Patent Number: 
Section: claims

1. A method for manufacturing a core barrel which is to be disposed in a reactor pressure vessel of a pressurized water reactor and includes a main body barrel including a flange configured to be attached to the reactor pressure vessel, an upper barrel extending downward from the flange, and a lower barrel extending downward from the upper barrel, the core barrel to couple with the lower core support plate thorough a short ring and to hold a reactor core including a plurality of fuel assemblies, the method comprising:welding a first end part of a short ring in an axial direction of the core barrel, which has an axial direction length shorter than the lower barrel, to an upper portion of a lower core support plate;machining the lower core support plate through an upper end portion of the short ring that has been welded to the lower core support plate, the machining of the lower core support plate including forming:a placement surface on which the plurality of fuel assemblies is to be placed; anda fuel alignment pin hole, in which a fuel alignment pin for positioning the plurality of fuel assemblies is to be inserted; andwelding, after the machining of the lower core support plate, a lower end of the lower barrel of the main body barrel which covers the reactor core including the plurality of fuel assemblies to be placed on the placement surface to a second opposite end part of the short ring in the axial direction. 2. The method for manufacturing a core barrel according to claim 1, wherein before the machining of the lower core support plate, a heat treatment is performed on a weld line formed between the short ring and the lower core support plate. 3. The method for manufacturing a core barrel according to claim 1, wherein the short ring has an axial direction length that the lower core support plate can be machined after welding the short ring to the lower core support plate. 4. The method for manufacturing a core barrel according to claim 1, wherein the core support plate includes a junction part is provided on an outer side, in the radial direction, of the placement surface, and the lower end of the short ring is welded to the junction part. 5. The method for manufacturing core barrel according to claim 1, wherein when of the lower core support plate is machined, the lower core support plate and the short ring are machined to final forms which are same shapes as when the core barrel is completed.