Fissile Exceptions – A General Scheme For Packages Based On CSI Control - Presentation

This paper a summarizes a methodology for deriving safely sub-critical mass limits for excepting packages containing small quantities of fissile material from the licensing requirementsof TS-R-1 (but only in respect of fissile material). The methodology uses the CSI concept to control both individual packages and consignments, and takes into account fissile material types (plutonium and uranium at selected enrichments), and other materials present in the fissile material and packaging. The scheme was first discussed at a meeting of transport and criticality specialists in Chester UK, 2008, hosted by the UK Department for Transport (DfT). Extensive criticality calculations have been undertaken for all of the categories of fissile and moderating materials to confirm that the “Table M” data, reported in the TS-R-1 Working Material issued for the 120-day review, are safely sub-critical. The paper explains the principles behind the methodology and briefly summarizes the calculations.