ML20140D888
| ML20140D888 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 01/28/1986 |
| From: | Danni Smith COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| 1210K, NUDOCS 8602030135 | |
| Download: ML20140D888 (4) | |
Text
Commonwealth Edison s
- ) One First Nittortti Plaza. Chicago. Ilknois O ] Addrzss R; ply to: Post Office Box 767 j Chicago. Illinois 60690 January 28, 1986 Mr. Harold R. Denton U.S.
Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Washington, DC. 20555
Subject:
Braidwood Station Units 1 and 2 Containment Coatings NRC Docket Nos. 50-456 and 50-457
Dear Mr. Denton:
A conference call was held today between Commonwealth Edison Company and members of your staff to discuss the coating application in the containments of Braidwood Units 1 and 2.
The purpose of this letter is to provide information to address this issue and to create a basis for further discussion.
Additional information is being assembled and we would be prepared to present that information in a meeting between us and your staff as early as Friday, January 31, 1986, should that be necessary to obtain resolution of the issue.
We will coordinate further exchange of information with Mc.
Janice A. Stevens of your staff.
One signed original and 3 copies and enclosures are provided for your review.
Ve truly y urs, d61 <VJ David 11. Smith Nuclear Licensing Administrator
/klj Enclosures cc:
Resident Inspector Braidwood R. Gardner (RIII) 1210K 0602030135 h h 56
(
CARBOLINE COMPANY a
January 22, 1986 Mr. Theodore Rudaitis Sargent & Lundy Engineers 55 East Monroe Street Chicago, Illinois 60603
Subject:
Carbo Zinc 11/305 System Liner Plate Braidwood Station
References:
(1) Letter dated June 17, 1985 to Mr.
T.
- Rudaitis, Sargent & Lundy, from Steve Harrison.
(2) Letter dated July 10, 1985 to Mr.
R.
Leigh, Midway Industrial Contractors, Inc., from Steve Harrison.
(3) Letter dated December 9, 1985 to Mr. T.
- Rudaitis, Sargent & Lundy, from Steve Harrison.
~
Dear Mr. Rudaitis:
This letter is to clarify our position with respect to the subject coating system relative to the 50% thinning requirement for a second coat of Carbo Zinc 11.
In our letter of June 17, 1985 we concluded after observing adhesion data from tests performed on the liner plate coating that there is no technical reason why this system as applied will not perform under anticipated DBA conditions.
In our letter of December 9, 1985 we further reinforced our position based on additional tests that the coating as applied does perform as a system and, therefore, additional DBA tests are not required.
In addition, the 50% thinning requirement in our technical literature is not applicable to the conditions of the Braidwood liner.
Our letter of July 10, 1985 to Mr.
R.
Leigh, of Midway Industrial, Inc., was only intended to establish that the coating system as applied at Braidwood Station on the liner plate does not compromise DBA qualification.
Our only technical concern is that the coating behave as a system and exhibit appropriate adhesion characteristics.
In conclusion, based on the test results at Braidwood Station, it is our opinion that the coating system displayed acceptable adhesion characteristics.
The coating system as applied is qualified by existing DBA tests.
'ega rds,
Lr h J
n F.
Montle Vice President, Technology JFM/lft CC: Mr. Steve Harrison /Mr. Charlie Wiegers/Mr. Paul Litzsinger 1401 S. Hanley Rd.
- St. Louis, MO 63144 2985 o 314 644-1000 o Telex 44 7332 e Cable CARBOCO
COMMONWEALTli EDISON COMPANY BRAIDWOOD STATION CARBO ZINC ll/PIIENOLINE 305 CONTAINMENT LINER COATING SYSTEM The Braidwood Station containment liner coating system consists of a prime coat of Carbo Zinc 11 over the entire surface and a finish coat of Phenoline 305 from Elevation 377'-0" to 436'-0" (10' above mezzanine floor).
The prime coat of Carbo Zinc 11 was applied in the shop with exception of plate edges which were coated after the liner seam welding was completed.
The prime coat of Carbo Zinc 11 had become aged and weathered; therefore, it was restored prior to applying the finish coat of Phenoline 305.
The restoration consisted of brush blasting the original coat of Carbo Zinc 11 and applying a second coat of Carbo Zinc 11 to restore the original thickness of the prime coat.
Midway Industrial Contractors, Inc. Nonconformance Reports (NCR)
Nos. 31 and 32 and Commonwealth Edison Company NCR No. 748 were written to address the concern that the second coat of Carbo Zinc 11 was not diluted to 50% as recommended by the coatings manufacturer (Carboline Company).
The manufacturer's application instruction recommends 50% thinning when a second coat of Carbo Zinc 11 is applied over a base coat of Carbo Zinc 11.
The coating system which has been qualified by DBA test consists of Phenoline 305 finish over a prime coat of Carbo Zinc 11.
Our position is that we have maintained this system, and therefore, the current DBA tests are applicable.
In order to assure that the restored Carbo Zinc 11 behaved as a single coat system, adhesion tests were performed.
Tests were performed in-place on the completed liner coating system and on specimens which were coated with a second coat of Carbo Zinc 11 over a brush blasted prime coat of aged and weathered Carbo Zinc 11.
The tests showed no case of adhesion failure between the Carbo Zinc 11 coats.
In all cases, they failed in cohesion through the entire thickness of Carbo Zinc 11 as expected.
Therefore, the Carbo Zinc 11 as applied does behave as a single coat system.
In addition, the adhesion values observed on the in-place liner coating system do correlate to a range consistent with those exhibited by the current qualified DBA system.
1
The coatings manufacturer (Carboline Company) concurs with our position (see attached correspondence).
They have clarified their position relative to the 50% thinning recommendation as appropriate when applying a second coat to a fresh cured coat of Carbo Zinc 11 in order to promote adhesion.
Brush blasting of the first coat of Carbo Zinc, thereby establishing a roughened profile, prior to applying the second coat precludes the dilution requirement.
In conclusion, it has been shown that the coating system as applied is representative of that for which DBA tests have been performed.
Therefore, further DBA testing is not required.
2
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