环境空气中239＋240Pu的分析测定  

Analysis and measurement of ^(239+240)Pu in environmental air

作　　者：梁勇[1] 杨秀玉[1] 王志军 LIANG Yong, YANG Xiuyu, WANG Zhijun(404 Company Limited, CNNC, Lanzhou 73285)

机构地区：[1]中核四0四有限公司,兰州732850

出　　处：《辐射防护》2018年第2期119-122,共4页Radiation Protection

摘　　要：建立了环境空气中^(239+240)Pu的测量方法。该方法采用NF-2型滤膜采集空气样品5 000~10 000 m^3,干法灰化,硝酸加热浸取钚,氨基磺酸亚铁和亚硝酸钠将钚转化为四价态,用三正辛胺—聚三氟氯乙烯粉萃取色层柱分离纯化钚,0.025 mol/L草酸—0.15 mol/L硝酸解吸,最后电沉积制源,在α谱仪上测量^(239+240)Pu计数。通过实验确认了测量方法的主要条件和参数:电沉积制源极间距为4.0 mm,pH值为2.0;溶液萃取分离色层柱高度为6.0 cm,溶液流速2 mL/min;氧化还原时间为10 min。方法全程回收率为52.5%~82.5%,平均值68.3%;气溶胶样品量为10 000 m^3时,方法探测下限为1.31×10^(-7)Bq/m^3。该方法可用于环境气溶胶中^(239+240)Pu测量,采用本方法测定了我国西北某地区气溶胶中^(239+240)Pu活度浓度,结果平均值为3.25×10^(-6)Bq/m^3。A measurement method for ^（239＋240）Pu in environmental air was established. In this method,about 5 000 to 10 000 m^3 air is filtered with NF-2 filter cloth to obtain aerosol sample,the sample is ashed with a dry method,plutonium is leached with hot nitric acid and converted to tetravalent state with Fe（NH_2SO_3）_2 and NaNO_2, the tetravalent plutonium is separated and purified with tri-n-octylamine and polytrifluorochloroethylene,desorbed with 0. 025 mol/L oxalic acid and 0. 15 mol/L nitric acid. Finally,plutonium is electrodeposited on a stainless plate and measured by an alpha spectrometer. Key conditions and parameters of the measurement method were optimized by experiments as the following： 4 mm of the distance between two poles,2. 0 of pH,6 cm of the height for the extraction/separation column,2. 0 m L/min of the flow rate of solution,15 min of the oxidation-reduction time. The radiochemical recovery of plutonium was 52. 5% to 82. 5% with an average value of 68. 3%. The minimum detectable amount was 1. 31 × 10^（-7） Bq/m^3 when aerosol sample volume was 10 000 m3. It is concluded that this method can be used to measure^（239＋240）Pu of environmental aerosol samples. The concentrations of^（239＋240）Pu in aersol samples taken from a northwestern district of China were measured with this method and an average value of 3. 25 × 10^（-6） Bq/m^3 was obtained.

关 键 词：气溶胶 239+240Pu 萃取色层 Α谱仪 

分 类 号：X830.2[环境科学与工程—环境工程]