Risk assessment for occupational potential exposure at cobalt teletherapy units

The occupational potential exposure risk that could occur due to source stuck event at ⁶⁰Co teletherapy facility is estimated. Such risk estimation has been carried out quantitatively and qualitatively using probabilistic safety assessment and risk matrix methods, respectively. The event consequences for workers are evaluated by measuring the effective dose from the occupational potential exposure during the event response. Sets of thermoluminescent dosimeters are placed at different positions corresponding to worker locations while perform-ing the event response procedure. Both of the two estimation methods gave low and acceptable risk as a result of several safety barriers in the facility design and low event consequences. In view of the obtained results in this paper, it is recommended to use the risk matrix method in the future for risk analysis of ⁶⁰Co teletherapy units. Such a safety assessment process is an essential stage for licensing/renewal decision making