Be careful
(OP) only refers to external pressure. E=1 without RT.
100% RT does not guarantee the absence of leaks.
100% RT does not replace leak testing.
The blind threaded stud hole is essential for thick walls. The stud is shorter and only has one nut.
My experience: Reactor PV (nuclear): 76 M 220 studs, L = 2500 mm, 850 kg each.
This equipment requires rigorous detailed manufacturing analysis by an experienced team.
Using the internet is not recommended at this time.
I have never used popular calculation programs; I use my own. Be careful.
Example: Avoid welding lifting lugs.
RT 100% the butt weld and 100% PT the fillet weld.
More information is required to confirm the above: general dimensions, service, material, design pressure / temperature.
1) TEMA is a standard, not a code.
2) The 2 3/8" stud bolt is included in ASME B1.1, no problem.
3) The stud bolt (blind threaded hole), or whatever you prefer to call it, is clearly defined in ASME VIII. Please read it.
4) Do you think diaphragm seal is suitable for FV design?