Patent Number: 
Section: claims

1. A forged upper shroud section for a shroud of a boiling water nuclear reactor, the shroud comprising at least one cylindrical section, said upper shroud section comprising: a cylindrical shell;  a circular shaped flange at one end of said shell, said flange and said cylindrical shell machined from one forging as one piece;  at least one of a plurality of openings and a plurality of slots in said flange; and  a circumferential groove machined into and extending substantially completely around an inside surface of said cylindrical shell. 2. A forged upper shroud section in accordance with  claim 1  wherein said cylindrical shell comprises an end configured to be welded to a cylindrical section of the shroud. claim 1 3. A forged upper shroud section in accordance with  claim 1  wherein a thickness of said flange is selected to carry loads from a shroud head. claim 1 4. A forged upper shroud section in accordance with  claim 1  further comprising a gusset extending between said flange and cylindrical shell. claim 1 5. A forged upper shroud section in accordance with  claim 1  wherein a thickness of said cylindrical shell is selected to carry loads from a shroud head and radial loads from a top guide grid. claim 1 6. A shroud for a boiling water nuclear reactor, said shroud comprising: at least one cylindrical section;  a forged upper shroud section comprising a cylindrical shell and a circular shaped flange at a first end of said shell, said flange and said cylindrical shell machined from one forging as one piece, a second end of said cylindrical shell welded to one of said at least one cylindrical section;  at least one of a plurality of openings and a plurality of slots in said flange; and  a circumferential groove machined into and extending substantially completely around an inside surface of said cylindrical shell. 7. A shroud in accordance with  claim 6  wherein a thickness of said flange is selected to carry loads from a shroud head. claim 6 8. A shroud in accordance with  claim 6  further comprising a gusset extending between said flange and cylindrical shell. claim 6 9. A shroud in accordance with  claim 6  wherein a thickness of said cylindrical shell is selected to carry loads from a shroud head and radial loads from a top guide grid. claim 6 10. A method for fabricating an upper shroud section for a shroud of a boiling water nuclear reactor, the shroud comprising at least one cylindrical section, said method comprising the steps of: machining a flange in a single piece rectangular cross-section ring forging;  machining a cylindrical shell in the forging;  machining at least one of a plurality of openings and a plurality of slots in the flange; and  machining a circumferential groove into and extending substantially completely around an inside surface of the cylindrical shell. 11. A method in accordance with  claim 10  further comprising the step of preparing an end of the cylindrical shell to be welded to a cylindrical section of the shroud. claim 10 12. A method in accordance with  claim 10  further comprising the step of selecting a thickness of the flange to carry loads from a shroud head. claim 10 13. A method in accordance with  claim 10  further comprising the step of machining a gusset extending between the flange and the cylindrical shell. claim 10 14. A method in accordance with  claim 10  further comprising the step of selecting a thickness of the cylindrical shell to carry loads from a shroud head and radial loads from a top guide grid. claim 10