Preparation of a radio-isotopic standard solution to be used in the monitoring of liquids effluents from radioactive facilities by gamma spectrometry

摘要

A technical procedure based on the Venezuelan Standard COVENIN-ISO TR 10013:2002“Guidelines for the Documentation of Quality Management System”, it was developed and applied forthe preparation of a Radioactive Solution of Reference (RSR), used in the analysis of samples of liquideffluent coming from radioactive facilities, for the technique of gamma spectrometry of highresolution. Applying all the developed procedures, a dilution outline was continued to prepare a RSRwith a volume and activity known for ~(137)Cs, starting from a concentrated solution, elaborated with amass of a certified radioactive solution QCY.44. The activity of the present ~(137)Cs in the RSR was of21.43 ± 0.30 Bq/L. Later on, was carried out a count using a hiperpure germanium detector (HPGe)Canberra, with relative efficiency of 20% and a resolution (FWHM) of 1.9 keV for the energy line of1333 keV of Co-60. Later on, for two conditions, an analysis for gamma spectrometry of highresolution was carried out, in order to determine the activity of the present ~(137)Cs in the RSR. Theresults obtained for both conditions (21.20 ± 0.80 Bq/L and 18.80 ± 1.70 Bq/L respectively) theysuggest that the followed dilution outline and the applied procedure, they fulfilled their purpose. Ananalysis for gamma spectrometry of high resolution for ~(40)K and ~(137)Cs on a group of samples of liquideffluent, coming from of two radioactive facilities was carried out. The results indicate that lightlydifference do exist among the carried out analysis using two types of radioactive solution of reference.The procedures have been developed to be used in the preparation of the radioactive solutions ofreference used in the monitoring and radiological surveillance of the liquid effluent of the two mostimportant radioactive facilities in Venezuela.