Accession Number : AD0671902

Title :   GROUND ROUGHNESS EFFECTS ON FALLOUT SHIELDING.

Descriptive Note : Final rept.,

Corporate Author : RADIATION RESEARCH ASSOCIATES INC FORT WORTH TEX

Personal Author(s) : French,R. L. ; Price,J. H. ; Tompkins,K. W.

Report Date : 15 JAN 1968

Pagination or Media Count : 66

Abstract : The protection factor of a simple cylindrical structure exposed to an infinite plane 60Co source (approximately equals 1.25 MeV) on the ground surface was calculated by Monte Carlo. The 'buried-source' model was used to represent ground roughness. Source depths of 0, 0.5, and 1.0 in. were used to simulate smooth, rough, and very rough ground, respectively. The cylindrical structure was of concrete and had a 10-ft radius and an infinite height. Wall thicknesses of 20, 40, and 80 psf and detector heights of 3, 13, and 23 ft were considered. It was found that ground roughness enhances the protection factor of a structure (1) by reducing the incident radiation intensity and (2) by altering the energy and angle distribution of the incident radiation. The first effect was generally about twice as strong as the latter. Both effects are largest for the 3-ft detector height where, for all wall thicknesses, the protection factors were increased by a factor of approximately 4.5 by very rough ground. Calculations performed with the engineering method including ground roughness effects accounted for only about 75 percent of the protection factor enhancement. (Author)

Descriptors :   (*FALLOUT, SHIELDING), (*SOILS, ROUGHNESS), GAMMA RAYS, DISTRIBUTION, NUCLEAR SCATTERING, PENETRATION, NUCLEAR ENERGY, MONTE CARLO METHOD, COBALT, RADIOACTIVE ISOTOPES, PROTECTION, THICKNESS, CYLINDRICAL BODIES, DETECTORS, STRUCTURES, CONCRETE, MATHEMATICAL ANALYSIS, EXPOSURE(PHYSIOLOGY)

Subject Categories : Nuclear Radiation Shield, Protection & Safety
      Radioactiv, Radioactive Wastes & Fission Prod

Distribution Statement : APPROVED FOR PUBLIC RELEASE