Apparatus for inspecting peripheral surfaces of nuclear fuel pellets

• US 5,186,887 A
• Filed: 09/30/1991
• Issued: 02/16/1993
• Est. Priority Date: 10/02/1990
• Status: Expired due to Term

• Current Assignee: Mitsubishi Nuclear Fuel Co. Ltd. (Mitsubishi Materials Corporation)
• Original Assignee: Mitsubishi Nuclear Fuel Co. Ltd. (Mitsubishi Materials Corporation)
• Inventors: Yaginuma, Yoshitaka
• Primary Examiner(s): Walsh, Donald P.
• Assistant Examiner(s): CARROLL, CHRISMAN DION
• Application Number:
  US07/767,817
• Time in Patent Office: 505 Days
• Field of Search: 376/245, 376/248, 376/252, 376/259, 376/253, 376/251, 376/250, 376/257, 376/261, 376/265, 376/266, 376/337, 376/338, 356/237, 356/426, 356/394, 209/538, 209/587, 209/655, 209/657, 382/48
• US Class Current: 376/248
• CPC Class Codes: G21C 17/06 Devices or arrangements for monitoring or testing fuel or fuel elements outside the reactor core, e.g. for burn-up, for contamination G21C17/08, G21C17/10 take precedence; detecting leaking fuel elements during reactor operation G21C17/04
• CPC Class Codes: Y02E 30/30 Nuclear fission reactors

Abstract

There is disclosed an inspection apparatus for peripheral surfaces of nuclear fuel pellets which includes a handling unit, an image pick-up device, a judging device and a sorting unit. The handling unit holds a prescribed number of nuclear fuel pellets in a line and rotates the same on their axes. The image pick-up device is disposed adjacent to the handling unit, and picks up image data as to the peripheral surfaces of the nuclear fuel pellets. The judging device is operably connected to the image pick-up device, and analyzes the image data outputted from the image pick-up device to output judging signals. The sorting unit is operably connected to the judging device and separates defective pellets from non-defective pellets based on the judging signals. The sorting unit includes a plurality of sorting members and actuators. The sorting members are disposed adjacent to the handling unit so as to correspond to the nuclear fuel pellets, respectively. The actuators are operably connected to the judging device and the sorting members, and operate the sorting members based on the judging signals.

Claims

1. An apparatus for inspecting peripheral surfaces of nuclear fuel pellets, comprising:

a handling unit for holding a plurality of nuclear fuel pellets in a line and rotating the same on axes thereof;

a loading device for loading said nuclear fuel pellets onto said handling unit;

an image pick-up device disposed adjacent to said handling unit for picking up image data as to the peripheral surfaces of said nuclear fuel pellets;

a judging device operably connected to said image pick-up device for analyzing said image data outputted from said image pick-up device to output judging signals; and

a sorting unit operably connected to said judging device for separating defective pellets from non-defective pellets based on said judging signals, said sorting unit including a plurality of sorting members disposed adjacent to said handling unit so as to correspond to said nuclear fuel pellets, respectively, and operating means operably connected to said judging device and said sorting members for operating said sorting members based on said judging signals;

wherein;

said handling unit includes a first roller having a first predetermined diameter disposed rotatably about an axis thereof and adjacent to said loading device, a second roller having a second predetermined diameter which is comparatively larger than the first predetermined diameter of the first roller disposed adjacent to said first roller so as to be rotatable about an axis parallel to said axis of said first roller, said first roller and said second roller cooperating to define an inspecting position therebetween, said second roller including at least one ejecting groove for receiving and carrying said plurality of nuclear fuel pellets, said ejecting groove being formed in a peripheral surface of said second roller so as to extend axially thereof.

2. An inspection apparatus according to claim 1, further comprising a drive means operably connected to said first roller and said second roller for rotating said first roller and said second roller in an identical direction at an identical constant peripheral velocity.

3. An inspection apparatus according to claim 1, in which said operating means includes a plurality of actuators mounted so as to correspond to said plurality of sorting members, respectively.

4. An inspection apparatus according to claim 1, in which said image pick-up device includes a light source disposed adjacent to said inspecting position for radiating illuminating light to said plurality of nuclear fuel pellets located at said inspecting position, sensor means for receiving light reflected from said plurality of nuclear fuel pellets and for outputting video signals to said judging device.

5. An inspection apparatus according to claim 1, in which said judging device includes:

a binary conversion means for converting the image data into binary signals based on preset binary levels;

a projection data obtaining means operably connected to said binary conversion means for obtaining projection data and storing the same, said projection data being the number of picture elements which are located in a row corresponding to circumferential direction and have one of binary values;

a two-dimensional image conversion means for converting the image data from said image pick-up device into two dimensional digital images;

a window determining means connected to said projection data obtaining means for determining a window;

a gate means for overlaying said window determined in said window determining means, on said two dimensional digital images; and

a judging circuit for judging presence of defects on said nuclear fuel pellets based on data outputted from said gate to produce said judging signals.

6. An inspection apparatus according to claim 1, in which said second roller includes a plurality of said ejecting grooves arranged in circumferentially equally spaced relation to one another.

7. An inspection apparatus according to claim 6, further comprising a guide frame for preventing said pellets received in said ejecting grooves from falling out, said guide frame being disposed adjacent to said second roller so as to cover about half the peripheral surface thereof.

8. An inspection apparatus according to claim 1, wherein said sorting members of said sorting unit comprise pivotable plates, each of said plates being disposed vertically below said second roller, each of said plates being pivotable in response to said judging signals between a first position in which said plate defines a first path for receiving non-defective pellets from said ejecting groove of said second roller and guiding said non-defective pellets to a conveying means, and a second position in which said plate defines a second path for receiving defective pellets from said ejecting groove of said second roller and guiding said defective pellets to a recovery means.