Management of Ir-192 Disused Sealed Sources with Long-Lived Radioactive Contaminants
- Nuclear and Energy Research Institute - IPEN, Sao Paulo (Brazil)
Iridium-192 sealed sources are the most widely used sealed source in industrial applications in Brazil. They are not recyclable and in the end of the useful life, they are discarded as radioactive waste. The recommended management strategy of this waste is decay in storage and disposal as exempt waste because the half-life is only 73.8 days. Presently, thousands of Ir- 192 sources are under storage waiting release. Surprisingly, sources that were under storage for more than ten years and for which no measurable contact dose rate was expected still present significant remaining radioactivity. The examination of the gamma spectra of these sources showed the presence of Co-60 and the gamma emission lines from the Ir-192m2 isomer, the metastable isotope with half-life of 241 years, which is also formed by the irradiation of natural iridium. The aim of the study reported in this paper is to characterize the Ir-192 disused sources under interim storage at the Radioactive Waste Management Department, considering the presence of minor contaminants in the irradiated iridium and the fraction of the total initial activity of the sources that is attributable to that metastable isotope. The radioactive inventories at the end of the irradiation and after the decay period were predicted using the Scale 6.0 code and the results were compared with activity measurements of the disused sources by gamma spectrometry. (authors)
- Research Organization:
- Institute of Electrical and Electronics Engineers - IEEE, 3 Park Avenue, 17th Floor, New York, N.Y. 10016-5997 (United States)
- OSTI ID:
- 22531379
- Report Number(s):
- ANIMMA-2015-IO-331; TRN: US16V0359102320
- Resource Relation:
- Conference: ANIMMA 2015: 4. International Conference on Advancements in Nuclear Instrumentation Measurement Methods and their Applications, Lisboa (Portugal), 20-24 Apr 2015; Other Information: Country of input: France; 15 Refs.
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
07 ISOTOPES AND RADIATION SOURCES
BRAZIL
COBALT 60
COMPARATIVE EVALUATIONS
DOSE RATES
GAMMA SPECTRA
GAMMA SPECTROSCOPY
HALF-LIFE
IRIDIUM
IRIDIUM 192
IRRADIATION
ISOMERS
RADIOACTIVE WASTE MANAGEMENT
RADIOACTIVE WASTES
RADIOACTIVITY
SEALED SOURCES
SERVICE LIFE
WASTE STORAGE