Jónás Jácint, Somlai János, Tóth-Bodrogi Edit, Hegedűs Miklós, Kovács Tibor
University of Pannonia, Institute of Radiochemistry and Radioecology, Veszprém, Hungary; Social Organization for Radioecological Cleanliness, Veszprém, Hungary.
University of Pannonia, Institute of Radiochemistry and Radioecology, Veszprém, Hungary.
J Environ Radioact. 2017 Jul;173:75-84. doi: 10.1016/j.jenvrad.2016.11.010. Epub 2016 Dec 29.
Coal-fired power plants play a significant role in the production of electricity. The Ra-226 concentration of coals mined in the Ajka region can reach up to 3000 Bq/kg. This study focuses on the effects of a Hungarian (Ajka) remediated coal ash depository on the environment and the effectiveness of the cover layer. During the remediation, a method patented in Hungary was used, in which the upper layer of the depository, which had settled like concrete, was ploughed and mixed with woodchips before being planted with vegetation. The gamma dose rate H*(10) of the depository and its vicinity was measured using Automess 6150AD-b at 32 points, surface Rn-222 exhalation at 19 points and air radon concentration at 34 points; at 32 points, soil gas radon content was measured with AlphaGUARD and soil permeability with RADON-JOK. The nuclide content of nine samples was determined using an HPGe gamma spectrometer and their Rn-222 exhalation rates were measured using the AlphaGUARD. H*(10) was 290 (130-525) nSv/h at the covered depository; C was 1997 Bq/kg, 960 Bq/kg and 104 Bq/kg for the ash, cover layer and background soil respectively. C in the soil was 25-161 kBq/m, and soil gas permeability K was between 6.4E-13 and 1.80E-11 m. The radon exhalation of the uncovered and covered depository was 259-1100 mBq/ms. The exhalation and emanation coefficients of the samples were 0.05-0.32 mBq/kgs and 8-22%. The effects of vegetation on the migration of radon were also examined. The results show that the Ajka coal ash depository involves higher radiological risk than that reported by previously published studies on depositories. The applied cover layer halved the field radon exhalation; in addition, the vegetation reduced the convective airflow and, with this, the migration of Rn.
燃煤发电厂在电力生产中发挥着重要作用。阿伊卡地区开采的煤炭中镭 - 226浓度可达3000贝可勒尔/千克。本研究聚焦于匈牙利（阿伊卡）一处修复后的煤灰储存库对环境的影响以及覆盖层的有效性。在修复过程中，采用了匈牙利一项专利方法，即先对已像混凝土一样沉降的储存库上层进行深耕，并与木屑混合，然后再种植植被。使用Automess 6150AD - b在32个点测量了储存库及其附近的伽马剂量率H*(10)，在19个点测量了地表氡 - 222析出率，在34个点测量了空气中氡浓度；在32个点使用AlphaGUARD测量了土壤气体氡含量，使用RADON - JOK测量了土壤渗透率。使用高纯锗伽马能谱仪测定了9个样品的核素含量，并使用AlphaGUARD测量了它们的氡 - 222析出率。覆盖后的储存库H*(10)为290（130 - 525）纳希沃特/小时；灰、覆盖层和背景土壤的碳含量分别为1997贝可勒尔/千克、960贝可勒尔/千克和104贝可勒尔/千克。土壤中的碳含量为25至161千贝可勒尔/立方米，土壤气体渗透率K在6.4×10⁻¹³至1.80×10⁻¹¹米之间。未覆盖和覆盖后的储存库的氡析出率为259至1100毫贝可勒尔/平方米秒。样品的析出系数和散发系数分别为0.05至0.32毫贝可勒尔/千克秒和8%至22%。还研究了植被对氡迁移的影响。结果表明，阿伊卡煤灰储存库的放射性风险高于先前发表的关于储存库的研究报告。所应用的覆盖层使现场氡析出率减半；此外，植被减少了对流气流，从而减少了氡的迁移。
