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

Pablo Ruiz López, Luis Héctor Hernández Gómez, Yunuén López Grijalba, Alejandra Armenta Molina, Salatiel Pérez Montejo, Juan Alfonso Beltrán Fernández

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

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.

Original languageEnglish
Pages (from-to)1210-1219
Number of pages10
JournalJournal of Nuclear Science and Technology
Volume58
Issue number11
DOIs
StatePublished - 2021

Keywords

  • BWR
  • aging
  • asymmetric crack
  • crack part through-wall thickness
  • cracking
  • fracture
  • safety assessment
  • stainless steel
  • stress intensity factor

Fingerprint

Dive into the research topics of 'Evaluation of the structural integrity of a BWR core shroud with non-regular locations of circumferential cracks. Part I fracture analysis'. Together they form a unique fingerprint.

Cite this