ML12200A247
| ML12200A247 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse, Crystal River  |
| Issue date: | 12/15/2011 |
| From: | Hernandez P Division of Operating Reactor Licensing |
| To: | Erickson A Division of License Renewal |
| References | |
| FOIA/PA-2012-0121 | |
| Download: ML12200A247 (5) | |
Text
Hernandez, Pete LýL From: Hernandez, Pete ý Sent: Thursday, December 15, 2011 7:18 AM To: Erickson, Alice
Subject:
FW: ET/LT Brief 12-22 Containment Delamination Davis-Besse I CR-3 Attachments: 12142011 ET-LT Containment Delamination Brief 12-22-11.pptx Hi Alice, Bryce had you listed as his back up for this briefing. Let me know if I can do anything else.
- Thanks, Pete From: Hernandez, Pete Sent: Thursday, December 15, 2011 7:16 AM To: Lehman, Bryce Cc: Mahoney, Michael
Subject:
FW: ET/LT Brief 12-22 Containment Delamination Davis-Besse / CR-3 Good morning Bryce, Attached is the ppt. with comments from the region. Let me know if you need anything else.
- Thanks, Pete
2/22/2012 Agenda COTIMN AEA IAIN Li Davis-Besse Condition & Licensee's Position DAVISBESS
& RSAAIE " NRC's Position on Davis-Besse
" Impact on License Renewal o Status Update on Crystal River o Impact on License Renewal o Similarities & Differences Between Plants Davis-Besse Shield Building Initial Condition 0
i Free-standing steel containment ". Laminar crack identified in architectural flute vessel surrounded by reinforced shoulder area during hydro-demolition for concrete shield building replacement of reactor vessel closure head c Shield Building Functions: (October 10th)
El Environmental & external missile
" Crack found on the vertical side of the opening (left protection for containment vessel 13Biological shielding during normal side, looking from the outside), generally along operation and accident conditions Wn main reinforcing steel, and extends -6'across the E3Means for collection and filtration of top and -4' across the bottom fission product leakage following accident Construction Opening Flute/Shoulder Geometry W
I U U-AINAR CRACKS1 I
2/22/2012 Condition Assessment Condition Assessment "Chipping bock" along cracked IR testing performed on 15 of 16 ,o IRtesting performed on 4 of 8 u IR testing performed in 7 of 8 areas revealed crack extended flute sfoulders flute areas areas between flute shoulders beyond construction opening ci Two small regions adjacent to
- Impulse Response (IR) a Based on reswits licensee onsced u Core bores taken from 6 of 8 Main Steam Line penetration methodology employed to cracking throoghoutall shoulders flute areas blackouts are cracked investigate extent of crack u Core bores taken on 12 shoulders
- u. IRtesting and care bores a EWtentof cracking unique to
- IR testing indicated crack to confirm crack boondories penesntl-confirmed laminar cracking not extended -38' above ci Cracking regions exist at top 20' construction opening o Core bores inspected using present in flute areas of Shield Building wall outside
- (4) core bores taken to validate IR boroscope to identify crack depths a One flote did have a vertical shoulder area results and widths crack, but determined to be c Spring line area appears to have a Indcated crack exoited near outer a Very tght, less than 0.01" Isolated condition little or no cracking (top 5')
reinforcement mat Condition Assessment Summary Licensee's Position E Cracking is generic to all flute shoulder regions
- Believe sampling method of IR testing and core bores Cracks are confined to flute shoulder regions with has characterized the extent of cracking in the structure exception of top 20' of Shield Building wall and
- Primary concern is ability of outside rebar to perform two small regions near MSL penetrations its intended function. Observations of construction opening and testing indicate concrete is attached to ii Cracking exists at top 20' of Shield Building wall rebar mat outside shoulder region [delete (investigation
- Based on structural evaluation, cracking does not impact ongoing)]
ability of structure to perform its intended safety
- Cracks are very tight, <0.01 ", and located near the functions outer reinforcing mat D Root cause is underway NRC's Position NRC's Position In NRC informed licensee they could restart (12/2)
- NRC issued CAL which included commitments to:
a Licensee developed a model with reasonable assumptions a Determine root cause and develop a long-term monitoring which demonstrated adequate margin for operability program (due 2/28/12) a Staff continues to evaluate whether the shield building a Select multiple un-cracked areas to investigate to verify the cracking is not spreading (due 90 days) conforms to the design code requirements in the CLB a Analyze known cracked areas to verify the cracks are not
" This requires a 50.59 review and is currently being addressed by growing Region IIIin inspection space
" IS THERE A DUE DATE OR TIME LIMITON THIS? WHAT IS DRIVING : Decision was made to leave code compliance questions THISREVIEW? out of the CAL and to focus on confirming assumptions
" The ongoing inspection is continuing and the focus has shifted to made in the operability calculations tesolving the questioi iegarding compliance mwiththe design and O Focus on continued operability going forward licensinig basis. Region III is developing a plon/iimeline for a Address design through ongoing inspection iesolurioviand issuonceof the inspection repol t.
