Event Notification Report for March 24, 2012

DEGRADATION OF STEAM GENERATOR NOZZLE WELD AREAS

"On March 24, 2012, at 1855 [EDT] during the performance of work activities to support Alloy 600 dissimilar metal weld overlay work on the 'B' Reactor Coolant loop hot leg to the 'B' Steam Generator nozzle weld, two through-wall defects were identified. The workers noted a small amount of water seeping from the indications in the nozzle weld area. The indications are in the area of excavation that was being performed for the weld overlay project. Approximately 1 [inch] of weld material had been removed prior to the seepage being identified.

"Entered Technical Requirement 3.4 .6, 'ASME Code Class 1, 2 and 3 Components' and immediately initiated actions to isolate the 'B' Reactor Coolant loop. The 'B' Reactor Coolant loop stop valves were closed at 2312 hours on March 24, 2012, which isolated the defects from the reactor coolant system . An engineering evaluation of the defects will be performed and corrective actions implemented.

"This event is reportable in accordance to 10CFR50.72(b)(3)(ii)(A) for 'any event or condition that results in the condition of the nuclear power plant, including its principle safety barriers, being seriously degraded'."

The licensee notified the NRC Resident Inspector and will notify Louisa County.

AGREEMENT STATE REPORT - OVEREXPOSURE TO RADIOGRAPHER WHEN CAMERA SOURCE BECAME DISCONNECTED

The following information was received by facsimile:

"On March 24, 2012, the licensee notified the Agency that it one of its radiography teams had experienced a disconnect of a 65 curie iridium-192 on a QSA Delta 880 radiography camera at a temporary work site in Pasadena, Texas. The crank out drive cable had broken and the source had completely disconnected. After an authorized individual performed the source retrieval, the licensee's RSO learned that the radiographer trainer disconnected the source tube from the camera and had carried the source tube around his neck while he climbed down the ladder of the scaffold. The source was in the tube at this time, but it is uncertain at this time the source's location within the tube. When the radiographer trainer reached the platform he removed the source tube from his neck. The licensee's initial dose estimates for the radiographer trainer are a whole body dose of at least 56 rem and an extremity limit that may exceed 100 rem. The radiographer's film badge is being sent for immediate reading. The licensee is conducting an investigation.

"NOTE: During the licensee's initial phone call to the Agency, the Agency understood the whole body dose estimate to be 6 rem and considered the event to be a 24-hour report (the Agency did report to the NRC HOO within 24 hours). However, when the Agency received the written initial report this morning, March 26, 2012, it was discovered that the estimate is 56 rem, which requires immediate notification. This report is being submitted to update and upgrade the event. More information will be provided as it is obtained.

The State also corrected the source strength to 65 curie Ir-192 source. REAC/TS was notified on 03/26/12 and the licensee has made contact with them.

Texas Incident: I-8942

* * * UPDATE FROM KAREN BLANCHARD TO CHARLES TEAL ON 3/29/12 AT 1712 EDT * * *

"The radiographer's badge was processed on March 28, 2012. The badge reading was 812 mrem whole body (deep dose equivalent). Dose reconstruction continues as the investigation continues. More information will be provided as it is obtained."

Notified R4DO (Farnholtz) and FSME (McKenney).

* * * UPDATE AT 1414 EDT ON 09/12/12 FROM KAREN BLANCHARD TO S. SANDIN * * *

The following update from the State of Texas was received via email:

"Investigation of the event provided the following information. The radiographer stated he had performed a survey of the camera and source guide tube prior to disconnecting it. He stated he observed normal readings, including approximately 20 mr/hr at the camera. He lowered the camera and drive cable assembly down to the radiographer trainee who was working with him. After climbing down the ladder and removing the source guide tube from around his neck, the radiographer walked over to assist the trainee who was having trouble disconnecting the drive cable assembly. The radiographer stated he saw that the camera was not locked and was still in the red position. The radiographer stated he again surveyed the camera and then the source guide tube and got high readings at the end of the source guide tube. Sometime between the time the radiographer began attempting to disconnect the drive cable assembly and the time he surveyed the guide tube, both of their alarming rate meters (ARM) began alarming. They both moved back and notified the licensee's Radiation Safety Officer (RSO) of the apparent disconnect. The radiographer then used a pair of 3-foot long tongs to lift the guide tube from the collimator end. As he lifted the tube, the source fell out onto the floor. He again moved back, re-established a 2 mr/hr boundary, and waited on the RSO. The RSO arrived on-site as did an individual authorized to perform source retrieval. The source was then properly retrieved and secured. The RSO checked ARMs and the survey meter and all were working properly at that time.

