ML20211L705

(ANO) Units 1 & 2, Pre-Submittal Slide Presentation for August 4, 2020 Public Meeting

ML20211L705
Person / Time
Site:	Arkansas Nuclear
Issue date:	08/04/2020
From:	Entergy Operations
To:	Office of Nuclear Reactor Regulation
Wengert T
References
Download: ML20211L705 (13)

Text

Arkansas Nuclear One (ANO)

Units 1 & 2 10 CFR 50.69 License Amendment Request NRC Pre-submittal Meeting August 4, 2020

Agenda Introduction/Opening Remarks ANO 10 CFR 50.69 Overview PRA Technical Adequacy Deviations from NEI 00-04 Extreme Wind or Tornado Seismic Hazard Passive Categorization Schedule Closing Remarks 2

ANO 10 CFR 50.69 Overview LAR and Program follow NEI 00-04 (exceptions noted on later slides)

Standard approval timeframe requested (12 to 15 months) 3

PRA Technical Adequacy Internal Events (Including Flooding and Fire)

Probabilistic Risk Assessment (PRA) model technical adequacy previously evaluated by the NRC for TSTF-425 and NFPA 805.

Facts & Observations (F&O) closure peer reviews performed in accordance with the NEI 05-04 Appendix X approach in 2019.

Additional updates/upgrades have been peer reviewed. A Flood and LERF Peer Review was conducted in 2017 and 2019, respectively.

Changes to the as-built, as-operated plant are reviewed periodically to determine if model impacts require an off-cycle update.

Sensitivity studies will be performed in accordance with NEI 00-04 for areas such as Human Reliability Analysis (HRA) and Common Cause Failures (CCF).

Additional sensitivity studies will be performed to address applicable uncertainties associated with specific system(s) being categorized.

4

PRA Uncertainty Evaluation Process Defined in NUREG-1855 Revision 1 and EPRI Technical Reports 1016737 and 1026511 Identification of internal events/internal flooding PRA model plant-specific sources, and generic sources per EPRI 1016737 Identification of internal fire PRA model plant-specific sources, and generic sources per Appendix B of EPRI 1026511.

Consideration of generic Level 2 model sources per Appendix E of EPRI 1026511, as applicable to LERF.

Consideration of Parameter and Completeness uncertainties Documented in Sources of Uncertainty Reports / Model Notebooks NEI 00-04 specifies sensitivity studies to be conducted for each PRA model to address key sources of uncertainty.

Human Error, Common Cause, Maintenance, Fire Suppression 5

FLEX FLEX Feed Pump Internal Events - Credited in Unit 1 for extended loss of AC power (ELAP) cases Internal Events - Not Credited in Unit 2 (will be credited in future model)

Fire - Not Credited in either unit FLEX portable DG Internal Events - Not Credited.

Fire - Credited for long term DC power for Unit 2 ELAP Fire - Not Credited in Unit 1 6

Incipient Detection Very Early Warning Fire Detection System (VEWFDS)

Installed in Unit 2 Only Installed in Key Electrical Cabinets Procedures Established to Address System Operation and Response Credit in the Fire PRA removed during NFPA-805 Approval Process given NUREG 2180 was not published 7

Deviations from NEI 00-04 Tornado Safe Shutdown Equipment List (TSSEL)

ANO1/2 will use a Tornado Safe Shutdown Equipment List (TSSEL) for extreme wind or tornado hazard (missiles only)

Tornado Safe Shutdown paths developed to identify the safety functions and associated sets of equipment credited to achieve and maintain safe shutdown Similar to Seismic Margins Analysis (SMA) SSEL approach - High Safety Significant (HSS) components are identified by determining if the component is credited on the TSSEL.

ANO1/2 will ensure that the TSSEL reflects the as built as operated plant.

As stated in NEI 00-04, a structure, system, or component (SSC) identified as HSS by a non-PRA method for external events may not be re-categorized by the IDP.

8

Deviations from NEI 00-04 Tornado Safe Shutdown Equipment List (TSSEL) 9

Deviations from NEI 00-04 Seismic Justification Referencing EPRI 3002017583 ANO1/2 will reference EPRI 3002017583 for seismic considerations in the categorization process.

ANO1/2 will document justification for being a Tier 2 Plant and provide justification to the integrated decision-making panel (IDP).

Conclusions and results from existing seismic studies and walkdowns, as they apply to the system being categorized, will be included in information provided to the IDP.

ANO1/2 will follow the guidance for the lead Tier 2 plant, LaSalle.

10

Deviations from NEI 00-04 Passive components and the passive function of active components will be evaluated using the ANO Risk-Informed Repair/Replacement Activities (RI-PRA) method.

The use of this method was previously approved by the NRC in the Vogtle 10 CFR 50.69 application.

ASME Code Class 1 SSCs with a pressure retaining function, as well as supports, will be assigned as HSS for passive categorization. This will result in HSS for its risk-informed safety classification and cannot be changed by the IDP.

11

Schedule

• LAR Submittal expected by end of September 2020

• Standard approval timeframe requested (12 to 15 months) 12

Closing Remarks