Event Notification Report for June 16, 2011

ADDITIONAL PENETRATION IDENTIFIED FOR MITIGATION DURING WALKDOWN

"Operations identified a potential flooding issue in the Intake Structure 1007 ft. 6 in. level. The area of concern is a the hole in the floor at the 1007 ft. 6 in. level where the relief valve from FP-1A discharge pipe goes through the raw pump bay and discharges into the intake cell. There is one penetration of concern. Flooding through this penetration could have impacted the ability of the station's Raw Water (RW) pumps to perform their design accident mitigation functions.

"Efforts are in progress to seal the penetration.

"This eight-hour notification is being made pursuant to 10 CFR 50.72 (b)(3)(v)."

The licensee notified the NRC Resident Inspector.

* * * RETRACTION ON 9/26/12 AT 1949 EDT FROM ROBERT KROS TO DONG PARK * * *

"The penetration in question is not an external penetration and is not within the scope of the CLB [Current Licensing Basis] and therefore the condition is not reportable. The penetration is internal to the intake structure and does not affect internal flooding.

"The failure to retract this notification in a timely fashion was identified while reviewing flood related station notifications from 2011 and has been entered into the corrective action system."

The licensee has notified the NRC Resident Inspector. Notified R4DO (Werner).

CHEMICAL RELEASE FROM INTAKE PUMPING STATION.

"A notification of the event discussed below was made to the Tennessee Department of Environment and Conservation (TDEC) at approximately 09:48 [hrs EDT] on June 17,2011. As a result of the notification made to the state, NRC is being notified in accordance with 10 CFR 50.72(b)(2)(xi), 'News Release or Notification of Other Government Agency.'

"On June 16, 2011, a chemical treatment of the raw water system for Watts Bar Nuclear Plant (WBN) was underway. The treatment was a routine injection of biocide (Sodium Hypochlorite and Flogard MS6237) for the treatment of microbiologically induced corrosion (MIC) and to inhibit the growth of asiatic clams. At approximately 13:09 [hrs EDT] on June 16, 2011, WBN personnel noticed that a small stream of water was releasing through the splash guard of a trough on the outside (lake side) of the Intake Pumping Station (IRS) and entering the Intake Forebay. This initial leak was secured by approximately 14:30. At approximately 14:35, a second leak from a broken pipe was identified. The second leak was terminated at approximately 16:05. The cause of the initial leak was determined to be a tree growing in a trough in the intake structure and degraded sealant on the trough's splash guard. TVA's [Tennessee Valley Authority] biologist performed a survey of the intake channel and the river downstream from the plant and found no dead fish or abnormal bird activity. TVA's review of the chemical release to the lake determined that no Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) reportable quantities were exceeded.

"The reporting requirements contained in WBN's Environmental Protection Plan (EPP) were reviewed and not found applicable to this event. WBN's [NRC] Resident Inspector has been notified of the event and the need for the event notification."

PART 21 - EMERGENCY DIESEL GENERATOR FAILED AIR START MOTOR

The following information was received by facsimile:

"COMPONENT: Air start motors with friction-clutch inertia drives (not pre-engagement type)

"Engine Systems Inc. (ESI) began a 10CFR21 evaluation on 06/16/11 upon receipt of a failed air start motor from Exelon - Clinton. According to information provided by Clinton Nuclear Plant, they experienced a slow start of an EDG during one of their surveillance runs. Subsequent troubleshooting revealed that one of the air start motors had failed. Specifically, it was found that the starter drive had failed which prevented the air start motor from applying full starting torque to the engine. The inspections performed by Clinton indicated the failed motor had what appeared to be excessive preload applied to the springs of the drive clutch which led to spring roll and fragmentation. Clinton had also supplied six remaining air start motors from their inventory to ESI for evaluation of the drive clutch torque setting. The air starters are Pow-R-Quik type LS-60-RH1 and LS-60-LH1 (where RH and LH designate right hand and left hand rotation respectively).

"The evaluation was concluded on 08/01/11 and determined the air motor failure to be a reportable defect as defined by 10CFR21. The starter drive failure was attributed to excessive torque adjustment of the clutch assembly. This overstressed the clutch disc plates which lead to eventual failure of the friction-clutch inertia drive assembly. Failure of the clutch drive renders the air start motor inoperative. Depending upon the configuration of the engine's starting system, an inoperative air start motor could cause excessive starting times or a start failure. Either scenario has the potential to prevent the emergency diesel generator from performing its safety related function.

"Clutch torque testing was performed on the six (6) starters returned from Clinton's inventory. [Results indicate inconsistent clutch settings]. The specified torque setting for the clutch drive is 275-300 ft-Ibs. Of the six starters tested, only one was within specification.

"Based on the test data obtained from the six (6) Clinton starters, all previous shipments of air motors with the friction-clutch inertia drive are suspect for having inconsistent clutch drive torque settings."

Affected users of the air start motors that contain friction-clutch inertia drives include the following: Exelon-Clinton, Entergy-Indian Point 3 and PSE&G-Salem.

Engine Systems, Inc Report Number: 10CFR21-0102, Rev. 0.