Potential change in flaw geometry during pressurized-thermal-shock transients
This study presents preliminary estimates on the potential change in flaw geometry of an initially shallow, axially oriented, inner-surface finite-length flaw in a PWR-RPV during the course of a postulated PTS transient. Specifically, the question being addressed is whether a shallow, axially oriented, finite-length surface flaw would tend to elongate in the axial direction and/or deepen into the wall of the vessel during the transient. In the first part of the study, estimates are obtained based on the assumptions of linear-elastic material response. The thermo-elastic properties of the cladding and base material are explicitly considered. The flaw geometry corresponds to a family of modified-elliptical flaws characterized by the flaw`s half-length to maximum depth (aspect ratio). Requirements for numerical convergence of the finite element results are examined. In the second part of the study, the sensitivity of the numerical results and conclusions obtained in the first part of the study to the following three analysis assumptions are evaluated: (1) Reference flaw geometry along the entire crack front and especially within the cladding region; (2) Linear-elastic versus elastic-plastic description of material response; (3) Base-material-only vs bi-material cladding-base vessel-model assumption.
- Research Organization:
- Oak Ridge National Lab., TN (United States)
- Sponsoring Organization:
- Nuclear Regulatory Commission, Washington, DC (United States)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 10140901
- Report Number(s):
- CONF-930702--12; ON: DE93009709
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
210200
36 MATERIALS SCIENCE
360103
CRACK PROPAGATION
CRACKS
DEFECTS
ELASTICITY
FRACTURE MECHANICS
MECHANICAL PROPERTIES
POWER REACTORS
NONBREEDING
LIGHT-WATER MODERATED
NONBOILING WATER COOLED
PRESSURE VESSELS
PWR TYPE REACTORS
STEELS
THERMAL SHOCK
TRANSIENTS