ML18037A403
| ML18037A403 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 08/02/1993 |
| From: | Salas P TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-92-01, GL-92-1, TAC-M83438, TAC-M83439, TAC-M83440, NUDOCS 9308090281 | |
| Download: ML18037A403 (9) | |
Text
ACCELERATED DOCVMENT DISTRIBVTIONSYSTEM RESULRY INFORMATION DISTRISUTZ SYSTEM (RIDE)
ACCESSION NBR:9308090281 DOC.DATE: 93/08/02 NOTARIZED: NO DOCKET FACIL:50-.259 Browns Ferry Nuclear Power Station, Unit 1, Tennessee 05000259 260 Browns Ferry Nuclear Power Station, Unit 2, Tennessee 05000260 50-296 Browns Ferry Nuclear Power Station, Unit 3, Tennessee 05000296 AUTH.NAME AUTHOR AFFILIATION SALAS,P.
Tennessee Valley Authority RECIP.NAME RECIPIENT AFFILIATION Document Control Branch'-(Document Control Desk)
SUBJECT:
Forwards response to GL 92-01,Rev 1 re RV structural integrity,w/respect to Items 2.a a 2.b.
DISTRIBUTION CODE:
A028D COPIES RECEIVED:LTR ENCL SIZE:
TITLE: Generic Letter 92-01 Responses (Reactor Vessel Structural Integrity 1
NOTES:
D RECIPIENT.
ID CODE/NAME PD2-4-PD WILLIAMS,J.
COPIES LTTR ENCL 1
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2 RECIPIENT ID CODE/NAME ROSS,T.
COPIES LTTR ENCL 2
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INTERNAL: ACRS NRR/DRPW/OGCB NUDOCS-ABSTRACT OGC/HDS3 RES/DE/MEB EXTERNAL: NRC PDR 6
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1 NRR/DE/EMCB NRR/PDl-1 G -I FD.CB REG FI NSIC 01 2
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NOTE TO ALL"RIDS" RECIPIENTS PLEASE HELP US TO REDUCE WASTEI CONTACT THE DOCUMENT CONTROL DESK, ROOM Pl-37 (EXT. 504-2065) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEEDI D
TOTAL NUMBER OF COPIES REQUIRED:
LTTR 22 ENCL 20
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Tennessee Valley Authority. post Office Box 2000. Decatur, Alabama 35609
'WB 02 1993 U.S. Nuclear Regulatory Commission ATTN:
Document Control Desk Washington, DC 20555 Gentlemen:
In the Matter of Tennessee Valley Authority Docket Nos. 50-259 50-260 50-296 BROWNS FERRY NUCLEAR PLANT (BFN) RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION, GENERIC LETTER 92-01, REVISION 1 In reference to your letter to TVA dated May 27, 1993, "Request for Additional Information Regarding TVA Response to Generic Letter 92-01, Revision 1, Reactor Vessel Structural Integrity Browns Ferry Nuclear Plant (TAC NOS. M83438, M83439, and M83440)," TVA has reviewed the information and the enclosure to this letter provides the response to Items 2.a.
and 2.b.
If you have any questions regarding this response, please telephone me at (205) 729-2636.
Sincerely,
+ Pedro Salas Site Licensing Ma ge Browns Ferry Nuclea lant Enclosures cc:
See page 2
090026 9308090281 930802 PDR ADOCK 05000259 P
U.S. Nuclear Regulatory Commission Page 2
AUG 02 1993 cc (Enclosures):
Mr. R. V.'rlenjak, Project Chief U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 NRC Resident Inspector Browns Ferry Nuclear Plant Route 12, Box 637
- Athens, Alabama 35611 Mr. Thierry M. Ross, Project Manager U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852
ENCLOSURE
RESPONSE
TO GENERIC LI33TER 92-01 REQUEST FOR ADDITIONALINFORMATION
~t g 2~ The response to GL 92-01 indicated that the initial upper-shelf energy (USE) values for the beltline plates with no measured Charpy USE were derived from four surveillance plates and the Charpy USE of the beltline axial welds were derived from the surveillance electroslag (ES) weld.
A topical report, NED0-32205, titled "BWR Owners'roup Topical Report on Upper Shelf Energy-.
Equivalent Margin Analysis" regarding beltline materials with low USE, was submitted by General Electric Corporation on April 30, 1993.
