ENS 54864
ENS Event | |
|---|---|
04:00 Aug 26, 2020 | |
| Title | Design Change Altered Basis for ITAAC |
| Event Description | 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). |
| Where | |
|---|---|
Vogtle  Georgia (NRC Region 2) | |
| Reporting | |
| Other Unspec Reqmnt | |
| Time - Person (Reporting Time:+44 h1.833 days <br />0.262 weeks <br />0.0603 months <br />) | |
| Opened: | Nick Kellenberger 00:00 Aug 28, 2020 |
| NRC Officer: | Ossy Font |
| Last Updated: | Sep 22, 2021 |
| 54864 - NRC Website
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Unit 3 | |
|---|---|
| Reactor critical | Not Critical |
| Scram | No |
| Before | Under Construction (0 %) |
| After | Under Construction (0 %) |
Unit 4 | |
|---|---|
| Reactor critical | Not Critical |
| Scram | No |
| Before | Under Construction (0 %) |
| After | Under Construction (0 %) |
WEEKMONTHYEARENS 549632020-10-19T08:00:00019 October 2020 08:00:00
[Table view]Other Unspec Reqmnt Update to Acceptance Criteria for Itaac ENS 548642020-08-26T04:00:00026 August 2020 04:00:00 Other Unspec Reqmnt Design Change Altered Basis for ITAAC ENS 524122016-11-30T21:00:00030 November 2016 21:00:00 Other Unspec Reqmnt Reactor Coolant Pump Breaker Cabinet Modification - Itaac Postclosure Notification ENS 419342005-08-19T04:00:00019 August 2005 04:00:00 Other Unspec Reqmnt Violation of Maximum Core Power Level Per Operating License Requirements ENS 414982005-03-16T10:40:00016 March 2005 10:40:00 Other Unspec Reqmnt Discovery of After-The Fact Emergency Condition Unusual Event 2020-08-26T04:00:00 | |