MONTE CARLO STUDY OF STRUCTURE SHIELDING AGAINST FALLOUT RADIATION.
RADIATION RESEARCH ASSOCIATES INC FORT WORTH TEX
Pagination or Media Count:
Monte Carlo procedures were used to calculate reduction factors for an upright cylindrical concrete barrier with a 10-ft radius exposed to gamma rays from infinite and finite plane 60Co sources. The factors were calculated for detector heights of 3, 13, and 23 ft and for barrier thicknesses of 20, 40, and 80 psf. Comparisons with reduction factors calculated using the engineering method NBS 76 showed that the two methods agreed within 10 percent for the infinite plane source while for the finite sources they differed as much as 45 percent. Angle distributions of the various exposure components inside the barrier were used to calculate directional response functions for both wall-scattered and non-wall-scattered radiation. Comparison with corresponding data given in NBS 76 showed large differences in some cases. The Monte Carlo data indicated that separate directional response functions should be used for radiation coming from above and from below the detector plane. However, substitution of these and other quantities derived from the Monte Carlo results into the engineering method generally did not improve the agreement with the reduction factors calculated directly by Monte Carlo. It was concluded that any errors in the engineering method data and assumptions must tend to compensate one another, and that similar studies must be made of other aspects of the engineering method in order to fully understand these implications. Author
- Nuclear Radiation Shielding, Protection and Safety
- Radioactivity, Radioactive Wastes and Fission Products