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| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 54963 | 19 October 2020 08:00:00 | Other Unspec Reqmnt | Update to Acceptance Criteria for Itaac | In accordance with 10 CFR 52.99(c)(2) as described in NEI 08-01, Industry Guideline for the ITAAC Closure Process Under 10 CFR Part 52, Vogtle Units 3 and 4 Construction is making this notification to the NRC for determining that Inspections, Tests, Analyses and Acceptance Criteria (ITAAC) 2.3.05.13a.ii (Index No. 344) for Unit 4 requires additional actions to restore the completed status. The ITAAC Closure Notifications for Unit 4 ITAAC 344 was submitted on July 22, 2020 (ML20204B029). On October 19, 2020, it was determined that maintenance activities for the Unit 4 Polar Crane auxiliary hoist holding brake used a different approach for Post Work Verification (PWV) than the original test described in the ICN (ITAAC Closure Notification) for ITAAC 344. The alternate PWV used a test method that is standard industry practice and in accordance with ASME B30.2 to demonstrate that the Acceptance Criteria was met. An ITAAC Post Closure Notification will be submitted in accordance with 10 CFR 52.99(c)(2) and NEI 08-01. The 10 CFR 52.99(c)(4) All lTAAC Complete Notification has not been submitted for VEGP (Vogtle Electric Generating Plant) 4. The NRC Resident Inspector has been notified. | ||
| ENS 54864 | 26 August 2020 04:00:00 | Other Unspec Reqmnt | Design Change Altered Basis for ITAAC | In accordance with 10 CFR 52.99(c)(2), as described in NEI 08-01, 'Industry Guideline for the ITAAC Closure Process Under 10 CFR Part 52,' Vogtle Units 3 and 4 Construction is making this notification to the NRC for determining that Inspections, Tests, Analyses and Acceptance Criteria (ITAAC) 2.5.02.07a (Index No. 534) and ITAAC 2.5.02.07e (Index No. 538) for both units require additional actions to restore their completed status. The ITAAC Closure Notifications for ITAAC 534 were submitted on March 31, 2017 (Unit 3 ML17093A286, Unit 4 ML17093A535). The ITAAC Closure Notifications for ITAAC 538 were submitted on November 30, 2016 (Unit 3 ML16351A350, Unit 4 ML16351A334). On August 26, 2020, it was determined that a design change, issued for several Protection and Safety Monitoring System (PMS) isolation barrier assemblies (ISBs), materially altered the basis for determining that the ITAAC 534 and ITAAC 538 Acceptance Criteria were met. The modified ISBs will require testing per IEEE 384-1981, Standard Criteria for Independence of Class 1E Equipment and Circuits, to demonstrate that the Acceptance Criteria is met. System function is not required while the plant is under construction. ITAAC Post Closure Notifications in accordance with 10 CFR 52.99(c)(2) will be submitted following completion of corrective actions. The 10 CFR 52.99(c)(4) All ITAAC Complete Notification has not been submitted for VEGP ((Vogtle Electric Generating Plant)) 3 and 4. The NRC Resident Inspector has been notified.
Upon successful completion of the work to correct the identified impact to ITAAC 534, it has been determined there was no material impact to ITAAC 538. Confirmation was made that the credible fault only affected PMS to PLS analog ISBs and not PMS to PLS relay isolation ISBs. It was also confirmed that the relay isolation ISB testing and qualification summary information was unaffected by the modifications made to the analog ISBs to correct the credible fault scenario condition. Resolution of the credible fault scenario did not result in modifications to the relay isolation ISBs which are the subject of ITAAC 538. Therefore, the ITAAC Closure Notifications submitted for ITAAC 538 on November 30, 2016 (Unit 3 ML16351A350, Unit 4 ML16351A334) continue to be valid and ITAAC Post Closure Notifications are not required. The licensee has notified NRC Region 2. Notified R2DO (Miller) and NRR Vogtle Project Office (via email). | ||
| ENS 52412 | 30 November 2016 21:00:00 | Other Unspec Reqmnt | Reactor Coolant Pump Breaker Cabinet Modification - Itaac Postclosure Notification | In accordance with 10 CFR 52.99(c)(2), Vogtle Units 3 and 4 Construction is making this notification to NRC for determining that Inspection, Test, Analysis, and Acceptance Criteria (ITAAC) 2.6.01.02.ii (ECS System Seismic Category I Equipment Design Basis Loads) for both units requires additional actions to restore its completed status. The Closure Notification for this ITAAC (NRC Index No. 580) was originally submitted on May 17, 2016 (reference ML 16138A080 and ML 16166A030). On November 1, 2016, it was determined by the Vogtle 3&4 Contractor that modifications to the Reactor Coolant Pump (RCP) breaker (i.e., switchgear) cabinet design were required to ensure compliance with the applicable portions of IEEE 384, 'Standard Criteria for Independence of Class 1E Equipment and Circuits.' The modification involves an engineering change which adds different equipment to the RCP Breaker cabinet that function to trip the RCP. The new components were not previously qualified for use in the RCP breaker cabinet assembly. Additional seismic qualification type testing and analysis of components are being performed for the added components in the RCP breaker. Update of the Equipment Qualification Data Package and Equipment Qualification Summary Report for the RCP breaker to confirm the breaker withstands seismic design basis loads and Licensee's acceptance is in progress. The revised ITAAC Completion Notice will be submitted to the NRC once all related ITAAC activities have been completed. The licensee has notified the NRC Resident Inspector. | ||
| ENS 41934 | 19 August 2005 04:00:00 | Other Unspec Reqmnt | 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.
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). | Steam Generator | |
| ENS 41498 | 16 March 2005 10:40:00 | Other Unspec Reqmnt | Discovery of After-The Fact Emergency Condition Unusual Event | The licensee provided the following information about the event via facsimile (licensee test in quotes): On 3/16/2005 at approximately 0540 preparations were being made to drain down the RCS. A tagout needed to be released to support aligning the RCS for drain down. The tagout was not completely released prior to opening the intermediate leg loop drain valves. When the intermediate leg loop drain valves were opened, a flow path was created which resulted in draining the RCS. The Control Room noted approximately 70 gpm mismatch between letdown flow and charging. Personnel in containment manipulating the valves discovered that water was flowing unexpectedly to a trough in containment when they went to position the last set of intermediate leg loop drain valves and they quickly isolated the flow path. The time frame that the flow path existed was approximately 10 minutes. When the Shift Manager evaluated the event for Emergency classification the flow path had been isolated. The Shift Manager was not clear on if this event met the guidance for an NOUE declaration and asked for assistance from the Outage Control Center. Corporate licensing and Emergency preparedness were contacted for additional assistance. At 0930 it was decided to report the event per 50.72 (a) General Requirements even though it is not clear that the threshold for an EAL was met. Per NUREG-1022 the NRC staff does not consider actual declaration of the Emergency Class to be necessary when the event has rapidly terminated and the basis for the emergency class no longer exists. The licensee stated that the threshold for an Unusual Event declaration per the Vogtle EALs is 25 gpm identified RCS leakage. The NRC Resident Inspector has been notified as well as courtesy notifications to state and local authorities.
After further consideration, the licensee decided that this event should have been classified as an Unusual Event at the time of the occurrence. The licensee will notify the NRC Resident Inspector of this classification. |