TY - JOUR
T1 - Evaluation of the environmental fatigue at a long radius elbow of a piping system under transient thermo mechanical stresses
AU - Ramos-Cantú, Lenin
AU - Hernández-Gómez, Luis Héctor
AU - García-Illescas, Rafael
AU - Arreola-Valles, Tanya Nerina
AU - Moctezuma-Reyes, José Javier
AU - Carbajal-Figueroa, Laura Guadalupe
AU - Armenta-Molina, Alejandra
AU - Beltrán-Fernández, Juan Alfonso
N1 - Publisher Copyright:
© 2021 Trans Tech Publications Ltd, Switzerland.
PY - 2021
Y1 - 2021
N2 - Thermal fatigue widely takes place in light water reactor (LWR) piping systems. It is an important aging mechanism of a nuclear reactor. Thermal transient effects occur at the startup and shutdown of a nuclear power plant. During the thermal transients, local and global cyclic stresses are induced in the piping systems. They are exacerbated by local geometric imperfections and environmental factors, which may lead to crack initiation. The elbows of such piping systems are subject to various combinations of loads (internal pressure, bending, and torsion, as well as thermal fluctuations) during their service life. As can be seen, highstress concentrations are developed in these piping elements. Therefore, it is important to make a failure evaluation. In this paper, a 12” pipe system segment, which was made with SA 106 Gr C steel, has been considered. It was composed by two straight sections joined by a long radius elbow. Typical startup and shutdown transient effects of a BWR-5 were considered. A computer-aided thermomechanical analysis was carried out using the finite element method. The linearization of the stresses was considered, based on the ASME B & PVC Code Section III, subsection NB. Under these conditions, environmental fatigue was analyzed after 40-and 60-years operation.
AB - Thermal fatigue widely takes place in light water reactor (LWR) piping systems. It is an important aging mechanism of a nuclear reactor. Thermal transient effects occur at the startup and shutdown of a nuclear power plant. During the thermal transients, local and global cyclic stresses are induced in the piping systems. They are exacerbated by local geometric imperfections and environmental factors, which may lead to crack initiation. The elbows of such piping systems are subject to various combinations of loads (internal pressure, bending, and torsion, as well as thermal fluctuations) during their service life. As can be seen, highstress concentrations are developed in these piping elements. Therefore, it is important to make a failure evaluation. In this paper, a 12” pipe system segment, which was made with SA 106 Gr C steel, has been considered. It was composed by two straight sections joined by a long radius elbow. Typical startup and shutdown transient effects of a BWR-5 were considered. A computer-aided thermomechanical analysis was carried out using the finite element method. The linearization of the stresses was considered, based on the ASME B & PVC Code Section III, subsection NB. Under these conditions, environmental fatigue was analyzed after 40-and 60-years operation.
KW - Fatigue usage
KW - Peak stress
KW - Stress linearization
KW - Thermal transient
UR - http://www.scopus.com/inward/record.url?scp=85119206131&partnerID=8YFLogxK
U2 - 10.4028/www.scientific.net/DDF.412.197
DO - 10.4028/www.scientific.net/DDF.412.197
M3 - Artículo
AN - SCOPUS:85119206131
SN - 1012-0386
VL - 412
SP - 197
EP - 206
JO - Defect and Diffusion Forum
JF - Defect and Diffusion Forum
ER -