Determination of radionuclides 226Ra, 228Th and 40K in Building materials.
The legislation of many countries in Europe requires the determination of radionuclides in new building materials. High Resolution Gamma-Ray Spectrometry has sufficient sensitivity for this determination, activity concentrations are rather high compared to the limits of detection.
Example - Table 1 of Annex 10 of the Decree of The Czech State Office of Nuclear Safety No. 499/2005 Coll.: Limits of natural radionuclides in building materials
| BUILDING MATERIAL | used for construction of residential or accommodation of rooms | used only for buildings other than residential or accommodation of rooms |
| bricks and other construction products, in baked clay | 150 | 500 |
| building products of concrete, plaster, cement and lime | ||
| construction of aerated concrete products and cinder-concrete | ||
| building block | 300 | 1000 |
| construction products made of natural and artificial stone, artificial aggregates | ||
| ceramic wall tiles and tiles | ||
| sand, gravel, stone and clay | ||
| fly ash, bottom ash, slag, gypsum generated in industrial processes, tailings and sludge for construction, building products made from them not elsewhere specified | ||
| materials from the waste heaps, dumps and tailings for construction purposes in addition to radiation protection |
The guidance on the content of natural radionuclides in building materials is then expressed by the index of mass activity:
Index of Mass Activity ( I ) = aK/3000 + aRa/300 + aTh/200
where
aK mass activity concentration of 40K [Bq/kg]
aRa mass activity concentration of 226Ra [Bq/kg]
aTh mass activity concentration of 228Th [Bq/kg]
Table 2 of Annex 10 of the Decree of The Czech State Office of Nuclear Safety No. 499/2005 Coll.: Guideline values of natural radionuclides in building materials
| BUILDING MATERIAL | Index of Mass activity I |
| building materials for the construction of walls, ceilings and floors in buildings with residential or accommodation of a room, especially masonry elements, pre-fabricated products, blocks, bricks, concrete, drywall | 0.50 |
| other construction materials intended for use in construction of residential or accommodation of rooms | 1.00 |
| construction materials for use in buildings other than residential or accommodation of rooms, all construction materials intended solely for use as raw material for the production of building materials |
2.00 |
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