Radiation safety and accident experience at gamma irradiation plants

Gamma irradiation plants for the sterilization of medical products, preservation of food grains and for various other applications employ multikilocurie 60Co sealed sources inside shielded irradiation cells. A number of interlocks are provided between the cell entry door and the source raise mechanisms, in order to prevent the entry of any person to the cell when the source is in the exposed condition. The present paper gives the general safety features and the interlocks employed in these plants along with the safety features of irradiation plants at BARC, namely 106 Ci Isomed plant for the sterilization of medical products, 105 Ci FIPLY plant for research in food preservation and 105 Ci PANBIT plant for industrial research. Over the last two decades five cases of accidental exposure have been reported in literature in which the operator gained entry to the irradiation cell when the source was in the exposed condition. Two of these cases resulted in fatalities while the remaining three cases resulted in hospitalization of the exposed individuals for six to seven weeks. A brief outline of these accidental exposure cases and the causes of the accidents are discussed in this paper. (author). 19 refs