ML17264A889

Requests Approval of Relief Request 17,rev 1 Re Class 1,ASME Section XI Category B-J,to Address Cast Stainless Base Metal Ultrasonic Weld Exams

ML17264A889
Person / Time
Site:	Ginna
Issue date:	05/09/1997
From:	Mecredy R ROCHESTER GAS & ELECTRIC CORP.
To:	NRC (Affiliation Not Assigned), NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9705150125
Download: ML17264A889 (7)

Text

CATEGORY 1 iC> REGULATO INFORMATION DISTRIBUTION TEM (R1DS)

ACCE<SIQN"NBR:9705150125 DOC.DATE: 97/05/09 NOTARIZED: NO DOCKET N FACIE:50'-244 Robert Emmet Ginna Nuclear Plant, Unit 1, Rochester G 05000244 AUTH. NAME AUTHOR AFFILIATION MECREDY,R.C. Rochester Gas 6 Electric Corp.

" RECIP.NAME RECIPIENT AFFILIATION VISSING,G. Document Control Branch (Document Control Desk)

SUBJECT:

Requests approval of relief request 17,rev 1 re,Class 1,ASME Section XI Category B-J,to address cast stainless base metal ultrasonic weld exams.

DISTRIBUTION CODE: A047D COPIES RECEIVED:LTR ENCL SIZE:

TITLE: OR Submittal: Inservice/Testing/Relief from ASME Code GL-8 -04 T

NOTES:License Exp date in accordance with 10CFR2,2.109(9/19/72). 05000244 E

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD1-1 LA ~ 1 1 PD1-1 PD 1 1 VISSING,G. 1 1 INTERNAL: AEOD/SPD/RAB 1 1 CENTER 0 1 1 NRR/DE/EMEB 1 1 CT 1 1 OGC/HDS3 1 0 RES/DET/EIB 1 1 RES/DET/EMMEB 1 1 EXTERNAL: LITCO ANDERSON 1 1 NOAC 1 1 NRC PDR 1 1 D

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N NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE. TO HAVE YOUR NAME OR ORGANIZATION REMOVED FROM DISTRIBUTION LISTS OR REDUCE THE NUMBER OF COP1ES RECEIVED BY YOU OR YOUR ORGANIZATION, CONTACT THE DOCUMENT CONTROL DESK (DCD) ON EXTENSION 415-2083 TOTAL NUMBER OF COPIES REQUIRED: LTTR 13 ENCL 12

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ROCHESTER GAS AND ELECTRIC CORPORATION ~ 89 FASTAYENUE, ROCHESTER, N.Y. Id6d9-D001 AREA CODE716 546-2700 ROBERT C. MECREDY Vice President May 9, 1997 Nvdeor Operotions U.S. Nuclear Regulatory Commission Document Control Desk Attn: Guy Vissing Project Directorate I-1 Washington, D.C. 20555

Subject:

Relief Request No. 17, Rev. 1 Ginna Nuclear Power Plant Inservice Inspection ASME Section XI Required Examinations R.E. Ginna Nuclear Power Plant Docket No. 50-244

Dear Mr. Vissing:

The purpose of this letter is to seek approval of a relief request concerning Class 1, ASME Section XI Category B-J, to address Cast Stainless Base Metal Ultrasonic Weld Examinations. This letter supersedes, in its entirety, Relief Request No. 17 submitted April 9, 1997. The justification and proposed alternatives are included in the attachments to this letter. It is requested that this utilized relief request be approved by June 16, 1997 in order to be for the upcoming 1997 Outage at R.E. Ginna Nuclear Power Plant.

The request for relief is made in accordance with the provisions of 10CFR50.55a(a)(3)(ii), in that compliance with the specified requirement would result in an unusual difficulty without a compensating increase in the level of quality and safety. The basis of this relief deals with the employment of best effort ultrasonic examination techniques on welds associated with cast stainless I(

components. Due to the nature of cast stainless steel and associated welds, attenuation variables adversely impact the performance of ultrasonic examinations. The performance of other volumetric techniques, such as radiography, on associated cast components will provide little increased quantitative benefit due to the high levels of background radiation that exist for the items addressed. Note that this relief request uses the same rationale as was used to conform with Code Case N-481's part of the current ISI interval program. That code case was applied to RCP bowls made of cast stainless steel and was granted based on the inability of UT measures to be effective.

