ML121800306

Handouts at the June 29, 2012 NFPA 805 Meeting at the Hq - Power Point Slides

ML121800306
Person / Time
Site:	Arkansas Nuclear
Issue date:	06/28/2012
From:	David Bice Entergy Nuclear Operations
To:	Kalyanam N Plant Licensing Branch IV
Kalyanam N, NRR/DLPM, 415-1480
Shared Package
ML121800304	List: ML121800306 ML121800310 ML121800312 ML121800319 ML121800341
References
TAC ME8282
Download: ML121800306 (17)

Text

License Amendment Request NFPA 805 Acceptance Review Arkansas Nuclear One Unit 2 June 29, 2012

Technical Acceptance Issues

• Modification Details

- The modifications for transition need to be described and, as appropriate, modeled in the probabilistic risk analysis (PRA) to properly estimate the change in risk associated with transition

- The License Amendment Request (LAR) needs to be supplemented with the descriptions of these modifications and provide adequate information to review the evaluations supporting these modifications

• Risk Estimates for Recovery Actions (RAs)

- About one third of the fire areas in the Additional Risk of RAs column of Table W-2 of the LAR do not contain a quantitative risk result

- The LAR needs to be supplemented with the quantitative RA risk estimates to demonstrate that the evaluations supporting the transition have been satisfactorily completed

Technical Acceptance Issues

• RAs Credited for Control Room (CR) Abandonment

- Attachment G of the LAR states that ANO-2 has no primary control station, besides the main CR, yet only eight RAs are identified for Fire Area G

- Unclear how both the total change in risk and the additional risk from RA is bounded by a risk estimate of 0.0

- The LAR needs to be supplemented with additional discussion about the planned modifications and RAs, and how these are modeled d l d iin th the PRA iin sufficient ffi i t d detail t il tto explain l i th the unexpected results

• Sensitivity Study

- Two sensitivity studies compare the results based on one unaccepted method to results based on another unaccepted method

- The LAR needs to be supplemented with the risk results (in relation to the sensitivity analyses for non-suppression probability for long-term fires and adjustment factor for electrical cabinet ignition frequency) calculated using an acceptable analysis method

Technical Acceptance Issues Response Overview

• Modification Details

- Attachment S revised to provide additional detail for proposed modifications

• Risk Estimates for Recovery Actions (RAs)

- Additional analysis performed to address the risk estimates of the quantitative RAs and included in revised Table W-2.

• RAs Credited for Control Room (CR) Abandonment

- Additional information to be provided relating to Fire Area G and how the modifications and RAs were modeled in the Fire PRA. Table G-1 and Table W-2 are revised accordingly.

- List of defense-in-depth RAs will be included

• Sensitivity Study

- A new sensitivity analysis has been completed in compliance with NUREG/CR-6850 for comparison to the current results

- Further analysis is needed to accurately reflect the risk and minimize the need for unnecessary plant modifications

- Attachment V revised to capture revised sensitivity analysis.

Item 1 Modification Details

- The modifications for transition need to be described and, as appropriate, modeled in the PRA to properly estimate the change in risk associated with transition

- The LAR needs to be supplemented with the descriptions of these modifications and provide adequate information to review the evaluations supporting these modifications

Item 1 Modification Details

- Detailed final plant configuration descriptions have been completed and will be discussed for the 16 modifications identified

- Attachment S revised to provide additional detail for proposed modifications

- Modifications will be implemented in a manner that supports the assumptions of the Fire PRA

Proposed Attachment S Revision Item 2 Risk Estimates for RAs

- About one third of the fire areas in the Additional Risk of RAs column of Table W-2 of the LAR do not contain a quantitative risk result

- The LAR needs to be supplemented with the quantitative RA risk estimates to demonstrate that the evaluations supporting the transition have been satisfactorily completed

Item 2 Risk Estimates for RAs

- The delta risk from recoveries have been generated and the results are being finalized

- Delta risk of recoveries are based upon post transition model with modifications

- Results will be provided in a revision to Attachment W of the LAR

Item 2 Risk Estimates for RAs - Example

Item 3 RAs Credited for CR Abandonment

- Attachment G of the LAR states that ANO-2 has no primary control station, besides the main CR, yet only eight RAs are identified for Fire Area G

- Unclear how both the total change in risk and the additional risk from RA is bounded by a risk estimate of 0.0

- The LAR needs to be supplemented with additional discussion about the planned modifications and RAs, and how these are modeled in the PRA in sufficient detail to explain the unexpected results

Item 3 RAs Credited for CR Abandonment

- The 0.0 for delta CDF and LERF will be removed from Attachment W and replaced with actual change in risk values

- Attachment G updated for Fire Area G (CR) to show defense-in-depth defense in depth actions in addition to the key risk based RAs

- A description of the modeling details for CR abandonment will be included in the supplement

Item 4 Sensitivity Study

- Two sensitivity studies compare the results based on one unaccepted method to results based on another unaccepted method

- The LAR needs to be supplemented with the risk results (in relation to the sensitivity analyses for non-suppression non suppression probability for long-term long term fires and adjustment factor for electrical cabinet ignition frequency) calculated using an acceptable analysis method

Item 4 Sensitivity Study

- A new sensitivity analysis based upon post transition model with modifications is being completed to comply with NUREG/CR-6850 for comparison to the current results

- Public meeting on June 12, 2012 provided preliminary results of unscreened fire scenarios due to sensitivity without reliance on panel factors

- Additional unscreened scenarios have been added stemming from the adjustment of manual suppression of long term fires that were lower than .001

- Delta risk input has also been calculated and is available for review

- Further analysis is needed to accurately reflect the risk and minimize the need for unnecessary plant modifications

Impact on ANO-1 LAR

- The ANO-1 LAR will require revision to address items identified for ANO-2

- The ANO-1 LAR submittal is scheduled for August 31, 2012

Summary ANO-2 supplemental response will be provided by July 11, 2012 addressing identified gaps in the original LAR.

Questions ??