ASME Section III Stress Analysis of a Heat Exchanger Tubesheet With a Misdrilled Hole and Irregular or Thin Ligaments

A stress analysis is described for a nuclear steam generator tubesheet with a thin or irregular ligament associated with a mis-drilled hole using the rules of ASME B&PV Section III and Non-Mandatory Appendix A, Article A-8000 for Stresses in Perforated Flat Plates. The analysis demonstrates the proper application of the NB-3200 rules for this special application with discussion of the differences between an actual tube hole deviation from what is assumed in ASME Appendix A. This is a companion paper to “Technical Justification Supporting Operation with a Tube Installed in a Mis-Drilled Hole of a Steam Generator Tubesheet”.