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 Report dateSiteEvent description
05000278/LER-2017-00121 December 2017Peach Bottom

On 10/23/2017, during a walkdown of containment at the start of the Unit 3 refueling outage, a leak was identified in a socket weld for a 1-inch diameter instrument line. The line is connected to discharge piping for the 'B' recirculation pump and is part of the reactor coolant system pressure boundary. Because the leak was misting, the leakage rate could not be quantified. However, the reactor coolant system unidentified leakage prior to plant shutdown was 0.18 gpm. RCS pressure boundary leakage while in Mode 1 is a violation of Technical Specification 3.4.4 and is a reportable condition.

The cause of the event was a lack of fusion defect in the weld when it was done in the late 1980's. Normal vibration of the line since it was installed resulted in the crack initiating at the weld defect and propagating to the surface. The section of pipe and associated fitting were replaced, along with welds in similar sections of piping. There were no actual safety consequences as a result of this event.

05000278/LER-2013-0017 June 1121 JLPeach Bottom

Based on information received from a laboratory performing Main Steam Safety Relief Valve (SRV) / Safety Valve (SV) as-found testing, Site Engineering personnel determined on 10/01/13 that SRV / SV setpoint deficiencies existed with four SRVs and one SV that were in place during the Unit 3 19th operating cycle. The SRVs / SV were determined to have their as-found setpoints outside of the Technical Specification allowable ± 1% tolerance. All relief valves outside of their Technical Specification (TS) allowable setpoint range were within the ASME Code allowable ± 3% tolerance. The cause of the SRVs / SV being outside of their allowable as-found setpoints is due operating cycle. There have been previous LERs identified involving SRVs / SVs exceeding their Technical Specification ± 1% setpoint requirement. A license amendment request (LAR) was submitted to the NRC in June 2013 to modify the allowable setpoint from ±1% to ±3%, which is consistent with the setpoint typically used in the industry.

There were no actual safety consequences associated with this event.

NRC FORM 36(.3 (10-2010)