Experimental determination of heat transfer from transport casks with axial fins

Abstract

In order to achieve higher heat dissipation, the outer surface area of a transport and storage cask for radioactive material can be increased by the use of cooling fins. CASTOR® casks are fitted with cooling fins machined into the cask body, which run circumferentially around the outer surface of the cask. The first-generation CONSTOR® casks have a smooth outer surface without fins, which is made from a steel plate. This is possible because the heat capacity of their contents is relatively low. For CONSTOR® casks to have a higher heat capacity it is necessary to develop a special solution to allow heat to be dissipated from the outer surface of the cask. For the CASTOR® cask series it is also desirable to achieve higher rates of heat dissipation. From an economic point of view, a solution whereby separate cooling fins are attached to a smooth outer surface would be preferable to the currently machined fins. Several possible solutions are available for achieving this and one of the ideas has been investigated in detail. This concept comprises a series of aluminium profiles which are strapped to the smooth outer cask surface. This in effect provides a cask with axial fins. This solution also allows for the inclusion of moderator material within certain areas of the aluminium profiles. Several experiments have been performed to investigate this concept. A test specimen was investigated, consisting of a 2 m by 0.4 m segment of the finned profile attached to a heating plate. In order to simulate various cask orientations during transport and storage, measurements were taken for different test-piece orientations. Computational fluid dynamics simulations of the various tests were also performed.