The single-screw extruder is used for the continuous formation of solid rod of hydrogen ice and its isotopes. The extruded rod, further, requires to be cut into pellets and injected into the magnetically confined, hot plasma for the fuelling of long-pulse fusion reactors. An extruder is capable to produce and continuously supply the pellets at a frequency of 1–40 Hz. The design and development of a solid hydrogen screw-extruder system require a study of the visco-plastic behaviour of solid hydrogen and its effects on the pressure and speed of the extruder. A CFD tool (Polyflow) from ANSYSTM is employed to estimate the characteristics of the pressure developed by the extruder at different rotational speed of the screw. In the simulations, different Shear Stress Models developed by various researchers are implemented and the results of the same are investigated systematically for Single-Screw Hydrogen Extruder. The results obtained from these simulations are validated with the experimental results on single screw extruder from literature.