Abstract: The extraction force of irradiation supervision capsules is changed greatly due to the mounting pattern on the lower reactor internals. The gripping components at the end of the critical load path are limited by the size of the top plug of irradiation supervision capsules and become the weakest part of the tool. In order to ensure the safe operation, this paper analyzed the load limit of the gripping components, and obtains its maximum load limit. Based on the calculation result and load test, optimization measures to improve load limit of gripper are analyzed, which provides a reference for the design and improvement of similar equipment.