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The inclusion of weld residual stress in fracture margin assessments of embrittled nuclear reactor pressure vessels

Conference ·
OSTI ID:654172
Analyses were performed to determine the impact of weld residual stresses in a reactor pressure vessel (RPV) on (1) the generation of pressure temperature (P-T) curves required for maintaining specified fracture prevention margins during nuclear plant startup and shutdown, and (2) the conditional probability of vessel failure due to pressurized thermal shock (PTS) loading. The through wall residual stress distribution in an axially oriented weld was derived using measurements taken from a shell segment of a canceled RPV and finite element thermal stress analyses. The P-T curve derived from the best estimate load analysis and a t / 8 deep flaw, based on K{sub Ic}, was less limiting than the one derived from the current methodology prescribed in the ASME Boiler and Pressure Vessel Code. The inclusion of the weld residual stresses increased the conditional probability of cleavage fracture due to PTS loading by a factor ranging from 2 to 4.
Research Organization:
Oak Ridge National Lab., TN (United States)
Sponsoring Organization:
USDOE Office of Financial Management and Controller, Washington, DC (United States); Nuclear Regulatory Commission, Washington, DC (United States)
OSTI ID:
654172
Report Number(s):
ORNL/CP--96684; CONF-980708--; ON: DE98004935; BR: 40100106
Country of Publication:
United States
Language:
English