View source for ULNRC-06725, CFR 50.46 Annual Report Regarding ECCS Evaluation Model Revisions

{{Adams
| number = ML22081A319
| issue date = 03/22/2022
| title = CFR 50.46 Annual Report Regarding ECCS Evaluation Model Revisions
| author name = Mills K
| author affiliation = Ameren Missouri, Union Electric Co
| addressee name = 
| addressee affiliation = NRC/Document Control Desk, NRC/NRR
| docket = 05000483
| license number = NPF-030
| contact person = 
| case reference number = ULNRC-06725
| package number = ML22081A318
| document type = Letter type:ULNRC
| page count = 4
}}

=Text=
{{#Wiki_filter:Aiiiei MISSOURI en                                                                         Callaway Plant March 22, 2022 ULNRC-06725 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 10 CFR 50.46 Ladies and Gentlemen:
DOCKET NUMBER 50-483 CALLAWAY PLANT UNIT 1 UNION ELECTRIC CO.
RENEWED FACILITY OPERATING LICENSE NPF-30 10 CFR 50.46 ANNUAL REPORT REGARDING ECCS EVALUATION MODEL REVISIONS Ameren Missouri hereby submits the annual report required per 1 0 CFR 50.46(a)(3) for Callaway Plant.
Attachment 1 to this letter describes those changes to the Westinghouse ECCS Large Break and Small Break Loss of Coolant Accident (LOCA) Evaluation Models that have been implemented for Callaway during the time period from March 2021 to March 2022. Attachment 2 provides an ECCS Evaluation Model Margin Assessment which accounts for all peak cladding temperature (PCT) changes resulting from the resolution ofprior issues as they apply to Callaway. No new PCT penalties are identified in these attachments.
References 1 through 16 (listed on page 2 of this letter) are the annual 1 0 CFR 50.46 reports that have been submitted since the LOCA analyses were revised to reflect the installation of the replacement steam generators in 2005. As reported in each ofthese reports, the PCT values determined in the Large Break and Small Break LOCA analyses of record, when combined with all PCT margin allocations, remain below the 2200&deg;F regulatory limit. However, in March 20 14, Ameren Missouri was informed by Westinghouse that the absolute magnitude of the Large Break Loss of Coolant Accident (LBLOCA) penalty assessments accumulated in the analyses of record for Callaway (since replacement of the steam generators) had reached a value that exceeded 50&deg;F. The letter identified as Reference 9 was then submitted pursuant to the requirements of 10 CFR 50.46(a)(3)(ii), containing a commitment to reanalyze the Large Break and Small Break Loss of Coolant Accidents using the NRC-approved version of WCAP-l 6996-P, Realistic LOCA Evaluation Methodology Applied to the Full Spectrum ofBreak Sizes (FULL SPECTRUM LOCA Methodology). That reanalysis has not yet 83 15 County Road 459 : Steedman, MO 65077  AmerenMissouri.com

ULNRC-06725 March 22, 2022 Page 2 of 4 been performed; however, it should be noted that Ameren Missouri is currently in the process of evaluating a change in fuel vendors for Callaway Plant. After that determination is made, the required reanalysis will be completed on a schedule appropriate to the selected fuel vendor.
This letter does not contain new commitments. for any questions on this report, please contact Mr.
Tom Elwood at (314) 225-1905.
2 Director, Nuclear Regulatory Performance DRB

==References:==
: 1) ULNRC-05260 dated 3-9-06
: 2) ULNRC-05378 dated 3-7-07
: 3) ULNRC-05475 dated 3-4-08
: 4) ULNRC-05600 dated 3-4-09
: 5) ULNRC-05683 dated 3-1-10
: 6) ULNRC-05769 dated 3-1-11
: 7) ULNRC-05840 dated 3-1-12
: 8) ULNRC-05968 dated 3-6-13
: 9) ULNRC-06098 dated 3-25-14
: 10) ULNRC-06203 dated 3-31-15 1 1) ULNRC-06292 dated 3-30-16
: 12) ULNRC-06361 dated 3-30-17
: 13) ULNRC-06428 dated 3-29-18
: 14) ULNRC-06497 dated 3-28-19
: 15) ULNRC-06571 dated 3-31-20
: 16) ULNRC-06645 dated 3-31-21 Attachments:
1 Changes to the Westinghouse ECCS Evaluation Model and PCT Penalty Assessments
: 2. ECC$ Evaluation Model Margin Assessment for Callaway

ULNRC-06725 March 22, 2022 Page 3 of 4 cc:    Mr. Scott A. Morris Regional Administrator U. S. Nuclear Regulatory Commission Region IV 1 600 East Lamar Boulevard Arlington, TX 76011-4511 Senior Resident Inspector Callaway Resident Office U.S. Nuclear Regulatory Commission
       $201 NRC Road Steedman, MO 65077 Mr. M. Chawla Project Manager, Callaway Plant Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Mail Stop O8B1A Washington, DC 20555-000 1

ULNRC-06725 March 22, 2022 Page 4 of 4 Index and send hardcopy to QA File A160.0761 Hardcopy:
Certrec Corporation 6500 West Freeway, Suite 400 Fort Worth, TX 76116
( 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 Respo nses and Reports ULNRC Distribution:
F. M. Diya B. L. Cox F. J. Bianco D. Farnsworth M. A. McLachlan K. A. Mills T. A. Witt R. C. Wink T. B. Elwood J. Cordz NSRB Secretary STARS Regulatory Affairs Mr. Jay Silberg (Pillsbury Winthrop Shaw Pittrnan LLP)
Ms. Kathleen McNelis (Public Service Commission)
Ms. Claire Eubanks (Public Service Commission)}}