ML23338A039

NRR E-mail Capture - LIC-109 Acceptance Review - Unacceptable with Opportunity to Supplement - Callaway - RR from Requirements of ASME BPV Code, Section Xl, Subsect IWL-Exam & Test-Unbonded Post Tensioning System - EPID L-2023-LLR-0061

ML23338A039
Person / Time
Site:	Callaway
Issue date:	12/01/2023
From:	Mahesh Chawla Plant Licensing Branch IV
To:	Elwood T Ameren Missouri
References
L-2023-LLR-0061
Download: ML23338A039 (3)

Text

From: Mahesh Chawla Sent: Friday, December 1, 2023 2:18 PM To: Elwood, Thomas B Cc: Jennie Rankin; Ian Tseng; Shao Lai; George Wang

Subject:

LIC-109 Acceptance Review - Unacceptable with Opportunity to Supplement -

Callaway - RR from Requirements of ASME BPV Code, Section XL, Subsect IWL-Exam & Test-Unbonded Post Tensioning System - EPID L-2023-LLR-0061

Dear Mr. Elwood:

By letter dated October 26, 2023 (Agencywide Documents Access and Management System, Accession No. ML23299A195), Union Electric Company (Ameren Missouri, the licensee) submitted a request for relief from requirements of American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (BPV) Code,Section XI, Subsection IWL regarding examination and testing of the unbonded post-tensioning system (Relief Request C3R-01) for Callaway Energy Center (Callaway Plat). The ASME BPV Code,Section XI, Subsection IWL requires periodic visual examination of containment concrete as well as visual examination and physical testing of post-tensioning system. Ameren Missouri proposes extending the interval for post-tensioning system examinations and testing and detailed visual examination of concrete adjacent to tendon bearing plates from 5 years to 10 years. The purpose of this letter is to provide the results of the U.S. Nuclear Regulatory Commission (NRC) staffs acceptance review of this proposed alternative. The acceptance review was performed to determine if there is sufficient technical information in scope and depth to allow the NRC staff to complete its detailed technical review. The acceptance review is also intended to identify whether the application has any readily apparent information insufficiencies in its characterization of the regulatory requirements or the licensing basis of the plant.

Pursuant to 10 CFR 50.55a(z)(1) and 10 CFR 50.55a(z)(2), the applicant shall demonstrate that the proposed alternatives would provide an acceptable level of quality and safety, or that compliance with the specified requirements of 10 CFR 50.55a would result in hardship or unusual difficulty without a compensating increase in the level of quality or safety. The NRC staff has reviewed your application and concluded that the information delineated in the enclosure to this letter is necessary to enable the NRC staff to make an independent assessment regarding the acceptability of the proposed alternative in terms of regulatory requirements for the protection of public health and safety and the environment. In order to make the application complete, the NRC staff requests that the licensee supplement the application to address the following concerns expressed by staff by a later mutually agreed upon date (during the clarification call). This will enable the NRC staff to begin its detailed technical review.

The NRC staff noticed in Section 2.1 of Enclosure 2 of the application that the licensee requested duration of proposed alternative for multiple containment in-service inspection (CISI) intervals, i.e., Extend the interval of post-tensioning system examinations and tests and detailed visual examination of concrete adjacent to tendon bearing plates from 5 years to 10 years with future examinations to be performed in accordance with the following schedule: 2028 (45th), 2038 (55th), 2048 (65th), 2058 (75th).

It is the NRC staffs understanding that this relief request only seeks NRCs approval through the 40th year. However, the NRC staff does not find the proposed alternative beyond the 45th year reasonable, and thus does not provide an acceptable level of quality and safety, because:

1) the NRC staff only allows for one-time interval extension, based on its review of the plant-specific testing results and operating experience provided in the relief request; 2) the proposed alternative may allow undetected degradations every 5 years to advance for up to 10 years before taking the necessary corrective actions to preserve the intended function of the unbonded post-tensioning system; 3) the NRC staff does not find it reasonable to extend the CISI intervals for the fourth 10-year interval and beyond, without reviewing the results IWL CISI inspections conducted prior to the initiation of the subsequent CISI interval; and 4) the NRC staff has not authorized such requests beyond one 10-year interval for any plant, even though requests for authorization through end of license were made for at least three recent similar proposed alternative requests for unbonded post-tensioning system inspection intervals (i.e.,

Palo Verde (ML22124A241), Calvert Cliffs (ML21190A004), Braidwood and Byron (ML21134A006) and NRC staff stated its rationale in the safety evaluations.

If the information responsive to the NRC staffs request is not received by the mutually agreed upon date, the application will not be accepted for review pursuant to 10 CFR 2.101, Filing of application, and the NRC will cease its activities associated with the application. If the application is subsequently accepted for review, you will be advised of any further information needed to support the staffs detailed technical review by separate correspondence.

Please arrange a clarification call with the NRC staff within 5 working days from the receipt of this email. If you have any questions, please contact me.

Sincerely,

Mahesh Chawla, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Telephone: 301-415-8371, E-mail address: Mahesh.chawla@nrc.gov

OFFICEDORL/LPL4 /PM DORL/LPL4/BC

NAMEMChawla JRankin

DATE12/1/23 12/1/23

Hearing Identifier: NRR_DRMA Email Number: 2326

Mail Envelope Properties (SJ0PR09MB10405A7F49BBE1D95E6A45D02F181A)

Subject:

LIC-109 Acceptance Review - Unacceptable with Opportunity to Supplement -

Callaway - RR from Requirements of ASME BPV Code, Section XL, Subsect IWL-Exam &

Test-Unbonded Post Tensioning System - EPID L-2023-LLR-0061 Sent Date: 12/1/2023 2:17:42 PM Received Date: 12/1/2023 2:17:00 PM From: Mahesh Chawla

Created By: Mahesh.Chawla@nrc.gov

Recipients:

"Jennie Rankin" <Jennivine.Rankin@nrc.gov>

Tracking Status: None "Ian Tseng" <Ian.Tseng@nrc.gov>

Tracking Status: None "Shao Lai" <Shaohua.Lai@nrc.gov>

Tracking Status: None "George Wang" <George.Wang@nrc.gov>

Tracking Status: None "Elwood, Thomas B" <TElwood@ameren.com>

Tracking Status: None

Post Office: SJ0PR09MB10405.namprd09.prod.outlook.com

Files Size Date & Time MESSAGE 5296 12/1/2023 2:17:00 PM

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