Design and development of probe release mechanism for cable pusher module of PFBR SG inspection system

Abstract

Inspection of SG tubes in Prototype Fast Breeder Reactor (PFBR) requires pushing and retrieving of the probe along with the cable. A design of cable pusher module (CPM) has been carried out in this research work to deliver adequate axial force for the pushing and retrieval of the probe and cable. The change of the probe calls for the removal of the inspection system from the SG manhole causing extended inspection down-time. Considering all these uncertainties, a probe release mechanism (PRM) is designed, and tested for use. This is a major technological advancement to the PFBR SG inspection system. The probe release mechanism assists with moving the pulleys away to allow cable and probe replacement during maintenance. This is a major technological advancement to the PFBR SG inspection system. This paper describes the exact design of the pre-compressed springs that provide radial force on the inspection cable through the pulleys for smooth insertion and retrieval. Futhermore, the needed actuator force and the wedge configuration for the separation of the pulley modules during probe release are covered. An actuator is designed using a maximum cable weight and tube friction of 2.5 N and 2.3 N, respectively.