NDTsi 2001 Session: Structural Integrity and NDE I-II
Industry Response to Leak in Reactor Vessel Nozzle-to-Hot Leg Weld
J.L. Landrum, EPRI, USA; T. McAlister, South Carolina Electric & Gas, USA
ABSTRACT
In October 2000, the V.C. Summer Nuclear Station was performing routine inspections during a normal refueling outage. A visual inspection identified an accumulation of boric acid around the reactor coolant system (RCS) loop "A" hot leg air boot near the primary biological shield wall. Subsequent ultrasonic, eddy current and remote video examinations inside the hot leg pipe identified a 2.7-inch long axial crack on the inner surface of the weld. The crack was through-wall and aligned with a previously identified 3/16-inch hole in the weld near the top of the pipe. The "A" hot leg weld was subsequently removed and extensive metallurgical evaluations were performed. This paper provides details on the examination and repair of the reactor vessel nozzle-to-hot leg weld at V.C. Summer. The weld configuration, weld history, and the results of the metallurgical investigations will be discussed. In addition, the paper will discuss on-going efforts of an U.S. industry initiative sponsored by the EPRI Materials Reliability Program (MRP) to address Alloy 82/182 weld integrity issues. The MRP has aligned its resources to address the potentially generic implications of the hot leg cracking. This is especially important since the Ringhals Nuclear Station (Sweden) has also reported finding cracks in two of its reactor vessel nozzle-to-hot leg welds.
Publication Source: 3nd International Conference on NDE in Relation to Structural Integrity for Nuclear and Pressurized Components, November 14-16, 2001, Seville Spain. Publisher: Tecnatom s.a. - [Homepage]
