thus Smax < 69,600 psi and meets the code specified limits. The maximum
stress intensities, Pm (or PL) + Pb + Q + F, wherever calculable, meet
the 2 Sa limit of being less than 74,000 psi. For the 5.0 inch nozzles the
Stress Index Method may be used to determine the maximum stress intensity
since the nozzle was designed as an "acceptable" configuration. From
Paragraph 4-612 (b), the stress intensity at the inside corner of the nozzle
in the longitudinal plane is 3.3 times the primary membrane stress intensity
in the unpenetrated and unreinforced shell. For this shell, the primary
membrane stress is calculated as
Pm = 22,318 + 0.5(1000) = 22,818 psi
and
3.3 Pm = 75.300 psi > 2 Sa = 74,000 psi.
If no experimental verification is to be carried out and no other analytical
means of determining the maximum stress in the nozzle is available, then the
shell thickness should be increased slightly so as to reduce the 3.3 Pm
value to 74,000 psi. It should be noted that this 3.3 value is conservative
and that experimental verification should show that the maximum stress
intensity in the nozzle is actually lower than 3.3 Pm.
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