Core melt process

An important property of the primary condensation aerosols which is of high importance for the behavior of the volatile fission products is their large surface area. The surface area of the aerosols within the primary system of a severely damaged PWR can be approximately 500 times greater than that of the primary system structural surfaces (Beard et al., 1988 b). An aerosol mass of 1000 kg formed in a core melting process and having a specific surface area of 1 m /g has a total surface area of about 10 m. If one assinnes that the space needed for one fission... 

A Level 1 PSA is a core-melt analysis that may or may not include external events a Level 2 PSA encompasses Level 1 and extends to the physical processes of the accident and their effect on containment a Level 3 PSA encompasses Levels 1 and 2 and extends to public risk. 

The locally high pressure underneath the solid bed and the positive dP/dx in Film D causes some flow of resin from Film D to the melt pool. Thus, for a local Az increment for Film D, there is material entering the element from the melting process and from the drag motion of the screw core, and there is material leaving the increment from the motion of the screw core and from the flow of material into the melt pool due to a positive dP/dx. These complex flows are consistent with observations from Maddock solidification experiments. This flow is shown in detail for the Maddock experiment shown in Fig. 6.35. 

Figure 7.7 Direct melting process of making optical glass fiber. Qadding and core rods are melted in a double crucible and wound on a drum.

Fig. 2. Reservoirs and fluxes used in previous and present modelling work (not to scale). Rectangles used for reservoirs ellipses for loci of fractionation by melt processes, m-f, depleted mantle melting, oceanic crust (MORB) formation s-f, subduction zone melting leading to continental crust formation c-f, intracrustal fractionation leading to upper and lower crust formation. Bold arrows, fluxes involving trace element fractionation line arrows flirxes without trace element fractionation stippled arrows, fluxes operating only during accretion and core formation.

The plastic core (melt at the middle of the cavity) solidifies more slowly than the outer layers and can therefore be moved by means of the injected gas (marked yellow in Fig. 16). The GIT process is summarized by Eyerer et al. in Gas Injection Technique [18]. 

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