Pellet slide and inspection assembly in a nuclear fuel pellet surface defect inspection apparatus

In an apparatus for inspecting nuclear fuel pellets for surface defects, said apparatus including a pellet infeed conveyor and a pellet discharge conveyor, a pellet slide and inspection assembly comprising:

• (a) a pellet slide defining an inclined track having an exit end adjacent to said discharge conveyor and an entry and adjacent to said infeed conveyor and at a higher elevation than said exit end;
• (b) an inspection station located along said inclined track between and spaced from said entry and exit ends of said track, said station including lower and upper sound reflectors being configured to define an annular inspection chamber through which a pellet moves as the pellet slides down said inclined track, one of said lower and upper sound reflectors having a recess defined therein, a first semicircular cavity defined in said recess and a pair of first surface portions defined along opposite sides of said first semicircular cavity, the other of said lower and upper sound reflectors having a second semicircular cavity defined therein being complementary to said first semicircular cavity and a pair of second surface portions defined along opposite sides of said second semicircular cavity, said other of said lower and upper sound reflectors being inserted into said recess of said one of said lower and upper sound reflectors so as to mate therewith at said respective pairs of surface portions such that said first and second semicircular cavities together define said annular inspection chamber completely surrounding the circumferential surface of the pellet as the pellet moves through said chamber;
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• (c) an ultrasonic inspection head mounted at said inspection station and being operable to transmit and receive sound energy to and from a pellet as it moves through said inspection chamber;
• (d) said track of said pellet slide having an upper portion extending from said entry end of said track through said inspection chamber and a lower portion extending from said inspection chamber to said exit end of said track along which each pellet moves after passing through said inspection chamber, said upper portion of said track defining a substantially linear path of movement of a pellet from said entry end of said track through said inspection chamber, said lower portion of said track defining a substantially linear path of movement of a pellet from said inspection chamber to said exit end of said track, said lower portion having a shallower slope than said upper portion of said track so as to cause deceleration of the pellet as it moves from said upper portion to said lower portion of said track which reduces the velocity of the inspected pellet as it approaches said exit end of said track.

In an apparatus for inspecting nuclear fuel pellets for surface defects, said apparatus including a pellet infeed conveyor and a pallet discharge conveyor, a pallet slide and inspection assembly comprising:

• (a) a pellet slide defining an inclined track having an exit end adjacent to said discharge conveyor and an entry end adjacent to said infeed conveyor and at a higher elevation than said exit end;
• (b) an inspection station located along said inclined track between and spaced from said entry and exit ends of said track, said station including lower and upper sound reflectors being configured to define an annular inspection chamber through which a pallet moves as the pellet slides down said inclined track, one of said lower and upper sound reflectors having a recess defined therein, a first semicircular cavity defined in said recess and a pair of first surface portions defined along opposite sides of said first semicircular cavity, the other of said lower and upper sound reflectors having a second semicircular cavity defined therein being complementary to said first semicircular cavity and a pair of second surface portions defined along opposite sides of said second semicircular cavity, said other of said lower and upper sound reflectors being inserted into said recess of said one of said lower and upper sound reflectors so as to mate therewith at said respective pairs of surface portions such that said first and second semicircular cavities together define said annular inspection chamber completely surrounding the circumferential surface of the pellet as the pellet moves through said chamber, said upper sound reflector having an opening therethrough;
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• (c) an ultrasonic inspection head mounted at said inspection station and extending through said opening of said upper sound reflector, said head being operable to transmit and receive sound energy to and from a pellet as it moves through said inspection chamber such that the sound energy completely surrounds the moving pellet being inspected within said chamber;
• (d) said track of said pellet slide having an upper portion extending from said entry end of said track through said inspection chamber and a lower portion extending from said inspection chamber to an exit end of said track along which each pellet moves after passing through said inspection chamber, said lower portion having a shallower slope than said upper portion of said track so as to cause deceleration of the pellet as it moves from said upper portion to said lower portion of said track which reduces the velocity of the inspected pellet as it approaches said exit end of said track.