Modeling of an industrial environment: external dose calculations based on Monte Carlo simulations of photon transport.
External gamma exposures from radionuclides deposited on surfaces usually result in the major contribution to the total dose to the public living in urban-industrial environments. The aim of the paper is to give an example for a calculation of the collective and averted collective dose due to the contamination and decontamination of deposition surfaces in a complex environment based on the results of Monte Carlo simulations. The shielding effects of the structures in complex and realistic industrial environments (where productive and/or commercial activity is carried out) were computed by the use of Monte Carlo method. Several types of deposition areas (walls, roofs, windows, streets, lawn) were considered. Moreover, this paper gives a summary about the time dependence of the source strengths relative to a reference surface and a short overview about the mechanical and chemical intervention techniques which can be applied in this area. An exposure scenario was designed based on a survey of average German and Hungarian supermarkets. In the first part of the paper the air kermas per photon per unit area due to each specific deposition area contaminated by 137Cs were determined at several arbitrary locations in the whole environment relative to a reference value of 8.39 x 10(-4) pGy per gamma m(-2). The calculations provide the possibility to assess the whole contribution of a specific deposition area to the collective dose, separately. According to the current results, the roof and the paved area contribute the most part (approximately 92%) to the total dose in the first year taking into account the relative contamination of the deposition areas. When integrating over 10 or 50 y, these two surfaces remain the most important contributors as well but the ratio will increasingly be shifted in favor of the roof. The decontamination of the roof and the paved area results in about 80-90% of the total averted collective dose in each calculated time period (1, 10, 50 y).
Kis
Zoltán
Z
GSF-National Research Center for Environment and Health, Department of Radiation Protection, Ingolstaedter Landstrasse 1, D-85764 Neuherberg, Germany. kiszoltan@vmkorhaz.hu
Eged
Katalin
K
Voigt
Gabriele
G
Meckbach
Reinhard
R
Müller
Heinz
H
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000396:Air Pollutants, Radioactive / Q000032:analysis*; D016902:Air Pollution, Indoor; D002588:Cesium Radioisotopes / Q000032:analysis*; D002648:Child; D002675:Child, Preschool; D003198:Computer Simulation; D017753:Ecosystem; D004781:Environmental Exposure / Q000032:analysis; D005260:Female; D006801:Humans; D007221:Industry; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D015233:Models, Statistical; D009010:Monte Carlo Method; D016273:Occupational Exposure / Q000032:analysis*; D011829:Radiation Dosage; D011835:Radiation Protection / Q000379:methods; D011847:Radioactive Fallout / Q000032:analysis; D011874:Radiometry / Q000379:methods*; D018570:Risk Assessment / Q000379:methods*; D014505:Urban Population
D000396:Air Pollutants, Radioactive; D002588:Cesium Radioisotopes; D011847:Radioactive Fallout