L-PI-22-034, Response to RAI, Alternative RR-08 Related to Pressure Isolation Valve Monitoring and Testing

Response to RAI, Alternative RR-08 Related to Pressure Isolation Valve Monitoring and Testing

ML22195A251
Person / Time
Site:	Prairie Island
Issue date:	07/14/2022
From:	Hanson H Xcel Energy
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
L-PI-22-034
Download: ML22195A251 (4)

Text

1717 Wakonade Drive Welch, MN 55089 July 14, 2022 L-PI-22-034 10 CFR 50.55a ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 Prairie Island Nuclear Generating Plant, Unit 2 Docket No. 50-306 Renewed Facility Operating License No. DPR-60 Response to Request for Additional Information RE: Prairie Island Nuclear Generating Plant, Unit 2, Alternative RR-08 Related to Pressure Isolation Valve Monitoring and Testing (EPID: L-2022-LLR-0012)

References:

1) L-PI-22-004, Prairie Island Nuclear Generating Plant Unit 2 10 CFR 50.55a Request No. RR-08, Request for Alternative to ISTC 3630(f), submission date February 8, 2022 (ADAMS Accession Nos. ML22039A340 and ML22039A341)

2) Email from the NRC to NSPM, Request for Additional Information RE: Prairie Island Nuclear Generating Plant, Unit 2, Alternative RR-08 Related to Pressure Isolation Valve Monitoring and Testing, dated June 15, 2022 (ADAMS Accession No. ML22166A411)

In Reference 1, Northern States Power Company, a Minnesota corporation, doing business as Xcel Energy (hereafter NSPM), submitted 10 CFR 50.55a Request RR-08 proposing an alternative to American Society of Mechanical Engineers (ASME) Operation and Maintenance of Nuclear Power Plants (OM Code), Requirement ISTC-3630(f), for Prairie Island Nuclear Generating Plant (PINGP) Unit 2. In Reference 2, the NRC requested additional information needed for the NRC staff to complete its review. The enclosure to this letter provides NSPMs response to the NRC Request for Additional Information.

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

Document Control Desk Page 2 Please contact Mr. Jeff Kivi at (612) 330-5788 or Jeffrey.L.Kivi@xcelenergy.com if there are any questions or if additional information is needed.

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nager, Prairie 1sland Nuclear enerating Plant Northern States Power Company - Minnesota Enclosure cc: Administrator, Region Ill, USNRC Project Manager, Prairie Island, USNRC Resident Inspector, Prairie Island, USNRC

L-PI-22-034 NSPM Enclosure Response to Request for Additional Information RE:

Prairie Island Nuclear Generating Plant, Unit 2, Alternative RR-08 Related to Pressure Isolation Valve Monitoring and Testing

1.0 BACKGROUND

In Reference 1, Northern States Power Company, a Minnesota corporation, doing business as Xcel Energy (hereafter NSPM), submitted 10 CFR 50.55a Request RR-08 proposing an alternative to American Society of Mechanical Engineers (ASME) Operation and Maintenance of Nuclear Power Plants (OM Code), Requirement ISTC-3630(f), for Prairie Island Nuclear Generating Plant (PINGP) Unit 2. In Reference 2, the NRC requested additional information needed for the NRC staff to complete its review. NSPMs response to the NRC Request for Additional Information (RAI) is provided below.

2.0 NRC REQUEST FOR ADDITIONAL INFORMATION AND NSPM RESPONSE EMIB-RAI-1 Requirement:

ASME OM ISTC-3630(e) requires that leakage rate measurements shall be compared with the permissible leakage rates.

Issue:

Prairie Island Nuclear Generating Plant, Unit 2 Alternative Request RR-08, Section Reason for Request states that 2SI-6-4 failed the IST leakage rate testing performed with a leakage rate approximated to be 5.9 gallons per minute which is in excess of the 5 gallons per minute permissible leakage rate. Alternative RR-08 section Full Description of Proposed Alternative requests that in lieu of repair and replacement of 2SI-6-4 for the period of relief, a monitoring plan with the ability to evaluate increased accumulator leakage will be performed.

Request:

Alternative Request RR-08 only provides the leakage information of valve 2SI-6-4 for October 24, 2021. For the NRC staff to evaluate the proposal to implement a monitoring plan in lieu of repair/replacement of the valve, provide the remaining historical leakage data for the valve 2SI-6-4.

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L-PI-22-034 NSPM Enclosure NSPM Response The following table summarizes the measured leakage information for valve 2SI-6-4:

Valve Leakage Date (GPM) 5/23/2012 2.1 12/29/2013 0.3 3/20/2015 0.8 11/28/2015 0.3 11/13/2017 1.9 10/24/2019 1.0 10/25/2021 5.9 A review of work orders over the same period of time found two work orders to repair the valve:

One work order was completed in October 2013 to address the leakage identified on 5/23/2012. This work replaced the valve disk and lapped the valve seat.

One work order will be completed during the 2023 Unit 2 refueling outage to address the leakage found 10/25/2021.

3.0 REFERENCES

1. L-PI-22-004, Prairie Island Nuclear Generating Plant Unit 2 10 CFR 50.55a Request No. RR-08, Request for Alternative to ISTC 3630(f), submission date February 8, 2022 (ADAMS Accession Nos. ML22039A340 and ML22039A341)

2. Email from the NRC to NSPM, Request for Additional Information RE: Prairie Island Nuclear Generating Plant, Unit 2, Alternative RR-08 Related to Pressure Isolation Valve Monitoring and Testing, dated June 15, 2022 (ADAMS Accession No. ML22166A411)

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