昌江核电站周围环境土壤放射性本底调查

Survey of radioactive background in soil around Changjiang Nuclear Power Station

目的掌握昌江核电站周围环境土壤放射性本底水平。方法依据《辐射环境监测技术规范》(HJ/T61-2001)布点,总α、总β参照《生活饮用水标准检验方法-放射性指标》(GB/T5750.13-2006)监测,放射性核素活度浓度按照《土壤中放射性核素的γ能谱分析方法》(GB11743-2013)监测。结果土壤总α、总β及238U、232Th、40K、226Ra、137Cs放射性活度浓度均数分别为(221.72±201.84)、(254.64±152.80)、(20.80±20.00)、(47.56±46.38)、(480.31±285.79)、(33.58±21.22)、(0.71±0.42)Bq/kg,雅加林场238U、232Th、40K、226Ra均最高;232Th对总的环境地表γ辐射剂量率贡献最大,占49.22%,估算值28.73 n Gy/h;距核电站不同距离中,40K放射性活度浓度最大,137Cs最小,除了137Cs外,其余放射性核素活度浓度及总α、总β50 km最高,5 km最低。结论昌江核电站环境土壤中226Ra、232Th、40K、238U、137Cs放射性水平在我国正常天然辐射本底水平内,与国内其它地区相比处于相对低的水平。

Objective To master the levels of radioactive background in the soil around Changjiang Nuclear PowerStation. Methods The stationing was performed on the basis of the relevant provisions in the＂Technical criteria for radiationenvironmental monitoring＂（HJ/T61- 2001）. The sample preparation and detection for gross α and gross β radioactivemonitoring were processed according to the＂Standard examination methods for drinking water- radioactive index＂（GB/T5750.13-2006）. The sample preparation and radioactive detection for radionuclides were processed in accordance with the＂Gamma spectrometry method of analysing radionuclides in soil＂（GB11743-2013）. Results The monitoring results of soilradioactivity concentrations showed that the means of the gross α,gross β,238 U,232Th,40 K,226Ra,and137 Cs were respectively（221.72 ±201.84）,（254.64± 152.80）,（20.80±20.00）,（47.56±46.38）,（480.31±285.79）,（33.58±21.22）,and（0.71±0.42）Bq/kg. The maximum238 U,232Th,40 K,and226Ra radioactivity concentration levels were located in the Yajia Forest Farm. Thecontribution of232 Th to environmental terrestrial gamma radioactive dose rate of the total was maximum,accounting for 49.22%,with the estimated value of 28.73 n Gy/h. According to the radioactive levels in different distances from the nuclear powerstation,40 K radioactive levels was the maximal,and137 Cs was the minimum; for radionuclides,the gross α and gross β of 50 kmfrom the station was the highest,and radionuclides of 5 km from the station was the lowest except for137 Cs. Conclusions Around the Changjiang Nuclear Power Station,226 Ra,232Th,40 K,238U,and137 Cs activities in the soil were in the range of thenormal Chinese natural radioactive background levels,and in addition,they are in the relatively lower levels compared withthose in other regions in China.