ML24052A366

Regulatory Audit Plan in Support of Proposed Alternative to ASME Code,Section XI Requirements for Containment Building Inspections

ML24052A366
Person / Time
Site:	Callaway
Issue date:	02/26/2024
From:	Mahesh Chawla Plant Licensing Branch IV
To:	Diya F Union Electric Co
Chawla M
References
EPID L-2023-LLR-0061
Download: ML24052A366 (1)

Text

February 26, 2024

Mr. 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 PLAN IN SUPPORT OF PROPOSED ALTERNATIVE TO ASME CODE, SECTION XI REQUIREMENTS FOR CONTAINMENT BUILDING INSPECTIONS (EPID L-2023-LLR-0061)

Dear Mr. 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 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 unbonded post-tensioning system ins ervice inspection at Callaway Plant, Unit No. 1.

The U.S. Nuclear Regulatory Commission (NRC) staff reviewed the licensees alternative request and determined that a regulatory audit would support its review of the proposed alternative. The NRC staff will conduct a regulatory audit to support its review in accordance with the enclosed audit plan. A regulatory audit is a planned activity that includes the examination and evaluation of primarily non-docketed information.

The audit will be conducted to increase the NRC staffs understanding of the request and identify information that will need to be docketed to support the NRC staffs regulatory findings.

The audit will be conducted from March 15, 2024, through May 15, 2024, through an online portal (also known as electronic portal, ePortal, or electronic reading room) established by the licensee.

F. Diya

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

Sincerely,

/RA/

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

Docket No. 50-483

Enclosure:

Audit Plan

cc: Listserv

REGULATORY AUDIT PLAN

IN SUPPORT OF 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 unbonded post-tensioning system inservice inspections at Callaway Plant, Unit No. 1 (Callaway).

The U.S. Nuclear Regulatory Commission (NRC) staff has determined the need for a regulatory audit to be conducted in accordance with the Office of Nuclear Reactor Regulation Office Instruction LIC-111, Revision 1, Regulatory Audits (ML19226A274), 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.

2.0 REGULATORY AUDIT BASES

The NRC staff (i.e., audit team) will perform the audi t to support its evaluation of whether the licensees request provides plant-specific examination results on Callaway, as a basis for the proposed deviations from the ASME Code,Section XI, subsection IWL requirements.

3.0 REGULATORY AUDIT SCOPE AND METHODOLOGY

The audit team will review the licensees tendon surveillance reports, calculations, and analyses supporting the proposed alternative. The audit team will use this review to determine if the licensee needs to submit any additional information in support of the requested changes in order to support conclusions for the NRC staffs safety evaluation.

Enclosure

4.0 INFORMATION AND OTHER MATERIAL NECESSARY FOR THE REGULATORY AUDIT

The NRC staff requests that the licensee has the following information readily available and accessible for the NRC staffs review via an internet-based portal:

The 10th, 15th, 20th, 25th, 30th, and 3 5th year detailed inspection reports for the general visual examinations of containment c oncrete components, and the detailed visual examinations of suspect areas, as required by table IWL-2500-1(L-A) Examination Category L-A, Concrete, at Callaway.

The 10th, 15th, 20th, 25th, 30th, and 3 5th year detailed reports for the containment building tendon surveillance, as required by table IWL-2500-1(L-B) Examination Category L-B, Unbounded Post-Tensioning System, at Callaway, including but not limited to the following:

o Tendon force trends and forecasts, elongation measurements, and the minimum required tendon forces;

o Tendon wire sampling and testing results, and their evaluations against the acceptance criteria;

o Visual examination results on the anchorage hardware and surrounding concrete, and their evaluations, and conclusions;

o Corrosion protection medium testing results, their evaluations, and conclusions;

o Free water testing results, their evaluations, and conclusions.

Per enclosure 2, section 3.4.2 of the licensees request dated October 26, 2023:

evaluation reports relating to blocked drains that caused severe corrosion of the vertical tendon wires, reports/redesign documents detailing the corrective actions to remediate corroded wires, and updated maintenance procedures to address root cause of the end cap flooding.

Per enclosure 2, section 3.4.2 of the licensees request dated October 26, 2023:

engineering evaluation reports relating to failing anchor heads, enhanced examination program documents, and corrective action reports for replacing failed or cracked anchor heads.

Applicable calculations for supporting the containment building tendon surveillance and for the acceptability of tendon/wires by the responsible engineer.

Based on the review of the above documents, the NRC staff will determine whether it needs to request any additional documents to be made available on the portal or whether additional information needs to be submitted on the docket for the staff to complete the review of the requested changes.

5.0 AUDIT TEAM

The members of the audit team are:

Mahesh Chawla, Project Manager, NRC (Mahesh.Chawla@nrc.gov)

Shaohua Lai, Structural Engineer, NRC (Shaohua.Lai@nrc.gov)

George Wang, Structural Engineer, NRC (George.Wang@nrc.gov)

6.0 LOGISTICS

The audit will be conducted from March 15, 2024, through May 15, 2024, through an online portal (also known as electronic portal, ePortal, or electronic reading room) established by Callaway.

If requested, the audit team will conduct a webinar with the licensee for the purposes of introducing the team, discussing the scope of the audit, and describing the information to be made available on the internet portal. The audit team expects to request that the licensee answer audit team questions during the audit related to information provided online at a mutually agreeable day and time by webinar. An exit discussion will be held at the conclusion of the audit.

7.0 SPECIAL REQUESTS

The audit team would like access to the documents listed above in section 4.0 through an online portal that allows the audit team to access documents via the internet. Additional documents may be identified as the review progresses. The following conditions associated with the online portal must be maintained throughout the duration that the audit team has access to the online portal.

The online portal will be password-protected, and separate passwords will be assigned to the NRC staff who are participating in the audit.

The online portal will be sufficiently secure to prevent the NRC staff from printing, saving, downloading, or collecting any information on the online portal.

Conditions of use of the online portal will be displayed on the login screen and will require acknowledgement by each user.

Username and password information should be provided directly to the NRC staff. The NRC staff who should be granted access to the portal are those listed in the Audit Team section. All other communications should be coordinated with the NRC project man ager.

8.0 DELIVERABLES

An audit summary will be prepared within 90 days of the completion of the audit. If the NRC staff identifies information during the audit that is needed to support its regulatory decision, the staff will issue requests for additional information to the licensee after the completion of the audit.

ML24052A366 *concurrence via email OFFICE NRR/DORL/LPL4/PM* NRR/DORL/LPL4/LA* NRR/DEX/ESEB/BC*

NAME MChawla PBlechman ISeng DATE 2/20/2024 2/22/2024 2/22/2024 OFFICE NRR/DORL/LPL/BC* NRR/DORL/LPL4/PM*

NAME JRankin MChawla DATE 2/23/2024 2/26/2024