The licensee must either confirm that this topical report will be used as its licensing bases or provide its plant specific approach to demonstrate that all beltline materials that do not have measured USE will meet requirements of Appendix G, 10 CFR 50.
Browns Ferry Nuclear Plant will use NED0-32205, "BWR Owners'roup Topical Report on Upper Shelf Energy Equivalent Margin Analysis," as its licensing basis to demonstrate that beltline materials maintain adequate upper shelf energy (USE) margins.
2~ The response to GL 92-01 indicated that the initial RTNDT values of the beltline axial welds were derived from the surveillance electroslag ES weld, and that the chemistry data of the axial welds were derived from three ES welds from Babcock and Wilcox quality assurance records.
Confirm the existence of copper coating for all ES weld wires concerned, and provide initial data (initial RTNDT, and chemistry) for these axial welds or provide data and analysis from ES welds that were fabricated using the same vendor, fabrication time frame, fabrication process, and material specification to demonstrate that the initial RTNDT and chemistry values used for axial welds are justified.
Describe the methods that were used to determine the copper and nickel values.
In the early 1980's, Babcock and Wilcox (BEW) was contracted by TVA to conduct an extensive search of their records and provide a summary document detailing all available material and fabrication information pertaining to the BFN reactor vessel core region components.
This information was reported to TVA in a document, BAW-1845, "Browns Ferry Core Region Materials Information (Units 1, 2, and 3)."
The following information is a summarization of that document which is pertinent to addressing the NRC question-
Prolongation material parted from the vessel plate material after contour rolling was used to fabricate the surveillance plates.
The surveillance plates (one for each vessel) contained one or more heats of plate material from the ~essel and an electroslag weld (ES) performed by the vendor (B&W) at the time frame the shell courses were fabricated.
Welding processes and electrode material were consistent with that used for the vessel axial welds.
Records are available which describe the thermal and working history of each surveillance test plate.
Records of specific weld materials and their relation to the vessel axial welds were not available.
However, chemical and mechanical tests results are available for the three surveillance plate materials.
Neither records nor test results for the specific weld materials used to fabricate the axial seams of the six shell courses of the three vessels were available.
During the records
- review, B&W identified four procedure qualifications (PQs) performed in the general time frame that the axial seams were performed on the Browns Ferry vessels.
Three of the PQs contained chemistry data, while all four contained mechanical test results.
These PQs are considered by B&W to be the only ones applicable to the core region shell courses welded-by the ES process for the Browns Ferry units.
B&W also identified eight weld wire heat chemistries from the time frame of fabrication of the BFN vessels.
Since no specific BFN vessel ES weld analyses were available, B&W developed a generic chemistry which was based upon a combination of the three ES weld qualification chemistries (PQs) and the eight weld wire heat chemistries.
This generic chemistry consisting of 0.25K Cu, 0.35K Ni, and 0.016K P was applied to all the vessel welds.
- 121, 116, and 92 dated July 23, 1985, provides the results of the NRC staff review of this generic chemical composition and references additional related test data from prolongation material removed from the Peach Bottom Units 1 and 2 electroslag welds, which was also fabricated by B&W using Linde 124 flux.
The staff concluded that the estimated composition is acceptable.
No drop weight or Charpy V-Notch (CVN) tests are available for the vessel welds.
Drop weight data is not available for the surveillance welds, only CVN data exists-This surveillance CVN data indicates that thy 50 ft-lb temperatures for the three plates to be +33, +10, and -21 F.
Bayed on these temperatures, an estimate for RTNDT was amended to +10 F by the July 23,
Upper shelf energy data is available for the surveillance welds only (no vessel ES welds are available).
From the three USEs of 93,
- 116, and 124 ft-lbs from the surveillance welds, an estimated generic value of 95 ft-lbs was estimated and applied to all the vessel ES welds.
Spare unirradiated Charpy specimens representative of the surveillance material in the three vessels were analyzed for chemical content in 1983 by Combustion Engineering using emission spectrographic techniques'hese data include both base metal and ES weld chemistries and are given in Appendix F of BAW-1845.
The generic values that were estimated for the chemistry RTNDT, and USE for the ES axial welds in the reactor core region are conservative values.
Based upon the conservatism, it is TVA's belief that adequate margins exist for safe operation of the vessels within the requirements of Appendices G and H of 10 CFR 50 and is supported by the NRC staff conclusions reached in the July 23,