ML12004A010

Public Meeting NRC Slides

ML12004A010
Person / Time
Site:	Davis Besse
Issue date:	01/04/2012
From:	NRC/RGN-III
To:
References
Meeting Notice (ML113560164), FOIA/PA-2012-0121
Download: ML12004A010 (24)

Text

NRC Public Meeting NRC Public Meeting Davis Besse Shield Building Cracks January 5, 2012

Welcome C

thi P d 2

Cynthia Pederson Acting Regional Administrator NRC Region III

NRC Safety Mission

• The Nuclear Regulatory Commission (NRC) is an independent federal agency created b

U S C by U.S. Congress.

• The mission of the NRC is to license and regulate the Nations civilian use of nuclear materials in order to protect public health and safety, promote the common defense and security, and protect the environment.

3

Safety Issue

• On October 10, 2011, the NRC was informed by the licensee promptly upon their identification of cracking in the Davis Besse shield building.

4

• NRC determined there was no immediate safety concern. The plant was shut down at the time.

• NRC immediately responded with an onsite senior structural inspector.

Meeting Purpose

• Inform the public about the safety of the Davis Besse shield building through:

A presentation by the licensee on the results of their tests and analysis.

A presentation by the NRC on the NRCs inspection of the shield building and actions taken to ensure safety.

5

Meeting Information Kenneth OBrien D

t Di t

Di i i f

6 Deputy Director, Division of Reactor Safety NRC Region III

Meeting Agenda

• Introductions

• Background 7

• Licensee Presentation

• NRC Inspection & Conclusion

• Additional NRC Safety Actions

• Summary

• Public Questions and Comments

Introductions - NRC Cynthia Pederson, Acting Regional Administrator, Region III Kenneth OBrien, Deputy Director, Division of Reactor Safety 8

y Patrick Hiland, Director, Division of Engineering, Office of Nuclear Reactor Regulation David Hills, Chief, Engineering Branch 1 Jamnes Cameron, Chief, Reactor Projects Branch 6 Daniel Kimble, Senior Resident Inspector Adam Wilson, Resident Inspector Jared Heck, Meeting Facilitator

Meeting Contacts

• Followup Questions - Contact the NRC Region III Office of Public Affairs / Viktoria Mitlyng / Prema Chandrathil 630-829-9500 9

First Energy Nuclear Operating Company 10 Operating Company (FENOC) Introductions and Presentation

NRC Inspection &

Conclusions 11 David Hills Engineering Branch Chief NRC Region III

NRC Safety Focused Inspection

• At discovery of cracking, NRC inspectors already onsite inspecting reactor pressure vessel closure head 12 reactor pressure vessel closure head replacement.

• Added extra NRC structural expertise.

• Approximately 10 NRC engineers involved during the almost 8 week time period.

12

NRC Safety Focused Inspection

• NRC inspectors onsite independently observed and evaluated licensees ti iti t

d t i

th t

t f

13 activities to determine the extent of cracking.

• NRC structural engineers performed extensive, independent, & rigorous review of the licensees analysis including structural calculations.

NRC Safety Focused Inspection

• The NRC team engaged the licensees engineers and consultants in intense discussions while evaluating the 14 discussions while evaluating the licensees actions and analysis.

• Numerous technical questions were posed and answered - some in writing/many verbally.

14

NRC Safety Focused Inspection

• NRC questions resulted in additional licensee actions to determine the extent of cracking and the generation 15 extent of cracking and the generation of more extensive/detailed structural calculations.

15

• The licensee performed impulse response mapping and confirmatory core bores to characterize the extent of NRC Conclusion Basis 16 core bores to characterize the extent of cracking.

• Structural calculations reflected extent of cracking that was verified through testing.

16

• Licensee calculation assumptions and engineering judgments were appropriate NRC Conclusion Basis 17 appropriate.

• Calculation modeling adequately reflected the building condition including structural load path.

17

• The licensee evaluated the shield buildings ability to withstand the design basis earthquake tornado & tornado driven NRC Conclusion Basis 18 earthquake, tornado, & tornado driven missiles.

• The licensees calculations confirmed that building stresses remained within limits set in the original licensing basis.

18

Shield building remains capable of performing its safet f nction despite the NRC Safety Conclusion 19 performing its safety function despite the cracking and therefore licensee could safely restart plant.

19

• NRC structural engineers continue in their evaluation of whether the shield building meets licensing commitments. If NRC NRC Safety Conclusion 20 g

concludes commitments are not met, then licensee will need to correct.

• NRC inspection team is evaluating licensees ongoing root cause activities and determination of longer term corrective actions.

20

Additional NRC Safety Actions J

C 21 Jamnes Cameron Chief, Reactor Projects Branch 6 NRC Region III

Additional NRC Actions to Ensure Continued Safety of the Shield Building Confirmatory Action Letter issued on December 2, 2011 -

• Licensee to complete a root cause evaluation develop 22

• Licensee to complete a root cause evaluation, develop and implement corrective actions, including a long-term monitoring program.

• Licensee to implement a short-term monitoring program.

NRC will conduct a followup inspection of root cause evaluation and proposed corrective actions.

Summary C

thi P d 23 Cynthia Pederson Acting Regional Administrator NRC Region III

• NRC structural engineers conducted an extensive, independent, and rigorous evaluation.

• NRC concluded that the shield building remains Summary 24 NRC concluded that the shield building remains capable of performing its safety function.

• NRC determined that plant safety was not compromised. NRC has taken actions to ensure the plant remains safe going forward.

• NRC has continued to communicate to the media, public officials, and members of the public.