Gamma radiography with 75Se sources: Consequences of a violent fire

Due to the volatile nature of selenium and selenium dioxide, an important atmospheric dispersion of 75Se can occur in case of a violent fire (>800 C). This type of accident is possible when transporting or using a highly active 75Se source for gamma radiography. The consequences of this dispersion are analyzed. From the point of view of radiological protection, it can be concluded that in radiography the unprotected 75Se sealed sources have to resist for 1 h to a temperature of 1,200 C. If this is not the case, x-ray equipment and 192Ir sources have to be preferred above 75Se sources