ESTIMATION OF UNKNOWN ACTIVITIES BY COMPARATIVE CALIBRATION METHOD

Among the stored radioactive wastes in the Atomic Energy Authority Rad waste Waste Storage Facilities, several sources were identified as unk nown. These sources were brought to the storage facility 1 yr ago. Gam ma-Ray spectroscopic radioassays of these sources showed two main gamm a-energy lines of 1.17 and 1.33 MeV, which are the main characteristic feature of Co-60 radionuclides. Estimation of their activities were c arried out using a simple intercomparison technique with a Co-60 refer ence source of activity 146 MBq (3.95 mCi). The sources activities wer e found to be in the range 2.70-3.50 GBq (73 to 95 mCi). The authors b eneficially found and planned for future use of these sources in resea rch, routine radiation protection programs as well as in calibration.