The 2,2,6,6-tetramethylp'peridine-l-oxyl (TEMPO)-mediated oxidation was mainly studied in laboratory scale and needs to be scaled-up for any future industrial implantation. With this objective, the oxidation was applied at several steps in a thermomechanical pulp production system. Softwood chips were impregnated with a TEMPO mixture or treated in batch before refining, leading to a modification of pulp mechanical and optical properties. The TEMPO oxidation was also studied on softwood pulp with a usual batch oxidation, a high consistency treatment or by replacing the diluted water by a TEMPO oxidation medium during the secondary refining. Pulp from high-consistency oxidation presented a significant energy potential gain. However, optical properties were severely affected and could not be totally recovered by a conventional hydrogen peroxide bleaching. The refiner was also used as a nanofiber-producing apparatus for pulp with carboxylic group content higher than 1500 mmol/kg. For this application, the refiner appeared to be a high-efficiency dispersion system to produce significant amounts of nanofibers at low-energy consumption.