Failure domed

Chemical process plants do not have a large domed containment but rely on vessel integrity and offgas processing. Most nuclear plants have such containment for which the stresses may be calculated if a scenario is defined. However such calculations are uncertain regarding the time of failure, the hole size, and location. 

Numerous technical and human failures allowed gas to release from a salt dome storage facility. Lack of fail safe devices contributed to the explosion of the resulting vapor cloud. 

E 16, 32, 64, 71, 78 mg/L Gut miscoilin0 from 32 mg/L. Axis malformation and edema from 64 mg/L Eye malformation (failure of the choroid, irregular shape with abnormal pigmentation) from 32 to 78 mg/L. Heart malformation Lfnderdeveloped (1 larva/concentration at 71, 78 mg/L) External malformation Domed head with hydrocephaly (4 fetuses from 2 litters at 1,000 mkd, two with microglossia). Domed head with hydrocephaly in the preliminary study (4 fetuses from 2 litters at 1,000 mkd, one with microglossia). Visceral malformation 1 Microcardia... 

In many instances failure occurs in the dome or by boss blowout... 

Anticipated collapse modes are examined for contrasting small (200 m) and large (350 m) endogenous dome geometries, for varied inclinations of the detachment plane, and under different conditions of interior water- and gas-pressurization, and for lobe failures resulting from only rainfall induced overpressures [Figure I). 

Water pressures supplied from a moat ringing the dome, and elevated by topography to 50 m of head, and also those generated by incursion of a saturated rind to a depth of 50 m, are shown to have negligible impact on stability. However, also clear is that for the selected strength parameters, the larger dome is only metastable, and little disturbance is needed to induce failure. Regardless, the incursion of rainwater to 50 m is considered improbable. 

Figure 5. Variation in Fsfor failure of (a) a large dome (radius=350m) and (b) a small dome (radius=200m) subject to uniform and core pressurization.

Collapse styles anticipated for different dome sizes, effusive styles, and resulting modes of pressurization are summarized in Figure 6. For the large dome, uniform interior pressures of 0.1 MPa are adequate to induce failure through one side at an inclination of about 50°. When mirrored on both sides, this failure would remove about 20% of the edifice, honoring the observed collapse volume, but only loosely approximating the style. 

For the same strength parameters as previous, the unpressurized small dome is stable, but may be brought close to instability by steady core pressures of the order of 5 MPa. Minor augmentation by uniform rind-trapped pressures of the order of 0.2 MPa is sufficient to promote low-angle failure to as shallow as 40° and remove about 20% of the edifice on one side. Alternatively, if effusive gas discharge is flux, rather than overpressure-controlled, a three-order of magnitude (x5(X)) reduction in permeability in a rind of 5 m will... 

At 73.124 s, a circumferential white vapor pattern was observed blooming from the side of the external tank bottom dome. This was the beginning of the structural failure of the hydrogen tank that culminated in the entire aft dome dropping away. This released massive amounts of liquid hydrogen from the tank and created a sudden forward thrust of about 2.8 million pounds, pushing the hydrogen tank... 

Kimberly R, Brandstetter RD. Exacerbation of phenylbutazone-related renal failure by in-dome acin. Arch Intern Med ( 97S) 138,1711-12. 

Gravity driven injection system of borated water at high pressure makes up the Second Shutdown System. It actuates automatically when the Reactor Protection System detects the failure of the First Shutdown System or in case of LOCA. The system consists of tanks connected to the reactor vessel by two piping lines which valves are opened automatically when the system is triggered. Then one of the pipes -from the steam dome to the upper part of the tank- equalizes pressures, and the other -from a position below the reactor water level to the lower part of the tank- discharges the borated water into the primary system by gravity. 

The use of a thin layer of standard lubricant in a consistent fashion reduces scatter in test results, simulates production conditions more closely, reduces tooling damage, and simplifies specimen preparation. However, the use of lubrication makes the strain ratio at fracture more biaxial. This is undesirable for production simulation because production failures mostly occur in the plane-strain region or in a less biaxial manner. Specimens of different widths are used to control the strain ratio at fracture. This method has been modified further into the limiting dome height (LDH) test. 

One of the most difficult adhesive problems involves the underwater sonar systems. Elastomers (29) (Neoprene rubbers) are adhered to metals with adhesives. The applications include cable sheath, vibration isolator and damper, acoustic absorber, sound reflector, sonar-dome window, and transducer boot. A poor bond at the Neoprene-steel interface could easily lead to saltwater penetration and corrosion, which eventually causes the failure of the sonar dome. 

The foundation base slab is a concrete structure conventionally reinforced with high-strength reinforcing steel. A continuous access gallery is provided beneath the base slab for the installation and inspection of vertical tendons. The base liner, installed on top of the structural slab, is covered with concrete for post-tension. The containment completely encloses the entire reactor and RCS and ensures that an acceptable upper limit for leakage of radioactive materials to the environment would not be exceeded even if gross failure of the RCS were to occur. The approximate dimensions of the containment are 124 ft (37.8 m) inside diameter, 205 ft (62.5 m) inside height, 3-1/2 ft (1.07 m) wall thickness, and 2-1/2 ft (0.76 m) dome thickness. The internal net free volume approximates 2,000,000 fC (56,600 m3). 

In a state of incipient failure, the yield locus is tangent to the Mohr circle. The Mohr circle graphically represents the equilibrium stress condition at a particular point at any orientation for a system in a condition of static equilibrium in a two-dimensional stress field. The equilibrium static conditions can also be applied to sufficiently slow steady flows. The maximum principal stress in Fig. 6.4(b) is called the unconfined yield strength. This is the maximum normal stress, under incipient failure conditions, at a point where the other principal stress becomes zero. Such a situation occurs on the exposed surface of an arch or dome in a feed hopper at the moment of failure see Fig. 7.5(b). In the analysis of bridging in feed hoppers, the unconfined yield strength becomes a very important parameter. The magnitude of the unconfined yield strength is determined by the YL and depends, therefore, on the consolidation pressure and time. 

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