ML20325A376

(11/20/2020) E-mail from R. Guzman to S. Sinha - Acceptance Review, Unacceptable with Opportunity to Supplement Proposed LAR to Revise MPS2 TSs for Steam Generator Inspection Frequency

ML20325A376
Person / Time
Site:	Millstone
Issue date:	11/20/2020
From:	Richard Guzman NRC/NRR/DORL/LPL1
To:	Sinha S Dominion Energy Nuclear Connecticut
Guzman R
References
EPID L-2020-LLA-0227
Download: ML20325A376 (3)

Text

From: Guzman, Richard To: Shayan Sinha Cc: Jeffry A Langan; Kathryn H Barret

Subject:

Millstone Power Station, Unit No. 2 - Acceptance Review, Unacceptable with Opportunity to Supplement re:

Proposed LAR to Revise the MPS2 TSs for Steam Generator Inspection Frequency (EPID L-2020-LLA-0227)

Date: Friday, November 20, 2020 4:27:52 PM Mr. Sinha, By letter dated October 8, 2020 (ADAMS Accession No. ML20282A594), Dominion Energy Nuclear Connecticut, Inc. (DENC, the licensee) submitted a license amendment request for Millstone Power Station, Unit No. 2 (MPS2). The proposed amendment would revise MPS2 TS 6.26, "Steam Generator (SG) Program," Item d.2, to reflect a proposed change to the required SG tube inspection frequency from every 72 effective full power months (EFPM),

or at least every third refueling outage, to every 96 EFPM. The purpose of this communication is to provide the results of the U.S. Nuclear Regulatory Commission (NRC) staffs acceptance review of this amendment request. 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.

Consistent with Section 50.90 of Title 10 of the Code of Federal Regulations (10 CFR), an amendment to the license (including the technical specifications) must fully describe the changes requested, and following as far as applicable, the form prescribed for original applications. Section 50.34 of 10 CFR addresses the content of technical information required. This section stipulates that the submittal address the design and operating characteristics, unusual or novel design features, and principal safety considerations.

The NRC staff has reviewed your application and concluded that the information delineated below is necessary to enable the staff to make an independent assessment regarding the acceptability of the proposed amendment in terms of regulatory requirements and 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 information requested below by December 10, 2020. This will enable the NRC staff to begin its detailed technical review. If the information responsive to the NRC staffs request is not received by the above date, the application will not be accepted for review pursuant to 10 CFR 2.101, and the NRC will cease its review 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.

The information requested and associated time frame in this letter were discussed with your staff on November 20, 2020.

If you have any questions, please contact me.

Richard V. Guzman Senior Project Manager Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission OFFICE OF NUCLEAR REACTOR REGULATION ACCEPTANCE REVIEW - UNACCEPTABLE WITH OPPORTUNITY TO SUPPLEMENT PROPOSED LICENSE AMENDMENT REQUEST TO REVISE THE MPS2 TECHNICAL SPECIFICATIONS FOR STEAM GENERATOR INSPECTION FREQUENCY DOMINION ENERGY NUCLEAR CONNECTICUT, INC.

MILLSTONE POWER STATION, UNIT NO. 2 DOCKET NO. 50-336 By letter dated October 8, 2020 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML20282A594), Dominion Energy Nuclear Connecticut, Inc.

(DENC, the licensee) submitted a license amendment request for Millstone Power Station, Unit No. 2 (MPS2). The proposed amendment would revise MPS2 TS 6.26, "Steam Generator (SG) Program," Item d.2, to reflect a proposed change to the required SG tube inspection frequency from every 72 effective full power months (EFPM), or at least every third refueling outage, to every 96 EFPM. The U.S. Nuclear Regulatory Commission (NRC) staff has determined that the proposed LAR does not meet the criterion of Sufficiency of Information described in section 3.1.2 of LIC-109, Acceptance Review Procedures for Licensing Basis Changes, (ADAMS Accession No. ML20036C829) in that sufficient technical information was not provided for the staff to complete its review of the proposed application as outlined below.

The LAR states, Furthermore, the MPS2 SG operational assessment and experience supports the proposed TS changes. However, the operational assessment (OA) submitted by the licensee was for a three-cycle operating period which was developed at the completion of RFO24 in spring 2017 to demonstrate that the SG structural and accident induced leakage performance criteria would be met during the operating period preceding RFO27 in fall 2021. Also, the LAR does not provide a justification as to why an OA for a five-cycle operating period was not provided. To support the proposed LAR, the licensee is requested to supplement their LAR with a five-cycle operating period OA, to demonstrate that the SG structural and accident induced leakage performance criteria would be met during the operating period preceding RFO29 in fall 2024, for all existing and potential degradation mechanisms.

Millstone Unit 2 currently has two existing degradation mechanisms - fan bar wear and foreign object (FO) wear.

Section 3.11 in Attachment 1 of the LAR, includes five-cycle operating period information for fan bar wear and concludes there is reasonable assurance that the structural integrity performance criterion will be met for this mechanism for the five cycles of operation (at which time, another inspection and OA will be performed). Section 6.1 of the OA completed at the end of RFO24 concluded that there is reasonable assurance that the structural integrity performance criterion will be met for fan bar wear for the next three cycles of operation until 2R27, which is five total cycles of operation.

Section 6.2 of the OA completed at the end of RFO24 concluded that there is reasonable assurance that the structural integrity performance criterion will be met for FO wear for a three-cycle operating period. Section 3.9 in Attachment 1 of the LAR does not make a reasonable assurance statement that the structural integrity performance criterion will be met for FO wear for a five-cycle operating period. Therefore, neither the OA or the LAR makes a reasonable assurance statement that the structural integrity performance criterion will be met for a five-cycle operating period.

Per Section 3.1.2, Technical Staff Criteria, in NRR-LIC-109, the information provided should support a comparison of the RLA to the licensees existing processes or programs, if applicable, with justification for the change. The licensees existing process would be to develop an OA for the operating period preceding the next SG inspection and as noted above, the licensee did not justify why an OA for a five-cycle operating period was not provided. Additionally, the licensee cites similar LARs requesting a SG inspection frequency change, including recent one-time changes to SG inspection frequencies. In each of these instances, the licensee submitted OAs for the operating period preceding the next inspection. Meaning, for example, if the licensee is requesting that the SG inspection frequency be changed to a five-cycle operating period, then the OA was for a five-cycle operating period.