Risk assessment in the industrial radiography practice in India using probabilistic approach

Abstract

Industrial gamma radiography utilises appropriate radioisotopes housed in the radiography devices which provide shielding from the ionising radiations, for imaging of the weld joints and castings. The radiography devices are operated manually by rotating the control unit to project the gamma source outside the shielding, in a projection sheath. Deviation from the standard operating procedures or malfunctioning of the gamma radiography equipment may result in potential exposure to occupational workers. Probabilistic safety assessment has been carried out to calculate the probabilities of potential exposure to occupational workers in industrial gamma radiography practice in India. Fault trees have been designed for failure assessment of radiation area monitoring instruments, the functionality of which is crucial to ensure safe industrial gamma radiography operations. Operational procedures leading to the potential exposure scenarios have been sequenced in the event tree. The probability of most severe potential exposure category is calculated as 3.506E-04 for open field radiography operations and slightly lower value of 1.293E-04 for enclosed radiography operations. Assessment results identify the contributory factors to potential exposure, along with their relative contribution. Results indicate that probability of potential exposure can be reduced by adopting safe work practice by operators and responsible attitude of radiological safety officers towards trainees and untrained persons.