumulated residual stress damage from steam generator fabrication and operation.
4. Weld-induced stress damage at the sleeve-tube transition.
5. Post-weld heat treatment efficacy for repair of weld-induced damage.
6. "Far-field" stress damage in parent tube resulting from sleeve welds and post-weld heat treatment.
7. Steam-tube sludge deposits and corrosion scaling.
8. Tube deformations (tube bowing and lateral displacement) induced by sleeve insertion, welding, and sludge deposits.
9. Sludge deposit, tube plugging, and deformation-induced changes in pressure gradient and reactor coolant flow.
10. Increased likelihood of steam tube contact during reactor operation.
11. Non-uniform sleeve length fails to cover all parent tubing.
12. Stress resistance and corrosion resistance differentials between new sleeves and old parent tube and tube welds.
13. Reduced effectiveness of ultra-sonic weld inspections due to attenuation of signals by the extensive sludge deposits and tube scaling.
14. The dilapidated condition of the steam generator is a paradigm for the condition of the rest of the reactor at Maine Yankee. (Embrittled reactor vessel, obsolete spent-fuel storage facility, etc.)

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