Apparatus for assembling and welding final end plugs to nuclear fuel-containing cladding tubes and inspecting the welds, all on an automated basis
| Title: | Apparatus for assembling and welding final end plugs to nuclear fuel-containing cladding tubes and inspecting the welds, all on an automated basis |
|---|---|
| Patent Number: | 5,375,756 |
| Publication Date: | December 27, 1994 |
| Appl. No: | 08/040,974 |
| Application Filed: | March 31, 1993 |
| Abstract: | In an automated final weld apparatus, a transporter conveys nuclear fuel-loaded cladding tubes successively to a check station to verify the presence of a plenum spring in the open end of each cladding tube, a reader station where a unique first end plug serial number is read, an evacuation/backfill station where the cladding tube is backfilled with helium, a seam welding station where a final end plug is welded to the cladding tube open end, and a seal weld station where the tube is pressurized with helium through a pressurization hole in the final end plug, whereupon the pressurization hole is welded closed. After checking for helium leakage, the seam weld is inspected in a succession of inspection stations, and, depending on inspection results, the finished nuclear fuel rods are sorted into accepted and rejected lots. |
| Inventors: | Haughton, Robert A. (Wilmington, NC); Landry, James D. (Wilmington, NC); Reda, Ralph J. (Wilmington, NC); Sziemkiewicz, Robert J. (Wilmington, NC) |
| Assignees: | General Electric Company (San Jose, CA) |
| Claim: | What is claimed is |
| Claim: | 1. Automated apparatus for welding a separate final end plug to an open end of each a succession of nuclear fuel-loaded cladding tubes and for inspecting each final end plug of weld, said apparatus comprising, in combination |
| Claim: | a spring check station including a probe mounted for movement into detecting relation with a plenum spring residing in the open end of each cladding tube and a sensor for detecting a motion of said probe verifying the presence of a plenum spring; |
| Claim: | a reader station for reading a unique serial number imprinted on a first end plug welded to an end of each cladding tube opposite the open end; |
| Claim: | a welding station for welding a final end plug to the open end of each cladding tube; |
| Claim: | at least one inspection station for inspecting each final end plug weld and for generating weld inspection data; |
| Claim: | data acquisition means linked with said reader station and said inspection station and operating to correlate the weld inspection data with the associated first end plug serial number for each final end plug weld; |
| Claim: | an input queue for holding a plurality of cladding tubes; and |
| Claim: | a tube transporter operating to periodically pick individual cladding tubes from said input queue for conveyance to said spring check, reader, welding and inspection stations. |
| Claim: | 2. The apparatus defined in claim 1, wherein said tube transporter conveys said tube in a direction transverse to their tube access in indexing steps to index positions respectively axially aligned with such stations, said transporter further including separate drive means positioned at selected said index positions for axially reciprocating said tubes into and out of said stations. |
| Claim: | 3. The apparatus defined in claim 2, wherein said spring check station further includes a tube gripper mounted for vertical movement between a gripping position and a retracting position in non-interfering relation with the indexing step conveyance of said cladding tubes by said tube transporter, said gripper, in said gripping position, gripping a cladding tube axially aligned with said spring check station to prevent axial motion of said cladding tube in response to probing movement of said probe. |
| Claim: | 4. The apparatus defined in claim 3, wherein said probe is in the form of a forwardly spring-biased plunger mounted for forward and rearward reciprocating motion in coaxial relation to the open end of said cladding tube gripped by said gripper, said spring check station further including means for reciprocating said plunger, said sensor mounted for reciprocating movement with said plunger and positioned rearwardly of said plunger in gapped relation, whereby said sensor responds to closure of the gapped relation between said plunger and said sensor caused by engagement of a plenum spring by said plunger doing forward movement to provide verification of the presence of a plenum spring. |
| Claim: | 5. The apparatus defined in claim 4, which further comprises a controller responsive to said sensor for inhibiting reciprocation into and out of such stations by said drive means of a cladding tube lacking a plenum spring in the tube open end. |
| Claim: | 6. The apparatus defined in claim 2, which further includes an evacuation/backfill station to which each cladding tube is indexed prior to said welding station, said evacuation/backfill station including a housing having an entry through which each cladding tube is reciprocated by said drive means to position the open end thereof in said housing, said housing entry incorporating a fluid seal for expanding into sealing engagement with the cladding tube to prevent fluid leakage past said housing entry, a vacuum pump for evacuating said housing and the cladding tube interior, and a source of inert gas connectable with said housing to backfill the tube interior with the inert gas to a pressure of at least one atmosphere. |
| Claim: | 7. The apparatus defined in claim 6, wherein said evacuation/backfill station further includes a spring-biased element for engaging a portion of a plenum spring protruding from the tube open end to controllably axially orient the protruding spring portion such as to promote smooth entry and egress of the protruding spring portion through said housing entry. |
