延安市建筑材料天然放射性及其辐射危害

Natural radioactivity and associated radiation hazardous of main building materials in Yan’an, China

为研究延安市建筑材料天然放射性水平及其对居民的辐射影响,用低本底多道γ能谱仪测试了延安市建筑主体材料中天然放射性核素226Ra、232Th和40K的比活度,并分析其潜在辐射危害。结果表明,建筑主体材料中226Ra、232Th和40K的比活度分别为9.4-73.1、11.5-86.9和258.9-1055.1 Bq/kg。除砂子和碎石外,其他建筑材料中226Ra和232Th的平均值均显著高于该区域土壤中相应核素的平均值,空心砖、红砖、砂子和碎石中40K的平均含量也均高于该区域土壤中40K的平均值。调查建筑主体材料的内外照射指数及γ辐射指数均小于1,建筑材料的使用不受限制,对居民不会构成辐射危害。

Background： With the rapidly economic development and urbanization in Yan＇an city, more building materials were consumed in building construction. While the natural radioactivity level of building materials from Yan＇an is limited in the literatures. Purpose： The main objective of this study is to determine the natural radioactivity level and to analyze the associated radiation hazards of building materials in Yan＇an. Methods： The specific activities of natural radionuclides 226Ra, 232Th and 4~K in various building materials from Yan＇an city were determined using low-background gamma-ray spectrometry, and their radiation hazards were evaluated according to the standard methods. Results： The results show that the specific activities of 226Ra, 232Th and 4~K in the building materials are 9.4-73.1, 11.5-86.9 and 258.9-1055.1 Bq/kg, respectively. The activities of 226Ra and 232Th, except for sand and gravel aggregate, in all other building materials are higher than the corresponding means of local soil, and the activities of 4~K in hollow brick, red-clay brick, sand and gravel aggregate exceed the means of 4~K in soil. However, the values of internal exposure index, external exposure index and gamma radiation index in all investigated building materials are less than 1. Conclusions： The radiation levels of all analyzed building materials are within the national safety standard, which indicates that all analyzed building materials can be used anywhere and they can＇t cause radiation hazard to the local residents.