Neutrons and gamma rays emitted by a test fuel element were imaged through a linear array of pinholes. The ionizing radiations formed optical images on a plastic scintillator that was viewed by an intensified television (TV) system. The TV records provided a sequence of twelve 16-ms frames spanning a 2860-MW, 315-MW-s Transient Reactor Test Facility transient. Data show radial expansion of the test fuel pin.