ML15036A252

Supplement to 10 CFR 50.55a Requests (RR) 1-RR-5-7 and 2-RR-5-7 (TACs MF4843 and MF4844) Associated with Prairie Island Nuclear Generating Plant (PINGP) Fifth Ten-Year Interval Inservice Inspection (ISI) Program

ML15036A252
Person / Time
Site:	Prairie Island
Issue date:	02/04/2015
From:	Davison K Northern States Power Co, Xcel Energy
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
L-PI-15-0018, TAC MF4843, TAC MF4844
Download: ML15036A252 (4)

Text

Xcel Energy FEB 0 4 2015 U S Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Prairie Island Nuclear Generating Plant Units 1 and 2 Dockets 50-282 and 50-306 Renewed License Nos. DPR-42 and DPR-60 L-PI-15-0018 10 CFR 50.55a Supplement to 10 CFR 50.55a Requests (RR) 1-RR-5-7 and 2-RR-5-7 (TAGs MF4843 and MF4844) Associated with Prairie Island Nuclear Generating Plant (PINGP) Fifth Ten-Year lntervallnservice Inspection (lSI) Program By letter dated September 15, 2014 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML 14258A124), Northern States Power Company, a Minnesota corporation, doing business as Xcel Energy (hereafter "NSPM"), submitted for NRC approval10 CFR 50.55a Requests 1-RR-5-7 and 2-RR-5-7 associated with the fifth ten-year interval for the Prairie Island Nuclear Generating Plant (PINGP), Units 1 and 2, lnservice Inspection (lSI) Program. By email dated January 26, 2015 (ML 15030A008), the NRC requested additional information (RAis) to complete the review of these requests.

The enclosure to this letter provides the responses to the NRC Staff RAis for 1-RR-5-7 and 2-RR-5-7.

If there are any questions or if additional information is needed, please contact Mr. Dale Vincent, P.E., at 651-267-1736.

Summary of Commitments This letter contains no new commitments and no revisions to existing commitments.

?t-'

Kevin Davison Site Vice President, Prairie Island Nuclear Generating Plant Northern States Power Company -Minnesota Enclosures (1) 1717 Wakonade Drive East

• Welch, Minnesota 55089-9642 Telephone:

651.388.1121 Document Control Desk Page 2 cc: Administrator, Region Ill, USNRC Project Manager, PINGP, USNRC Resident Inspector, PINGP, USNRC Enclosure Supplement to 10 CFR 50.55a Requests (RR) 1-RR-5-7 and 2-RR-5-7 Associated with Prairie Island Nuclear Generating Plant (PINGP) Fifth Ten-Year Interval lnservice Inspection (lSI) Program By letter dated September 15, 2014 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML 14258A124), Northern States Power Company, a Minnesota corporation, doing business as Xcel Energy (hereafter "NSPM"), submitted for NRC approval10 CFR 50.55a Requests 1-RR-5-7 and 2-RR-5-7 associated with the fifth ten-year interval for the Prairie Island Nuclear Generating Plant (PINGP), Units 1 and 2, lnservice Inspection (lSI) Program. By email dated January 26, 2015 (ML 15030A008), the NRC requested additional information (RAis) to complete the review of these requests.

Responses to these RAis are provided below. NRC RAI1: In the relief request, NSPM states that the bare metal visual examination (VE) for Unit 1 was scheduled for the upcoming Unit 1 refueling outage (1 R29 refueling outage) scheduled to commence in October 2014. Please provide a discussion of the examination results. NSPM response:

A direct visual examination of the Unit 1 reactor vessel head, including the outer surface and 1 00% of the intersection of each nozzle with the head, was performed in accordance with American Society of Mechanical Engineers (ASME) Code Case N-729-1 on October 15, 2014. The examination showed no indications.

However, items to note for future examinations are as follows. There are three rust stains near penetrations 2 to 18, 3 to 19, and 4 to 20. (Only one stain was noted in refueling outage 1R27.) These stains are likely due to water that had dripped onto the head, ran down the head, contacted a penetration, and continued to run down the head. The stains do not show residual boric acid and have no volume. A white mark near the head vent nozzle documented in refueling outage 1 R27 was not observed in refueling outage 1 R29. There is a minimal amount of small debris near the top of the head. The head shows light scattered surface rust typical of unpainted low alloy steel. The surface rust has not noticeably changed since refueling outage 1 R27. None of these items is considered adverse to quality. Page 1 of2 Enclosure-10CFR50.55a Request 1/2-RR-5-7 Supplement NRC RAI2: In Section 6 of the enclosure to the relief request, NSPM states that relief is requested for the duration of the fifth inservice inspection (lSI) interval for PINGP Units 1 and 2. The fifth lSI interval is effective for Units 1 and 2 from December 21, 2014, through December 20, 2024. In Section 5 of the enclosure, NSPM states that this request would extend Unit 2 examinations, currently scheduled for the fall of 2015, to 2025. The Unit 1 examinations would be extended from the fall of 2016 to 2026. The 20 nominal year request would, therefore, fall outside of the fifth lSI interval.

Please provide clarification for the specified duration of the proposed alternative.

NSPM Response:

The intent of the proposed alternative was to request a nominal 20 year inspection interval for each reactor vessel head from the time each head was placed in service as an alternative to the nominal 10 year inspection interval required by ASME Code Case N-729-1. Pursuant to a phone call between the NRC and NSPM on January 29, 2015, NSPM revises the duration of 10 CFR 50.55a Requests 1RR-5-7 and 2-RR-5-7 to a nominal15 year inspection interval from the time each head was placed in service. The duration of the proposed alternative is enveloped by lSI fifth interval.

The fifth lSI interval is effective for Units 1 and 2 from December 21, 2014 through December 20, 2024. The corresponding vessel head examinations are projected to be performed fall of 2019 for Unit 2 and fall of 2020 for Unit 1. In no case would reactor vessel head examinations of either unit be started after December 20, 2020. Page 2 of2