Bleached kraft pulp is produced for various end-uses such as bleached packaging, wrappings, printing papers, smooth papers, or tissues. A common requirement for virgin kraft fibres is their high strength. The pulping, bleaching, and paper-making steps can alter the kraft fibres strength by mechanically and chemically introducing local defects . Bleaching is the chemical process of removing residual lignin from unbleached pulp by the successive use of strong oxidants and alkaline extraction stages. Chlorine dioxide is today the most widely used bleaching agent and commonly employed in Elemental Chlorine Free (ECF) bleaching sequences. Its main drawback resides in the generation of bioaccumulable chlorinated organics in the bleach plant effluent. Totally Chlorine Free (TCF) bleaching sequences may perform better environmentally but have suffered from technical limitations such as insufficient brightness, poor brightness stability, or high cost ). Among TCF chemicals, ozone is a candidate for totally substituting chlorine dioxide but provokes an inevitable depolymerisation of the pulp carbohydrates (cellulose and hemicelluloses).