Inspection tool for detecting cracks in jet pump beams of boiling water reactor

An inspection tool for detecting cracks in a structural member having a curved surface, comprising:

• a support frame;
• a curved track attached to said support frame;
• a rolling carriage coupled to said curved track;
• first drive means mounted on said carriage for driving said carriage to roll along said curved track;
• a pivot pivotably mounted on said carriage;
• second drive means mounted on said carriage for driving said pivot to swivel;
• a crack detecting device carried by said pivot and having a tip,
• wherein said tip of said crack detecting device travels along a first path lying in a first plane during rolling of said carriage along said track, and said tip travels along a second path lying in a second plane perpendicular to said first plane during swiveling of said pivot, and said curved track comprises a first groove having first and second guide surfaces, each of said first and second guide surfaces comprising a first arcuate section having a predetermined radius and a first arc length, a straight section having one end connected to an end of said first arcuate section, and a second arcuate section having one end connected to another end of said straight section and having said predetermined radius and a second arc length longer than said first arc length, wherein said first arcuate section of said first guide surface and said second arcuate section of said second guide surface are contiguous over said first arc length, said second arcuate section of said first guide surface and said first arcuate section of said second guide surface are contiguous over said first arc length, said straight section of said first guide surface and said straight section of said second guide surface are equal in length and contiguous along only a first portion thereof, said second arcuate section of said first guide surface and a second portion of said straight section of said second guide surface being adjacent, and a second portion of said straight section of said first guide surface and said second arcuate section of said second guide surface being adjacent, said second portion of said straight section being coplanar with a chord connecting two points along said second arcuate section in each instance.

An inspection tool for detecting cracks in a structural member having a curved surface, comprising:

• a support frame;
• a curved track attached to said support frame;
• a rolling carriage coupled to said curved track;
• first drive means mounted on said carriage for driving said carriage to roll along said curved track;
• a pivot pivotably mounted on said carriage;
• second drive means mounted on said carriage for driving said pivot to swivel;
• a crack detecting device carried by said pivot and having a tip,
• wherein said tip of said crack detecting device travels along a first path lying in a first plane during rolling of said carriage along said track, and said tip travels along a second path lying in a second plane perpendicular to said first plane during swiveling of said pivot, further comprising a spring mounting plate attached to said pivot and having first and second flexible support arms, said pivot comprising a clamp having first and second means for attaching to said first and second support arms, respectively, of said spring mounting plate, wherein said crack detecting device is held securely by said clamp in a position between said first and second support arms.