ML20087P188
| ML20087P188 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 03/08/1984 |
| From: | Tucker H DUKE POWER CO. |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| Shared Package | |
| ML20087P186 | List: |
| References | |
| NUDOCS 8404060138 | |
| Download: ML20087P188 (3) | |
Text
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Dmce NOWER GOMPANY P.O. BOK G3189 CHARLOTTE, N.C. 28242 HAL B. TUCKER TELEPHONE (704) 373-4531 13 g nce runsment y,
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March 8, 1984 Mr. James P. O'Reilly, Regional Administrator U. S. Nuclear Regulatory Commission
. Region ll 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30303 Re: Ril:RWW-50-113/83-17 50 414/83-16
Dear Mr. 0'Reilly:
Please find attached a Final Report of corrective action taken in response to Violation No. 414/83-16-02 as identified in the above referenced inspection report.
Very.truly yours,
&b
-Hal B. Tucker LTP/php.
' Attachment cc:
NRC Resident inspector Catawba Nuclear Station Mr. Robert Guild,.Esq.
Attorney-at-Law P. O. Box 12097 Charleston, South' Carolina 29412 Palmetto Alliance 2135i Devine Street Columbia, South Carolina 29205 i
9 8404060138 840402
-PDR ADOCK 05000 0
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'Page 1 of 2 JP0/HBT/LTP
~NRC VIOLATION 414/83-16-02 March 8, 1984
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IMPROPER-CONCRETE MIX PLACED in order-to insure-that the: Design Engineering specifled concrete
< mix' strengths were placed with a high degree of' confidence, a statistical-evaluation of'previously' completed work was conducted.
- This evaluation was_done Jointly by:the qualityLAssurance and Construction Departments.
First Phase Enfthe_firstphase.ofoursampilng,.atotalof422placementsoutof i
a total of approximately 4200 were chosen for' review.
For Identifi-
-cation purposes,~the prepour numbers' assigned..by the Structural
^ Inspection group were used. jThe prepour numbers selected for review
' were chosen _using' a random number. generator programmed for the ' selected population size. -An individual' comparison.between the mix specifled
-and placed was conducted. The drawings-were compared with the actual placement' documents.
The(results of_'ouriinitial sampling program were satisfactory and.
indicated that,a 95% confidence level In previous work was achieved.
Out of-the sample,'two improperly specified mixes were found to have
- been'placed lThe'following errors were detecte'd during the first phase of sampling:
1 Error #1 T' PrepourgNumber 4457,; Repair of two (2)1.10.. Inch-pipe. sleeves, elevation z ~
594,' Auxiliary Building, Unit'1. ' Variation Notice' number.10154'was.
Twritt'en;to -detal.1 the; repair... Mix C-li(5000) psi) was 'specifiedl on the.
- Varlation. Notice,, Mix ~A-1for A-2 (3000 psi)'was spectfied on the M-2A'
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_Prepour: Site.-inspectioniand Mix A-1J(3000 psi)Jwas'actuM iy placed.
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Mix A-11os A-2 was /the' mix that would normally be required In this area.
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This? error w'as reported to Design Engineering on NCI'17640. After'
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reviewing. the data, Design Engineeri_ng de.termined.that the repairswas a>
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.satirfactoryland no rework would be required. The compressive cylinder-R l breaks forithisiparticular placementi satisfied'the:5000 psi requirements.
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- Error- #2 -
. 4461, Auxillary: Building. Hatch Covers-(H-51)E9 each.
Prepour~ Number:
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(Mix'B-2 was specified on Design' drawing-CN11215-1,Chowever, Mix A-1 g
-~(3000 ipsi)~was specified on:the.M-2A,'Prepour Site inspection,'and.
o" subsequently.'placed..This;errorJwas. reported to Design Engineering
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Jon'NCI 117639.. Design-Engineering concludedithat"for this. specific
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appl _ication,.the concrete?pla'ced.for theihatch covers'was acceptable.
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JP0/HBT/LTP March 8, 1984 gi ~
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l Analysis of the First Phase Results.
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/Afterzreviewing th'e first phase results,~we felt that it was Important lto; provide more than the minimal.st'andards for this-Item.
It was-
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- determined that.thel sample' size should be increased to reflect some 1
c of.the items-that may have-been problem areas.. These " problem areas"
.identifiediforTspecial review / emphasis were defined as pours / areas requiring higher strength mixes than.the others for a'particular elevation / series. Several.other-hundred were chosen atLcomplete f'
random. These. items were notiselected by statistical' sampling techniques-7 but by.using good judgement and relevantiobservations'made during the
.c, first phase of:this review.
4 a
__Second Phase
-During the " expanded"'second phase of thisJinvestigation,-the areas determined to h' ave 'a high' potential for error were evaluated. -Once
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again,' the Design-drawings were compared to' the documents detailing the actual mix placed.
One-.partIcular area that.seemed to have the most potential for -problems-1~
was the: Auxiliary Building, Unit?1 and 2 concrete hatch covers. An especially c1cse evaluation was.made of;this area. One~ minor item was
.noted,zdetermined to be readily correctable.and was corrected during-O
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'the? course of this inv'stigation. :However,Lno additional-problems-e Jwere-found outside of:the original; problem found In this area and
- reported on[NCIL#17639'(see errors found'inithe first phase of this 4
. investigation above).
- A'tetal of approx 1mately(1114 additionalSitems were evaluated'during
=the second: phase analysis..No errors wereidetected during this phase of--the:Investigstion.
Final' Analysis' In'~summarh,atotalsof;approximately1500itemswere-reviewedoutof'-
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- a; tota 1' population'of approximately14200 placements.
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Thirty-seven percent-(37%) of theitotaliplacements made were reviewed during the f i rs tl and fsecon'd ; phases : of ' ou r. i nves t i gat l on.
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,jBased'onthisanal'ysis,.wehavedeterminedthataconfidencelevel i
' -exceeding-95%=haslbeen established that,thejstrength mix;specifled e
.byl Design Engineering ' n ~the: Design drawings / documents: was L indeed T
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' place'd in every' case. Therefore, we. plan'to do no' additional reviews b-
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