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The Effectiveness of Soil as Shielding for Expedient Fallout Shelters

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Final rept. 17 Jun 1975-30 Apr 1976

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A series of Monte Carlo calculations were made to evaluate the effectiveness of soil in upgrading the fallout shielding effectiveness of typical light structures. In particular, exposure rates at several locations with one and two story thin-walled warehouse structures of different sizes were examined. Exposure rates at a number of locations within a small wood frame house were obtained. Results were obtained for various countermeasures involving different amounts of soil loaded on the roof and bermed against the outer walls of the structures considered. Conclusions are summarized as follows 1 It is possible to obtain protection factors greater than 1000 for warehouse structures by the use of 12 ft. berms against the walls and 3 ft. soil depths placed on shored up roofs of one story structures or on the second floor of multi-storied structures. 2 The next best alternative is the use of 7 ft. berms truncated at 6 ft. and the piling of sandbags on top to a 12 ft. height, and use of 2 ft. of soil depths on the roof. Better results are obtained by this method than by using 10 ft. berms and 2 ft. of roof soil. In the latter case, radiation incident upon the top 1 ft. or 2 ft. of the berm strongly increases the radiation dose at points within the building. 3 The 50 ft. x 50 ft. one story warehouse protection factors can be extrapolated to yield protection factors for any rectangular structure with dimensions that are not too small. 4 Addition of further soil rho1.5 to roof soil depths greater than 1 ft. causes a further rate of drop in reduction factor by about a factor 0f 10 per foot.

Subject Categories:

  • Structural Engineering and Building Technology
  • Civil Defense
  • Nuclear Radiation Shielding, Protection and Safety

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