Coal is the main energy source for electricity generation in the world. In Morocco, 37% of electricity generation comes from combustion coal in thermal power plants. This combustion process generates large amounts of ...Coal is the main energy source for electricity generation in the world. In Morocco, 37% of electricity generation comes from combustion coal in thermal power plants. This combustion process generates large amounts of fly and bottom ashes. In recent years, these ashes became a great topic of interest because of their different uses and especially in construction materials. In this work, we assess radiation risks due to natural radioactivity in samples of fly and bottom ashes collected from JLEC (Jorf Lasfar Energy Company) thermal power plant, and different analyses are performed through two nuclear techniques such as gamma spectrometry and alpha dosimetry based on the use of LR115 films detectors. Our analysis shows that <sup>226</sup>Ra activities and <sup>232</sup>Th in both ash samples are well above the permissible activity. The values of the external risk index (H<sub>ex</sub>) and internal one (H<sub>in</sub>) for these ashes are below unity, with the exception of 1.28 in fly ash for H<sub>in</sub>. The obtained values for the equivalent radium Ra<sub>eq</sub> and annual effective doses Ėin fly and bottom ashes are 324 Bq/kg and 210 Bq/kg, and 0.18 mSv/y and 0.11 mSv/y, respectively. The surface radon exhalation rates for the samples of fly and bottom ashes are 276 mBq⋅m<sup>-2</sup>⋅h<sup>-1</sup> and 381 mBq⋅m<sup>-2</sup>⋅h<sup>-1</sup>, respectively. Based on these results, we have shown that fly ash and bottom one from thermal power plant JLEC didn’t have, in any case, a health risk to the public so it can be effectively used in various construction activities.展开更多
Coal fired power plants produce significant amounts of ashes, which are quite often being used as additives in cement and other building materials. Coal contains trace quantities of 226Ra, 232Th and 40K. The concentra...Coal fired power plants produce significant amounts of ashes, which are quite often being used as additives in cement and other building materials. Coal contains trace quantities of 226Ra, 232Th and 40K. The concentrations of these radionuclides are usually low in the coal, but enriched in fly ash. The activity concentrations of natural radionuclides in fly ash and soil samples in the vicinity of Orji River thermal power station in Nigeria was determined by gamma ray spectroscopy method using NaI(Tl) detector. The mean activity concentrations of 226Ra, 232Th and 40K in the fly ash were 40.8 ± 11.6, 49.1 ± 9.3 and 321 ± 17 Bq·kg–1, respectively. Coarse fly ash collected from the dump site had mean activity concentrations of 28.2 ± 8.3, 37.6 ± 5.0 and 335 ± 32 Bq·kg–1, respectively for 226Ra, 232Th and 40K. Soil samples collected at about distances of 10 m from the dump site had 32.7 ± 4.3, 40.0 ± 4.2 and 298 ± 15 Bq·kg-1, respectively. Those collected at about distances of 100 m from the dump site had 39.1 ± 11.2, 34.1 ± 5.2 and 257 ± 19 Bq·kg-1, respectively. Occupational dose received by workers due to exposure to the fly ash ranged between 33.0 and 61.2 μSv·y-1 with a mean value of 47.1 ± 8.4 μSv·y-1, which is below the intervention exemption level of 1 mSv·y-1. The radium equivalent activity concentration, external and internal hazard indices of the fly ash were below the recommended maximum values for building materials. The mean outdoor absorbed dose rate and the annual effective dose obtained in the vicinity of the plant were 49.7 ± 4.0 nGy·y-1 and 0.30 ± 0.02 mSv (dump site), 51.7 ± 3.6 nGy·y-1 and 0.32 mSv (soil 10 m from dump site), 49.4 ± 4.9 nGy·y-1 and 0.30 ± 0.03 mSv (soil 100 m away from dump site), which are lower than the world average. The results obtained in this study show that there is no significant radiological impact of the fly ash on both the workers and the public from radiation protection point of view.展开更多
