Analytical assessment of an inclad defect in a PWR vessel belt line

• Published in: Nuclear engineering and design Vol. 130; no. 3; pp. 323 - 331
• Main Authors: Vagner, J., Guichard, D., Pellissier Tanon, A., Hedin, F.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.10.1991; Elsevier
• Subjects: Applied sciences; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fission nuclear power plants; Installations for energy generation and conversion: thermal and electrical energy; Finite element method; LOCA; Unsteady state; Cleavage; Elastoplastic analysis; Risk analysis; Clad; Crack propagation; Pressurized water reactor; Nuclear reactor; Weld
• ISSN: 0029-5493; 1872-759X
• DOI: 10.1016/0029-5493(91)90224-6

The French approach to the assessment of the integrity of PWR vessels requires, in particular, that existence of large margins with respect to fast fracture shall be demonstrated for all kinds of defects which can be produced during manufacturing, taken with envelope sizes. The case of defects in the cladding with one tip against the base metal interface raises several difficult problems, mainly on the effect of residual stresses in the cladding, and on the choice of a relevant criterion for the risk of initiating cleavage cracking in the base material. The behaviour of a typical defect has been computed with elastic-plastic analyses and the criteria of the local approach of fracture: the effect of residual stresses is negligible and the margins with respect to fast fracture are much larger than those indicated previously by LEFM computations with plasticity corrections. The values obtained ensure that the integrity of the vessel would not be affected if such defects had occurred during manufacturing.