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Rochester Gas and Electric will continue to evaluate new emerging inspection technology as they become available for this industry problem of performing ultrasonic examinations on cast stainless components.

Very truly yours, Robert C. Mecredy Attachment REZ5460 xc: Mr. Guy Vissing (Mail Stop 14B2)

Project Directorate I-1 Washington, D.C. 20555 U.S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406 Ginna Senior Resident Inspector

Relief Request No. 17, Rev. 1 Category B-J, Cast Stainless Base Metal Ultrasonic Examination I. Components for Which Relief is Requested:

1~ Class 1, Category B-J, Reactor Coolant Cast Pump Terminal End to Cast Elbow Circumferential Welds and Associated Longitudinal Seam Welds.

Weld ID ~Te PL-FW-XIII Elbow-to-Pump PL-FW-XII-LR (XIII) Longitudinal PL-FW-XV Elbow-to-Pump PL-FW-XI-LR (XV) Longitudinal

2. Class 1, Category B-J, Reactor Coolant Inlet/Outlet Cast Elbow to Nozzle Safe End/Pipe Circumferential Welds.

Weld ID ~Te PL-FW-I-ASW Elbow-to-Safe End PL-FW-IX-ASW Safe End-to-Elbow PL-FW-III Elbow-to-Safe End PL-FW-X Safe End-to-Elbow PL-FW-IX Elbow-to-Pipe PL-FW-X-BSW Elbow-to-Pipe II. ASME Requirements for Which Relief is Requested:

1~ Category B-J within Table IWB-2500-1, specifies volumetric examination requirements that are to be performed on Terminal Ends, Longitudinal welds, as well as other welds associated with required Circumferential Welds.

2. Code Case N-460 specifies that a reduction in examination coverage on any Class 1 or Class 2 weld may be accepted provided the reduction in coverage for that weld is less than 10%.

III. Basis:

Supplement 4 (b)(4) of Appendix III identifies ultrasonic requirements on Austenitic and Dissimilar Metal scanning Welds. This paragraph further identifies that Cast items such as fittings, valve bodies, and pump casings may preclude meaningful examinations because of geometry and attenuation variables.

At R.E. Ginna Nuclear Power Plant, the Reactor Coolant Pump, Westinghouse Model 93, is cast stainless (A-351 Gr CF8M). The associated fittings (elbows) are also cast stainless (ASTM A-

351 Gr CFSM) and contain longitudinal seam welds. The Reactor Coolant Inlet/Outlet Wrought Safe End/Pipe to Elbow circumferential welds consists of fittings (elbows) that are cast stainless (ASTM A-351 Gr CFSM). When employing optimized ultrasonic techniques on these cast/wrought welds, the techniques may detect large flaws (254 or greater through wall) but are relatively ineffective in detecting smaller flaws. Therefore, the sensitivity is less than that required by the code.

Cast Stainless base metal and associated welds contain large grain structures, attenuation variables impact on performance of ultrasonic examinations. Experience has shown that these materials are not always amenable to ultrasonic examination and does not produce reliable and meaningful results.

Currently, the industry s Performance Demonstration Initiative (PDI) is not addressing Cast Stainless Ultrasonic Examinations.

Due to the highly attenuative characteristics of the austenitic grain structure, ultrasonic examination coverage to the extent that is specified within Code Case N-460 may not always be achievable.

Radiography is an impractical technique to use and, if applied, the alternative volumetric examinations are not expected to provide any meaningful increase in benefit beyond the alternative presented due to the high levels of background radiation emitting from these areas.

IV. Proposed Alternate Method:

None. Applicable code-required volumetric examination will be completed to the maximum extent practical (a best effort ultrasonic examination of the cast stainless welds based on state-of-the-art techniques and associated achievable examination coverage). Ultrasonic examinations shall be performed from the wrought side of applicable components. We will continue to evaluate new emerging inspection technology as they become available. The code required surface examinations and system leakage tests will be performed.

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