Sudden, Catastrophic Failure

BLEVE types of incidents arise from the reduction in yield stress of a vessel or pipe wall to the point that it cannot contain the imposed stresses by the design and construction of the container and are also influenced by the relief valve set point. This results in a sudden catastrophic failure of the containment causing the violent discharge of the contents and producing a large intense fireball. 

The most important materials failure to avoid in the design of metal equipment is sudden catastrophic failure. This occurs when the material fractures under impulse instead of bending. Catastrophic failure can cause complete destruction of piping or equipment, and can result in explosions, huge spills, and consequent fires. Causes of some of the more common types of catastrophic failures are ... 

In order to verify that the RFS technique can detect, particles greater than 10 pra, the U.S. Department of Defense Joint Oil Analysis Program Technical Support Center (JOAP-TSC) prepared samples using M50 alloy particles. M50 alloy is often present in aero-derivative turbines. Some failure modes of J52 engines appear to be sudden catastrophic failures where the root cause began with the lack of lubrication of the 4 A bearing area. Initially, analysis of the samples by RDE spectroscopy did not indicate the failure mode [6]. The composition and specifications for MSO alloy are as shown below (Table 3). 

In rigid pavements, the concrete slab is sited over the cement-bound layer and the tensile stresses that developed owing to traffic loading or ground reaction are very low. Even if they are high, they cannot cause sudden catastrophic failure of the pavement, as in other structures. The surface cracks may appear to affect the aesthetics and certainly accelerate pavement deterioration, but the structure will still be in use for a certain period (years). 

Escalation as rapid as this cannot be caused by the corrosion-erosion or overheating mechanisms described above. An external mechanical cause either from a seismic event, impact of a foreign body, or sudden catastrophic failure of a tubeplate, would be needed. To predict the consequences of such an event in which the sodium side of an SGU is suddenly raised to the steam-side pressure, the flow and pressure in the secondary circuit and the protective systems have to be calculated taking account of the compressibility of the sodium. 

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