Convective Effects in a Regulatory and Proposed Fire Model

Radiation is the dominant mode of heat transfer in large fires. However, convection can be as much as 10 to 20 percent of the total heat transfer to an object in a large fire. The current radioactive material transportation packaging regulations include convection as a mode of heat transfer in the accident condition scenario. The current International Atomic Energy Agency (IAEA) Safety Series 6 packaging regulation states, \"the convection coefficient shall be that value which the designer can justify if the package were exposed to the specified fire.\" The current Title I 0, Code of Federal Regulations, Part 71 (I 0 CFR 71) packaging regulation states \"when significant, convection heat input must be included on the basis of still, ambient air at 800°C ( 1475°F).\" Two questions that can arise in an analyst's mind from an examination of the packaging regulations are whether convection is significant and whether convection should be included in the design analysis of a radioactive materials transportation container. The objective of this study is to examine the convective effects on an actual radioactive materials transportation package using a regulatory and a proposed thermal boundary condition.