基于NaI的在线水体γ放射性监测系统的研制
|
摘要
自2011年日本福岛核事故以来,水体放射性污染受到广泛关注,进行水体放射性监测是判断水体环境安全与否的重要措施。研制了一套在线水体γ放射性监测系统,将待测水域的水样抽入铅室内的取样容器中,采用76.2 mm NaI探测器对水样的γ放射性核素进行监测。综合考虑探测效率、环境本底、测量时间等因素,确定本系统取样容器半径为10 cm,铅室厚度为35 cm。效率刻度结果:对137Cs的全能峰探测效率为0.072 2 s~(-1)/(Bq·L~(-1));在天然本底条件下,取95%置信度时,对137Cs的探测下限为0.982 Bq·L~(-1)(1 h)。结果表明,本监测系统实现了快速取样并获取水中γ放射性核素活度浓度,可应用于水体环境日常放射性监测和事故状态下的应急放射性监测。
The radioactive contamination in water has received widespread attention since the Japan's Fukushima accident happened in 2011. The monitoring of radioactivity in water is an important measure to judge whether the water environment is safe or not. An On-line water γ Radioactivity Monitoring System was developed,the water sample from the water area under test will be pumped into the system 's sampling container covered by a lead chamber and then its gamma radioactive nuclide will be monitored by a 76.2 mm NaI( Tl) scintillation crystal detector. Taking into account the factors such as detection efficiency,environmental radioactivity background and measurement time,it was determined that the sampling container radius was 10 cm and the lead chamber thickness was 35 cm. Test results of detection efficiency calibration: the detection efficiency of the system for full-energy peak of137 Cs is 0.072 2 s~(-1)/( Bq·L~(-1)),and the minimum detective activity concentration of the system for ~(137)Cs is 0.982 Bq·L~(-1) in1 h under natural background when the confidence level is set to 95%. Results show that the monitoring system, which has realized sampling water rapidly and obtaining γ radioactive nuclide activity concentration in water in time,can be applied in routine monitoring of water radioactivity and in emergency monitoring under accident situation.
The radioactive contamination in water has received widespread attention since the Japan's Fukushima accident happened in 2011. The monitoring of radioactivity in water is an important measure to judge whether the water environment is safe or not. An On-line water γ Radioactivity Monitoring System was developed,the water sample from the water area under test will be pumped into the system 's sampling container covered by a lead chamber and then its gamma radioactive nuclide will be monitored by a 76.2 mm NaI( Tl) scintillation crystal detector. Taking into account the factors such as detection efficiency,environmental radioactivity background and measurement time,it was determined that the sampling container radius was 10 cm and the lead chamber thickness was 35 cm. Test results of detection efficiency calibration: the detection efficiency of the system for full-energy peak of137 Cs is 0.072 2 s~(-1)/( Bq·L~(-1)),and the minimum detective activity concentration of the system for ~(137)Cs is 0.982 Bq·L~(-1) in1 h under natural background when the confidence level is set to 95%. Results show that the monitoring system, which has realized sampling water rapidly and obtaining γ radioactive nuclide activity concentration in water in time,can be applied in routine monitoring of water radioactivity and in emergency monitoring under accident situation.
引文
[1]刘长安,陈肖华.福岛核实公共卫生启示录[M].北京:军事医学科学出版社,2013:54.
[2] Buesseler K,Aoyama M,Fukasawa M. Impacts of the Fukushima nuclear power plants on marine radioactivity[J]. Environmental Science&Ttechnology,2011,45(23):9931-9935.
[3]Nakano M,Povinec P P. Long-term simulations of the137Cs dispersion from the Fukushima accident in the world ocean[J]. Journal of Environmental Radioactivity,2012,111(0):109-115.
[4]沃兰,卜晓琴.关于自来水中放射性物质的检测技术研究[J].科技传播,2013,1:55-56.
[5]余雯,李奕良,何建华,等.海洋核应急情况下的监测项目和检测方法[J].辐射防护,2013,33(1):49-53.
[6]张志龙,付翠明,李静,等.RWM-B放射性水连续监测系统[J].原子能科学技术,2007,41(3):372-374.
[7]Kazennov A Y,Gaponov I A,Pimenov A E. Method for performing rapid radiation surveys of the water areas at shore bases of the Naval fleet using submersible gamma spectrometers[J]. Atomic Energy,2010,109(2):127-136.
[8]赵绍华,侯胜利,许江,等.海洋走航式放射性探测仪的研制与试验[J].海洋通报,2012,31(1):88-93.
[9]曾志,苏健,衣宏昌,等.海水放射性监测装置研制及初步测试结果[J].辐射防护,2013,33(1):46-48.
[10]苏健,曾志,何建华,等.用于海水放射性监测的船载装置的研制[J].核电子学与探测技术,2014,34(7):878-882.
[11]曾国强,朱珠,葛良全,等.水体γ放射性测量中高纯锗探测效率刻度[J].核技术,2017,40(12):120402.
[12]Wedekind Ch,Schilling G,Gruttmuller M,el al.Gamma-radiation monitoring network at sea[J].Applied Radiation and Isotopes,1999,50:733-741.
[13]苏耿华,曾志,程建平,等.海水就地测量探测器探测效率的Monte Carlo研究[J].核电子学与探测技术,2010,30(4):451-454.
[14]复旦大学,清华大学,北京大学.原子核物理实验方法[M].北京:原子能出版社,1997.
[2] Buesseler K,Aoyama M,Fukasawa M. Impacts of the Fukushima nuclear power plants on marine radioactivity[J]. Environmental Science&Ttechnology,2011,45(23):9931-9935.
[3]Nakano M,Povinec P P. Long-term simulations of the137Cs dispersion from the Fukushima accident in the world ocean[J]. Journal of Environmental Radioactivity,2012,111(0):109-115.
[4]沃兰,卜晓琴.关于自来水中放射性物质的检测技术研究[J].科技传播,2013,1:55-56.
[5]余雯,李奕良,何建华,等.海洋核应急情况下的监测项目和检测方法[J].辐射防护,2013,33(1):49-53.
[6]张志龙,付翠明,李静,等.RWM-B放射性水连续监测系统[J].原子能科学技术,2007,41(3):372-374.
[7]Kazennov A Y,Gaponov I A,Pimenov A E. Method for performing rapid radiation surveys of the water areas at shore bases of the Naval fleet using submersible gamma spectrometers[J]. Atomic Energy,2010,109(2):127-136.
[8]赵绍华,侯胜利,许江,等.海洋走航式放射性探测仪的研制与试验[J].海洋通报,2012,31(1):88-93.
[9]曾志,苏健,衣宏昌,等.海水放射性监测装置研制及初步测试结果[J].辐射防护,2013,33(1):46-48.
[10]苏健,曾志,何建华,等.用于海水放射性监测的船载装置的研制[J].核电子学与探测技术,2014,34(7):878-882.
[11]曾国强,朱珠,葛良全,等.水体γ放射性测量中高纯锗探测效率刻度[J].核技术,2017,40(12):120402.
[12]Wedekind Ch,Schilling G,Gruttmuller M,el al.Gamma-radiation monitoring network at sea[J].Applied Radiation and Isotopes,1999,50:733-741.
[13]苏耿华,曾志,程建平,等.海水就地测量探测器探测效率的Monte Carlo研究[J].核电子学与探测技术,2010,30(4):451-454.
[14]复旦大学,清华大学,北京大学.原子核物理实验方法[M].北京:原子能出版社,1997.