Patent ID: 7720190

Claim:
A working apparatus for doing works below an annular shroud support plate arranged substantially horizontally between an inner surface of a nuclear reactor pressure vessel and an outer surface of a shroud, the apparatus comprising: a working equipment for doing works; a folding/unfolding mechanism that can be folded when moving the working equipment and unfolded when doing work; a conveyance mechanism for conveying the working equipment and the folding/unfolding mechanism to the site of the work; a pressing mechanism for pressing the working equipment upward against a lower surface of the annular shroud support plate; a traveling mechanism including wheels for traveling under and along the annular shroud support plate and positioning the apparatus; and ball casters so as to be held in contact with the lower surface of the annular shroud support plate when the pressing mechanism presses the working equipment against the lower surface of the annular shroud support plate, wherein the folding/unfolding mechanism is so constructed that the working equipment can be positioned by pressing the wheels to the inner surface of the nuclear reactor pressure vessel and the outer surface of the shroud when the folding/unfolding mechanism is unfolded.