Evaluation of indoor gamma radiation dose in dwellings

Abstract

The use of materials containing naturally occurring radionuclides for house construction may enhance the natural radiation background to which some population groups are exposed. External exposure results from gamma emitter radionuclides existing in the walls, floor and ceiling. Mathematical models can be used to predict external dose rates inside a room, provided the compartment geometry and the radionuclide concentration activities are known. This paper presents a methodology and a computer code for theoretical evaluation of indoor external gamma doses in the air. The room was modelled as three pairs of rectangular slabs of finite thickness. Doses were evaluated by applying a photon transport model, taking into account self-absorption and radiation build-up. Calculations were performed for 40K, 226Ra and 232Th, considering concrete walls. The results obtained show good agreement with those reported in the literature. Dose conversion factors are presented in a practical manner, ready to use for radiological impact screening.

Activity concentrations and dose rates from decorative granite countertops

“…Overviews of the different approaches and direct comparisons of their results are available in Refs. (Markkanen, 1995;Markkanen, 1999;Ahmad et al, 1998;Máduar and Hiromoto, 2004;Allam, 2009;Risica et al, 2001). Generally, the predictions from the different A&B approaches are consistent to the 10e15% level.…”

“…(Koblinger, 1978;Stranden, 1979;Mustonen, 1985a,b) have been developed with slightly different assumptions in Fortran Markkanen, 1995;Markkanen, 1999;Mirza et al, 1991;Ahmad et al, 1998;Máduar and Hiromoto, 2004), Maple (Ademola and Farai, 2005), and Pascal (Allam, 2009). Overviews of the different approaches and direct comparisons of their results are available in Refs.…”

The dose of gamma radiation from building materials and soil

“…The integration over the volumetric radiation source was performed using the program Mathematica [19], which was applied for all interpolations in this study. Specifi c absorbed dose rates of 238 U, 232 Th and 40 K were determined for the detection point placed at the centre of the room with standard dimensions: 4 × 5 × 2.8 m 3 , without doors and windows [17] and with variable thickness of the walls: from 10 to 25 cm.…”

“…As the density and thickness of the materials used for room construction belong to a wide range (and can differ signifi cantly from the standard room values) in this study, for the purpose of the calculation of the conversion factors q, we took into account the effect of these parameters' variability as discussed in [18,19]. Furthermore, the effective dose was evaluated by applying the conversion coeffi cients for room geometry obtained by interpolation of their published values for isotropic (ISO) irradiation.…”

Doses of external exposure in Jordan house due to gamma-emitting natural radionuclides in building materials

“…Such materials were shown to have specific activities of 210 Pb from 390 to 430 Bq kg À1 , of 226 Ra from 300 to 440 Bq kg À1 , and of 238 U from 14 to 37 Bq kg À1 (Al-Jundi et al, 2008). Living in a house built with gypsum containing enhanced levels of natural radionuclides could cause increased radiation doses to the residents (Maduar and Hiromoto, 2004;Turhan et al, 2008). Other building materials with elevated concentrations of radioactivity may be introduced in the future.…”