CALCULATIONS, USING THE ALBEDO CONCEPT, OF THERMAL-NEUTRON FLUXES, EPICADMIUM-NEUTRON FLUXES, AND FAST-NEUTRON DOSE RATES ALONG THE CENTER LINES OF SQUARE CONCRETE DUCTS: COMPARISON WITH EXPERIMENT,
Abstract
Monte Carlo calculations that use the albedo concept and a particularly demanding source geometry and spectrum were carried out to determine subcadmium- and epicadmium-neutron fluxes and fast-neutron dose rates along the center lines of one-, two-, and three-legged square concrete ducts open on the source end. Secondary gamma-ray dose rates arising from the capture of neutrons in the duct walls were also calculated. The calculations used previously reported albedo data that are differential in both the reflected angles and the reflected energy. A comparison of the calculated neutron fluxes and dose rates with those obtained in geometrically identical experiments conducted at the Tower Shielding Facility shows agreement generally within 25 percent through five orders of duct attenuation. The results thus place on a firm foundation the method of treating neutron transmission through large-sized ducts as a multiple-reflection phenomenon describable by the differential albedo properties of the walls. The conclusion is also reached that wall-capture gamma-ray dose rates arising from capture of thermal-neutrons and the dose from the thermal neutrons themselves (whether due to an epicadmium source or a subcadmium source) can comprise a very important part of the total absorbed dose rate in tissue at locations deep inside a multilegged duct. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1967
- Accession Number
- AD0660657
Entities
People
- F. J. Muckenthaler
- R. E. Maerker
Organizations
- Oak Ridge National Laboratory