Patent ID: 6888908

Claim:
A method of making a reactor upper closure head assembly for a pressurized water reactor, the assembly having a reactor closure head with a plurality of control rod guide tube nozzles arranged about the closure head for housing movable control rod extensions therethrough, each guide tube nozzle being integral with the closure head and having a bore extending therethrough, at least some of the bores being of differing length, with the outermost guide tube nozzles defining a maximum bore length, comprising: providing a dome-shaped forging having a concave inner surface and a thickness greater than the maximum bore length; machining a convex outer surface and all the plurality of guide tube nozzles from the forging the guide tube nozzles projecting upward beyond the convex outer surface; and forming the associated plurality of bores through said plurality of guide tube nozzles, each bore having a bore surface extending from the concave surface and terminating in a nozzle tip.