NRC: Inadequate design review led to Vermont Yankee tower problem

摘要

Entergy Nuclear did not conduct an adequate review of a design change to the circulating water system piping in the east cooling tower at Vermont Yankee before placing it in service this summer, NRC inspectors concluded in an October 10 special inspection report. The inadequate review led to the failure of pipe supportsrnEntergy plans to replace all of the structural supports in the safety-related cell in the west cooling tower, with the exception of the relatively new partition walls, over the next three refueling outages, the NRC report said. Entergy also plans to conduct inspections for "the normally inaccessible columns" during the next three refuelings and to eventually replace wood components in the adjacent, seismic-designed cell, it said.rn"The inspectors concluded that Entergy's scope of efforts to replace key load-bearing members with FRB [fiberglass reinforced plastic], improve inspection procedures and processes, and align cooling tower inspections with industry standards and best practices were adequate to improve the structural reliability of the non-safety-related portions of the cooling towers," the NRC report said.