[en] A technique for avoiding cold-shut defects in deep, single-pass, electron beam welds is described and evaluated. Shims of an appropriate alloying metal are interleaved in the joint before welding, and during the welding process the shim is melted and mixed into the weld metal, lowering the solidification temperature and thus preventing the formation of cold-shuts. For uranium and some of its low-dilution alloys, the shim may be made of copper