ML20009C643

Significant Deficiency Rept SD 413/81-13,initially Reported on 810611,re Linear Indication in Base Metal on Carbon Steel Pipe.Cause Unknown.Reassessment of Insp Programs Will Be Conducted

ML20009C643
Person / Time
Site:	Catawba
Issue date:	07/10/1981
From:	Parker W DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
10CFR-050.55E, 10CFR-50.55E, NUDOCS 8107210308
Download: ML20009C643 (3)

Text

,

a '

e 912_

OFFICIAL COPY DUKE POWER COMPANY Powna Duitonwo 422 Sourn Cnuncu SrazzT, CitantorTE, N. C. aca4a , ,

WI LLI AM O.PARMER,JR.

WCr Passiormt Tetramont: Anta 704 seta= Pneovevion July 10, 1981 373-4c e s Mr. James P. O'Reilly, Director '

F'-'

U. S. Nuclear Regulatary Commission g 3 Region II Q /, $s 101 Marietta Street, Suite 3100 gy %g N 3 -

Atlanta, Georgia 30303 ~/ hg -7 9ona -

Re: Catawba Nuclear Station \ C\t II q Unit 1 ,- g [8 5' Docket No. 50-413 1 .c Q

/ .h sd / l iy \

Dear Mr. O'Reilly:

Pursuant to 10CFR 50.55e, please find attached Significant. Deficiency Report SD 413/81-13.

Very truly yours, William O. Parker, Jr. [4/gg RWO:1s Attachment cc: Director Resident Inspector Office of Inspection and Enforcement Nuclear Regulatory Con: ission U. S. Nuclear Regulatory Commission Catawba Nuclear Station Washington, D. C. 20555

, TGl*7 s

/ /

8107210308 810710 PDR ADOCK 05000413 S PDR

t .

Report Number: SD 413/81-13 Report Date: July 10, 1981 Facility: ?atawba Nuclear Station - Units 1 & 2 Identification of Deficiency During Code MT of a 4" butt weld in the NF Systems, a linear indication was picked-up in the base metal. Further investigation disclosed other indications on the pipe and that at least one of them encroached on material specification minimum wall. On this basis, Non-conforming Item Report 11,837 was generated.

Initial Report On June 11, 1981, Mr. J. Bryant of NRC Region II, Atlanta, Georgia was notified of the deficiency by Mr. W. O. Henry of Duke Power Company, Charlotte N.C. 28242. This notification was as a result of Potentially Reportable Item CA-81-21.

Supplier and/or Component The material in question is 4" Sch. 40 Smls. Carbon Steel Pipe to ASME SA-106 Grade B. dest Number N-76739. Pipe was manufactured by U.S. Steel Corporation and supplied to Duke Power by Hub Incorporatad of Greensbbro,, '

N.C.

Description of Deficiency Further investigation of the indications revealed that in three cases there was localized violation of minimum wall. The deepest of these resulted in a remaining wall thickness of .175" as opposed to the material specification minimum of .207".

We found no unique cause to which these indications might be attributed.

They appear to be the normal seams, laps or tears which are inherent to some degree in all carbon steel pipe. ,

PAGE 1 0F 2

9. -

Report Number: SD 413/81-13 Report Date: July 10, 1981 Analysis of Safety Implications A check was made and none cf this heat of pipe was found at Oconee, McGuire, or Cherokee.

Review of our records at Catawba indicated that all of this heat except 8' (found in the Fab. Shop) had been installed. Our records indicate that this pipe has been installed in the following safety-related Systems with design conditions as listed:

SYSTEM DESIGN CONDITIONS RN-Nuclear Service Water 165 psia @ 150 F WZ-Groundwater Drainage 75 psia @ Amb.

KD-Diesel Generator Cooling Water 125 psia 0 250 F NF-Ice Condenser 225 psia @ 150 F VQ-Containment Air 30 psia 0 260 F VY-Containment Hydrogen 40 psia 0 2200F YC-Chilled Water 275 psia 0 100 F KC-Component Cooling 150 psia @ 200 F Using the highest design conditions above the Code minimum wall required is .041" Based on our investigation of typical defects and a statistical evaluation, there is a 95% confidence level that if all indications were examined, 95% would result in a remaining wall thickness of .122" or greater. Comparing the .122" expected minimum to the required .041 Code minimum gives us margin of 3 to 1 in addition to the safety factor of approximately 4 already built into the Code.

Based on these considerations, the pipe is acceptable for the intended service. ,

Corrective Action No further action is required as far as this particular pipe is concerned.

Reassessment will be made of our Inspection Programs to insure that such problems are screened upon Receipt Inspection.

PAGE 2 0F 2

.-- - - . - .