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Wolf Creek Generating Station performed a planned shutdown for the start of a refueling outage. As part of the procedure GEN 00-005, Minimum Load to Hot Standby, a planned manual reactor trip was initiated from 25 percent power level with the plant in Mode 1. As part of this planned shut down sequence, an anticipated automatic Auxiliary Feedwater (AFW) actuation signal was generated. This is a non-emergency event notification in accordance with 10 CFR 50.72(b)(3)(iv)(A) due to preplanned manual actuation of the reactor protection system and auto-initiation of auxiliary feed water system. All systems and components operated as designed with the exception of the main generator output breakers. They did not open as designed. They were manually opened using the main control room hand switches as directed by EMG ES-02, Reactor Trip Response. The plant is stable in Mode 3 with AFW secured, with plans to cool down and enter Mode 5 for the planned refueling outage. The NRC Resident Inspector has been notified.

• * * EVENT RETRACTED ON 03/11/15 AT 13:05 EDT FROM BRET DAVIS TO JEFF HERRERA * * *

WCNOC (Wolf Creek Nuclear Operating Corporation) is retracting the 10 CFR 50.72(b)(3)(iv)(A) notification based on further review of the event. A valid AFAS (Auxiliary Feedwater Actuation signal) actuation occurred during the planned shutdown as a result of SG (Steam Generator) water level reaching the lo lo level setpoint. The AFAS actuation was an expected actuation that occurred due to preplanned activities covered by GEN 00-005. On-shift control room personnel were aware that an AFAS actuation would occur as a result of tripping the plant between 30% and 25% power. The AFAS actuated consistent with the planned shutdown with no anomalies. This is consistent with NUREG-1022, Rev. 3, Section 3.2.6 that states, in part: 'With regard to preplanned actuations, operation of a system as part of a planned test or operational evolution need not be reported. Preplanned actuations are those that are expected to actually occur due to preplanned activities covered by procedures. Such actuations are those for which a procedural step or other appropriate documentation indicates that the specific actuation is actually expected to occur. Control room personnel are aware of the specific signal generation before its occurrence or indication in the control room.' The NRC Resident Inspector was notified. Notified R4DO(Okeefe).

6/26/11 at 1609 CDT, the reactor was manually tripped due to the trip of the 'B' Main Feed Pump while operating in Mode 1 at approximately 82% reactor power. The unit was increasing power to 95% after the current refuel outage. The cause of the trip of the 'B' Main Feed Pump is not known at this time. All equipment functioned normally as expected. The investigation into the cause of the 'B' Main Feed Pump trip is ongoing at this time. Current plant status is Mode 3. The NRC Senior Resident has been contacted. All rods fully inserted upon reactor trip. The unit is stable with Auxiliary Feedwater supplying the Steam Generators. Decay heat is being removed to the Main Condenser via steam dumps. The electrical system is in a normal post-trip alignment. The licensee characterized the reactor trip as uncomplicated.

• * * UPDATE FROM MARCY BLOW TO DONALD NORWOOD AT 1923 EDT ON 6/26/2011 * * *

A valid Auxiliary Feed(water) actuation signal (occurred) due to trip of both of the Main Feed pumps from a turbine trip and low steam generator levels. This is reportable under 10CFR50.72 (b)(3)(iv)(A), 8-hour report. All auxiliary feed pumps started and operated as expected. The licensee will notify the NRC Resident Inspector. Notified R4DO (Deese).

Wolf Creek experienced a reactor trip at 1549 CDT. The first out annunciator was TURBINE TRIP and P9 Reactor TRIP. At approximately the same time the unit experienced a momentary loss of offsite power. The emergency diesel generators started (and loaded) as expected to supply power to the safety busses due to the loss of offsite power. Auxiliary Feedwater and Feedwater Isolation actuations occurred as expected. All control rods inserted into the core during the trip. All Reactor Coolant Pumps tripped due to the loss of offsite power. Decay heat was initially being removed by the Steam Generator Atmospheric Relief Valves. Presently the plant is stable in Mode 3. The 'D' Reactor Coolant Pump has been restarted. The licensee is continuing to investigate the cause of the trip. The atmospheric relief valves lifted for approximately 10 minutes, however there was no primary to secondary leakage. Both A & B EDG's loaded for about 2 minutes. At the present time the electrical lineup is normal and the EDG's are shutdown. Plant is at Normal Operating Pressure and just below Normal Operating Temperature. Decay heat and S/G levels are being maintained with the Auxiliary Feedwater pumps. The licensee has notified the NRC Resident Inspector. The Licensee may issue a press release on this event.

• * * UPDATE FROM DAVE DEES TO VINCE KLCO AT 1135 EDT ON 8/21/2009 * * *

The atmospheric relief valves lifted for approximately 2 minutes, not 10 minutes as stated above. Also the A & B EDG's did not load for only 2 minutes. Actually "the B Safety Bus was paralleled to its normal off site source and the B Emergency Diesel was realigned for auto-start at 1740. The A Safety Bus was paralleled to its normal off site source and the A Emergency Diesel was realigned for auto-start at 1844. Notified the R4DO (Jones).

• * * UPDATE FROM DAVE DEES TO VINCE KLCO AT 1730 EDT ON 8/25/2009 * * *

The initial report stated that there was no primary to secondary leakage. Actual primary to secondary leakage as measured on 8/14/2009 was a value of less than 0.722 gallons per day. The licensee notified the NRC Resident Inspector. Notified the R4DO (Miller)