堆芯混凝土样品中^(63)Ni的分析测量

Measurement of ^(63)Ni in Concrete Samples in Reactor

为建立堆芯混凝土材料中^(63)Ni活度测量的方法,进行了溶样方法的确定、淋洗曲线的绘制、液闪测量效率的确定、回收率实验、去污实验及空白实验等方面的研究工作。混凝土样品磨至粒径小于0.074mm,用混合酸(V(HNO_3)∶V(HClO_4)∶V(HF)=3∶2∶1)进行溶解,再通过阴离子交换分离、氢氧化物沉淀及萃取和反萃等样品纯化程序去除杂质离子后,用液体闪烁能谱仪测量其中^(63)Ni的活度。该方法的化学回收率为73.05%,放化回收率为71.99%,通过空白实验得出计数的标准偏差为0.200/s,相对标准偏差为12.8%(n=12),方法检出限为3.596Bq/g。该方法可应用于堆内混凝土材料及非堆材料中63 Ni的常规监测及应急监测。

In order to develop a new method of measuring 63 Ni in concrete samples of reactor, these study were done, including the ways of dissolving the samples, drawing the elution curve, the measurement efficiency, recovery tests, decontamination experiments and blank tests. Samples were ground to 0. 074 mm and were pretreated before liquid scintillation counting（LSC） by leaching with mixed acid （V（HNO3） ： V（HC104） ： V（HF）=3： 2 ： 1）, anion exchange, hydroxide precipitation, and solvent extraction. The chemical yield of this method is 73.05%, and the radiochemical yield of this method is 71.99%. The standard de- viation is 0. 200/s and the relatively standard deviation is 12.8% （n= 12）. The detection limit of the method is 3. 596 Bq/g. This method can be applied to the routine and emergency moni- toring for 63 Ni of the concrete materials in or not in the reactor.