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 From:
Sent:
To:
Subject:
Attachments:
Hernandez, Pete ý LýL Thursday, December 15, 2011 7:18 AM Erickson, Alice FW: ET/LT Brief 12-22 Containment Delamination Davis-Besse I CR-3 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 COTIMN AEA IAIN DAVISBESS RSAAIE Agenda Li Davis-Besse Condition & Licensee's Position
" 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 i Free-standing steel containment vessel surrounded by reinforced concrete shield building c Shield Building Functions:
El Environmental & external missile protection for containment vessel 13 Biological shielding during normal operation and accident conditions Wn E3 Means for collection and filtration of fission product leakage following accident 0
Initial Condition
". Laminar crack identified in architectural flute shoulder area during hydro-demolition for replacement of reactor vessel closure head (October 10th)
" Crack found on the vertical side of the opening (left side, looking from the outside), generally along main reinforcing steel, and extends -6'across the top and -4' across the bottom Construction Opening I
U Flute/Shoulder Geometry W
U-AINAR CRACKS1 I
2/22/2012 Condition Assessment Condition Assessment "Chipping bock" along cracked IR testing performed on 15 of 16 areas revealed crack extended flute sfoulders beyond construction opening Impulse Response (IR) a Based on reswits licensee onsced methodology employed to cracking throoghout all shoulders investigate extent of crack u Core bores taken on 12 shoulders IR testing indicated crack to confirm crack boondories extended -38' above construction opening o Core bores inspected using (4) core bores taken to validate IR boroscope to identify crack depths results and widths a Indcated crack exoited near outer a Very tght, less than 0.01" reinforcement mat Condition Assessment Summary
,o IR testing performed on 4 of 8 u IR testing performed in 7 of 8 flute areas areas between flute shoulders ci Two small regions adjacent to u Core bores taken from 6 of 8 Main Steam Line penetration flute areas blackouts are cracked
- u. IR testing and care bores a EWtent of cracking unique to confirmed laminar cracking not penesntl-ci Cracking regions exist at top 20' present in flute areas of Shield Building wall outside a One flote did have a vertical shoulder area crack, but determined to be c Spring line area appears to have Isolated condition little or no cracking (top 5')
Licensee's Position E Cracking is generic to all flute shoulder regions Cracks are confined to flute shoulder regions with exception of top 20' of Shield Building wall and two small regions near MSL penetrations ii Cracking exists at top 20' of Shield Building wall outside shoulder region [delete (investigation ongoing)]
- Cracks are very tight, <0.01 ", and located near the outer reinforcing mat
- Believe sampling method of IR testing and core bores has characterized the extent of cracking in the structure
- Primary concern is ability of outside rebar to perform its intended function. Observations of construction opening and testing indicate concrete is attached to rebar mat
- Based on structural evaluation, cracking does not impact ability of structure to perform its intended safety functions D Root cause is underway NRC's Position In NRC informed licensee they could restart (12/2) a Licensee developed a model with reasonable assumptions which demonstrated adequate margin for operability a Staff continues to evaluate whether the shield building conforms to the design code requirements in the CLB
" This requires a 50.59 review and is currently being addressed by Region III in inspection space
" IS THERE A DUE DATE OR TIME LIMIT ON THIS? WHAT IS DRIVING THIS REVIEW?
" The ongoing inspection is continuing and the focus has shifted to tesolving the questioi iegarding compliance mwith the design and licensinig basis. Region III is developing a plon/iimeline for i esoluriovi and issuonce of the inspection repol t.
NRC's Position
- NRC issued CAL which included commitments to:
a Determine root cause and develop a long-term monitoring program (due 2/28/12) a Select multiple un-cracked areas to investigate to verify the cracking is not spreading (due 90 days) a Analyze known cracked areas to verify the cracks are not growing
- Decision was made to leave code compliance questions out of the CAL and to focus on confirming assumptions made in the operability calculations O Focus on continued operability going forward a Address design through ongoing inspection 2
.I 2/22/2012 License Renewal Impact 1 The degraded shield building is a Part 50 issue affecting license renewal
" DLR needs to understand if the degradation is age-related, and if so how it will be managed
" DLR will issue an RAI asking the applicant to explain how the unique OE will be addressed by its AMPs 1 This will be tracked as an Open Item in the SER CR-3 Update: Timeline o Dec. 2008:
License Renewal Application (LRA) submitted.
- Od. 2009:
Delamination of containment concrete in Boy 3-4.
n Nov. 2009:
Applicant starts repair of concrete in Boy 3-4.
oDec. 2010:
SER issued with open item for containment repair.
n Jan. 2011:
ACRS Subcommittee meeting.
- Committee requested additionol meeting ofter closeout of open item forcontoinment repair.
oMar. 2011:
New delamination identified in containment Boy 5-6.
oJun. 2011:
NRC informs the applicant that a revised schedule for LRA review 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: Recent Activities Ei Licensee reviewing repair proposals from Bechtel 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 I-Doom nintion d"
Ontus., 2009
.Btrs s I t
- 4 CR-3 Update: Original Delamination Delamination between buttress 3 & 4 3
2/22/2012 CR-3 Update: Possible Impacts on LR-AMPs iI Program Impact Concrete and prestressing tendons: Enhanced inspection IWL cnd surveillance frequency; additional devices such as strain 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 Cracking in the reirforced concrete o Cracking in the prestressed shield building concrete containment building Crack widths between 5 - 10 mils Cracking along outer reinforcemern o Crack widths between 500-mat (2-3" from exterior face) 4000 mils Root cause still under investigation Cracking along post-tension o
,l n*il (cci nsau bindn and tendons (8-9" from exterior face) butnur d Wncuniitl-OK f.r n ci i~keY nI-iF: IcC o Cracking due to prestressing
- .t-vstlgc'rc~nt pOii"G ;Jcl nr (In'1
- well forces, lack of transverse shear rt cau. _U-*
reinforcement and weak aggregate Comparison of Davis-Besse & CR-3 L* Similar crack geometry 1 Laminar cracking around circumference of building
- Similarities end there Summary
" Although similar at first glance, Davis-Besse and Crystal River are different issues a Acceptance of one has no bearing on the other.
" Both issues are Part 50 concerns which have an impact on license renewal
" The Regions and Headquarters will continue to work together to ensure continued functionality (Part 50) and to ensure aging is properly managed (Part 54) 4