Abstract The USITER Project is responsible for providing a generic design of 18 diagnostics upper port plugs (UPPs). These plugs are designed to provide effective nuclear shielding, adequate nuclear heat removal capability, and allowance for personnel accessibility shortly after shutdown. In addition, the design limits for other parameters should not be exceeded during ITER lifetime. This includes the accumulative DPA and helium production in the UPP structure and the vacuum vessel, fast neutron fluence reaching the neighboring TF and PF magnets, and the accumulative local heating in their coil casings. In the present work, we assess these performance characteristics in three generic upper port plug (GUPP) designs of the in-plug shield and labyrinths that span possible configurations ranging from a conservative to worst case. The cases considered are: (1) Case A: “Visible-IR Camera diagnostic” with an intact port-attached blanket shield module (BSM), and (2) Case B: vis/IR system where the port-based BSM is replaced by overlapping adjacent vessel-attached BSM and (3) Case C: a “Large Aperture diagnostic” that is loosely resembles ECH style shielding plugs and aperture. These cases were modeled in a 20-degree sector of ITER. The 3D FEM Discrete Ordinates Code, ATTILA, was used in the analysis along with FENDL2.1 data and the FORNAX activation file.