Studies of natural radioactivity in terms of External radiation (radioactive risk index)
Radioactive risk index (I)
In 1999, the document of the European Union Radiation Protection 112: Radiological protection principles concerning the natural radioactivity of buildings materials, proposed to the calculation of an index (I) to limit concentrations of activity of natural radionuclides present in construction materials, only taking into account gamma radiation emitted by them.
In different standards and publications, this index is identified with different names such asindex of radioactive risk, activity index, index of activity radioactive, index of activity, index concentration index, gamma radiation gamma or gamma, among others activity index.
At the level of the European union, the Radiation Protection 112 sets the citedradioactive risk (I) according to the following expression:
where CRa,ThC, are CK concentrations of Radio (226 Ra), thorium (232Th), and potassium (40K), respectively, in Bq/kg present in the material of construction.
Studies of natural radioactivity in Internal radiation (Radon Gas)
Radon is a (resistant to chemically react) radioactive, inert noble gas, colorless, odorless, tasteless and invisible, more heavy than air and soluble in water or other liquids. There are three main isotopes of radon from three naturally occurring radioactive chains:
-from uranium 238 (238U) which develops radio-226 (226Ra) which becomes radon 222 (222Rn) or Radon
(238U)-> (226Ra) - > (222Rn) - > (206Pb)
-that of uranium 235 (235U) gives rise to the radio-223 (223Ra), which disintegrates into radon-219 (219Rn) or Actinon
(235U)-> (223Ra) - > (219Rn) - > (207Pb)
-of the thorium 232 (232Th) which produces radio-224 (224Ra) which happens to be radon 220 (220Rn) or Thoron
(232Th) - > (224Ra) - > (220Rn) %u2013 > (208Pb)
There is an isotope of radon gas that escapes of natural material and is incorporated into the atmosphere in the form of radon-222 and radon-219 radon-220 respectively in each of the radioactive series. These three chemical forms, which is in greater proportion in nature is the first one called radon (222Rn), having important significance for health since it provides around 50% of all the doses of natural radiation that the human being receives.
Fig. 1. Typical sources of radon and entry routes. Source: NTP 440: Radon in indoor environments.Notes prevention techniques
Entry of radon from the soil. Cracks and fissures in solid soils / construction joints / cracks and cavities in walls and ceilings / cracks in the walls under the ground level / spaces in suspended soils / spaces around pipes and service lines
Emanation of radon from building materials
Radon with outside air tickets
Radon released from water
There are more information for more information aboutGas Radónin this publication.
MSCE - Materials and Construction Systems for Buildings
Universidad de Alicante Carretera de San Vicente del Raspeig s/n 03690 San Vicente del Raspeig Alicante (Spain)