The studied area at Wadi Nugrus, Southeastern Desert, Egypt, is located between lat. 24°41'00'' and 24°41'35''N and long. 34°36'47'' and 34°37'09''E....The studied area at Wadi Nugrus, Southeastern Desert, Egypt, is located between lat. 24°41'00'' and 24°41'35''N and long. 34°36'47'' and 34°37'09''E. The rock types are represented by layered metagabbros, biotite schists, gneisses, granodiorites, and Muscovite granites. The muscovite granite of Wadi Nugrus, is small exposure in size (~5.0 km<sup>2</sup>), emplaced along NW-SE trend, with about 0.5 - 4.5 Km in length and 100 - 250 m in width and intruding the biotite schists. The studied muscovite granite is composed mainly of plagioclases, potash feldspars, quartz, biotite and muscovite. The recorded minerals assemblage can be classified into secondary U-minerals (uranophane and meta-autunite), U-bearing minerals (uranothorite and columbite) and accessory minerals (zircon, flourite, allanite, zinnwaldite and hematite). The U/eU is more unity where, the measured chemical uranium is higher than the measured equivalent uranium in the most analyzed samples especially in trenches, which reflect disequilibrium state. The activity concentrations range from 251.72 to 1096.2 Bq·kg<sup>-</sup><sup>1</sup> for <sup>232</sup>Th, from 494 to 2593.5 Bq·kg<sup>-1</sup> for <sup>226</sup>Ra, and from 1314.6 to 1846.7 Bq·kg<sup>-1</sup> for <sup>40</sup>K. The obtained radiological data show that the average internal and external hazard indices are 9.11 and 5.78, respectively which are more than unity and highly exceeding the permissible limits (International Commission on Radiation Protection, ICRP). The internal and external hazards are mainly due to <sup>226</sup>Ra nuclei while the absorbed dose rate (nGy/h) is related to<sup> 232</sup>Th nuclei. The contributions of the three nuclei in the total absorbed dose rates and internal and external hazardous, for <sup>226</sup>Ra, it contributes by 72% in H<sub>in</sub>, 57% in H<sub>ex </sub>and 55% of D<sub>R</sub>, for <sup>232</sup>Th it contributes by 24% in H<sub>in</sub>, 37% in H<sub>ex</sub> and 36.9% of D<sub>R</sub>, while for <sup>40</sup>K it contributes by 4.1% in H<sub>in</sub>, 6.4% in H<sub>ex</sub> and 8.1% of D<sub>R</sub>.展开更多
This report addresses the role of radiation dose rate effects on stochastic risks for low linear energy transfer (LET) radiation .The chernobyl nuclear power
文摘The studied area at Wadi Nugrus, Southeastern Desert, Egypt, is located between lat. 24°41'00'' and 24°41'35''N and long. 34°36'47'' and 34°37'09''E. The rock types are represented by layered metagabbros, biotite schists, gneisses, granodiorites, and Muscovite granites. The muscovite granite of Wadi Nugrus, is small exposure in size (~5.0 km<sup>2</sup>), emplaced along NW-SE trend, with about 0.5 - 4.5 Km in length and 100 - 250 m in width and intruding the biotite schists. The studied muscovite granite is composed mainly of plagioclases, potash feldspars, quartz, biotite and muscovite. The recorded minerals assemblage can be classified into secondary U-minerals (uranophane and meta-autunite), U-bearing minerals (uranothorite and columbite) and accessory minerals (zircon, flourite, allanite, zinnwaldite and hematite). The U/eU is more unity where, the measured chemical uranium is higher than the measured equivalent uranium in the most analyzed samples especially in trenches, which reflect disequilibrium state. The activity concentrations range from 251.72 to 1096.2 Bq·kg<sup>-</sup><sup>1</sup> for <sup>232</sup>Th, from 494 to 2593.5 Bq·kg<sup>-1</sup> for <sup>226</sup>Ra, and from 1314.6 to 1846.7 Bq·kg<sup>-1</sup> for <sup>40</sup>K. The obtained radiological data show that the average internal and external hazard indices are 9.11 and 5.78, respectively which are more than unity and highly exceeding the permissible limits (International Commission on Radiation Protection, ICRP). The internal and external hazards are mainly due to <sup>226</sup>Ra nuclei while the absorbed dose rate (nGy/h) is related to<sup> 232</sup>Th nuclei. The contributions of the three nuclei in the total absorbed dose rates and internal and external hazardous, for <sup>226</sup>Ra, it contributes by 72% in H<sub>in</sub>, 57% in H<sub>ex </sub>and 55% of D<sub>R</sub>, for <sup>232</sup>Th it contributes by 24% in H<sub>in</sub>, 37% in H<sub>ex</sub> and 36.9% of D<sub>R</sub>, while for <sup>40</sup>K it contributes by 4.1% in H<sub>in</sub>, 6.4% in H<sub>ex</sub> and 8.1% of D<sub>R</sub>.
文摘This report addresses the role of radiation dose rate effects on stochastic risks for low linear energy transfer (LET) radiation .The chernobyl nuclear power
