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| Entered date | Event description | |
|---|---|---|
| ENS 41934 | 19 August 2005 20:32:00 | 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.
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). |
| ENS 41813 | 30 June 2005 11:52:00 | During daily maintenance check of alert notification siren system, a siren technician discovered that the radio transmitter used to communicate with the sirens was not available. Investigation revealed that an encoder that utilizes a T1 phone line to send signals from a siren encoder to the transmitter had failed. This failure produced a signal to key the transmitter. After the transmitter is keyed for approximately 15 seconds the transmitter will lock out and therefore not be available for use. Since the transmitter was unavailable this rendered all offsite sirens inoperable. This notification is made under 10CFR50.72(b) because of a significant loss off offsite public notification capability. This failure was promptly diagnosed, corrected, and the system tested satisfactorily within approximately 62 minutes from time of discovery of 0800 Eastern Time. The tone alert radio portion of the alert notification system was available for notification during this event. The NRC Resident Inspector and Burke County was notified of this event by the licensee. |