"The camera, drive cable assembly, and source guide tube were sent to the manufacturer for evaluation. The manufacturer reported that . . . 'the cable was severed directly behind the 550 connector. The male connector passed the no go gauge but is heavily worn . . . The cable is corroded/rusted and stiff at the broken area and was dry of any lubricant grease . . . the control pistol assembly components showed significant signs of rusting and the control housings were taped to allow continued use . . . there are no indications of improper manufacture or defect in the Teleflex drive cable . . . Based on this evaluation, the drive cable failed due to a combination of wear, corrosion and lack of lubrication indicative of improper maintenance.' The radiographer stated he did not check the condition of the crank out drive cable prior to using it (as required) even though he initialed the daily work sheet indicating he had completed his daily equipment check.

"The survey meter and ARMs were sent to the manufacturer for evaluation. All were within the calibration date and all were operating properly. The ARMs began alarming at 400 mr/hr when they were checked.

"The radiographer was wearing his dosimetry badge on his right chest pocket. It was sent for immediate processing following the incident. The badge reading was 812 mrem. The licensee performed dose assessment calculations for the event and assigned an estimated dose of 29.32 rem for this event.

"Key issues identified:

1. Failure to perform proper survey.
2. Failure of licensee to properly inspect and maintain equipment (specifically the drive cable in this instance).
3. Failure of radiographer to perform daily equipment inspections and remove from service components in need of maintenance.
4. Failure to ensure camera is in locked position after cranking source into camera and before proceeding."

Notified R4DO (Lantz) and FSME via email.

SEWAGE SPILL IN THE TURBINE BUILDING THAT DISCHARGES TO THE KEOWEE RIVER

"On 3/24/12 at 1810 hrs EDT, a four inch sewage line in the turbine building failed. This allowed sanitary wastewater to spill into the turbine building basement. An estimated 100 gallon entered into trench drains and then to the station sump which discharges into the conventional wastewater system. This conventional wastewater system is discharged to the Keowee River from NPDES [National Pollutant Discharge Elimination System] outfall 002. The discharge of outfall 002 is into the Keowee River below the Keowee River Hydro Station. The normal discharge path for sanitary wastewater is to the City of Seneca. South Carolina DHEC [Department of Health and Environmental Control] was notified of the spill on 3/24/12 at 2259 hrs EDT. After further review, this was determined to be reportable under 10CFR50.72(b)(2)(xi)."

This event was determined to be reportable at 2150 EDT on 3/28/2012. The event was entered into the corrective action program. There was no impact on plant operations and the cleanup has been completed. The licensee notified the NRC Resident Inspector.

INVALID PROTECTION SYSTEM ACTUATION DURING STATION ELECTRICAL TRANSIENT

"The purpose of this report is to provide a telephone notification for an invalid actuation. On March 24, 2012, following the completion of switch yard work, the Control Room received switching orders to open Bus Tie 9-10 Bus 9 disconnect and close Bus Tie 9-10 Bus 10 disconnect. Operations was unaware that a grounding device, installed for personnel protection during the work activities, had not been removed. Consequently, when the Bus Tie 9-10 Bus 10 disconnect was closed the switchyard was grounded resulting in an electrical transient. Protective relaying operated as designed to clear the fault, and there were no injuries.

"During the electrical transient, the voltage depression tripped the Unit 1 "A" Reactor Protection System (RPS) bus which caused a 1/2 scram and certain protective logic systems to de-energize by design. The following invalid actuations occurred as a result of the loss of power to the RPS bus: partial Group 11 Isolation (Primary Containment); Group III Isolation (Reactor Water Cleanup); Reactor Building Ventilation Isolation; Control Room Ventilation Isolation; and Standby Gas Treatment Initiation.

"The electrical transient also tripped the Unit 1 ECCS keepÀfill pump, resulting in the Core Spray (CS) discharge pressure decreasing to the alarm setpoint. Both CS subsystems were conservatively declared inoperable and entry into Technical Specifications (TS) 3.0.3 occurred at 1936 hours. Subsequent fill and vent activities confirmed no air existed in the discharge headers of the CS subsystems (no loss of safety function) and both subsystems were declared operable with TS 3.0.3 being exited at 2017 hours. Following the electrical transient, the Unit 1 generator was temporarily limited to approximately 90% load due to elevated vibration on Turbine Bearing No. 10. In-plant walk-downs identified no other equipment concerns. Unit 1 returned to full power on April 2, 2012, following confirmation the bearing vibration is acceptable for long-term operation. Unit 2 was in a scheduled refueling outage during the event and was unaffected by the electrical transient. A Root Cause Investigation is ongoing."

The licensee notified the NRC Resident Inspector.