Abstract: A method of forming a neutron-absorbing tube or a section of such tube, and the resulting tube. An elongate, generally rectangular metal ingot having a hollow interior is formed with at least one elongate metal divider in the interior forming chambers. The chambers are filled with a uniformly dispersed mixture of finely divided boron and particles of a finely divided metal, the ingot is then soaked to an elevated temperature and hot rolled to form a thin, rigid neutron-absorbing sheet having opposite metal edge portions and an elongated metal spacer portion at each metal divider. The sheet is then longitudinally bent at each spacer portion. A tube is formed by welding one or more bent sheet along the side edge portions.