Sealing performance of reactor coolant pump is an important indicator for safety evaluation of sodium-cooled fast reactor. A double-end self-pumping mechanical seal was proposed for certain type of coolant pump for sodium-cooled fast reactor. Fluent numerical simulation at conditions of orthogonal design of experiments was performed to study influence of structural and operational parameters on open force and leakage rate of end surface. The pressure adjustment range of blocking fluid was analyzed to meet the requirement of zero argon leakage in the pump chamber. The results show that although both affect the open force within the experimental range of these parameters

the influence of ratio of groove to face width is more significant than that of helix angle. The open force was increased with the increase of ratio of groove over face width and helix angle. Also

the ratio of groove to face width had a significant effect on the leakage rate

which was increased rapidly with the increase of the ratio of groove to face width. The relationship between pressure of blocking fluid with both leakage rate and open force was obtained for conditions of maximum speed and shutdown. The mechanical seal is assured to be safe and effective at 0.05 MPa pump working pressure as long as blocking fluid pressure is controlled within 0.0528-1.6378 MPa.