Abstract: Vitrification is worldwide recognized as the most reliable technology for high level liquid waste(HLLW) immobilization. At present, the mainstream technologies for vitrification of high level liquid waste(HLLW) worldwide include joule-heated ceramic melter vitrification and two-step cold crucible induction melter(CCIM) vitrification. In the two-step cold crucible vitrification process, HLLW undergoes denitration and calcination sequentially in a rotary calciner to form calcined waste. The calcine is then fed into a cold crucible induction melter, where it is melted together with a glass-forming batch. Upon cooling, a homogeneous waste form is produced, achieving safe immobilization of radioactive waste. This study is based on the two-step cold crucible induction melter vitrification technology. Previous studies regarding glass formulation and process optimization have mainly focused on the direct treatment of high-level radioactive liquid waste. However, to meet practical engineering operation requirements, slag flushing water co-generated during reprocessing must also be co-treated. According to source-term characterization, the main component of slag flushing water is metallic zirconium scraps(accounting for more than 90%(mass fraction, the same below)), accompanied by minor insoluble radionuclides including U, Pu, Ru, and Tc. Therefore, during the co-treatment of HLLW and slag flushing water, the effects of metallic zirconium scraps on the vitrification process and glass formulation must be carefully evaluated. In the two-step cold crucible vitrification process, metallic zirconium scraps are converted into zirconia(ZrO₂) during the first-stage rotary calcination. From the perspective of glass formulation design, the influence of slag flushing water is thus dominated by the effects of ZrO₂ on the structure and performance of the final glass waste form. In this study, glasses containing simulated HLLW and different amounts of ZrO₂ were prepared. The results show that the glass wasteform structure is able to accommodate up to 6% ZrO₂ content. With the increase of ZrO₂ doping content in the borosilicate glass matrix, the glass density rises obviously while the molar volume decreases; meanwhile, both the chemical durability and high-temperature viscosity of the glass are enhanced. However, when 2% RuO₂ coexists in glass, the glass density and molar volume slightly change with ZrO₂ content while the glass viscosity largely increases. Moreover, the nuclear magnetic resonance(NMR) ²⁹Si and ¹¹B results suggest that ZrO₂ will depolymerize the SiO₄ connections in network backbone, whereas increase the ratio of BO₄/BO₃, thereby increasing the stability of glass network.