Patent Number: 048779695
Section: summary

The present invention concerns a flask for the transport of radioactive material. BACKGROUND OF THE INVENTION A flask for the transport of high level vitrified radioactive waste operates dry under all conditions. The waste is contained in sealed containers which are housed within the flask and it is necessary to provide for thermal transfer between the containers and the flask wall in order to dissipate the heat generated by radioactive decay of the waste. It is known to provide a monolithic support structure within the flask to receive the sealed containers. Heat transfer from the waste through the support structure and into the flask wall is determined by the degree of thermal contact between the components. Due to the size and complexity of a monolithic support structure, good thermal contact is often difficult to achieve and distortion of the structure during use can make subsequent withdrawal from the flask a difficult operation. FEATURES AND ASPECTS OF THE INVENTION According to the present invention, a flask for the transport of radioactive material comprises a hollow cylindrical body, a plurality of substantially identical individual elongate members releasably secured within the body to define longitudinally extending channels to receive and accommodate containers for radioactive material, each member having concave longitudinally extending side surfaces which each form only a portion of a channel, another portion of which is formed by a side surface of an adjacent one of the members, and each member having a radially outer surface curved to conform to the curvature of the interior of the hollow cylindrical body whereby to maximize thermal contact therebetween for dissipation of heat generated by decay of the radioactive material. Preferably a radially inner surface of each member defines a portion only of a central channel in the hollow body and cooperates with radially inner surfaces of the other members to define a complete central channel. A stepped longitudinally extending groove may be formed in the radially outer surface of each member, and shaped keys fixedly secured to the inner wall of the hollow body may be provided to cooperate with the stepped grooves such that the keys slidably receive the stepped grooves. A clamping bar may cooperate with the keys to releasably secure the member to the wall of the hollow body. The keys may extend the length of the hollow body. Preferably each member is individually releasably secured to the body and is individually insertable into and removable from the body.