The following information was provided by the licensee via phone and email:
On May 6, 2025, with Callaway Plant in mode 3 ascending from refueling outage 27, plant personnel identified a dry white residue resembling boric acid at the interface between the reactor vessel and bottom-mounted instrument nozzle No.48. At 2220 CDT, the shift manager determined that a reactor coolant pressure boundary leak had been identified. The determination was based on the residue appearing to be in the annulus of the nozzle where it penetrates the bottom head and the residue did not previously exist during earlier inspections of the area during refueling outage 27.
Detailed examination of the apparent leak has not yet been performed due to radiological conditions, but the condition is being treated as a reactor coolant pressure leak. As such, the condition is being reported pursuant to 10 CFR 50.72 (b)(3)(ii)(A) as an eight-hour, non-emergency notification.
The NRC Resident Inspector has been notified."
The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:
The apparent leak placed the plant in
LCO 3.4.13.B. The plant is evaluating the leak repair corrective actions and preparing for cooldown.
