Event Notification Report for March 20, 2013

UNUSUAL EVENT DECLARED BASED ON INDICATION OF FIRE WITHIN PROTECTED AREA

The licensee declared a Unusual Event based on EAL HU-2 due to indication of a fire in the Protected Area for greater than 15 minutes. The licensee received initial indication of a fire alarm and startup of fire water pumps. The alarm was located in the vicinity of the Auxiliary Building Unit 2 HVAC supply unit. The licensee declared an unusual event at 0246 EDT. Upon investigation, it was determined that the heater strips in an HVAC unit were overheated and caused a fire alarm and no fire actually existed.

The licensee notified state and local agencies and will notify the NRC Resident Inspector.

Notified DHS, FEMA, DHS NICC and NuclearSSA (email).

* * * UPDATE AT 0409 EDT ON 3/20/13 FROM BISHOP TO CROUCH * * *

The licensee terminated its unusual event at 0341 EDT on 3/20/13 after confirming there was no fire within the Unit 2 Auxiliary Building HVAC supply unit.

The licensee notified state and local agencies and will notify the NRC Resident Inspector.

R2DO (Rich) and NRR EO (Lund) notified.

Notified DHS, FEMA, DHS NICC and NuclearSSA (email).

PART 21 - ASCO DIRECT ACTING 3-WAY SOLENOID VALVE FAILURE

The following is a summary of a Part 21 report received from ASCO Valves Inc., via facsimile:

ASCO received a failed solenoid actuated valve from its distributor (Areva). The valve has been qualified for 1-E nuclear use and is referred to as a NP8320 direct acting 3-way valve. The valve that failed would not shift when de-energized. Information accompanying the valve identified that it was operating for approximately three months since August 2012. The valve was manufactured in May 2010.

"The valve was disassembled and the spring was observed to be not on the core completely. The valve was re-assembled with the spring properly on the core and subjected to cycling. During cycle testing the second turn of the spring was shown to completely overlap the first turn coming over the edge of the core, pulling the first turn off of the core. The spring came completely off the core in 97 cycles. ASCO identified that the spring was not properly manufactured as the beginning of the second turn was not wound to the same diameter of the first turn.

"ASCO and the spring supplier identified the manufacturing lot that was the source of the spring for serial number A483456-001. ASCO identified 10 nuclear valves manufactured with this manufacturing lot. The remaining 3990 springs from this lot were used in commercial valves. ASCO uses this same spring in approximately 40,000+ commercial valves per year and no commercial returns have been found with the same condition of this spring coming off the core.

"Neither ASCO's incoming inspection nor the spring manufacturer detected the nonconformance for this manufacturing lot.

"ASCO evaluated other valves that used this same spring manufactured from other lots received in 2010. These valves represent a time period shortly before and shortly after the manufacture of the above valve. ASCO's investigation concluded that these springs are conforming.

"This condition may cause the spring to work itself off the core and present a situation where the valve would not shift to its de-energized position. ASCO believes the condition would present itself relatively early into its cycle life.

"ASCO has contacted the customer, AREVA, who received the 10 valves in question. ASCO has implemented corrective actions to include inspection of the spring assembled to the core at nuclear dedication inspection to verify that the spring is properly seated and the second turn does not overlap the first at the springs working length.

"ASCO does not have adequate knowledge of the actual installation and operating conditions of these valves to determine whether their malfunction could create a 'substantial safety hazard' as defined in 10 CFR 21.3. We are providing this information to inform you of our investigation results, corrective action and customer notification.

"If you have any questions, you can contact Bob Amone at 803-641-9395."

AGREEMENT STATE REPORT - RADIOGRAPHER OVEREXPOSURE

The following report was received via e-mail:

"[The Oklahoma Department of Environmental Quality was] informed of an over-exposure of a radiographer employed by Tulsa Gamma Ray (OK-17178-02). The dose involved is 6700 mR, but it isn't clear if this is the dose from just this exposure or if that is for the year to date. We [Oklahoma] will provide more details as they become available."

HIGH PRESSURE COOLANT INJECTION (HPCI) TURBINE OIL LEAK

"After securing the Unit 1 HPCI turbine from service following a planned pump, valve, and flow surveillance test an oil leak of approximately 1 pint per minute developed. The oil leak was stopped by securing the auxiliary oil pump for the HPCI system.

"There was no loss of oil pressure while the HPCI turbine was operating. This issue has caused the Unit 1 HPCI system to be declared inoperable and unavailable. Per LGS [Limerick Generating Station] Unit 1 Technical Specifications section 3.5.1, the HPCI system must be restored to operable status within 14 days.

"The cause of the oil leak is being investigated."

The licensee notified the NRC Resident Inspector.


* * * UPDATE FROM DANIEL WILLIAMSON TO DONALD NORWOOD AT 1510 EDT ON MARCH 21, 2013 * * *

"UNIT 1 HPCI has been restored to operable status following repairs and post-maintenance testing at 1300 EDT on March 21, 2013."

The licensee changed the reporting requirement from 10CFR50.72(b)(3)(ii)(A) to 10CFR50.72(b)(3)(v((D).

The licensee will notify the NRC Resident Inspector. Notified R1DO (Trapp).

MANUAL REACTOR TRIP DUE TO LOSS OF GENERATOR STATOR COOLING WATER

"At 1951 CDT on March 20, 2013, Byron Unit 2 Reactor was manually tripped due to the loss of all Generator Stator Cooling Water. 2BEP-0, 'Reactor Trip or Safety Injection Unit 2' was entered and a transition was made to 2BEPES 0.1, 'Reactor Trip Response Unit 2.' The auxiliary feedwater pumps automatically actuated upon the expected low steam generator level. Upon the trip, it was noted that a Digital Rod Position Indication System Urgent Failure occurred with a General Warning on Control Rod position M12. Indication for the Train 'B' Reactor Trip breaker was lost. All Control Rods inserted upon Reactor trip and the Train 'B' Reactor trip breaker was locally verified open."

The plant is in its normal shutdown electrical lineup. No safeties or reliefs lifted during the event. There was no impact on unit-1.

The licensee notified the NRC Resident Inspector.