A process for polymerizing ethylene, and optionally one or more comonomers, to obtain an ethylene-based polymer in a high-pressure polymerization system comprising a) a continuously operated polymerization reactor having a reactor inlet and having a reactor outlet and b) a reactor blow down system comprising a fluid communication system, adapted and arranged to be in fluid communication with the polymerization reactor via the fluid communication system, comprising b1) a reactor blow down vessel containing an aqueous quenching medium, b2) at least one first emergency valve arranged in the fluid communication system and adapted to open and close the fluid communication between the polymerization reactor and the reactor blow down system, b3) a reactor blow down dump vessel arranged and adapted to be in fluid communication with the reactor blow down vessel, and b4) at least one drain valve in the fluid communication between the reactor blow down vessel and the reactor blow down dump vessel adapted and arranged to open or close the fluid communication between the reactor blow down vessel and the reactor blow down dump vessel, wherein the reactor blow down vessel is installed above the reactor blow down dump vessel, and wherein the process comprises A) monitoring the high-pressure polymerization system with respect to an occurrence of a disturbance, and B) opening the at least one first emergency valve in case of a disturbance to allow the content of the polymerization system comprising polymer and gaseous components to expand into the reactor blow down vessel via the fluid communication system, wherein the at least one drain valve b4) is closed, C) contacting said content in the reactor blow down vessel with the aqueous quenching medium to obtain an aqueous polymer slurry, D) separating the aqueous polymer slurry and the gaseous components and E) transferring the aqueous polymer slurry to the reactor blow down dump vessel by opening the at least one drain valve b4). a) a continuously operated polymerization reactor having a reactor inlet and having a reactor outlet and b) a reactor blow down system comprising a fluid communication system, adapted and arranged to be in fluid communication with the polymerization reactor via the fluid communication system, comprising b1) a reactor blow down vessel containing an aqueous quenching medium, b2) at least one first emergency valve arranged in the fluid communication system and adapted to open and close the fluid communication between the polymerization reactor and the reactor blow down system, b3) a reactor blow down dump vessel arranged and adapted to be in fluid communication with the reactor blow down vessel, and b4) at least one drain valve in the fluid communication between the reactor blow down vessel and the reactor blow down dump vessel adapted and arranged to open or close the fluid communication between the reactor blow down vessel and the reactor blow down dump vessel, wherein the reactor blow down vessel is installed above the reactor blow down dump vessel, and b1) a reactor blow down vessel containing an aqueous quenching medium, b2) at least one first emergency valve arranged in the fluid communication system and adapted to open and close the fluid communication between the polymerization reactor and the reactor blow down system, b3) a reactor blow down dump vessel arranged and adapted to be in fluid communication with the reactor blow down vessel, and b4) at least one drain valve in the fluid communication between the reactor blow down vessel and the reactor blow down dump vessel adapted and arranged to open or close the fluid communication between the reactor blow down vessel and the reactor blow down dump vessel, A) monitoring the high-pressure polymerization system with respect to an occurrence of a disturbance, and B) opening the at least one first emergency valve in case of a disturbance to allow the content of the polymerization system comprising polymer and gaseous components to expand into the reactor blow down vessel via the fluid communication system, wherein the at least one drain valve b4) is closed, C) contacting said content in the reactor blow down vessel with the aqueous quenching medium to obtain an aqueous polymer slurry, D) separating the aqueous polymer slurry and the gaseous components and E) transferring the aqueous polymer slurry to the reactor blow down dump vessel by opening the at least one drain valve b4).