On the investigation of cracking in safety injection PWR lines due to thermal stratification [electronic resource].

Published: Washington, D.C : United States. Dept. of Energy. Office of Energy Research, 1990.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
Physical Description: Pages: (7 pages) : digital, PDF file
Additional Creators: U.S. Nuclear Regulatory Commission, United States. Department of Energy. Office of Energy Research, and United States. Department of Energy. Office of Scientific and Technical Information

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Summary

Circumferential cracking in injection lines as well as feedwater lines has been observed in a number of PWRs around the world while its exact cause has been continuously sought through a number of independent investigations. The comprehensive conclusion of all studies is that the primary but not the only, cause of pipe failure is the thermal stratification phenomenon that occurs in pipes experiencing temperature differentials across their cross section. This phenomenon becomes more critical when it occurs in a cyclic manner and is associated with a number of transients as well as thermal shocks during each cycle. The resulting fatigue loading mechanism and its impact on the integrity of an auxiliary injection line is the focus of the present analysis. Thermal loadings which can simulate real temperature conditions are imposed on a 3-D finite element model of a portion of an injection line that has already experienced cracking. The induced thermal stress field is utilized to obtain excessive fatigue damage in the vicinity of the observed cracks. Finally, the impact of different levels and types of stratification as well as the geometric configuration of such lines on the pipe integrity is addressed. 12 refs., 12 figs.

Report Numbers

E 1.99:bnl-nureg-44440
E 1.99: conf-900617--9
conf-900617--9
bnl-nureg-44440

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Note

Published through SciTech Connect.
01/01/1990.
"bnl-nureg-44440"
" conf-900617--9"
"DE90009830"
Pressure vessels and piping conference: be in tune for the 90's, Nashville, TN (USA), 17-21 Jun 1990.
Philippacopoulos, A.J.; Reich, M.; Simos, N.; Hartzmann, M. . Mechanical Engineering B.

Funding Information

AC02-76CH00016

View MARC record | catkey: 14367492