ML101870008

Request for Additional Information Regarding Measurement Uncertainty Recapture Power Uprate

ML101870008
Person / Time
Site:	Limerick
Issue date:	07/15/2010
From:	Peter Bamford Plant Licensing Branch 1
To:	Pacilio M Exelon Nuclear
Bamford, Peter J., NRR/DORL 415-2833
References
TAC ME3589, TAC ME3590
Download: ML101870008 (4)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 July 15, 2010 Mr. Michael J. Pacilio President and Chief Nuclear Officer Exelon Nuclear 4300 Winfield Road Warrenville, IL 60555

SUBJECT:

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

Dear Mr. Pacilio:

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 Nuclear Regulatory Commission staff has been reviewing the response and has determined that additional information is needed to complete its review. The specific questions are found in the enclosed request for additional information (RAI). The questions were sent via electronic transmission on July 8, 2010, to Mr. Kevin Borton, of your staff. The draft questions were sent to ensure that the questions were understandable, the regulatory basis for the questions was clear, and to determine if the information was previously docketed. The draft questions were discussed in a teleconference with your staff on July 14, 2010, where clarifying edits were made to question numbers 1 and 8. It was agreed that a response to this RAI would be submitted by August 16, 2010.

Please contact me at 301-415-2833, if you have any questions.

Peter Bamford, Project Manager Plant Licensing Branch 1-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-352 and 50-353

Enclosure:

As stated cc w/encl: Distribution via Listserv

REQUEST FOR ADDITIONAL INFORMATION LIMERICK GENERATING STATION. UNITS 1 AND 2 MEASUREMENT UNCERTAINTY RECAPTURE (MUR)

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, the licensee) submitted a license amendment request (LAR) proposing to revise the operating license and technical specifications (TSs) 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 thermal power measurement accuracy, which would be achieved through the utilization of the Cameron International (formerly Caldon) CheckPlus' leading edge flowmeter ultrasonic flow measurement instrumentation. The Nuclear Regulatory Commission staff has been reviewing the submittal and has determined that additional information is needed to complete its review.

1. The Power Grid Uprate Voltage Analysis for LGS (Attachment 12) of the LAR did not consider a LGS dual unit trip scenario and its impact on grid stability after the increased loading of the power uprate? Explain in detail why an LGS dual unit trip scenario after uprate was not considered and analyzed?

2. In the LAR, Attachment 1, Section 3.4.1, the licensee concludes that there will be a minor increase in normal power system loads. Provide a detailed discussion demonstrating that the minor increase in normal power system loads due to the uprate will not impact the degraded voltage relay (DVR) allowable value for loss of power covered by LGS, Unit 1 and 2, TS 3/4.3.3, Table 3.3.3-2.

3. In the LAR, Attachment 1, Section 3.4.1, the licensee concludes that there will be small increases in normal operational radiation levels. Discuss in detail how the small increases in normal operational radiation levels will not affect the existing equipment qualification (EO) per 10 CFR 50.49.

4. In the LAR, Attachment 12, Section 4, of the Power Grid Uprate Voltage Analysis for LGS, the licensee states that in situations where voltage drops exceeded 0.03 per unit, additional analysis was performed to incorporate system adjustments between contingencies. Transformer taps and automatically switched capacitors were allowed to change to regulate voltage. Provide a detailed discussion about the load tap changing transformers and automatic switched capacitor banks which were allowed to function automatically in the additional analyses. Clarify if these system adjustments and the transformer tap changes will result in any plant design modifications to ensure that voltage drop will not exceed 0.03 per unit.

-2

5. The LAR, Attachment 61 , Table 6-2, shows the main generators maximum nominal rating for the uprated condition as 1138.47 MWe [Megawatts electric] and 551.39 MVar

[Megavolt-amp-reactive]. The main generators maximum nominal rating of 1138.47 MWe is significantly lower than the expected full load generator output value of 1240 MWe for winter following MUR power uprate, as specified in the LAR, Attachment 12, Appendix B page 2 of 5. Please explain how the main generators worst case (winter) expected MWe output can exceed the maximum nominal MWe rating.

6. Please specify the worst case MWe and MVar loadings on LGS, Unit 1 and 2 main generator step-up transformers for both existing and uprated conditions, and discuss how the uprated loading is within the capability of the transformers.

7. The LAR, Attachment 6, Section 10.3.1 states that the conservatism in the equipment qualifications were originally applied to the environmental parameters and no change is needed for the TPQ [thermal power optimization] uprate. Please discuss in detail what specific conservatism in the environmental parameters of the original EO evaluations, when applied to uprated conditions, results in the existing EO evaluations bounding the uprated normal and accident conditions.

8. Provide EO profiles for the EO areas where temperature and or pressure will increase due to uprate to demonstrate that the existing EO profiles bound the uprated EO profiles for both normal and accident conditions. In addition, confirm that the EO margins required per IEEE-323,2 Section 6.3.1.5 ("Margin"), for both inside and outside containment will be maintained for the uprated condition.

9. The LAR, Attachment 6, Section 10.3.1.1, states, "Normal temperatures may increase slightly near the Feedwater and Reactor Recirculation lines and will be evaluated throuqh the EO temperature monitoring program ... " Discuss the expected magnitude, and resulting expected impact, of the increased temperatures on the safety-related equipment in the area.

1 Attachment 6 is 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.

2 The LGS Updated Final Safety Analysis Report provides a description of the LGS commitment to IEEE 323.

July 15, 2010 Mr. Michael J. Pacilio President and Chief Nuclear Officer Exelon Nuclear 4300 Winfield Road Warrenville, IL 60555 SUB"IECT: LIMERICK GENERATING STATION, UNIT NOS. 1 AND 2 - REQUEST FOR ADDITIONAL INFORMATION REGARDING MEASUREMENT UNCERTAINTY RECAPTURE POWER UPRATE (TAC NOS. ME3589 AND ME3590)

Dear Mr. Pacilio:

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 Nuclear Regulatory Commission staff has been reviewing the response and has determined that additional information is needed to complete its review. The specific questions are found in the enclosed request for additional information (RAI). The questions were sent via electronic transmission on July 8, 2010, to Mr. Kevin Borton, of your staff. The draft questions were sent to ensure that the questions were understandable, the regulatory basis for the questions was clear, and to determine if the information was previously docketed. The draft questions were discussed in a teleconference with your staff on July 14, 2010, where clarifying edits were made to question numbers 1 and 8. It was agreed that a response to this RAI would be submitted by August 16, 2010.

Please contact me at 301-415-2833, if you have any questions.

Sincerely,

/raJ Peter Bamford, Project Manager Plant Licensing Branch 1-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-352 and 50-353

Enclosure:

As stated cc w/encl: Distribution via Listserv DISTRIBUTION:

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NAME PBamford SUttle for ABaxter " RMathew** HChernoff DATE 07/15/2010 07/15/2010 07/01/2010 07/15/2010 OFFICIAL RECORD COpy