Patent ID: 7206372
Filing Date: 2007-04-17
Classification: F16L,G21C,Y02E

Abstract:
1. An in-situ repair method to seal a hollow, elongate member which extends into a reactor pressure vessel of a boiling water reactor and penetrates through a bottom head dome opening of a bottom head dome forming a lower end of the reactor pressure vessel, the reactor pressure vessel including a stub tube having a first end, a second end and a stub tube bore extending between the first and second ends that is aligned with the bottom head dome opening, the elongate member extending upward from the bottom head dome through the bottom head dome opening and through the stub tube bore, the elongate member secured to the stub tube adjacent the first, end with an upper stub tube attachment weld, the method comprising: cutting the elongate member at a given location below the second end of the stub tube to remove a section of the elongate member so as to form an upper portion which extends upward into the stub tube bore and reactor pressure vessel interior of the boiling water reactor, and a lower portion which extends downward through the bottom head dome opening to an undervessel area beneath the reactor pressure vessel, wherein an opening is provided at the given location between the upper and lower portions where the section was removed, and applying a weld to attach the lower portion to the reactor pressure vessel so as to seal off potential leakage paths of reactor coolant between the upper portion and lower portion and through the bottom head dome sidewall to the undervessel area.