Nuclear fuel element

A description is given of a nuclear fuel element which comprises: 1) an elongated clad container, 2) a body of nuclear fuel material disposed in and partially filling the container forming an internal cavity at one end of the container and an internal gap between the fuel material and the cladding, 3) a refractory metal liner disposed in the internal gap between the body of nuclear fuel material and the clad container and partially filling the internal gap, 4) an enclosure integrally secured and sealed at each end of the container, and 5) a helical member positioned in the internal cavity. (author)