ML24212A282

Regulatory Audit Summary Concerning Review of Request No. C3R-01 for Proposed Alternative to ASME Code,Section XI Requirements for Containment Building Inspections

ML24212A282
Person / Time
Site:	Callaway
Issue date:	08/02/2024
From:	Mahesh Chawla Plant Licensing Branch IV
To:	Diya F Ameren Missouri, Union Electric Co
Chawla M
References
EPID L-2023-LLR-0061
Download: ML24212A282 (1)

Text

August 2, 2024

Fadi Diya Senior Vice President and Chief Nuclear Officer Ameren Missouri Callaway Energy Center 8315 County Road 459 Steedman, MO 65077

SUBJECT:

CALLAWAY PLANT, UNIT NO. 1 - REGULATORY AUDIT

SUMMARY

CONCERNING REVIEW OF REQUEST NO. C3R-01 FOR PROPOSED ALTERNATIVE TO ASME CODE, SECTION XI REQUIREMENTS FOR CONTAINMENT BUILDING INSPECTIONS (EPID L-2023-LLR-0061)

Dear Fadi Diya:

By letter dated October 26, 2023 (Agencywide Documents Access and Management System (ADAMS) Package Accession No. ML23299A195), as supplemented by )|letter dated December 21, 2023]] (ML23355A180), Union Elec tric Company, doing business as Ameren Missouri (the licensee), submitted a relief request for the third 10-year interval of the containment inservice inspection program at Callaway Plant, Unit No. 1.

The proposed alternative would change the inspect ion frequency from 5 to 10 years for the concrete containment unbonded post-tensioning system from the requirements of subsection IWL-2420(a), of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components.

To support its review of the alternative request, the U.S. Nuclear Regulatory Commission (NRC) staff conducted a regulatory audit via the use of an online reference portal set up by the licensee. The NRC staff reviewed surveillance re ports and analyses supp orting the licensees alternative request. The audit summary is enclosed with this letter.

F. Diya

If you have any questions, please contact me at (301) 415-8371 or by email at Mahesh.Chawla@nrc.gov.

Sincerely,

/RA/

Mahesh Chawla, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Docket No. 50-483

Enclosure:

Audit Summary

cc: Listserv

REGULATORY AUDIT

SUMMARY

PROPOSED ALTERNATIVE TO ASME CODE, SECTION XI REQUIREMENTS FOR

CONTAINMENT BUILDING INSPECTIONS

UNION ELECTRIC COMPANY

CALLAWAY PLANT, UNIT NO. 1

DOCKET NO. 50-483

1.0 BACKGROUND

By letter dated October 26, 2023 (Agencywi de Documents Access and Management System

( A D A MS ) Package A c c es s i o n N o. ML23299A195), as supplemented by )|letter dated December 21, 2023]] (ML23355A180), Union Electr ic Company, doing business as Ameren Missouri (the licensee), submitted a proposed alternative to subsection IWL of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),

Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, regarding the frequency of certain containment inservice inspections (CISIs) on the containment unbonded post-tensioning system at Callaway Plant, Unit No. 1 (Callaway).

The proposed alternative would change the inspection frequency from 5 to 10 years for the concrete containment unbonded post-tensioning system from the requirements of ASME Code,Section XI, subsection IWL-2420(a) during the third 10-year CISI interval. Per the ASME Code, the periodic visual examination and physical testing of containment building concrete are required in accordance with table IWL-2500-1 (L-A), as well as physical testing of unbonded post-tensioning systems in accordance with table IWL-2500-1 (L-B) of ASME Code Section XI.

The U.S. Nuclear Regulatory Commission (NRC) staff reviewed the licensees alternative request and determined that a regulatory audit would assist in the timely completion of the licensing review process. The audit was conducted in accordance with the audit plan dated February 26, 2024 (ML24052A366).

2.0 AUDIT DATES AND LOCATION

The regulatory audit was conducted via an internet portal established by the licensee from March 15, 2024, through May 15, 2024.

3.0 AUDIT ACTIVITIES

The purpose of the audit was for the NRC staff to examine the licensees non-docketed information with the intent to gain a better understanding of the alternative request, to verify information, and to identify information that may require docketing to support the basis of the NRC staffs licensing decision. The audit activities conducted by the NRC staff included a review of surveillance and evaluation reports supporti ng the licensees proposed alternative request.

Enclosure

The licensee provided the following supporting calc ulations and evaluations for the NRC staff review via the online reference portal:

Tenth Year Physical Surveillance Callaway Unit 1 Containment Building, Post-Tensioning Surveillance Report, Revision 0, October 28, 1994

Fifteenth Year Physical Surveillance of the Callaway Unit 1 Containment Building, Post-Tensioning Surveillance Report, Revision 0, August 12, 1999

Twentieth Year Physical Surveillance of the Post-Tensioning System at the Callaway Nuclear Plant, Post-Tensioning Surveillance Report, Revision 0, April 28, 2005

Final Report for the 25th Year Containment IWL Inspection, Callaway 25 th Year Tendon Surveillance, Revision A, July 26, 2010

30th Year Tendon Surveillance at Callaway Nuclear Power Plant, Final Report for the 30th Year Tendon Surveillance at Callaway Plant, Revision C, October 7, 2015

Final Report for the 35th Year Tendon Surveillance at Callaway, 35 th Year Tendon Surveillance at Callaway, Revision 2, July 2, 2021

Callaway Action Request No. 201004223, May 4, 2010

NCR89N353 - Callaway Plant Nuclear Safety Evaluation, Evaluate PSC Tendon Surveillance Findings, September 25, 1989

4.0 RESULTS OF THE AUDIT

During the audit, the NRC staff did not make any regulatory decisions regarding the alternative request under the NRC staff review. At the conclusion of the audit, the NRC staff informed the licensee that it would not be issuing a request for additional information following the completion of its review of the audit portal information. The NRC staff noted that the audit facilitated the NRC staffs timely review of the request.

5.0 AUDIT PARTICIPANTS

NRC Participants from the Office of Nuclear Reactor Regulation

Shaohua Lai, Division of Engineering and External Hazards (DEX), Structural, Civil, and Geotechnical Branch (ESEB)

George Wang, DEX, ESEB

Mahesh Chawla, Division of Operating Reactor Licensing, Plant Licensing Branch IV

6.0 EXIT BRIEFING

The NRC staff reviewed the documents on the portal. The NRC staff did not identify any issues which resulted in audit questions or the need for any further discussion with the licensee. On July 29, 2024, Mahesh Chawla of the NRC staff informed Thomas Elwood of Ameren Missouri, via telephone, that the NRC staff did not need to review any additional calculations or evaluations and, accordingly, the audit was concluded.

ML24212A282 *by email OFFICE NRR/DORL/LPL4/PM NRR/DORL/LPL4/LA* NRR/DEX/ESEB/BC*

NAME MChawla PBlechman ITseng DATE 7/29/2024 8/1/2024 8/1/2024 OFFICE NRR/DORL/LPL/BC* NRR/DORL/LPL4/PM*

NAME JRankin MChawla DATE 8/1/2024 8/2/2024