Event Notification Report for June 27, 2011

OFFSITE POWER SOURCES DECLARED INOPERABLE

"At 1344 CDT on June 27, 2011, off-site A.C. power sources to Unit 2 were declared inoperable as a result of Transformer 2RY lockout and less than the required minimum voltage on the transmission system.

"At 1310 CDT on June 27, 2011, Transformer 2RY was locked out. The Transformer 2RY lockout resulted in entering Technical Specification 3.8.1, Condition A and a single path to the transmission system. At 1344 CDT, the site was notified by transmission systems operations that the 345 KV grid voltage could not be maintained at the minimum voltage required per procedure C20.3. The path to the transmission system was declared inoperable and Unit 2 entered Technical Specification 3.8.1, Condition C. Although inoperable, transmission system sources remained connected to Unit 2; emergency diesel generators were available but not required to run.

"By securing a cooling tower pump and fans, the required minimum transmission system voltage was met and determined to be sustainable. Technical Specification 3.8.1, Condition C, was exited on June 28, 2011 at 0038 CDT.

"After additional analysis, it was determined that this condition was a safety system function failure for Unit 2 and reportable under 10 CFR 50.72(b)(3(v)(D). This condition should have been reported on June 27, 2011 under the eight-hour reporting criteria.

"The NRC Resident Inspector has been informed."

AGREEMENT STATE REPORT - IRIDIUM SOURCE DISCONNECTED FROM RADIOGRAPHY CAMERA

The following information was received from the State of Texas via e-mail:

"On July 6, 2011, the Agency [Texas Department of Health] received a written report from the licensee's Radiation Safety Officer (RSO) that on June 27, 2011, there was a source disconnection at a temporary field site [Dralco, Inc] in Weatherford, Texas. Upon discovering the disconnection, the radiographers roped off the area at the 2 millirem/hour boundary and notified the RSO.

"The RSO arrived on site and confirmed that the source was disconnected. The RSO performed the retrieval by removing the source tube from the camera, shaking the source out of the source tube and placing a lead shield and shot bag(s) over the source with the pigtail exposed. He reconnected the drive cable and the source was cranked back into the camera. The camera was disconnected so that the drive cable and the pigtail connectors could be inspected. No damage was noted and the camera was immediately returned to service.

"The RSO stayed on site approximately one hour to make sure there were no more issues. The RSO stated that the radiographers had failed to connect the pigtail to the drive cable before cranking out the source. The RSO received a dose of 52 mrem. Corrective action includes the event being discussed at the next safety meeting, the radiographers (who were trainers) were instructed to pay attention to safety and the process of connecting the drive cable to the source."

Camera: Amersham Model 660B, SN: 4894
Source: QSA Global Model A424-9, SN: 69176B, Iridium-192, 22 curies

Texas Incident #: I-8867

APPENDIX R ANALYSES FAILS TO RECOGNIZE HOT-SHORT FAILURE RESULTING IN THE LOSS OF AN ESSENTIAL ELECTRICAL BUS

The following Part 21 report was received via fax:

"10 CFR 21: Appendix R analyses conducted for Virgil C. Summer Nuclear Station (VCSNS) failed to identify that a fire-induced hot-short failure in an ammeter circuit would result in a loss of the B-train 7.2KV essential electrical bus (XSW1DB).

"Appendix R analyses performed by Gilbert/Commonwealth (now Worley Parsons) in the early 1980s failed to recognize the possibility of a fire-induced hot-short condition in a circuit that was identified as being required for safe shutdown. This circuit connects a set of sensing current transformers (CTs) to an ammeter on the Main Control Board, and provides over-current sensing for an over-current relay. Gilbert/Commonwealth recognized that a fire-induced open circuit in this ammeter circuit would result in damage to, or a fire in, the B-train 7.2kV essential switchgear. Thyrite protectors were added to the circuit to protect the CTs from this open circuit condition as part of the Appendix R analysis.

"However, this analysis and resolution failed to consider the hot-short-to-ground failure mode. Current from a hot-short could flow through the ammeters, or neutral conductor, and then through the bus neutral over-current relay to ground. This could actuate the over-current relay, which in turn would actuate a lock-out relay and trip all incoming breakers to bus XSW1DB. This bus provides credited B-train power to safe-shutdown components credited for this scenario. The Appendix R analyses conducted for VCSNS by Gilbert/Commonwealth did not address the hot-short scenario and is considered to be a defect, or omission. reportable under 10 CFR 21.

"This condition was identified during the circuit analysis review for transitioning the Appendix R Fire Protection Program to NFPA 805 and was reported to the NRC as an unanalyzed condition on 05/03/2011 (see Event Notification No. 46811). Corrective actions have been taken to address this issue."

The licensee informed the NRC Resident Inspector.

* * * UPDATE FROM JOE MARSDEN TO MARK ABRAMOVITZ ON 6/30/2011 AT 1643 * * *

"Worley Parsons Investigation Results:

"Although this design was not a generic or standard design, Worley Parsons performed further evaluation, including extent of condition, for other Nuclear Power Plants that Worley Parsons performed the original design and performed Appendix R Compliance Review/Modifications.
Five plants were identified as follows:

"1) Crystal River 3: Worley Parsons discussed the issue with Progress Energy and jointly concluded that Crystal River 3 is not impacted because their corresponding current transformer circuit design has a different configuration. The circuit design is not generic or programmatic.

"2) TMI Unit 1: TMI is not impacted because their corresponding current transformer circuit design has a different configuration. The circuit design is not generic or programmatic.

"3) Perry: The Appendix R Compliance Review was accomplished by a team of Worley Parsons and others. Since Worley Parsons was involved with the Appendix R analysis and the affected electrical drawings are not readily available at Worley Parsons, it was concluded that Worley Parsons could not complete the evaluation to determine if the Perry design condition could cause a substantial safety hazard. Worley Parsons issued letter PNPP-O-CO-011-WCLT-0001 to the Perry Design Engineering Manager, recommending Perry to complete the evaluation pursuant to 10CFR21.21(a).

"4) V.C. Summer: V.C. Summer is the subject plant and is impacted. VC. Summer is issuing LER #2011-001-00, which constitutes the Part 21 Notification for this design defect, or omission.

"5) R.E. Ginna: Worley Parsons did not perform the Appendix R analysis for Ginna.

"Corrective Action:

"V.C. Summer has implemented immediate compensatory measures for this condition until a permanent solution is identified. A root cause analysis was jointly performed with V.C. Summer. The root cause analysis and Worley Parsons corrective action program review considered this an isolated incident due to human error. No programmatic/procedure corrective actions were identified due to the historical nature of the issue.

"Actions to preclude recurrence: Human performance issues from this event will be communicated to the Worley Parsons Nuclear Engineering staff under our corrective action and lessons learned program."

Notified R1DO (Welling), R2DO (Franke), and R3DO (Lipa). Notified the Part 21 Group via e-mail.