Prediction of residual stress field in mechanically expanded 0.750 inch diameter steam generator tube plugs. Part 1: 2-D solution
- Sharoden Engineering Consultants, Matthews, NC (United States)
One of the most formidable classes of problems that arises in the commercial nuclear power industry is the determination of the residual stress field in steam generator tubes. As early as 1983, it was reported that primary water stress corrosion cracking (PWSCC) of Alloy 600 steam generator tubes had occurred at a low frequency. The degradation of steam generator tubing by PWSCC has resulted in unplanned nuclear plant outages and costly repair operations such as tube plugging and eventually steam generator replacement. Although the previous discussion centered around the PWSCC of the Inconel 600 tubes, the repair plugs which are intended to isolate the damaged tubes from the primary system, have also begun to show similar types of cracking in the rolled transitions. Plug severance is highly undesirable in the nuclear plant because the primary-to-secondary barrier would then be voided and radioactive fluid would escape to the non-radioactive feedwater system. At the present time, although the tube problems have been discussed extensively in the literature roll plugs and their associated SCC have yet to be fully addressed. In addition, roll plus present a different set of loads, expansion regions, discontinuities, and displacement boundary conditions to be analyzed. The method of solution to the subject roll expansion problem employs the use of a general purpose finite element program to mathematically simulate the expansion process. The hydraulic expansion simulation is accomplished by matching the final displacements of an installed plug for which field measurements are available. Because of the symmetry which exists in the geometry and loading, this problem is modeled and analyzed as an axisymmetric problem. The resulting stress field throughout the plug, and in particular, in the rolled transition region, is calculated.
- OSTI ID:
- 403199
- Report Number(s):
- CONF-960706-; ISBN 0-7918-1774-1; TRN: 97:000155
- Resource Relation:
- Conference: American Society of Mechanical Engineers (ASME) pressure vessels and piping conference, Montreal (Canada), 21-26 Jul 1996; Other Information: PBD: 1996; Related Information: Is Part Of Residual stresses in design, fabrication, assessment and repair. PVP-Volume 327; Warke, R.W. [ed.] [Edison Welding Inst., Columbus, OH (United States)]; Dong, P. [ed.] [Battelle Memorial Inst., Columbus, OH (United States)]; Dermenjian, A. [ed.] [Sargent and Lundy, Chicago, IL (United States)]; PB: 207 p.
- Country of Publication:
- United States
- Language:
- English
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