Reactor head with integral nozzles

Abstract

A reactor closure head assembly has guide tube nozzles which are integral with the reactor closure head. A dome-shaped forging having a concave surface is prepared with extra thickness equal to or greater than the desired nozzle height. Nozzles having bores therethrough are machined opposite the concave surface. Weld buttering is applied to the ends of the nozzles, the concave surface is clad with a corrosion resistant layer, and the forging is then heat treated. A guide tube flange is attached to the ends of the nozzles. The surfaces of the nozzle bores are covered with a protective layer which is preferably applied without heating, for example by electrochemical deposition, thereby avoiding the need for subsequent post weld heat treatment.

1 . A closure head assembly for a reactor pressure vessel, comprising: 
 a closure head having a concave inner surface and a convex outer surface, the closure head made of a first material;    a plurality of nozzles integral with the closure head, each nozzle terminating in a nozzle tip and having a bore therethrough defining a bore surface extending from the inner surface of the closure head to a nozzle tip; and    a corrosion-resistant second material established adjacent to each bore surface.    
   
   
       2 . The closure head assembly of  claim 1 , wherein the corrosion-resistant second material is established without heating.  
   
   
       3 . The closure head assembly of  claim 2 , wherein the corrosion-resistant second material is applied via electrochemical deposition.  
   
   
       4 . The closure head assembly of  claim 1 , wherein the corrosion-resistant second material is established by inserting a sleeve adjacent each bore surface.  
   
   
       5 . The closure head assembly of  claim 1 , wherein the nozzle is a control rod guide tube nozzle.  
   
   
       6 . The closure head assembly of  claim 1 , wherein weld buttering is applied to the nozzle tips.  
   
   
       7 . The closure head assembly of  claim 1 , further comprising a corrosion-resistant third material applied to the inner surface of the closure head.  
   
   
       8 . A closure head assembly for a reactor pressure vessel, comprising: 
 a closure head having a concave inner surface and a convex outer surface, the closure head made of a first material, the closure head inner surface clad with a corrosion-resistant second material;    a plurality of control rod guide tube nozzles, each nozzle integral with the closure head and terminating in a nozzle tip, each nozzle further having a bore therethrough defining a bore surface extending from the inner surface of the closure head to a nozzle tip;    a control rod guide tube flange attached to each nozzle end tip with weld buttering therebetween; and    a corrosion-resistant third material established adjacent the bore surfaces.    
   
   
       9 . The closure head assembly of  claim 8 , wherein the corrosion-resistant third material is established adjacent the bore surfaces via electrochemical deposition.  
   
   
       10 . The closure head assembly of  claim 8 , wherein the corrosion-resistant third material comprises a sleeve adjacent each bore surface.  
   
   
       11 . The closure head assembly of  claim 8 , wherein the first material is selected from one of carbon steel and low alloy steel.  
   
   
       12 . The closure head assembly of  claim 8 , wherein the second material is selected from one of stainless steel and a nickel-chromium alloy.  
   
   
       13 . The closure head assembly of  claim 8 , wherein the third material is selected from one of stainless steel, nickel, nickel-based alloys, and nickel-chromium alloys.  
   
   
       14 - 27 . (canceled)