ML20004C641
| ML20004C641 | |
| Person / Time | |
|---|---|
| Site: | Midland |
| Issue date: | 05/29/1981 |
| From: | Jackie Cook CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, 79-12-#8, 79-12-8, NUDOCS 8106040371 | |
| Download: ML20004C641 (7) | |
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Mr J G Keppler, Regional Director Office of Inspection and Enforcement
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US Nuclear Regulatory Co=tission
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MIDLAND PROJECT -
DOCKET NOS 50-329, 50-330 CV
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CONTAINMENT INTERNAL STRUCTURES COATING DEFICIENCY
,i FILE: 0.4 9.37 UFI: 73*10'01, 00210(S) SERIAL: 12009
References:
CPCo letters to J G Keppler; Sa=e Subject;
- 1) Serial Hove-309-79; dated December 13, 1979
- 2) Serial Hove-26-80; dated February 7,1980
- 3) Serial Hove-75-80; dated April 15, 1980 h) Serial 9125; dated June 11, 1980
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- 5) Serial 8823; dated September 9, 1980
- 6) Serial 10051; dated October 31, 1980
- 7) Serial 11199; dated February 23, 1981 This letter, as were the referenced letters, is an interim 50.55(e) report on the containment internal structures coating deficiency.
provides a su=tary of the actions being taken to correct the deficiencies and preclude their recurrence.
Another report, either interin or final, vill be sent on or before August 1,1981.
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l WRB/1r f : MCAR-35, Final Report, dated May 15, 1981 "Containnent Internal Structures Coating" CC: Director of Office of Inspection & Enforcement Att Mr Victor Stello, USNRC (15) 8 Director, Office of Management Information & Program Control, USNRC (1) l RJCook, USNRC Resident Inspector, Midland (1) 81060.4037I S
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Serial 12009 79-12 #8 CC: CBechhoefer, ASLB Panel RSDecker, ASLB Panel FPCowan, ASLB Panel AS&L Appeal Panel-MMCherry, Esq MSinclair CRStephens, USNRC WDPaton, Esq, USNRC
- FJKelly, Esq, Attorney General SHFreeman, Esq, Asst Attorney General GTTaylor, Esq, Asst Attorney General-WHMarshall-GJMerritt, TNK&J h
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.c Enclcsura 1 Serial 12009 79-12 #8 030376 MCAR 35 (ISSUED 11/13/79)
CONTAINMENT INTERNAL STRUCTURES COATING FINAL REPORT MAY 15. 1981 CONSUMERS POWER COMPAhi MIDLAND PLANT UNITS'1 AND 2
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SUBJECT:
MCAR 35 (Issued 11/13/79)
Containment Internal Structures Coating FINAL REPORT DATE: May 15, 1981 PROJECT:
Consumers Power Company Midland Plant Units 1 and 2 Bechtel Job 7220-I.
Introduction This final report is a summary of the investigations and findings concerning MCAR 35.
It includes a description of the corrective actions to be taken to correct deficiencies and prevent the dela-minations from reoccurring.
II.
Description of Deficiency Coating System 9 is a decontaminable coating system applied to con-crete walls. As applied, System 9 consists of two coats of Ameron's Nu-Klad 117 and two finish coats of Ameron's Amercoat 90.
Nu-Klad 117 is an epoxy coating that was used to fill'and seal the concrete surface.
Amercoat 90 is a modified phenolic epoxy coating which provides a decontaminable finish cost. Delamination has occurred between the two coats of Nu-Klad 117.
III. Investigation Investigation of the delamination causes included the items listed below:
Selection of the coating system: Coating System 9, as speci-a.
fled, was selected in part because it had successfully passed irradiation and design basis accident (DBA) tests prior to i ;
s being selected for this project.
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b.
Review of Technical Specification 7220-A-15(Q) and the subcon-tractor's quality assurance prograu: The review did not i
t reveal any deficiency which would result in misapplication of the coating.
i c.
