Patent Number: 
Section: claims

1. In combination with a nuclear reactor pressure vessel, said nuclear reactor vessel being positioned in a pedestal, reactor pressure vessel drain piping being positioned on the bottom of said nuclear reactor pressure vessel, an inspection apparatus for piping, said inspection apparatus for piping comprising: a carriage set on a rail arranged under said reactor pressure vessel drain piping in parallel with a horizontal portion of said reactor or pressure vessel drain piping inside a said pedestal;  a driving means for moving said carriage along said rail;  a falling prevention mechanism for preventing said carriage from falling from said rail;  a camera mounted on said carriage and monitoring a relative position between said camera and said reactor pressure vessel drain piping; and  a thickness measuring means mounted on said carriage for measuring the thickness of said reactor pressure vessel drain piping. 2. An inspection apparatus for piping according to  claim 1 , further comprising: claim 1 a control means for controlling said driving means;  a displaying means for displaying an image monitored by said camera; and  an outputting means for outputting a measurement result obtained by sa d thickness measuring means; and  wherein said means each are installed outside said pedestal. 3. An inspection apparatus for piping according to  claim 1 , wherein said rail is bendable, said carriage is supported by said rail, and said rail has end portions which are fixed. claim 1 4. An inspection apparatus for piping according to  claim 3 , wherein said rail comprises a plurality of plate members and hinge mea s for flexibly connecting adjacent plate members. claim 3 5. An inspection apparatus for piping according to  claim 3 , wherein said end portions of said rail are fixed to control rod drive housings adjacent to said end portions. claim 3