Method for examining irradiated fuel bundle spacer springs using fiber-optic visual inspection equipment

A fiber-optic scope for inspecting a spacer spring of a nuclear fuel bundle assembly, comprising:

• first and second light guides for carrying light from a light source to a distal end of said scope;
• means for redirecting the light carried by said light guides onto a surface to be inspected;
• an ocular lens;
• an image guide for carrying light from said distal end of said scope to said ocular lens;
• means for redirecting light reflected from said surface along said image guide,
• wherein said guides are arranged so that the centers of said guides are located at the vertices of a triangle.

A method for inspecting spacer springs of a nuclear fuel bundle assembly having a plurality of spacers, each of said spacers comprising an array of ferrules, respective pairs of said ferrules having a common spacer spring, comprising the steps of:

• inserting a distal end of a fiber-optic scope having image and light guides through an upper tie plate and between the fuel rods of said fuel bundle assembly at the top thereof;
• lowering said distal end of said scope into the space between a group of spacer ferrules until a side aperture of said scope is at the elevation of a spacer spring to be inspected;
• supplying light to said light guide and redirecting said light out said side aperture to a spot proximal to the field of view of said image guide;
• rotating said distal end of said scope until said spacer spring to be inspected is visible through an ocular lens coupled to said image guide;
• and
• visually inspecting for defects that portion of said spacer spring which appears in the image received by said ocular lens.