Reactor installation tools and methods for installing reactor components in a reactor tube are described herein. A reactor installation tool can include a releasable attachment assembly for securing the tool to a reactor or support for holding reactor components. The tool can include a movable cylinder that can be actuated to engage and push on a reactor component in an interior region of the reactor for positioning the contents of the reactor in a desired location. The tool can further include means for supply blasts of compressed gas to an interior region of the reactor to aid in the expansion and positioning of the reactor contents. A skirt seal can be used to ensure that the blasts of compressed gas are contained in the interior region of the reactor.