Tube structural integrity evaluation of Palo Verde Unit 1 steam generators for axial upper-bundle cracking

Book · Fri Dec 01 04:00:00 EST 1995

OSTI ID:131839

Woodman, B W; Begley, J A; Brown, S D ^[1]; Sweeney, K; Radspinner, M; Melton, M ^[2]

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1. Packer Engineering Plant Component Analysis Division, Pittsburgh, PA (United States)
2. Arizona Public Service, Phoenix, AZ (United States)

The analysis of the issue of upper bundle axial ODSCC as it apples to steam generator tube structural integrity in Unit 1 at the Palo Verde Nuclear generating Station is presented in this study. Based on past inspection results for Units 2 and 3 at Palo Verde, the detection of secondary side stress corrosion cracks in the upper bundle region of Unit 1 may occur at some future date. The following discussion provides a description and analysis of the probability of axial ODSCC in Unit 1 leading to the exceedance of Regulatory Guide 1.121 structural limits. The probabilities of structural limit exceedance are estimated as function of run time using a conservative approach. The chosen approach models the historical development of cracks, crack growth, detection of cracks and subsequent removal from service and the initiation and growth of new cracks during a given cycle of operation. Past performance of all Palo Verde Units as well as the historical performance of other steam generators was considered in the development of cracking statistics for application to Unit 1. Data in the literature and Unit 2 pulled tube examination results were used to construct probability of detection curves for the detection of axial IGSCC/IGA using an MRPC (multi-frequency rotating panake coil) eddy current probe. Crack growth rates were estimated from Unit 2 eddy current inspection data combined with pulled tube examination results and data in the literature. A Monte-Carlo probabilistic model is developed to provide an overall assessment of the risk of Regulatory Guide exceedance during plant operation.

• OSTI ID: 131839
• Report Number(s): CONF-950740--; ISBN 0-7918-1334-7
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
CRACK PROPAGATION
EDDY CURRENT TESTING
EXPERIMENTAL DATA
INTERGRANULAR CORROSION
MATHEMATICAL MODELS
PALO VERDE-1 REACTOR
PROBABILISTIC ESTIMATION
STEAM GENERATORS
STRESS CORROSION
TUBES