A Method for Radioactivity Analysis of Ca-41 in Concrete Waste

Abstract

An analytical method for determination of radioactivity concentration of ⁴¹Ca in waste concrete of the decommissioned nuclear power plant, using a low energy photon spectrometer was investigated. In the present days, the standard source of ⁴¹Ca is not available for efficiency calibration, therefore, alternative standard sources of ⁵⁵Fe were used to determine counting efficiency for ⁴¹Ca, considering some corrections based on the difference of photon attenuation. The minimum detectable radioactivity concentration was 1/5 to 1/60 of the clearance level (⁴¹Ca:100Bq/g) for counting time of 1000 to 80000 seconds. It was proved that the method was practical, simple and of low cost, compared to other methods using expensive instruments such as AMS.