本文通过分析1992—2010年期间中国燃煤火电发电量、煤灰渣中天然γ核素含量、煤灰渣综合利用情况及掺煤灰渣的主体墙材所建居室内的辐射照射情景,采用居室内墙体所致居民的内外照射剂量估算模式,评估了在主体墙材中利用燃煤火电煤灰渣...本文通过分析1992—2010年期间中国燃煤火电发电量、煤灰渣中天然γ核素含量、煤灰渣综合利用情况及掺煤灰渣的主体墙材所建居室内的辐射照射情景,采用居室内墙体所致居民的内外照射剂量估算模式,评估了在主体墙材中利用燃煤火电煤灰渣引起的附加辐射剂量。结果表明:主体墙材中掺入煤灰渣后,所建居室内的居民受到的辐射剂量增加,这与类似的研究结论一致;我国掺燃煤火电煤灰渣的墙材相对于红砖所致居民的总附加年有效个人剂量为0.01~0.30 mSv/a,均值约0.22 m Sv/a,其中内照射贡献占82%的份额;1992—2010年期间我国燃煤火电煤灰渣在主体墙材中的利用所致居民归一化附加集体剂量在1.92×10~3~5.85×10~3人·Sv/GWa之间;煤灰渣的利用对室内222Rn浓度升高的贡献份额均值为28%,范围为7%~38%。该研究结果可为燃煤火电煤灰渣利用政策的制定和燃煤火电放射性环境风险分析提供必要的基础数据。展开更多
文摘Coal is the main energy source for electricity generation in the world. In Morocco, 37% of electricity generation comes from combustion coal in thermal power plants. This combustion process generates large amounts of fly and bottom ashes. In recent years, these ashes became a great topic of interest because of their different uses and especially in construction materials. In this work, we assess radiation risks due to natural radioactivity in samples of fly and bottom ashes collected from JLEC (Jorf Lasfar Energy Company) thermal power plant, and different analyses are performed through two nuclear techniques such as gamma spectrometry and alpha dosimetry based on the use of LR115 films detectors. Our analysis shows that <sup>226</sup>Ra activities and <sup>232</sup>Th in both ash samples are well above the permissible activity. The values of the external risk index (H<sub>ex</sub>) and internal one (H<sub>in</sub>) for these ashes are below unity, with the exception of 1.28 in fly ash for H<sub>in</sub>. The obtained values for the equivalent radium Ra<sub>eq</sub> and annual effective doses Ėin fly and bottom ashes are 324 Bq/kg and 210 Bq/kg, and 0.18 mSv/y and 0.11 mSv/y, respectively. The surface radon exhalation rates for the samples of fly and bottom ashes are 276 mBq⋅m<sup>-2</sup>⋅h<sup>-1</sup> and 381 mBq⋅m<sup>-2</sup>⋅h<sup>-1</sup>, respectively. Based on these results, we have shown that fly ash and bottom one from thermal power plant JLEC didn’t have, in any case, a health risk to the public so it can be effectively used in various construction activities.
文摘Coal fired power plants produce significant amounts of ashes, which are quite often being used as additives in cement and other building materials. Coal contains trace quantities of 226Ra, 232Th and 40K. The concentrations of these radionuclides are usually low in the coal, but enriched in fly ash. The activity concentrations of natural radionuclides in fly ash and soil samples in the vicinity of Orji River thermal power station in Nigeria was determined by gamma ray spectroscopy method using NaI(Tl) detector. The mean activity concentrations of 226Ra, 232Th and 40K in the fly ash were 40.8 ± 11.6, 49.1 ± 9.3 and 321 ± 17 Bq·kg–1, respectively. Coarse fly ash collected from the dump site had mean activity concentrations of 28.2 ± 8.3, 37.6 ± 5.0 and 335 ± 32 Bq·kg–1, respectively for 226Ra, 232Th and 40K. Soil samples collected at about distances of 10 m from the dump site had 32.7 ± 4.3, 40.0 ± 4.2 and 298 ± 15 Bq·kg-1, respectively. Those collected at about distances of 100 m from the dump site had 39.1 ± 11.2, 34.1 ± 5.2 and 257 ± 19 Bq·kg-1, respectively. Occupational dose received by workers due to exposure to the fly ash ranged between 33.0 and 61.2 μSv·y-1 with a mean value of 47.1 ± 8.4 μSv·y-1, which is below the intervention exemption level of 1 mSv·y-1. The radium equivalent activity concentration, external and internal hazard indices of the fly ash were below the recommended maximum values for building materials. The mean outdoor absorbed dose rate and the annual effective dose obtained in the vicinity of the plant were 49.7 ± 4.0 nGy·y-1 and 0.30 ± 0.02 mSv (dump site), 51.7 ± 3.6 nGy·y-1 and 0.32 mSv (soil 10 m from dump site), 49.4 ± 4.9 nGy·y-1 and 0.30 ± 0.03 mSv (soil 100 m away from dump site), which are lower than the world average. The results obtained in this study show that there is no significant radiological impact of the fly ash on both the workers and the public from radiation protection point of view.
文摘本文通过分析1992—2010年期间中国燃煤火电发电量、煤灰渣中天然γ核素含量、煤灰渣综合利用情况及掺煤灰渣的主体墙材所建居室内的辐射照射情景,采用居室内墙体所致居民的内外照射剂量估算模式,评估了在主体墙材中利用燃煤火电煤灰渣引起的附加辐射剂量。结果表明:主体墙材中掺入煤灰渣后,所建居室内的居民受到的辐射剂量增加,这与类似的研究结论一致;我国掺燃煤火电煤灰渣的墙材相对于红砖所致居民的总附加年有效个人剂量为0.01~0.30 mSv/a,均值约0.22 m Sv/a,其中内照射贡献占82%的份额;1992—2010年期间我国燃煤火电煤灰渣在主体墙材中的利用所致居民归一化附加集体剂量在1.92×10~3~5.85×10~3人·Sv/GWa之间;煤灰渣的利用对室内222Rn浓度升高的贡献份额均值为28%,范围为7%~38%。该研究结果可为燃煤火电煤灰渣利用政策的制定和燃煤火电放射性环境风险分析提供必要的基础数据。
