Production of sealed radioactive sources from Со-57

Current conditions are favourable for the production of isotopes and sealed sources for industrial and medical applications in Uzbekistan. The Institute of Nuclear Physics at the Academy of Sciences of Uzbekistan possesses equipment which makes it possible to develop appropriate commercial activity. This equipment includes a 10 MWt WWR-СМ nuclear reactor, and U -150 and U-115 cyclotrons. Hot cells are also available for treatment of irradiated targets and the isolation and cleaning of isotopes.

After the collapse of the USSR, the Institute started commercialising and supplying raw isotopes such as phosphorus-32, phosphorus-33, iodine-125 and cobalt-57 to the world market. However, it proved impossible to establish production of finished radioactive sources because of lack of infrastructure, experience and funding. Only in 2006-2007 with the support of CNCP did the Institute implement a project. The purpose of the project was to set up production of sealed sources from cobalt-57 for X-ray fluorescent analyses (XFA).

The X-ray fluorescent method is based on excitation of the characteristic radiation of atoms in a sample and measurement of the energy and the intensity of this radiation. This makes it possible to identify the atomic number and concentration of a corresponding chemical element. Excitation can be performed with the help of an x-ray tube. This is expensive and restricts opportunities for application of the x-ray fluorescent method. Use of radionuclide sources for analyses has a number of advantages: compactness, low energy consumption and low cost of the equipment. These advantages are particularly important for portable devices used for sampling rocks in the field, for borehole logging and for laboratory devices for mass analyses and for production line control.

During the Soviet period geological companies in Uzbekistan were equipped with x-ray fluorescent spectrometers, but at present this equipment is out of date and much of it is out of order. Currently foreign companies, in particular Canberra Industries, Ortek, Tennelec and others, manufacture portable, cheap devices for XFA and these devices are beginning to appear on the Uzbek market. However, there is a problem relating to the provision of excitation sources for them. Import of the required radionuclide sources is very complicated. This opens a niche for the domestic manufacture of radionuclide products.

With financial support from CNCP, the necessary production equipment has been bought, an original plant for Co-57 electrochemical sedimentation developed, the methodology for measurement of volumetric activity of sources finalized and a new methodology for vacuum testing has been proposed. Manufactured sources were tested in the Radio Analytical Centre of INP and were assessed positively.

Former nuclear weapons scientists who had never dealt with commercial manufacture of radionuclide sources mastered new technologies and acquired business skills. Most important, they realized that the possibilities of working in this field have great potential. This project can, therefore, help establish sustainable manufacture of sealed sources in Central Asia.

Serik Yegamediev
Project manager, Head of Laboratory at INP