Structural Integrity Analysis of a BWR Core Shroud with an Irregular Distribution of Cracks: Limit Load Analysis

Ruiz-López, Pablo; Hernández-Gómez, Luis Héctor; Urriolagoitia-Calderón, Guillermo; Serrano-Ramírez, María L.; Ocampo-Ramírez, Arturo; Beltrán-Fernández, Juan Alfonso; Urriolagoitia-Sosa, Guillermo

doi:10.1007/978-981-10-1602-8_32

Cited by 2 publications

(1 citation statement)

References 2 publications

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“…In a previous paper [6], a methodology for the plastic limit load analysis was discussed. The shape of the cracks along the circumferential welds varied and the evaluation depended on the geometry of the cracked cylinder.…”

Section: Statement Of the Problemmentioning

confidence: 99%

Evaluation of the structural integrity of a BWR core shroud with non-regular locations of circumferential cracks. Part I fracture analysis

López¹,

Hernández-Gómez

Grijalba

et al. 2021

Journal of Nuclear Science and Technology

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Boiling water reactors have internal components manufactured with stainless-steel type 304. Some relevant cracks have been detected through the periodic inspections of their internal components. Regarding the core shroud, cracks have been observed along the circumferential welds. The causes of such cracks are: radiation, vibration, stress corrosion cracking (SCC) and residual stresses, acting alone or simultaneously. Initially, the material was ductile. However, it becomes brittle as hours of operation are accumulated. In the case of this paper, three asymmetric cracks, at the circumferential horizontal weld H7, have been postulated after 25 years of operation. The loading case considered was the combination of an earthquake with a loss of coolant accident (LOCA). The structural integrity was evaluated after 30 and 60 years of operation. In the last case, such evaluation was carried out during an extended period of operation of 30 years. In all cases, a fracture mechanics approach was followed. The results showed that one of such cracks was below the safety factor. In order to get an accurate evaluation, an elastoplastic and limit load analysis is required. This has been discussed in a companion paper.

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Section: Statement Of the Problemmentioning

confidence: 99%

Evaluation of the structural integrity of a BWR core shroud with non-regular locations of circumferential cracks. Part I fracture analysis

López¹,

Hernández-Gómez

Grijalba

et al. 2021

Journal of Nuclear Science and Technology

View full text Add to dashboard Cite

show abstract

Evaluation of the Structural Integrity of a Boiling Water Reactor Core Shroud with an Irregular Distribution of Circumferential Cracks: Elasto-plastic and Plastic Analysis

Ruiz-López¹,

Hernández-Gómez

Grijalba

et al. 2022

J Fail. Anal. and Preven.

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Three asymmetric cracks were postulated at the circumferential horizontal weld H7 of a boiling water reactor type 5 core shroud after 25 years of operation. They were arranged in an irregular distribution with different depths. Unstable crack propagation can be induced when an earthquake and a loss of coolant accident take place. In this paper, a ductile failure analysis has been reported. It has been done following an elastoplastic analysis and a plastic limit load analysis. The crack conditions after 30 and 60 years of operation were evaluated. The results show that the core shroud will keep its structural integrity during sixty years under normal conditions of operation. On the other hand, its operational life is reduced five years under failure conditions. In general terms, the methodology, which has been developed, can be applied for any number of circumferential cracks located in the same cross section. Fast and reliable outputs can be obtained. It can be applied in any moment of the life of the plant, to support the decision on “Use as is”, “Mandatory Repair”, or “Estimation of the remaining life.”

show abstract

Structural Integrity Analysis of a BWR Core Shroud with an Irregular Distribution of Cracks: Limit Load Analysis

Cited by 2 publications

References 2 publications

Evaluation of the structural integrity of a BWR core shroud with non-regular locations of circumferential cracks. Part I fracture analysis

Evaluation of the structural integrity of a BWR core shroud with non-regular locations of circumferential cracks. Part I fracture analysis

Evaluation of the Structural Integrity of a Boiling Water Reactor Core Shroud with an Irregular Distribution of Circumferential Cracks: Elasto-plastic and Plastic Analysis

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