Patent Number: 048658049
Section: claims

1. An end plug for welded disposition within the end of a tube, comprising: a circumferentially extending, axially oriented land surface, having a radial extent defined by means of a first predetermined dimension, for disposition within said end of said tube;  a circumferentially extending, axially oriented land surface, having a radial extent defined by means of a second predetermined dimension which is greater than said first predetermined dimension, for disposition outside of said end of said tube, said second land surface being disposed upstream of said first land surface;  an annularly extending, radially oriented shoulder portion, defined at the downstream end of said second land surface and having a radially inward depth which is greater than the difference defined between said first and second radial dimensions of said first and second land surfaces, for engaging said end of said tube in a butt contact fashion; and  annular groove means defined between the upstream end of said first land surface and said shoulder portion of said end plug, for eliminating porosity defects normally developed within a weldment defined between said tube end and said end plug when said end plug is welded within said tube end, and including a conical surface which extends radially outwardly from the innermost radial depth extent of said shoulder portion to said upstream end of said first land surface.  said conical surface is disposed at an angle of 45.degree. with respect to said shoulder portion of said end plug.  said end plug is a nuclear reactor fuel rod end plug for disposition within the end of a nuclear reactor fuel rod cladding tube.  said groove is defined to a radially inwardly extending depth of 0.100 inches.  means for forming said weldment defined between said tube and said end plug by laser beam welding.  TIG welding means for forming said weldment defined between said tube and said end plug.  said end plug is fabricated from stainless steel.  said end plug is fabricated from a zirconium alloy.  said weldment is an annular girth weld defined about the outer periphery of said juncture defined between said end plug and said tube.  a first circumferentially extending, axially oriented land surface, having a radial extend defined by means of a first predetermined dimension, for disposition within said end of said tube;  a second circumferentially extending, axially oriented land surface, having a radial extent defined by means of a second predetermined dimension which is greater than said first predetermined dimension, for disposition outside of said end of said tube, said second land surface being disposed upstream of said first land surface;  an annularly extending, radially oriented shoulder portion, defined at the downstream end of said second land surface and having a radially inward depth which is greater than the difference defined between said first and second radial dimensions of said first and second land surfaces, for engaging said end of said tube in a butt contact fashion; and  annular groove means defined between the upstream end of said first land surface and said shoulder portion of said end plug, for eliminating porosity defects normally developed within a weldment defined between said tube end and said end plug when said end plug is welded within said tube end under said laser beam welding conditions, and including a conical surface which extends radially outwardly from the innermost radial depth extent of said shoulder portion to said upstream end of said first land surface.  said end plug is a nuclear reactor fuel rod end plug for disposition within the end of a nuclear reactor fuel rod cladding tube.  a first circumferentially extending, axially oriented land surface, having a radial extent defined by means of a first predetermined dimension, for disposition within said end of said tube;  a second circumferentially extending, axially oriented land surface, disposed upstream of said first land surface and having a radial extent defined by means of a second predetermined dimension which is greater than said first predetermined dimension, for disposition outside of said end of said tube;  an annularly extending, radially oriented shoulder portion, defined at the downstream end of said second land surface and having a radially inward depth which is greater than the difference defined between said first and second radial dimensions of said first and second land surfaces, for engaging said end of said tube in a butt contact fashion; and  annular groove means defined between the upstream end of said first land surface and said shoulder portion of said end plug, for eliminating porosity defects normally developed within a weldment defined between said end plug and said tube end when said end plug is welded within said tube end by means of said welding process, and including a conical surface which extends radially outwardly from the innermost radial depth extent of said shoulder portion to said upstream end of said first land surface.  means for forming said weldment defined between said tube and said end plug by laser beam welding.  a generally right circular cylindrical smaller diameter portion and a coaxially joined generally right circular cylindrical larger diameter portion, the juncture of said smaller and larger diameter portions having a generally radially inwardly extending circumferential groove as defined by means of a radially oriented shoulder surface for engaging said each end of said cladding tube and a conical surface extending radially outwardly from the radially innermost portion of said shoulder surface, with said smaller diameter portion frictionally longitudinally engageable with the interior surface of said tube and with said larger diameter portion having a chamfered free end and having a generally constant diameter from said juncture to said chamfered free end.  (a) a cladding tube;  (b) a plurality of nuclear fuel pellets disposed in said tube; and  (c) an end plug welded to each end of said tube, said end plug including a generally right circular cylindrical smaller diameter portion and a coaxially joined generally right circular cylindrical larger diameter portion, the juncture of said smaller and larger diameter portions having a generally radially inwardly extending circumferential groove as defined by means of a radially oriented shoulder surface for engaging said each end of said cladding tube and a conical surface extending radially outwardly from the radially innermost portion of said shoulder surface, with said smaller diameter portion frictionally longitudinally engaged with the interior surface of said tube and with said larger diameter portion having a chamfered free end and having a generally constant diameter from said juncture to said chamfered free end.  said conical surface is disposed at an angle of 45.degree. with respect to said shoulder portion of said end plug.  said radially inward depth of said shoulder portion is 0.100 inches.  said end plug is fabricated from a zirconium alloy.  said conical surface is disposed at an angle of 45.degree. with respect to said shoulder portion of said end plug.  said radially inward depth of said shoulder portion is 0.100 inches.  said welding process comprises laser beam welding techniques.  said end plug is fabricated from a zirconium alloy. 2. An end plug as set forth in claim 1, wherein: 3. An end plug as set forth in claim 1, wherein: 4. An end plug as set forth in claim 1, wherein: 5. An end plug as set forth in claim 1, further comprising: 6. An end plug as set forth in claim 1, further comprising: 7. An end plug as set forth in claim 1, wherein: 8. An end plug as set forth in claim 1, wherein: 9. An end plug as set forth in claim 1, wherein: 10. An end plug for welded disposition within the end of a tube by means of laser beam welding techniques, comprising: 11. An end plug as set forth in claim 10, wherein: 12. A nuclear reactor fuel rod end plug for fixation within the end of a nuclear reactor fuel rod cladding tube by means of a welding process, comprising: 13. A nuclear reactor fuel rod end plug as set forth in claim 12, wherein: 14. An end plug for welding to each end of a nuclear reactor fuel rod cladding tube, said end plug comprising: 15. A nuclear reactor fuel rod, comprising: 16. An end plug as set forth in claim 10, wherein: 17. An end plug as set forth in claim 10, wherein: 18. An end plug as set forth in claim 10, wherein: 19. An end plug as set forth in claim 12, wherein: 20. An end plug as set forth in claim 12, wherein: 21. An end plug as set forth in claim 12, wherein: 22. An end plug as set forth in claim 12, wherein: