The effects of cladding on propagation of finite-length flaws in PTS analysis
Licensing issues within the nuclear industry dictate a need to investigate the effects of cladding on the extension of small finite-length cracks near the inside surface of a vessel. Limited experimental data and analyses indicate that cladding can inhibit the propagation of certain shallow flaws. This paper describes an analytical study which was carried out to determine (1) the minimum flaw depth for crack initiation under pressurized-thermal-shock (PTS) loading for semicircular surface flows in a clad reactor pressure vessel and (2) the impact, in terms of the conditional probability of vessel failure, of using a semicircular, as opposed to an infinite-length surface flaw as the initial flaw. The analytical results indicate that for initiation the critical crack depth required for the finite-length flaw is substantially greater than for the infinite-length flaw. The calculated minimum flaw depths required for initiation of finite-length flaws were incorporated in a modified version of the OCA-P code. The modified code was applied to the analysis of selected PTS transients, and the results indicated a substantial decrease in the conditional probability of failure, when the semicircular flaw is considered.
- Research Organization:
- Oak Ridge National Lab., TN (United States)
- Sponsoring Organization:
- NRC; Nuclear Regulatory Commission, Washington, DC (United States)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 6413617
- Report Number(s):
- CONF-930803-12; ON: DE93015202
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
220200* -- Nuclear Reactor Technology-- Components & Accessories
CALCULATION METHODS
CLADDING
CONTAINERS
CRACK PROPAGATION
CRACKS
DEFECTS
DEPOSITION
FINITE ELEMENT METHOD
NUCLEAR FACILITIES
NUCLEAR POWER PLANTS
NUMERICAL SOLUTION
POWER PLANTS
PRESSURE VESSELS
PRESSURIZATION
REACTOR VESSELS
SURFACE COATING
THERMAL POWER PLANTS
THERMAL SHOCK