Dry Sand Burial

This accident scenario involved the reactor being buried in Si02 with a density of 1.5 g/cc. This is a median point between the density of loose sand (1.4 g/cc) and. dry, packed sand (1.6 g/cc). The core is not flooded in this case, and the radial reflectors have been removed. While little moderation occurred in the sand and Si02 is an inferior scattering medium to BeO (and is also without the (n,2n) reaction), the reactor was going from somewhat reflected to essentially infinite reflection conditions. In a variety of cores this had led to a net increase in reactivity. This effect is highly dependent on the density of the sand. This core had a k-effective of 0.981 0.001 for this scenario. 

The results from these runs can be found in table 5-3 

These results show that the reactor is substantially subcritical in all of these accident scenarios. The most problematic of the accident cases is the dry sand immersion case, which is also the least credible of the accident scenarios. The likelihood of a reactor 

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