ML101330375

Electronic Transmission, Draft Request for Additional Information Regarding Measurement Uncertainty Recapture Power Uprate(Tac ME3589 and ME3590)

ML101330375
Person / Time
Site:	Limerick
Issue date:	05/24/2010
From:	Peter Bamford Plant Licensing Branch 1
To:	Chernoff H Plant Licensing Branch 1
Bamford, Peter J., NRR/DORL 415-2833
References
TAC ME3589, TAC ME3590
Download: ML101330375 (4)

Text

May 24, 2010 MEMORANDUM TO: Harold K. Chernoff, Chief Plant Licensing Branch I-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

FROM: Peter Bamford, Project Manager /ra/ Plant Licensing Branch I-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

SUBJECT:

LIMERICK GENERATING STATION, UNITS 1 AND 2 - ELECTRONIC TRANSMISSION, DRAFT REQUEST FOR ADDITIONAL INFORMATION REGARDING MEASUREMENT UNCERTAINTY RECAPTURE POWER UPRATE (TAC NOS. ME3589 AND ME3590)

The attached draft request for additional information (RAI) was transmitted by electronic transmission on May 13, 2010, to Mr. Kevin Borton, at Exelon Generation Company, LLC (Exelon). This draft RAI was transmitted to facilitate the technical review being conducted by the Nuclear Regulatory Commission (NRC) staff and to support a conference call (if needed) with Exelon in order to clarify the licensee's submittal. The draft RAI is related to Exelon's submittal dated March 25, 2010, regarding Limerick Generating Station, Units 1 and 2, Measurement Uncertainty Recapture Power Uprate. The draft questions were sent to ensure that they were understandable, the regulatory basis was clear, and to determine if the information was previously docketed. Additionally, review of the draft RAI would allow Exelon to evaluate and agree upon a schedule to respond to the RAI. This memorandum and the attachment do not represent an NRC staff position.

Docket Nos. 50-352 and 50-353

Enclosure:

As stated May 24, 2010 MEMORANDUM TO: Harold K. Chernoff, Chief Plant Licensing Branch I-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

FROM: Peter Bamford, Project Manager /ra/ Plant Licensing Branch I-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

SUBJECT:

LIMERICK GENERATING STATION, UNITS 1 AND 2 - ELECTRONIC TRANSMISSION, DRAFT REQUEST FOR ADDITIONAL INFORMATION REGARDING MEASUREMENT UNCERTAINTY RECAPTURE POWER UPRATE (TAC NOS. ME3589 AND ME3590)

The attached draft request for additional information (RAI) was transmitted by electronic transmission on May 13, 2010, to Mr. Kevin Borton, at Exelon Generation Company, LLC (Exelon). This draft RAI was transmitted to facilitate the technical review being conducted by the Nuclear Regulatory Commission (NRC) staff and to support a conference call (if needed) with Exelon in order to clarify the licensee's submittal. The draft RAI is related to Exelon's submittal dated March 25, 2010, regarding Limerick Generating Station, Units 1 and 2, Measurement Uncertainty Recapture Power Uprate. The draft questions were sent to ensure that they were understandable, the regulatory basis was clear, and to determine if the information was previously docketed. Additionally, review of the draft RAI would allow Exelon to evaluate and agree upon a schedule to respond to the RAI. This memorandum and the attachment do not represent an NRC staff position. Docket Nos. 50-352 and 50-353

Enclosure:

As stated DISTRIBUTION

Public RidsNrrPMLimerick LPL1-2 R/F Accession No.: ML101330375

• via memo OFFICE LPL1-2/PM EMCB/BC AFPB/BC NAME PBamford MKhanna* AKlein* DATE 05/24/2010 04/16/2010 05/12/2010 OFFICIAL RECORD COPY Draft Enclosure REQUEST FOR ADDITIONAL INFORMATION LIMERICK GENERATING STATION, UNITS 1 AND 2 MEASUREMENT UNCERTAINTY RECAPTURE POWER UPRATE REQUEST DOCKET NOS. 50-352 AND 50-353

By letter dated March 25, 2010 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML100850380), Exelon Generation Company, LLC (Exelon) submitted a license amendment request (LAR) proposing to revise the operating license and technical specifications for Limerick Generating Station (LGS), Units 1 and 2. This LAR proposes to implement an increase of approximately 1.65% in rated thermal power from the currently licensed thermal power limit of 3458 megawatts thermal. The increase would be based on the improved flow measurement accuracy which would be achieved through the utilization of ultrasonic feedwater flow meters. The Nuclear Regulatory Commission (NRC) staff has been reviewing the submittal and has determined that additional information is needed to complete its review.

