ML19025A071

Response to Request for Additional Information Pertaining to Relief Request 14R-05 for Relief from Requirements of ASME Code Case N-770-2 Regarding Inspection Intervals for Reactor Vessel Nozzle Dissimilar Metal Welds

ML19025A071
Person / Time
Site:	Callaway
Issue date:	01/25/2019
From:	Abel S L Ameren Missouri, Union Electric Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
Shared Package
ML19025A070	List: ML19025A071 ULNRC-06479, Attachment a - Mitsubishi Responses to NRC Wjp RAIs
References
ULNRC-06479
Download: ML19025A071 (4)

Text

WAiIIerefl Callaway Plant MISSOURI January25, 2019 ULNRC-06479 U.S.Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 10 CFR 50.55a Ladies and Gentlemen:

DOCKET NUMBER 50-483 CALLAWAY PLANT UNIT 1 UNION ELECTRIC CO.RENEWED FACILITY OPERATING LICENSE NPF-30 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION PERTAINING TO RELIEF REQUEST 14R-05 FOR RELIEF FROM REQUIREMENTS OF ASME CODE CASE N-770-2 REGARDING INSPECTION INTERVALS FOR REACTOR VESSEL NOZZLE DISSIMILAR METAL WELDS

References:

1.Ameren Missouri letter ULNRC-06420,"Request 14R-05 for Relief from Requirements ofASME Code Case N-770-2 Regarding Inspection Intervals for Reactor Vessel Nozzle Dissimilar Metal Welds,"dated April 9, 20 1 8 (ADAMS Accession Number ML1 8099A120)2.NRC electronic correspondence,"Fonnal release ofRAIs Ref: Callaway Relief Request EPID L-20l8-LLR-005l,"

dated November 27, 2018 (ADAMS Accession Number ML1 833 lA205)In the letter identified as Reference 1 , Union Electric Company (Ameren Missouri)submitted Relief Request 14R-05 to request relief from the inspection frequency requirements, as incorporated by reference in 10 CFR 50.55a(g)(6)(ii)(F), ofASME Code Case N-770-2, Inspection Item A-2."Unmitigated butt weld at Hot Leg operating temperature 625°F (329°C),"and Inspection Item B,"Unmitigated butt weld at Cold Leg operating temperature."

Since the examination schedule of Code Case N-770-2 does not address the effects of Surface Stress Improvement by water-jet peening (as completed at Callaway Plant during Refuel 22 in the fall of 201 7)as an alternative to the inspection frequency requirements therein, Ameren Missouri proposed that the inspections be conducted in accordance with the inspection requirements for Alloy 82/1 82 dissimilar metal welds mitigated by water-jet peening, based on Item L ofTable 4-1 in MRP-335, Revision 3A,"Materials Reliability Program: Topical Report for Primary Water Stress Corrosion Cracking Mitigation by Surface Stress: 83 15 Zounty Road 459 Steedrnan, 1s'IJ 65077: i\riereiiI\'1issouri.coiri ULNRC-06479 January 24, 2019 Page 2 of 4 Improvement,"(November 2016)on the basis that the proposed alternative provided an acceptable level of quality and safety.From review of the Reference 1 submittal, the NRC staff issued per Reference 2 a request for additional information (RAI)regarding Relief Request 14R-05.This letter provides Arneren Missouri's response to the RAT.Specifically, Ameren Missouri's water-jet peening vendor has prepared responses to the RAT questions which are hereby provided in the enclosure to this letter.This letter does not contain new commitments.

Ifthere are any questions, please contact Mr.Tom Elwood at 314-225-1905.

Sincerely,-1 f/I I I i i2/i'-_f'JN Shannon L.Abel, Director, Engineering Design&Projects JPK!

Enclosure:

Attachment A-Mitsubishi Responses to NRC WJP RATs ULNRC-06479 January24, 2019 Page 3 of 4 cc: Mr.Scott A.Morris Regional Administrator U.S.Nuclear Regulatory Commission Region IV 1600 East Lamar Boulevard Arlington, TX 76011-4511 Senior Resident Inspector Callaway Resident Office U.S.Nuclear Regulatory Commission 8201 NRC Road Steedman, MO 65077 Mr.L.John Klos Project Manager, Callaway Plant Office of Nuclear Reactor Regulation U.S.Nuclear Regulatory Commission Mail Stop 09E3 Washington, DC 20555-0001 ULNRC-06479 January 24, 2019 Page 4 of 4 Index and send hardcopy to QA File A160.0761 Hardcopy: Certrec Corporation 6100 Western Place, Suite 1050 Fort Worth, TX 76107 (Certrec receives ALL attachments as long as they are non-safeguards and may be publicly disclosed.)

Electronic distribution for the following can be made via Other Situations ULNRC Distribution:

F.M.Diya T.E.Hemriaim B.L.Cox F.J.Bianco S.P.Banker R.C.Wink T.B.Elwood S.L.Abel J.C.Claunch W.P.Muskopf Corporate Communications NSRB Secretary STARS Regulatory Affairs Mr.Jay Silberg (Pillsbury Winthrop Shaw Pittman LLP)Missouri Public Service Commission