Plug for closing envelope of fissionable material rod - welds securely without thermal losses or damage to rod

摘要

A plug for closing the end of the envelope of a rod of fissionable material by TIG welding, has two sections. It consists of a section which is introduced into the envelope and a second which remains outside. After welding, this section forms the butt of the rod. Between the two sections there is a collar which is welded to the envelope, and at least the part of the inner section and the part of the outer section immediately adjacent to the colar have a smaller dia. than the other parts. The thickness of the collar is pref. 1-3 times that of the envelope and the dia. of the collar lies between the internal and the external dias. of the envelope. The inner section of the plug has a centralising piece in which there are lengthways slots permitting the escape of gas. Prevents the loss of equilibrium between the masses of the envelope and the plug, overheating and shearing of the joint accentuated by shrinkage.