On March 29, 2016, Entergy notified the Atomic Safety and Licensing Board that workers had identified degradation of bolts used to assemble the core former and core baffle plates within the reactor pressure vessel on Indian Point Unit 2 (Fig. 1).
Fig. 1 (Source: NRC ML15337A264)
This notification was necessary because Entergy had applied to the NRC in 2007 for renewal of the operating licenses for Indian Point Units 2 and 3 and the State of New York had intervened. One of the contentions raised by the State involved inadequate aging management of the reactor pressure vessel and its internals.
Entergy amended its license renewal application to add a commitment to follow aging management guidance developed by the Electric Power Research Institute for reactor vessel internals. That guidance included inspecting the core former and baffle plate bolts (which had not been routinely inspected during Indian Point’s operation) and re-inspecting them every ten years. The initial inspection revealed degradation in about ten percent of the bolts.
UCS prepared a slideshow providing background information on the core former and baffle assembly, the safety implications of degraded bolts, and prior experience with degraded bolts at U.S. and foreign nuclear power plants. We also pose questions that we hope Entergy and the NRC will answer as soon as practical.