Pressure boundary sealing system of control rod driving mechanism

The invention belongs to the technical field of control rod driving mechanisms, and particularly relates to a pressure boundary sealing system of a control rod driving mechanism, which is arranged on a support cylinder (15) of a pressure vessel of a reactor and comprises a straight cylinder type sealing cylinder (5), and a detachable sealing structure is arranged at a top opening of the sealing cylinder (5). And an opening in the bottom end of the sealing cylinder (5) can be detachably connected with the supporting cylinder (15) in a sealing manner. The pressure boundary of the CRDM is formed, and radioactive gas can be contained in a gas cavity of the CRDM; the pressure boundary sealing system can be used for a gear rack type CRDM, the structure is simple, the sealing mode is static sealing, and the sealing performance is reliable; and disassembly and assembly are convenient, welding operation is not needed on a reactor site, disassembly and assembly can be completed only through simple tools such as a torqu