Review of application records: Deviations from the specif1-cation and the manufacturer's dsta sheets were found. The specification stated that Nu-Klad 117 was to be applied as a filler and as a surfacer. The filler was to be used to patch small voids or holes. The surfacer was to be applied as a full coat to seal the concrete.
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.MCAR 35' May 15, 1981 Final Report
=Page 2.
The deviations from these requirements are listed below:
1)
Two full coats _ of Nu-Klad 117 were' applied in most cases.
- 2) - Several areas were' identified where.the time between coats of Nu-Klad 117 exceeded manufacturer's instrue-tions.
3)
A few areas have more then two coats of Nu-Klad 117.
4)
A few isolated areas have a full coat of Nu-Klad 117 over Amercoat 90.
d.
Investigation of solvent addition to Nu-Klad 117: Although the specification and the manufacturer's data sheets prohibit the addition of solvent to Nu-Klad 117, solvent was added to the coatings. as ascertained by extensive laboratory tests.
e.
Adhesion of the surfacer to the concrete and the finish coats to the surfacer and to each other: Extensive adhesion tests and other investigations did not. reveal any significant de la-minations. DBA tests of coating samples caused some delami-nation of finish coats. However, evaluation of test results has 'shown that the delamination that occured in the DBA test is an isolated, atypical condition unrelated to the subject coating failure.
f.
Pot Life: Coatings applied at or near the end of pot life could have coctributed to delamination.
g.
Other possible causes: Variations of product and packaging, application method, surface contamination, and coating thick-ness were investigated. None of these factors were found to have contributed to the delamination.
IV.
Conclusions Derived from the Investigations a.
Delamination occured at the interface of two full surfacer coats of Nu-Klad 117.
b.
Delanination occurred at random locations that could not be predicted.
c.
Causes and possible causes of delamination are listed below:
1)
Excessive curing time between coats of Nu-Klad 117 2)
Variations in mixing, temperature, and humidity l
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HCAR 35 May 15, 1981 Final Report Page 3 3)
Application of Nu-Klad 117 near the end or after the effective pot life 4)
Application of two full surfacer coats of Nu-Klad 117 5)
Addition of solvents l
V.
Corrective Actions Qualification of the applied System 9 Coatings a.
1)
An adhesion test procedure has been developed. This test is performed by cutting a 1/4-inch wide strip in the coating system and attempting to remove it with a knife.
Samples which passed the knife test have been tested at Oak Ridge National Laboratories and have met DBA rad 1rradiation requirements of ANSI N101.2.
2Property "ANSI code" (as page type) with input value "ANSI N101.2.</br></br>2" contains invalid characters or is incomplete and therefore can cause unexpected results during a query or annotation process.)
Where delanination has been found, the coating shall be removed. The remaining coated area will be divided into test grids.
Each grid shall be tested at a statistically significant number of locations selected at random.
If the allowed number of failed locations within a grid is exceeded, the entire grid is deemed unacceptable. An evaluation will be made and corrective action will be taken for each unacceptable grid. Acceptable grids will be considered loss-of-coolant accident qualified and will be allowed to remain.
b.
Coating System 9 Repair Procedure Qualifications To establish and qualify repair procedures, test coating applications were made over surfaces where the coating had been removed. Samples of the test coating were submitted to Oak Ridge National Laboratories for irradiation and DBA testing. Test results showed that tested repair coatings are qualified in accordance with ANSI N101.2.
Procedures for System 9 coating repair will be included in Specification 7220-A-56(Q) and will be based upon procedures established in the test application program.
Repairs will be made when the procedures are issued.
VI.
Prevention of Recurrence Specification 7220-A-56(Q) has been issued for the contractor's use when applying decontaminable coatings to concrete.
This specification
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t Bechtel Associates Professional Corporation MCAR 35 May 15, 1981 Final Report Page 4 is based on a thorough review of items addressed in MCAR 35 raports tr. ensure coating integrity.
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Approved by:
Concurrence by:
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