QUALITY CONTROL IN RADIATION PROCESSING IN THE VINČA INSTITUTE RADIATION PLANT- CASE STUDY

Abstract

The irradiation process control has to define facility parameters, validation of product and routine control of the irradiation process during exploitation. To meet the regulations, it is necessary to stop the exploitation and do the qualification exercises after changes in the source loading, source geometry or product transport system. In order to save time, the new combined approach has been analyzed for qualification of sterilization process used in the Vinča Institute Radiation Plant. The absorbed dose is calculated assuming that the irradiation process runs with specified parameters. The results of absorbed dose measurements in an experiment done during the sterilization process were used for dose calculations. The calculated absorbed doses are compared with measured ones. The criterion for a positive qualification is the superposition of calculated and measured values. Two different types of dosimeters are used for measurements: ethanolchlorobenzene and alanine. The measurement traceability is achieved through the calibration by the Riso National Laboratory, Denmark. In this case study, the determined dwell time for target dose is 450s. 1.23 is dose uniformity ratio in the box with plastic products with dose minimum at the bottom corners in the center and dose maximum at the top of the surface plane of the box parallel to the source. The calculated and measured absorbed doses show the same difference of 13% between the surface and the central plane in the box. The dose reproducibility for irradiation process is 3.5%.