Attached to the March 25, 2010 letter was a report by General Electric (GE)-Hitachi Nuclear Energy, NEDC-33484P, titled "Safety Analysis Report for Limerick Generating Station Units 1 and 2 Thermal Power Optimization," Revision 0, dated March 2010. A non-proprietary version of this report (NEDO-33484, same title) is available at ADAMS Accession No. ML100850403.

RAI 1 Section 3.4, "Flow Induced Vibration," of NEDC-33484P and NEDO-33484, notes, in part, that main steam (MS) and feedwater (FW) piping will experience about a 4% increase in vibration levels due to increased flow velocities for Thermal Power Optimization (TPO) uprate conditions, and asserts that: "the MS and FW lines vibration will remain within acceptable limits during TPO." The reports do not document the implementation of a vibration surveillance program during TPO to confirm this assertion.

In the application dated March 25, 2010, Exelon states that the effects of the uprate request have been evaluated using an approach developed by GE-Hitachi and documented in NEDC-32938P-A, "Licensing Topical Report / Generic Guidelines and Evaluations for General Electric Boiling Water Reactor Thermal Power Optimization," Revision 2, May 2003. A non-proprietary version of this report (NEDO-32938, same title) is available at ADAMS Accession No. ML023170607. Appendix K, "Methods and Assumptions for Piping Evaluation of TPO Uprate," of NEDC-32938P-A and NEDO-32938 notes, in part, that: "For plants whose licensing basis includes the results of main steam line and/or FW line vibration measurements taken during startup testing, the effects of power uprate on vibratory displacements will also be included." Further, the NRC staff notes that Table 3.9-7, "Non-NSSS Piping Systems Power Ascension Testing," of the LGS Updated Final Safety Analysis Report documents both dynamic transient and steady-state vibration tests for the MS and FW piping systems during plant startup. Please indicate how the assessment of the effects of power uprate on the vibratory displacements of the MS and FW lines will be implemented during TPO.

DRAFT RAI 2 Section 3.5.2, "Balance-of-Plant Piping Evaluation," of NEDC-33484P and NEDO-33484 notes, in part, that: "For the MS system piping outside containment, the turbine stop valve (TSV) closure transient was reviewed against conditions that bound operations under TPO." Please indicate how the TSV closure transient will be reviewed for TPO, and if this review considers the results of any testing of the TSV closure transient conducted during original plant startup.

RAI 3 Section 6.7, of NEDC-33484P and NEDO-33484, "Fire Protection," states that "-There is no change in the physical plant configuration and the potential for minor changes to combustible loading as result of TPO uprate-" The staff requests the licensee to summarize any changes to the combustible loading, however minor, and discuss the impact of these changes on the plant's compliance with the fire protection program licensing basis, Title 10 of the Code of Federal Regulations Part 50 (10 CFR50.48), or applicable portions of 10 CFR 50, Appendix R.

RAI 4 Section 6.7, of NEDC-33484P and NEDO-33484, "Fire Protection," states that "-The fire safe-shutdown analysis includes consideration of equipment needed to achieve and maintain hot shutdown, fire barriers, operator actions, personnel resources, and repair activities credited to achieve and maintain cold shutdown-" The staff requests the licensee to verify that (1) the measurement uncertainty recapture (MUR) power uprate will not require any new operator actions; (2) any effects from additional heat in the plant environment from the increased power will not prevent required post fire operator manual actions, as identified in the LGS, Units 1 and 2, fire protection program, from being performed at and within their designated time; and (3) procedures and resources necessary for systems required to achieve and maintain safe-shutdown will not change and are adequate for the MUR power uprate.

RAI 5 Some plants credit aspects of their fire protection system for other than fire protection activities, e. g, utilizing the fire water pumps and water supply as backup cooling or inventory for non-primary reactor systems. If LGS, Units 1 and 2, credit the fire protection system in this way, the MUR power uprate LAR should identify the specific situations and discuss to what extent, if any, the MUR power uprate affects these "non-fire-protection" aspects of the plant fire protection system. If LGS, Units 1 and 2, do not take such credit, the staff requests that the licensee verify this as well.