The effects of cladding on propagation of finite-length flaws in PTS analysis

Conference · Tue Jun 01 04:00:00 EDT 1993

OSTI ID:10163099

Keeney, J A; Dickson, T L

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: Nuclear Regulatory Commission, Washington, DC (United States)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 10163099
• Report Number(s): CONF-930803--12; ON: DE93015202
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
220200
CLADDING
COMPONENTS AND ACCESSORIES
CRACK PROPAGATION
CRACKS
DEFECTS
FINITE ELEMENT METHOD
NUCLEAR POWER PLANTS
PRESSURE VESSELS
PRESSURIZATION
REACTOR VESSELS
THERMAL SHOCK