Model for Calculating the Leakage

The model used to calculate the leakage from the transport container C-30 complies with the ISO 12807 International Standard Safe Transport of Radioactive Materials - Leakage Testing Packages [224]. 

We determine the leakage of the gases and via the Knudsen equation, which is the recommended approach [224], The penetration of the gas through small cavities depends on the thermodynamic properties of the gas, flow regimes and routes. The calculation of the ideal capillary diameter is used. It is possible to use the following modified Knudsen equation for the applicable leakage range (10 to 10 Pam s )  

The Knudsen equation can only be applied to the viscous laminar flow regime, the molecular flow regime or the transition flow regime. For predominantly laminar flow, the calculated contribution for molecular flow becomes negligible, and similarly for predominantly molecular flow, the calculated contribution for laminar flow becomes negligible. The first part of this equation represents the viscous laminar flow component, Q, which is derived from Poiseuille s law for laminar flow, and the second part represents the molecular flow component, Q, which is derived from Knudsen s law for free molecular flow. 

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