An Assessment of Steam-Explosion-Induced Containment Failure. Part I: Probabilistic Aspects

Lower head integrity under steam explosion loads

“…11, this simple approach is able to case here, have most commonly been based on plastic equivalent strains, with typically conservative 'ball park' values in the 12 -18% range (Theofanous et al 1987). All experimental evidence, however, and theoretical interpretations indicate that failures are not obtained until much greater strains, say in the 50 -100% range.…”

“…Before we get into the specifics, another interesting general perspective on the potential for failure can be obtained from the results of Theofanous et al (1987). Based on an isochoric, and instantaneous equilibration (between the fuel and mixed coolant), followed by an ideal thermodynamic path in the expansion, the results are conservative for our present purposes.…”

“…Failure occurred at 2.7 ms, and the explosion yield of 1460 MJ was found to partition about evenly in the upward and downward directions -850 MJ were delivered to an upward accelerated slug, while 610 MJ were vented downward. Theofanous et al (1987), as part of a comprehensive a-mode failure study, loaded a finite element model (using the STRAW computer code) with a simple, thermodynamics-based equation of state of the explosion zone in the lower head. Eleven calculations were carried out for a variety of explosion characteristics (parameterized by volume of the explosion zone and the fuel and steam volume fractions in it), spanning the range of energy yields from 0.4 to 11.6 GJ.…”

“…They noted that the lower head static capability in Sizewell is 650 bar, that there is no evidence of the kilobar pressures found from ideal thermodynamic models, and that experiments and more realistic modeling suggest that for 1 GJ explosions, peak pressures will more probably be in the range 400 -800 bar. Both Theofanous et al (1987) and Turland et al (1995) had indicated the need to re-examine these results, once the capability to properly represent the dynamic explosion loads became available. This time has come.…”

Environmental and multi reinforcing effects of micro and nano fibers on adhesion properties of slow setting epoxy adhesives

“…In an atomic plant only slow setting at room temperature epoxy resins can be used. There are so many limitations for the adaptation of new epoxy resin system, because of quite a long term test and well accumulated approved data at various and in some cases in very severe conditions [3][4][5][6].…”