Potential change in flaw geometry of an initially shallow finite-length surface flaw during a pressurized-thermal-shock transient
- Oak Ridge National Lab., TN (United States)
This study presents preliminary estimates on whether an shallow, axially oriented, inner-surface finite-length flaw in a PWR-RPV would tend to elongate in the axial direction and/or deepen into the wall of the vessel during a postulated PTS transient. Analysis results obtained based on the assumptions of (1) linear-elastic material response, and (2) cladding with same toughness as the base metal, indicate that a nearly semicircular flaw would likely propagate in the axial direction followed by propagation into the wall of the vessel. Note that these results correspond to initiation within the lower-shelf fracture toughness temperature range, and that their general validity within the lower-transition temperature range remains to be determined. The sensitivity of the numerical results aid conclusions to the following analysis assumptions are evaluated: (1) reference flaw geometry along the entire crack front and especially within the cladding region; (2) linear-elastic vs elastic-plastic description of material response; and (3) base-material-only vs bimaterial cladding-base vessel-model assumption. The sensitivity evaluation indicates that the analysis results are very sensitive to the above assumptions.
- Research Organization:
- Nuclear Regulatory Commission, Washington, DC (United States). Div. of Engineering; Oak Ridge National Lab., TN (United States)
- Sponsoring Organization:
- Nuclear Regulatory Commission, Washington, DC (United States)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 10186644
- Report Number(s):
- NUREG/CR--5968; ORNL/TM--12279; ON: TI94001152
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
210200
22 GENERAL STUDIES OF NUCLEAR REACTORS
220900
36 MATERIALS SCIENCE
360103
CRACK PROPAGATION
CRACKS
DEFECTS
ELASTICITY
FRACTURE MECHANICS
FRACTURE PROPERTIES
HEAT TRANSFER
HYDRAULICS
LOSS OF COOLANT
MECHANICAL PROPERTIES
PLASTICITY
POWER REACTORS
NONBREEDING
LIGHT-WATER MODERATED
NONBOILING WATER COOLED
PRESSURE VESSELS
PRESSURIZATION
PWR TYPE REACTORS
REACTOR SAFETY
RESPONSE FUNCTIONS
STEELS
TEMPERATURE DEPENDENCE
THERMAL SHOCK
TRANSIENTS