Risk based inspection of jackets submited to through-wall cracks

• Published in: Volume 2: Safety and Reliability; Pipeline Technology
• Main Authors: Schoefs, Franck, Rguig, Mustapha
• Other Authors: Institut de Recherche en Génie Civil et Mécanique (GeM), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-École Centrale de Nantes (ECN)-Centre National de la Recherche Scientifique (CNRS)
• Format: Conference Object
• Language: English
• Published: HAL CCSD 2003
• Subjects: Fracture; Risk-based inspection; Probability; Maintenance; Nondestructive evaluation; Offshore structures; Risk analysis; [SPI.MECA]Engineering Sciences [physics]/Mechanics [physics.med-ph]; [SPI.MAT]Engineering Sciences [physics]/Materials; Arctic
• Online Access: https://hal.archives-ouvertes.fr/hal-01008852; https://hal.archives-ouvertes.fr/hal-01008852/document; https://hal.archives-ouvertes.fr/hal-01008852/file/Schoefs2003.pdf; https://doi.org/10.1115/OMAE2003-37330

The actual challenge for the requalification of existing offshore structures through a rational process of reassessment leads to state the importance of Risk Based Inspection methodology. This paper points out the inspection results modelling and their contribution to decision aid tools. The study of the impact of through cracks on structural integrity of jacket platforms is still a challenge. The detection of large cracks is first addressed. In order to minimize inspections and maintenance costs, all the available data from inspection results, such as probability of detection and probability of false alarm, must be addressed, as well as the probability of crack presence. This can be achieved by the use of the decision theory. These capabilities of Non Destructive Testing give a first input for the risk study. A cost function is suggested to introduce this modelling into a risk analysis and is devoted to help rank the NDT tools. The case of large through-wall cracks is specifically addressed.