Containment of radioactive powders by seals

Safety regulations require that the possible loss of radioactive material from a packaging is restricted to very low levels for both normal and accident conditions. This can be achieved by using a robust steel containment vessel with double O-rings seals to validate access ports. The effectiveness of each seal can be demonstrated by pressurizing the interspace and calculating any leak rate from the pressure drop. For packagings containing radioactive gas or liquid, it is then possible to quantify any resulting activity release rate but for fine particulate material the relationship of likely solid transport in a known gas flow is much harder to define. Because of this, more reliance has to be placed on experimental evidence of powder retention by seals and powder flow through capillaries and orifice plates, sometimes with unduly arduous assumptions made such as the existence of an aerosol within the container