| Claim: | 8. The apparatus defined in claim 7, wherein said entry seal includes a spool-shaped elastomeric material having a pair of axially spaced sides radially extending from a cylindrical base, said base having a bore through which a cladding tube extends to position the tube open end in said housing, and a ring-shaped rigid member position between said sides to define with said base an annular chamber, said ring-shaped member having at least one passage through which a high pressure fluid is introduced into said cavity to expand said base into sealing engagement with the cladding tube. |
| Claim: | 9. Automated apparatus for welding a separate final end plug to an open end of each of a succession of nuclear fuel-loaded cladding tubes and for inspecting each final end plug weld, said apparatus comprising, in combination |
| Claim: | an evacuation/backfill station for backfilling each cladding tube with an inert gas to a pressure of at least one atmosphere; |
| Claim: | a first welding station for effecting a seam weld to affix a final end plug to the open end of each cladding tube in an inert gas atmosphere; |
| Claim: | a second welding station operating to pressurize an interior of each cladding tube with an inert gas through a pressurization hole in the final end plug and then to weld the pressurization hole closed; |
| Claim: | an inspection station for inspecting each final end plug weld and for generating weld inspection data; |
| Claim: | a tube transporter operating to periodically pick individual cladding tubes from said input queue for conveyance to said evacuation/backfill station, said reader station, said first and second welding stations and said inspection station. |
| Claim: | 10. The apparatus defined in claim 9, wherein said tube transporter conveys said tubes in a direction transverse to their tube axis in indexing steps to index positions respectively, axially aligned with said stations, said transporter further including separate drive means positioned at selected said index positions for axially reciprocating said tubes into and out of said stations. |
| Claim: | 11. The apparatus defined in claim 10, wherein said evacuation/backfill station includes a housing having an entry through which each cladding tube is reciprocated by said drive means to position the open end thereof in said housing, said housing entry including a fluid seal for expanding into sealing engagement with the cladding tube to prevent fluid leakage past said housing entry, a vacuum pump for evacuating said housing and the cladding interior, and a source of inert gas connectable with said housing to backfill the tube interior with inert gas to a pressure of at least one atmosphere. |
| Claim: | 12. The apparatus defined in claim 11, which further includes a spring check station including a probe mounted for movement into detecting relation with a plenum spring residing in the open end of each cladding tube and a sensor for detecting a motion of said probe verifying the presence of a plenum spring. |
| Claim: | 13. The apparatus defined in claim 12, wherein said evacuation/backfill station further includes a spring biased element for engaging a portion of the plenum spring protruding from the tube open end to controllably axially orient the spring protruding portion such as to promote smooth transition of the protruding spring portion through said housing entry. |
| Claim: | 14. The apparatus defined in claim 13, wherein said entry seal includes a spool-shaped elastomeric material member having a pair of axially spaced sides radially extending from a cylindrical base, said base having a bore through which the cladding tube extends to position the tube open end in said housing, and a ring-shaped rigid member positioned between said sides to define with said base an annular cavity, said ring-shaped member having at least one passage through which a high pressure fluid is introduced into said cavity to expand said base into sealing engagement with the cladding tube. |
| Claim: | 15. The apparatus defined in claim 14, wherein said spring check station further includes a tube gripper mounted for vertical movement between a gripping position and a retracted position in non-interfering relation with the indexing step conveyance of the cladding tubes on said tube transporter, said gripper, in said gripping position, gripping a cladding tube axially aligned with said spring check station to prevent axial motion of the cladding tube in response to probing movement of said probe. |
| Claim: | 16. The apparatus defined in claim 15, wherein said probe is in the form of a forwardly spring-bias plunger mounted for reciprocating movement in coaxial relation to the open end of the cladding tube gripped by said gripper, said spring check station further including means for reciprocating said plunger, said sensor mounted for reciprocating a movement with said plunger and positioned rearwardly of said plunger in gapped relation, whereby said sensor responds to closure of the gapped relation caused by engagement of a plenum spring by said plunger during forward plunger movement to provide verification of the presence of the plenum spring. |
| Claim: | 17. The apparatus defined in claim 16, which further comprises a controller responsive to said sensor for inhibiting reciprocation into and out of said stations by said drive means of a cladding tube lacking a plenum spring in the open tube end. |
| Current U.S. Class: | 228/10; 228/9; 228/42; 228/60; 29/723 |
| Current International Class: | B23K 902; B23K 3700 |
| Patent References Cited: | 4511075 April 1985 Yeo 4660270 April 1987 Rieben 4857260 August 1989 Schoening, Jr. et al. 4919884 April 1990 Chotard |
| Primary Examiner: | Bradley, P. Austin |
| Assistant Examiner: | Knapp, Jeffrey T. |
| Attorney, Agent or Firm: | McGinness, J. E. |
| Accession Number: | edspgr.05375756 |
| Database: | USPTO Patent Grants |
| Language: | English |
|---|