Structural integrity analysis of a BWR core shroud with an irregular distribution of cracks: Limit load analysis

Pablo Ruiz-López, Luis H. Hernández-Gómez, Guillermo Urriolagoitia-Calderón, María L. Serrano-Ramírez, Arturo Ocampo-Ramirez, Juan A. Beltrán-Fernández, Guillermo Urriolagoitia-Sosa

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

© Springer Science+Business Media Singapore 2017. Mexico has a nuclear power plant with two BWR reactors. Their internal components were manufactured with type 304 stainless steel. Since the initiation of their commercial operation, some relevant cracks have been detected through the periodic inspections of their internals components. Specifically, there have been crack found at the core shroud and jet pumps. The causes of such cracks have been: excessive vibration, wear, stress corrosion cracking and residual stresses, acting alone or simultaneously. There are several aspects that have to be considered in the evaluation of the structural integrity of the core shroud, for instance: its shape is a cylinder and its R/t ratio is in the range between 60 and 100, as well as the water environment and the neutron irradiation. The last one has modified the mechanical properties of the material. Besides, each circumferential weld has a different non-symmetrical and irregular distribution of cracks with various depths. These cracks are monitored every 18 months, only during the plant shutdowns. Furthermore, the potential unstable cracking of the lower circumferential welds could induce important safety consequences if a loss of coolant accident and an earthquake event are postulated. Due to these reasons, it is very important to apply or develop adequate analytical procedures that can provide fast and reliable results. These procedures must cover elastic-plastic fracture analysis and plastic limit load analysis. In this paper, a methodology for the plastic limit load analysis was developed. The critical limit load for any crack distribution was calculated with a great degree of confidence. Operating conditions were considered. The shape of the cracks varies and the evaluation depends on the geometry of the cracked cylinder. In the problem at hand, the neutral axis varies, as it translates and rotates simultaneously at every cracked cross section, depending on the loading condition. This situation was also taken into account.
Original languageAmerican English
Title of host publicationStructural integrity analysis of a BWR core shroud with an irregular distribution of cracks: Limit load analysis
Pages413-427
Number of pages370
ISBN (Electronic)9789811016011
DOIs
StatePublished - 1 Jan 2017
EventAdvanced Structured Materials -
Duration: 1 Jan 2017 → …

Publication series

NameAdvanced Structured Materials
Volume33
ISSN (Print)1869-8433

Conference

ConferenceAdvanced Structured Materials
Period1/01/17 → …

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Structural integrity
Load limits
Cracks
Plastics
Welds
Jet pumps
Loss of coolant accidents
Boiling water reactors
Plant shutdowns
Neutron irradiation
Stainless Steel
Stress corrosion cracking
Nuclear power plants
Residual stresses
Earthquakes
Stainless steel
Inspection
Wear of materials
Mechanical properties
Geometry

Cite this

Ruiz-López, P., Hernández-Gómez, L. H., Urriolagoitia-Calderón, G., Serrano-Ramírez, M. L., Ocampo-Ramirez, A., Beltrán-Fernández, J. A., & Urriolagoitia-Sosa, G. (2017). Structural integrity analysis of a BWR core shroud with an irregular distribution of cracks: Limit load analysis. In Structural integrity analysis of a BWR core shroud with an irregular distribution of cracks: Limit load analysis (pp. 413-427). (Advanced Structured Materials; Vol. 33). https://doi.org/10.1007/978-981-10-1602-8_32
Ruiz-López, Pablo ; Hernández-Gómez, Luis H. ; Urriolagoitia-Calderón, Guillermo ; Serrano-Ramírez, María L. ; Ocampo-Ramirez, Arturo ; Beltrán-Fernández, Juan A. ; Urriolagoitia-Sosa, Guillermo. / Structural integrity analysis of a BWR core shroud with an irregular distribution of cracks: Limit load analysis. Structural integrity analysis of a BWR core shroud with an irregular distribution of cracks: Limit load analysis. 2017. pp. 413-427 (Advanced Structured Materials).
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abstract = "{\circledC} Springer Science+Business Media Singapore 2017. Mexico has a nuclear power plant with two BWR reactors. Their internal components were manufactured with type 304 stainless steel. Since the initiation of their commercial operation, some relevant cracks have been detected through the periodic inspections of their internals components. Specifically, there have been crack found at the core shroud and jet pumps. The causes of such cracks have been: excessive vibration, wear, stress corrosion cracking and residual stresses, acting alone or simultaneously. There are several aspects that have to be considered in the evaluation of the structural integrity of the core shroud, for instance: its shape is a cylinder and its R/t ratio is in the range between 60 and 100, as well as the water environment and the neutron irradiation. The last one has modified the mechanical properties of the material. Besides, each circumferential weld has a different non-symmetrical and irregular distribution of cracks with various depths. These cracks are monitored every 18 months, only during the plant shutdowns. Furthermore, the potential unstable cracking of the lower circumferential welds could induce important safety consequences if a loss of coolant accident and an earthquake event are postulated. Due to these reasons, it is very important to apply or develop adequate analytical procedures that can provide fast and reliable results. These procedures must cover elastic-plastic fracture analysis and plastic limit load analysis. In this paper, a methodology for the plastic limit load analysis was developed. The critical limit load for any crack distribution was calculated with a great degree of confidence. Operating conditions were considered. The shape of the cracks varies and the evaluation depends on the geometry of the cracked cylinder. In the problem at hand, the neutral axis varies, as it translates and rotates simultaneously at every cracked cross section, depending on the loading condition. This situation was also taken into account.",
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Ruiz-López, P, Hernández-Gómez, LH, Urriolagoitia-Calderón, G, Serrano-Ramírez, ML, Ocampo-Ramirez, A, Beltrán-Fernández, JA & Urriolagoitia-Sosa, G 2017, Structural integrity analysis of a BWR core shroud with an irregular distribution of cracks: Limit load analysis. in Structural integrity analysis of a BWR core shroud with an irregular distribution of cracks: Limit load analysis. Advanced Structured Materials, vol. 33, pp. 413-427, Advanced Structured Materials, 1/01/17. https://doi.org/10.1007/978-981-10-1602-8_32

Structural integrity analysis of a BWR core shroud with an irregular distribution of cracks: Limit load analysis. / Ruiz-López, Pablo; Hernández-Gómez, Luis H.; Urriolagoitia-Calderón, Guillermo; Serrano-Ramírez, María L.; Ocampo-Ramirez, Arturo; Beltrán-Fernández, Juan A.; Urriolagoitia-Sosa, Guillermo.

Structural integrity analysis of a BWR core shroud with an irregular distribution of cracks: Limit load analysis. 2017. p. 413-427 (Advanced Structured Materials; Vol. 33).

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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Ruiz-López P, Hernández-Gómez LH, Urriolagoitia-Calderón G, Serrano-Ramírez ML, Ocampo-Ramirez A, Beltrán-Fernández JA et al. Structural integrity analysis of a BWR core shroud with an irregular distribution of cracks: Limit load analysis. In Structural integrity analysis of a BWR core shroud with an irregular distribution of cracks: Limit load analysis. 2017. p. 413-427. (Advanced Structured Materials). https://doi.org/10.1007/978-981-10-1602-8_32