Patent Number: 
Section: claims

1. An apparatus configured to perform a decontamination operation inside a jet pump of a nuclear reactor in which the jet pump includes an opening with a tapered surface, the apparatus comprising:an apparatus body having an elongated tubular member sized to be fully inserted down into the jet pump of the nuclear reactor, the tubular member having an upper portion that defines a top end of the apparatus body and is attached to a wire for support;the elongated tubular member having a circumferential wall with a plurality of holes, the plurality of holes being connected to a hose, the hose being connected to an open upper end of the elongated tubular member, the hose and the plurality of holes configured to guide core water from the jet pump to an analytical filter located outside the nuclear reactor;a weight for imparting gravitational force on the apparatus body, the weight having an upper portion that is coupled to a lower portion of the tubular member via a bellows;a guide rod abuttedly connected to a lower portion of the weight, the lower portion of the weight defining a bottom end of the apparatus body, the guide rod being elastically biased toward a predetermined, non-zero angle relative to a vertical axis of the apparatus body;wherein the biased, predetermined non-zero angle of the guide rod facilitates entry of the guide rod into the tapered surface of the jet pump opening and wherein, after the guide rod is inserted into the jet pump opening, the apparatus is lowered via the wire so that the apparatus body is essentially fully inserted into the jet pump to perform the decontamination operation. 2. The apparatus of claim 1, wherein the bellows comprises an elastic member coupling the lower portion of the tubular member to the upper portion of the weight. 3. The apparatus of claim 1, wherein the bellows is configured to impart a biasing force to restore the guide rod to the predetermined, non-zero angle relative to a vertical axis of the apparatus body. 4. An apparatus configured to perform an inspection operation inside a jet pump of a nuclear reactor in which the jet pump includes an opening with a tapered surface, the apparatus comprising:an apparatus body having an elongated tubular member sized to be essentially fully inserted down into the jet pump of the nuclear reactor, the tubular member having an upper portion that defines a top end of the apparatus body and is attached to a wire for support;the elongated tubular member having a circumferential wall with a plurality of holes;a plurality of signal cables connected to the elongated tubular member for connecting inspection means fixed to the plurality of holes to a controller exterior to the nuclear reactor;a weight for imparting gravitational force on the apparatus body, the weight having an upper portion that is coupled to a lower portion of the tubular member via a bellows;a guide rod abuttedly connected to a lower portion of the weight, the lower portion of the weight defining a bottom end of the apparatus body, the guide rod being elastically biased toward a predetermined, non-zero angle relative to a vertical axis of the apparatus body;wherein the biased, predetermined non-zero angle of the guide rod facilitates entry of the guide rod into the tapered surface of the jet pump opening and wherein, after the guide rod is inserted into the jet pump opening, the apparatus body is lowered via the wire so that the apparatus body is essentially fully inserted into the jet pump to perform the inspection operation. 5. The apparatus of claim 4, wherein the bellows comprises an elastic member coupling the lower portion of the tubular member to the upper portion of the weight. 6. The apparatus of claim 4, wherein the bellows is configured to impart a biasing force to restore the guide rod to the predetermined, non-zero angle relative to a vertical axis of the apparatus body.