This paper describes an irradiation test of high-power-density internally and externally cooled annular fuel samples in the 5-MW Massachusetts Institute of Technology (MIT) research reactor MITR-II. The design of the irradiation facility is briefly reviewed, with an emphasis on the thermal-hydraulic behavior of the irradiation capsules. The irradiation test is described, including the thermal history of the two irradiated samples. A discussion of the observed asymmetrical temperature profiles is provided. Results of preliminary postirradiation examination consisting of collimated gamma scans of the irradiation capsules to confirm burnup estimates and estimate fission gas release (FGR) are also presented. It is concluded that the vibropacked fuel samples' FGR is below 1%, and that is within the predictable range by a specially equipped FRAPCON model.