During a scheduled refueling outage, an inspection of containment components revealed a suspected
through wall leak on
1CV-200B, Letdown Orifice 'B' Outlet Control. Non-destructive engineering inspection has been completed and determined that an indication exists.
10 CFR 50.2(2)(i) defines the reactor coolant pressure boundary as being connected to the reactor coolant system, up to and including the outermost containment isolation valve in system piping which penetrates primary reactor containment. 1CV-200B is isolable from the Reactor Coolant System (RCS) by a single motor operated valve, 1RC-427, Reactor Coolant Loop 'B' Leg to CVCS Letdown Isolation valve.
1CV-200B is located inside of containment between 1RC-427 and the two containment isolation valves for the letdown line, 1CV-371 and 1CV-371A. Based on the definition provided in 10 CFR 50.2, the condition is considered pressure boundary leakage and is considered reportable under 10 CFR 50.72(b)(3)(ii).
Unit 1 is currently in Mode 6. Repairs for the condition are being determined.
The NRC Resident Inspector has been notified.
