The invention relates to a method for measuring the
activity concentration of kalium-subtracted total beta radionuclides in
seawater, and the method is characterized in that the method comprises the following steps: (a) adding a
cobalt carrier into used
seawater, forming
cobalt ion solution, adjusting the pH value of the
cobalt ion solution to be greater than seven, and then adding
thioacetamide into the solution to form
cobalt sulfide sediments through reaction; (b) extracting and putting the
cobalt sulfide sediments under the temperature from 600 DEG C to 800 DEG C for
ashing; (c) adding porphyrized
ashing products to a measuring disc, adding an ethyl
alcohol sample, and putting the mixture on a flow-gas type
proportional counter for measurement and calculation. The method achieves the measurement of beta radionuclides with the
enrichment ratio being greater than 95% which is discharged into the
seawater in an operation process of
nuclear facilities, such as 58Co, 60Co, 59Fe, 65Zn, 110mAg and so on, thereby guaranteeing that the sediments prepared through the method are more uniform and moderate in weight. The detection
lower limit is 3mBq / L, so the method is suitable for the monitoring of the
activity concentration of kalium-subtracted total beta radionuclides in seawater, and is also suitable for heavy-
salt water similar to a seawater sample, and heavy-
salt water which contains radionuclides and is obtained through
processing.