In Kalsi Engineering Valve and Actuator Program (KVAP) Error Report 2011-02, Kalsi Engineering identified an error in the KVAP software that provides default flow and
torque coefficients for ball and plug valves which can affect margin predictions. Communication between Kalsi and Duke Energy personnel confirmed that non-conservative
torque values were calculated for select ball valves used at Oconee for containment isolation. As a result of the Kalsi error, the non-conservatively calculated
torque values resulted in negative actuator margins, calling into question the actuators' capability to close the valves under all design conditions. Therefore, it has been determined that the KVAP software program error constitutes a defect, reportable under
10CFR21.
Four safety-related containment isolation valves in the High Pressure Injection system were impacted, requiring entry into TS 3.6.3, Containment Isolation Valves, on two Oconee units [Units 2 and 3].
Unit 1 was shutdown for a refueling outage at the time of this event and the actuator spring was replaced during the outage. The valves on units 2 and 3 required a Notification of Enforcement Discretion (NOED) which occurred on June 2, 2011. Three of the four valves were declared operable on June 10, 2011 and the remaining valve was declared operable the next day.
The licensee notified the NRC Resident Inspector.
