UFC 4-390-01
23 July 2003
life of the design.
Pressure vessels designed to comply with the requirements of the
ASME Boiler and Pressure Vessel Code, Section VIII, Division 1,
may not require a fatigue analysis if SCA concurrence is
obtained. Pressure vessels designed to comply with the
requirements of the ASME Boiler and Pressure Vessel Code, Section
VIII, Division 2, do not require a fatigue analysis if condition
A or condition B of Article AD-160.2 are met.
B.2.2 Fracture Toughness. The applicant should ensure that the
materials used to fabricate the pressure vessel, or any pressure
boundary component exhibit adequate resistance to fracture.
Specifically, the design analysis submitted to the SCA should
demonstrate that brittle fracture is not a possible mode of
failure by considering at least the following:
a)
Magnitude, nature and rate of stresses (both applied
and residual);
b)
Temperature range to which the structure may be
subjected in service;
c)
Size, location and density of flaws initially present
in the material and those that occur as a result of
cyclic operations;
d)
Environmental effects such as corrosion and/or erosion;
Specifically, the environmental effects on crack
initiation and propagation (e.g., stress-corrosion
cracking) must be evaluated;
e)
Effects of creep and strain rate on fracture toughness;
f)
Localized effects due to penetrations, attachments and
other vessel or component restraints (i.e., stress
risers);
g)
Effects of fabrication processes and heat treatments on
the fracture characteristics of the material. In
particular for welded construction, properties of the
weld rod and base metal within the heat-affected zone and
resultant induced internal stresses should be considered;
h)
Material thickness
The material properties used in the fracture analysis should be
based on appropriate tests such as tensile and compressive
corrosion cracking) tests, Charpy V-notch impact tests, dynamic
tear tests, drop-weight tests and explosion bulge tests as
discussed in Appendix A. Where appropriate test data is not
available, fracture mechanics type tests should be conducted.
Further, the design analysis must consider possible variations in
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