BOTTOM HEAD FOR BOILING WATER REACTOR

摘要

PROBLEM TO BE SOLVED: To provide an integral stub tube which simplifies the reactor pressure vessel fabrication process, provides a structural transition between the penetration and head and facilitates future remote inspection of the attachment weld. SOLUTION: A stub tube 54 is machined into a bottom head dome 52. Specifically, a penetration 58 is formed in the bottom head dome 52 by a bore 60 having a stub tube portion 62. The stub tube portion 62 has a cylindrical shape and a length of the stub tube portion 62 is selected to provide a transition between a penetration housing 56 and an adjacent portion 64 of the bottom head dome 52. The penetration housing 56 extends through the penetration 58 in the dome 52. A weld 66 attaches the stub tube portion 62 to the penetration housing 56.