ML12221A264

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NRC Public Meeting NRC Presentation 8/9/12
ML12221A264
Person / Time
Site: Davis Besse 
Issue date: 08/09/2012
From:
Division of Nuclear Materials Safety III
To:
Atif Shaikh
References
Download: ML12221A264 (29)
v • d • e


Text

NRC Public Meeting NRC Public Meeting Davis Besse Shield Building Cracks August 9, 2012

Welcome Ch l

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2 Charles Casto Regional Administrator NRC Region III

Meeting Information Steve Reynolds 3

y Director Division of Reactor Safety NRC Region III

Meeting Agenda

  • Meeting Purpose & Background
  • Licensee Presentation 4
  • Summary
  • Break
  • Public Questions and Comments

Meeting Purpose

Presentation by licensee on results of root cause evaluation and corrective actions Presentation by NRC on NRCs inspection of licensees root cause activities and actions going forward 5

Safety Issue

  • On October 10, 2011, licensee promptly notified NRC upon identifying cracking in the Davis Besse shield building.

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  • NRC determined there was no immediate safety concern. The plant was shut down at the time.
  • NRC conducted a rigorous inspection resulting in licensee performing additional testing and more extensive, sophisticated calculations.
  • Shield building is safe despite the cracking NRC Safety Conclusion Regarding Operability 7
  • Licensee could safely restart the plant
  • Public meeting held 1/5/12 on NRCs safety conclusion 7

Confirmatory Action Letter Issued to Licensee

  • Letter dated December 2, 2011 8
  • Implement a short-term monitoring program
  • Complete a root cause evaluation
  • Develop and implement corrective actions
  • Develop and implement a long-term monitoring program

Additional NRC Actions to Ensure Continued Safety of the Shield Building

  • Conducted a follow-up inspection of root cause evaluation and proposed corrective actions
  • Continued relentless monitoring of licensee correction actions
  • Scrutinous oversight of licensee actions going forward 9

Introductions - NRC

  • Charles Casto, Regional Administrator, Region III
  • Steve Reynolds, Director, Division of Reactor Safety 10
  • Melvin Holmberg, Senior Reactor Inspector

Introductions - NRC

  • David Hills, Chief, Engineering Branch 1 J

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  • Brian Harris, Project Manager, DLR, Office of Nuclear Reactor Regulation
  • Bryce Lehman, Structural Engineer, DLR, Office of Nuclear Reactor Regulation

First Energy Nuclear Operating Company 12 Operating Company (FENOC) Introductions and Presentation

NRC Root Cause Inspection Mel in Holmberg 13 Melvin Holmberg Senior Reactor Inspector Division of Reactor Safety NRC Region III

NRC Safety Focused Inspection

  • Early NRC Engagement with the Root Cause Investigation - December of 2011.

- Provided NRC with real time results 14

- Facilitated independent NRC observations and interaction with licensee and vendor staff

- Facilitated coordination of independent NRC inspections onsite 14

NRC Safety Focused Inspection

  • NRC Actions - Assess Validity of the Causes of the Shield Building Cracking.

- Team of 4 NRC Inspectors 15 Team of 4 NRC Inspectors

- Independently observed cracks in:

1. SB access opening
2. Core bores
3. Removed core samples

- Observed offsite vendor test facilities-core bore samples 15

NRC Safety Focused Inspection

- Reviewed licensee and vendor Root Cause Reports

- Evaluated licensee cause determination process

- Evaluated inputs/assumptions/modeling for SB calculations

- Evaluated licensee and vendor experience and education 16

  • Sufficient basis established for the causes of the shield building laminar cracking:

NRC Conclusion - Causes of Shield Building Cracking 17

- Blizzard of 1978

- Lack of exterior moisture barrier

- Structural design elements of shield building 17

Basis for NRC Conclusion

  • Systematic Root Cause Process Followed with Qualified Subject Matter Experts

- Experts in concrete degradation and root cause 18 Experts in concrete degradation and root cause analysis considered and eliminated a wide range of possible causes

- Comprehensive analysis in accordance with well known and accepted root cause processes 18

Basis for NRC Conclusion

  • Causes Supported by:

- Objective Evidence:

j Weather records, core bore sample and impulse response test results

- Analytical Analysis Five analytical model results

- Operating Experience Similar structures identified with laminar cracking which supports the identified causes 19

  • The NRC determined that the licensees proposed corrective actions, if adequately implemented, should keep the shield building safe to operate NRC Conclusions - Corrective Actions 20 keep the shield building safe to operate.

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Basis of NRC Conclusion -

Correction Actions

  • Exterior moisture barrier to prevent additional moisture related laminar cracking.

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  • Procedures to examine the exterior moisture barrier and monitoring of extent of existing cracking
  • NRC follow-up inspections to closely monitor licensee implementation of corrective actions 21

NRC Identified Weakness in Root Cause Report

  • Certain details associated with supporting the licensees analysis and conclusions 22 licensee s analysis and conclusions

- The licensee entered these weaknesses into the Corrective Action Program

  • Two examples for which the corrective actions proposed by licensee were too narrow

- The licensee entered these observations into the Corrective Action Program.

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License Renewal Inspections 23 Ann Marie Stone Engineering Branch Chief Division of Reactor Safety NRC Region III

License Renewal Perspectives

- Incorporation of Shield Building cracking in the 24 p

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License Renewal process

- Perform detailed technical reviews and audits

- Perform independent inspections

License Renewal Perspectives

- In-plant walk downs, and review of current credited programs, planned future programs/actions, and operating experience.

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- Determine if licensees programs, when implemented, will be consistent with requirements.

- Inspection Results Documented in Inspection Reports 05000346/2011010 and 05000346/2011012

License Renewal Perspectives

  • Current and future actions

- Application: Licensees proposed aging management program titled Shield Building 26 Monitoring Program being reviewed

- (If a renewed license is granted) Post Renewal:

Additional NRC inspections to verify the licensee completed the commitments and license conditions

Regulatory Overview

  • NRC continues to provide close oversight going forward
  • NRC will keep the public informed 27

Summary Ch l

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28 Charles Casto Regional Administrator NRC Region III

Meeting Contacts

  • Followup Questions - Contact the NRC Region III Office of Public Affairs Vikt i

Mitl

/ P Ch d

thil Viktoria Mitlyng / Prema Chandrathil Tel: (630) 829-9500 OPA3@nrc.gov 29

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