ML19268C032

Responds to IE Bulletin 79-03 Followup Rept.Data Developed on Generic Basis & Considered Applicable to All Snupps Units.Fabrication & Installation of Youngstown Pipe Spools Will Proceed W/All Matl Analyzed Prior to Use

ML19268C032
Person / Time
Site:	Wolf Creek, Callaway, Sterling
Issue date:	10/05/1979
From:	Petrick N STANDARDIZED NUCLEAR UNIT POWER PLANT SYSTEM
To:	Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19268C033	List: ML19268C032 ML19268C034
References
IEB-79-03, IEB-79-3, NUDOCS 7912190197
Download: ML19268C032 (3)

Text

. . _ - . .

9

, t

~ ' / __ J__ F

.. .

SNUPPS Stenderdised Nuclear Unit Power Plent System 5 Choke' ry Rood Nichotas A. Petrick ekv r lend 20850 Executive Director October 5,1979 SLNRC 79-16 FILE: 0278.10 SUBJ: NRC/IE Bulletin 79-03: Pipe Manufactured by Youngscown_

Welding and Engineering Co.

Mr. Boyce Grier Director, Region 1 Office of Inspection and Enforcement US Nuclear Regulatory Commission 631 Park Avenue King of Prussia, Pennsylvania 19406 Docket Hos. STN 50-4B2 STN-485 STN 50-483 STN-486

References:

(1) Union-Electric Letter, ULNRC-314 dtd. 5/11/79 to Keppler, Region III USNRC re IE Bulletin 79-03 (2) KG&E Letter KLNRC 79-12 dtd. 5/11/79 to Seyfrit, Region IV, USNRC re IE Bulletin 79-03 (3)RG&ELetterRLNRC-0026dtd.5/10/79toGrier, Region I. USNRC re IE Bulletin 79-03 ,

Dear Mr. Grier:

The reference letters concerning the use or potential use of fusion welded pipe manufactured by Youngstown Welding and Engineering Co. were forwarded to NRC as an interim response to the subject Bulletin and were indicated to be oenerically applicable to all SNUPPS units. The reference responses identdied pipe spools delivered to the Callaway and Wolf Creek jobsites containing Youngstown-manufactured pipe and indicated that the longitudinal seam weld of ea:h such spool would be ultrasonically examined in accordance with NRC direccives. Commitments to ultrasonically examine pipe in the process of 'abrication at Dravo's shops were also indicated. The reference letters further indicated the results of the site and shop examinations would be submitted to NRC in a follow-up report.

The purpose of this letter is to provide a follow-up to the reference letter reports. The data contained in this report have been developed on a generic basis and are cor.sidered applicable to all SNUPPS units. A program of ultra-sonic (UT) examination was initiated at the SNUPPS jobsites and at Dravo, using procedures, reference standards and acceptance criteria specified by ASME Section III Code. The results of initial jobsite examinations were T912190 1

• '

. .

e SLNRC 79 16 October 5, 1979 Page Two judged to be inconclusive and have since been suspended primarily on the basis of generic Bechtel studies indicating inability of ultrasonic or radiographic techniques in detecting centerline lack-of-penetration con-dition in the Youngstown double-welded pipe materials.

Data supporting these conclusions were reviewed with the NRC on August 15, 1979 and are detailed in the June,1979 Bechtel Report entitled "Investi-gation of Weld Imperf'ctions in ASME SA-312 Double-Welded Austenitic Stainless Steel Pipe for Compliance with NRC I&E Bulletin 79-03", a copy of which is enclosed for NRC information and evaluation. Although no final conclusions were indicated by the NRC at the August 15th meeting, the S!1UPPS and Bechtel representatives were advised that some modifica-tions to the subject Bulletin could be anticipated. Pending NRC clarifi-cation, further volumetic examinations are, at this time, considered in-appropriate and have been suspended.

Fabrication and installation of Youngstown pipe spools is currently pro-ceeding. All piping systems containing Youngstown materials are being analyzed and, as suggested by Bechtel, those systems subject to design hoop stresses of less than 85 percent of ASME Code allowables will be in-stalled without restriction. This 85 percent value is cited in the enclosed Bechtel report and is based upon ASME Section III, Division 1 allowable stress values for austenitic stainless steels. Specifically, Note 3 to Table I-7.2 of Appendix I of the Code, which is applicable to all grades of stainless steel within the SA-312 material specification, provides a series of ' efficiency factors' for longitudinally welded pipe. The effi-ciency factors are percentages of the stress values and depend upon the type of longitudinal weld joint. For welds without filler metal pipe of the SA-312 type, the efficiency factor is 85 percent when no volumetric examination of the longitudinal weld is performed. Piping systems subject to stresses equal to or greater than the 85 percent criterion will be acid etched and evaluated on the basis of criteria recommended by Bechtel in the generic report, referenced above. Straight lengths of pipe that have yet to be fabricated into spools, components or subassemblies will also be acid etched and examined for centerline lack-of-penetration condition. The data resulting from these analyses and tests will be retained and made available for subsequent NRC examinations. To date, no piping systems con-taining Youngstown materials have been found with hoop stresses equal to or in excess of the 85 percent Code allowable criterion.

Very truly yours,

%h NicholayA. Petrick SJS:dck

Enclosure:

June 1979 Bechtel Report on Investigation of Weld Imperfection, in ASME SA-312 Double Welded Austenitic Stainless Steel Pipe for Compliance with NRC I&E Bulletin 79-03 cc list Page Three

,

. l ', .' , . .

. .

SLNRC 79- 16 October 5, 1979 Page Three cc: Mr. Victor Stello, Jr., Director, Office of Inspection and Enforcement USNRC, Washington, D.C. w/ enclosure Mr. James G. Keppler, Director, Region III, USNRC w/ enclosure Mr. Karl V. Seyfrit, Director, Region IV, USNRC w/ enclosure