2
.I 2/22/2012 License Renewal Impact CR-3 Update: Timeline o Dec. 2008: License Renewal Application (LRA)submitted.
1 The degraded shield building is a Part 50 issue
- Od. 2009: Delamination of containment concrete in Boy 3-4.
affecting license renewal n Nov. 2009: Applicant starts repair of concrete in Boy 3-4.
" DLR needs to understand if the degradation is age- oDec. 2010: SER issued with open item for containment repair.
related, and if so how it will be managed n Jan. 2011: ACRS Subcommittee meeting.
- Committee requested additionol meeting ofter closeout of
" DLR will issue an RAI asking the applicant to explain open item forcontoinment repair.
oMar. 2011: New delamination identified in containment Boy 5-6.
how the unique OE will be addressed by its AMPs oJun. 2011: NRC informs the applicant that a revised schedule for 1 This will be tracked as an Open Item in the SER LRAreview will be established after information on the containment repair plan is submitted.
oJul. 2011: Spoiling identified in Boy 1-2.
- Concrete sectionslapprox. 1.5"X I 2'X3' & 5")fell on Intermediate Building CR-3 Update: Original Delamination CR-3 Update: Recent Activities I-Doom nintion #4 Ei Licensee reviewing repair proposals from Bechtel Ontus.,2009 d"
.Btrs s It and URS 0 Anticipate contracts to be in place by Jan. 31 o Repairs expected to require 2 to 3 years to complete
" Licensee continues to install temporary anchors to limit propagation of delaminations and prevent future delaminations
" Licensee preparing to detension the containment building tendons in preparation for the repair
" Staff expects licensee to submit a license amendment but that is not certain at this point CR-3 Update: Original Delamination Delamination between buttress 3 & 4 3
2/22/2012 CR-3 Update: Possible Impacts on LR-AMPs Comparison of Davis-Besse & CR-3 iI Program Impact L* Similar crack geometry Concrete and prestressing tendons: Enhanced inspection 1 Laminar cracking around circumference of building IWL cndsurveillance frequency; additional devices such as strain
- Similarities end there gouges to monitor cracks; and scanning of concrete at different locotions.
Containment Leakage Type A, B, and C tests: Test 10 CFR 50 App. J frequency.
TLAA Tendonsw Revision to the program and data since most of the vertical and hoop tendons will be re-tensioned.
Containment Tendons: Major revision to the program to identify sample Tendon Prestress ine, frequency; new regression analysis based on re-tensioned data.
Differences Between Davis-Besse and CR-3 Summary
" Although similar at first glance, Davis-Besse and Crystal River are different issues Cracking in the reirforced concrete o Cracking in the prestressed shield building concrete containment building a Acceptance of one has no bearing on the other.
.. Crack widths between 5 - 10 mils Cracking along outer reinforcemern o Crack widths between 500- " Both issues are Part 50 concerns which have an mat (2-3" from exterior face) 4000 mils impact on license renewal Root cause still under investigation Cracking along post-tension o n*il,l(cci nsau bindn and tendons (8-9" from exterior face) " The Regions and Headquarters will continue to butnur d Wncuniitl-OK f.r n ci i~keYnI- iF:IcC o Cracking due to prestressing work together to ensure continued functionality
- .t-vstlgc'rc~nt pOii"G ;Jclnr (In'1
- well forces, lack of transverse shear (Part 50) and to ensure aging is properly rt cau. _U-* reinforcement and weak aggregate managed (Part 54) 4