ISO 18589-5:2019 环境中放射性的测量 土壤 第5部分：锶90 使用比例计数或液体闪烁计数的试验方法

标准编号：ISO 18589-5:2019

中文名称：环境中放射性的测量 土壤 第5部分：锶90 使用比例计数或液体闪烁计数的试验方法

英文名称：Measurement of radioactivity in the environment — Soil — Part 5: Strontium 90 — Test method using proportional counting or liquid scintillation counting

发布日期：2019-12

标准范围

This document describes the principles for the measurement of the activity of ⁹⁰Sr in equilibrium with ⁹⁰ Y and ⁸⁹Sr, pure beta emitting radionuclides, in soil samples. Different chemical separation methods are presented to produce strontium and yttrium sources, the activity of which is determined using proportional counters (PC) or liquid scintillation counters (LSC). ⁹⁰Sr can be obtained from the test samples when the equilibrium between  ⁹⁰Sr and⁹⁰Y is reached or through direct  ⁹⁰Y measurement. 
The selection of the measuring method depends on the origin of the contamination, the characteristics of the soil to be analysed, the required accuracy of measurement and the resources of the available laboratories.
These methods are used for soil monitoring following discharges, whether past or present, accidental or routine, liquid or gaseous. It also covers the monitoring of contamination caused by global nuclear fallout.
In case of recent fallout immediately following a nuclear accident, the contribution of ⁸⁹Sr to the total amount of strontium activity will not be negligible. This standard provides the measurement method to determine the activity of ⁹⁰Sr in presence of ⁸⁹Sr.
The test methods described in this document can also be used to measure the radionuclides in sludge, sediment, construction material and products by following proper sampling procedure.
Using samples sizes of 20 g and counting times of 1 000 min, detection limits of (0,1 to 0,5) Bq·kg^-1 can be achievable for ⁹⁰Sr using conventional and commercially available proportional counter or liquid scintillation counter when the presence of ⁸⁹Sr can be neglected. If Sr⁸⁹ is present in the test sample,  detection limits of (1 to 2) Bq·kg^-1 can be obtained for both ⁹⁰Sr and ⁸⁹Sr using the same sample size, counting time and proportional counter or liquid scintillation counter as in the previous situation.

标准预览图