Failure analysis methodology is applied to the principal mechanisms by which boiler tubes fail during service. sThe failure analysis procedure, or methodology for evaluation, is provided in a step by step approach. Among the case histories discussed are: fatigue, erosion, short-term overheating, and hydrogen damage.
Subsea flowlines and risers experience fatigue cycles due to thermal and/or pressure transients or vortex induced vibration (VIV). Tests were performed under constant stress intensity factor (K) levels, in a mildly sour environment and in seawater under cathodic protection to understand the difference in the CRG.
Pressure tubes, manufactured from Zr-2.5Nb, are used within a CANDU power reactor to contain the fuel bundles and coolant forming the primary pressure boundary in the core with an expected operating lifetime of 25 years. As part of the Canadian Standards Association (CSA) fitness-for-service requirements for pressure tubes, flaws or stress risers that potentially lead to cracks cannot exist in pressure tubes in operating reactors. Flaws may include: fuel bundle scratches, crevice corrosion marks, fuel bundle bearing pad fretting flaws and debris fretting flaws.
This paper presents the features of the Fusion Bonded Joint sleeve and addresses its design, manufacturing, and the outcomes of the comprehensive physical testing campaign that was performed. The summary of the tests that were carried out begin from the proof of concept phase to the integrated system tests, covering both carbon steel and High-Density PolyEthylene components assembled under conditions representative of its offshore operating conditions.The present paper covers preliminary manufacturing testing phase, electro-fusion welds qualification along with the required equipment and finally full-scale testing demonstrating the sleeve is compatible with standard welding processes. An in-depth analysis of the conditions and results of the fatigue testing campaign specifics, covering both carbon steel and electro-fusion welds dynamic behavior is proposed.