G-2222/2223: Nozzle / Flange Discontinuity Alpha · 2026-06-12

ASME BPVC Section XI (2025) Appendix G — Nozzle / Flange Discontinuity Fracture (G-2222 / G-2223)

Nozzle / Flange Discontinuity Fracture (G-2222 / G-2223)

This tool applies ASME XI (2025) Appendix G-2220 (nozzles, flanges and shell regions near geometric discontinuities) and G-2400(b). Discontinuity regions need a separate assessment beyond the shell remote from discontinuities (G-2215), because of combined membrane+bending stress (G-2222) or nozzle corner stress concentration (G-2223).

Two sub-paths are available:

• The nozzle corner crack path (G-2223) finds the corner stress intensity factor (SIF) K_{Ip} from a hoop stress × F(a/r_n) method or a fitted stress polynomial, and checks 2K_{Ip}+K_{It} \lt K_{Ic}; it also runs the G-2223(e) thickness exemption (t_{noz}\le63 mm).
• The flange path (G-2222) sums four primary/secondary membrane and bending terms and checks 2K_{Im}+2K_{Ib}+K_{Im}^{(2)}+K_{Ib}^{(2)} \lt K_{Ic}, where M_b=\tfrac23 M_m (G-2214.2); for this path it also gives the post-fuel-loading hydrostatic test minimum temperature (G-2400(b), with the 1.5 coefficient).

This tool does no discontinuity FEA or shell-theory stress analysis: you supply the membrane/bending stress components (or a stress profile) from your own analysis, and the thermal SIF K_{It} as input (e.g. pre-computed from the main Appendix G calculator, 0 for isothermal). Bolt/stud preload is counted as primary stress and thermal load as secondary. Results use SI units only.

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