Event Notification Report for August 19, 2005

NRC BULLETIN 91-01 VIOLATION OF CRITICALITY SPACING REQUIREMENTS

"Criticality spacing configuration requirements for Integrated Fuel Burnable Absorber (IFBA) rod caskets were violated in the IFBA loading dock (Dock 9). IFBA rod caskets are used for transport of IFBA rods from the IFBA loading dock to the Quality Control (QC) Inspection Area. Criticality spacing requirements for the caskets are posted on the lid of each container. The requirements state that loaded caskets are required to remain in the same horizontal array with 12-inch spacing between all other containers not in the same array. As such, stacking of loaded caskets is prohibited. Contrary to this requirement, Westinghouse operations personnel identified several caskets loaded with IFBA rods that were stacked in the IFBA loading dock (Dock 9). It is believed that this spacing condition was present for less than 24 hours, although this has not yet been confirmed.

"Notification is being made based on the loss of spacing of the caskets in conjunction with the failure to limit the potential pathway for moderator introduction into the caskets (see discussion below for more detail).

"Double Contingency Protection
The criticality safety analysis considers criticality not credible for normal and credible process upset conditions. However, the criticality safety analysis (ISA-12) also establishes that criticality is possible if large quantities of rods were stacked and interstitial moderation was provided and retained among the stacked fuel rods.

"Introduction of interstitial moderation is limited by the casket covers and through limitation of available sources. While no liquid moderator was present in any of the caskets, the potential pathway for moderator introduction was not addressed by either the criticality safety posting (deficiency in the criticality safety analysis) or operating procedures. In addition (as discussed under the Reason for Notification), the caskets were improperly spaced in a stacked configuration.

"It was determined that the criticality safety analysis is deficient and that less than two unlikely, independent, and concurrent changes in process conditions would be required before a criticality accident would be possible. A criticality is judged to be credible through the introduction of moderation and the incorrect configuration of the caskets.

"In accordance with Westinghouse Operating License (SNM-1107), paragraph 3.7.3 (b.3), this event satisfies the criteria for a 4-hour notification.

"Summary of Activity:
IFBA casket loading operations were discontinued.
Operations Management reviewed the procedural requirements prohibiting stacking of caskets with all of the operations personnel.
The program to train and re-certify all Operations personnel is continuing, per schedule.
The program to assess and reconstitute the plant's criticality safety basis is continuing, per schedule.

"Conclusions:
Problem was self identified by Westinghouse Operations personnel. As stated previously it is believed that the improper spacing configuration was present for less than 24 hours.
Less than double contingency protection remained.
No liquid moderator was present in any of the caskets.
At no time was the health or safety to any employee or member of the public in jeopardy. No exposure to hazardous material was involved.
The Incident Review Committee (IRC) determined that this is a safety significant incident in accordance with governing procedures.
A causal analysis will be performed.
The plant programs for training and recertification of operations personnel and for assessment and reconstitution of the plant's criticality safety basis are appropriate corrective actions for this type of event and are continuing according to plan."

There is no NRC Resident Inspector at the site. The loading operations are estimated to be discontinued for 3 to 7 days.

VIOLATION OF MAXIMUM CORE POWER LEVEL PER OPERATING LICENSE REQUIREMENTS

"Pursuant to the reporting requirements of Item 2.H of the [Vogtle Electric Generating Plant] VEGP Unit 1 and Unit 2 operating licenses, [Southern Nuclear Company] SNC is notifying the NRC of overpower events in violation of the maximum core power level of 3565 MWt authorized by Item 2.C.(1) of the licenses.

"Based on a review of operating data dating back to January 2, 2002, SNC has identified occurrences where the daily average core power exceeded 3565 MWt by as much as 0.4 MWt for Unit 1 and 0.9 MWt for Unit 2."

The temperature signal from the steam generator blowdown, used as input into the computer calorimetric, was determined to be out of calibration in each unit. The licensee is evaluating this situation for a causal effect.

The licensee notified the NRC Resident Inspector.

* * * UPDATE AT 1434 EDT ON 9/2/05 FROM STEVE WALDRUP TO S. SANDIN * * *

The licensee is retracting this report based on the following:

"On 8/19/05, VEGP notified the NRC Operations Center (Notification # 41934) of overpower events in violation of the maximum core power level of 3565 MWt authorized by Item 2.C.(1) of the Unit 1 and Unit 2. operating licenses.

"The non-conservative measurement of a plant parameter used in the calorimetric heat balance resulted in underestimating the calculated reactor thermal power. Correcting the calculated reactor thermal power for non-conservatism resulted in the conclusion that the licensed power level was exceeded. This led to the notification described above.

"Further engineering evaluation identified conservatisms in the heat balance calculation that were demonstrated to more than offset the non-conservatism discussed above. It was therefore concluded that the maximum core power level did not exceed the power level authorized by Item 2.C.(1) of Unit 1 and Unit 2 operating licenses."

The licensee notified the NRC Resident Inspector. Notified R2DO (Mark Lesser).

LICENSE REQUIRED 24 HOUR NOTIFICATION OF UNUSUAL FISH KILL

"Section 4.1 of Appendix B of the Operating License for Units 2 and 3 requires Southern California Edison (SCE) to report to the NRC within 24 hours any unusual or important environmental events, which includes unusual fish kills.

"Between August 19 and August 20, 2005, SCE removed an unusually large number of fish from the Units 2 and 3 intake structure. At approximately 1000 PDT on August 20, 2005, SCE estimated the quantity to be approximately 11,070 pounds (approximately 6420 pounds from Unit 2 and 4650 pounds from Unit 3). While the NRC has not specified a reporting limit for an unusual fish kill, SCE has internally defined this quantity as 4500 pounds. This unusual influx of fish is unrelated to plant operation and a heat treat of the intake structure was not being performed. However, there is a heat treat of the San Onofre Unit 2 intake structure scheduled for later today."

The licensee stated that the fish kill was apparently the result of a large school of anchovies that swam to close to the intake.

The licensee notified the NRC Resident Inspector.