Event Notification Report for December 13, 2010

MANUAL ACTUATION OF AUXILIARY FEEDWATER SYSTEM IN RESPONSE TO LOSS OF ONE MAIN FEEDWATER PUMP

"At 2119 EST on December 13, 2010, operators manually started all Auxiliary Feedwater (AFW) pumps in response to a loss of the Unit 1 East Main Feedwater Pump.

"Operators were responding to decreasing condenser vacuum on the East Main Feedwater Pump and reducing turbine load when the East Main Feedwater Pump was manually tripped at approximately 21 inches of vacuum Hg. Operators entered the abnormal operating procedure for Loss of One Main Feedwater Pump, which directs starting all three AFW pumps.

"Plant power was stabilized at approximately 49%.

"The licensee will be notifying the NRC Senior Resident Inspector.

"This notification is being made in accordance with 10CFR50.72(b)(3)(iv)(A) due to the valid actuation of the AFW system in response to equipment failure."

No maintenance was in progress, and the cause of the decreasing condenser vacuum in the MFP was due to debris in the traveling water screen.

RESEARCH REACTOR RADIOGRAPHY INCIDENT

On 12/13/10 at 1500 EST, North Carolina State University [NCSU] was conducting routine radiography with the reactor at 1MW when unknown to the technician, the shutter stuck open. The technician entered the shielded room and noticed the shutter wasn't closed and immediately left the exposure room. After the technician left the room and secured the area, he notified other personnel including the control room. NCSU reports that the reactor was shut down by the operator because of this event. After the reactor was shut down, personnel entered the room and closed the shutter. The shutter door interlock had malfunctioned due to a mechanical interference. It was noted that the technician was not wearing personal dosimetry. NCSU estimates (based on cameras and a re-enactment conducted with the technician) that the technician was exposed for a maximum of 18 seconds with a resulting dose rate of about 150 mRem.

NCSU corrective actions include a research reactor shutdown, closing of the radiography shutter, installing interlocks to prevent shielded room access with the shutter not fully closed, and safety training of personnel related to use of the radiography facility.

NCSU is making this report in accordance with their research reactor technical specifications.

TECHNICAL SPECIFICATION REQUIRED SHUTDOWN DUE TO NOT MEETING ROD GROUP ALLIGNMENT LIMITS

"On 12/13/10 at 1210 CST a Technical Specification (TS) required shutdown was initiated on Unit 2. TS Limiting Condition for Operation (LCO) 3.1.4, Rod Group Alignment Limits, was not met as a result of Surveillance Requirement (SR) 3.1.4.2 not being met. TS Action Condition (TSAC) 3.1.4.A was entered which requires the shutdown margin to be within the limits of the Core Operating Limits Report (COLR) or boration be initiated to restore shutdown margin to within the limits within one hour and that the reactor to be in MODE 3 within 6 hours. Shutdown margin has been verified to be within the limits specified in the COLR and a reactor shutdown has been initiated.

"On 12/10/10 at 1350 [CST], during performance of Technical Specification surveillance procedure TS-06 Rod Exercise Test, rod control urgent and non-urgent failure alarms occurred while stepping Control Bank B rods out. These alarms were verified locally in the Unit 2 rod drive room. On 12/10/10 at 2212 [CST], the test recommenced and control bank B was stepped out one step as procedurally required with no alarms. When control bank B was subsequently stepped inward one step, both rod control urgent and non-urgent failure alarms were received. Both of the times that Control Bank B rods failed to move, the movable gripper coil power supply fuse blew for control rod F-6. On 12/12/10 at 2143 CST, the surveillance procedure for Control Banks A, C, and D and Shutdown Banks A and B were completed satisfactorily, however, the failure of the Control Bank B rods to step in correctly resulted in the inability to satisfy SR 3.1.4.2, and entry into TSAC 3.1.4.A being required. During continuation of the surveillance on 12/12/10, it was not recognized that troubleshooting and repairs could not be conducted satisfactorily prior to the expiration of the surveillance interval. Therefore, a TS-required shutdown in accordance was not initiated.

"The likely cause of the failure is a damaged cable in the movable gripper circuitry for control rod FÀ6. Troubleshooting is continuing and a repair plan has been developed.

"The NRC Senior Resident Inspector and Region III have been notified."

* * * UPDATE FROM PLESSAS TO KLCO ON 12/15/10 AT 1736 * * *

"On 12/13/10 at 1210 CST, a Technical Specifications (TS) required shutdown was initiated on the Unit 2 reactor. TS Limiting Condition for Operation (LCO) 3.1.4 Rod Group Alignment Limits was not met due to exceeding the specified Frequency and Grace Period for Surveillance Requirement (SR) 3.1.4.2, which required a verification of the freedom of movement (trippability) of each control rod not fully inserted into the core. TS LCO 3.1.4 is not met, and TS Action Condition 3.1.4.A was entered which requires the shutdown margin to be within the limits of the Core Operating Limits Report or boration be initiated to restore shutdown margin to within the limits within one hour as well as requiring that the reactor to be in Mode 3 within 6 hours. Shutdown margin has been verified to be within the limits specified in the Core Operating Limits Report and a reactor shutdown has been initiated.

"On 12/10/10 at 1350 CST, during performance of TS Surveillance-6 (TS-6) Rod Exercise Test, Rod Control Urgent and Non-Urgent failure alarms occurred while stepping Control Bank B rods out. These alarms were verified locally in the Unit 2 rod drive room. On 12/10/10 at 2212 CST, TS-6 recommenced and Control Bank B was stepped out one step as procedurally required with no alarms. When control bank B was subsequently stepped inward one step, both Rod Control Urgent and Non-Urgent failure alarms were received again. Both of the times that the Control Bank B rods failed to move, the movable gripper coil power supply fuse blew for control rod F-6. On 12/12/10 at 2143 CST, TS-6 for control banks A, C, & D and Shutdown Banks A & B was completed satisfactorily.

"Troubleshooting is continuing and a repair plan has been developed.

"The NRC Resident Inspector has been notified."

Notified R3DO (Kozak), IRD (Grant), NRR (Evans)