ML16132A441

Supplement to Submittal of Relief Requests Associated with the Fourth 10-Year Interval Inservice Inspection (ISI) Program

ML16132A441
Person / Time
Site:	Limerick
Issue date:	05/11/2016
From:	Jim Barstow Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
CAC MF7585, CAC MF7586
Download: ML16132A441 (5)

Text

Exelon Generation.

200 Exelon Way Kennett Square PA 19348 www exe1oncorp com 10 CFR 50.55a May 11, 2016 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Limerick Generating Station, Units 1 and 2 Renewed Facility Operating License Nos. NPF-39 and NPF-85 NRC Docket Nos. 50-352 and 50-353

Subject:

Supplement to Submittal of Relief Requests Associated with the Fourth 10-Year Interval lnservice Inspection (ISi)

Program

References:

1) Letter from Exelon Generation Company, LLC (D. P. Helker) to the U.S.

NRC regarding "Submittal of Relief Requests Associated with the Fourth 10-Year Interval lnservice Inspection (ISi) Program" dated April 13, 2016.

2) Email correspondence from T. Hood (U.S. Nuclear Regulatory Commission) to S. Hanson (Exelon Generation Company, LLC),

regarding "Limerick Generating Station, Units 1 and 2 - DRAFT Supplemental Information Needed for Acceptance of Requested Licensing Action (CAC Nos. MF7585 and MF7586)," dated May 5, 2016.

In the Reference 1 letter, Exelon Generation Company, LLC (EGC), requested U.S.

Nuclear Regulatory Commission (U.S. NRC) review and approval of relief requests associated with the Fourth lnservice Inspection (ISi) Interval for Limerick Generating Station (LGS), Units 1 and 2. The Fourth ISi Program complies with the 2007 Edition through the 2008 Addenda of the American Society of Mechanical Engineers (ASME)

Boiler and Pressure Vessel (B&PV) Code. LGS will be starting the Fourth 10-Year ISi Interval on February 1, 2017.

In the Reference 2 correspondence, the U.S. NRC requested supplemental information.

Attached is our response.

U.S. Nuclear Regulatory Commission Relief Requests Fourth 10-Year Interval ISi Program Docket Nos. 50-352 and 50-353 May 11, 2016 Page 2 There are no commitments contained within this submittal.

If you have any questions or require additional information, please contact Stephanie J.

Hanson at 610-765-5143.

Respectfully, James Barstow Director, Licensing & Regulatory Affairs Exelon Generation Company, LLC

Attachment:

Response to DRAFT Supplemental Information Needed for Acceptance of Requested Licensing Action for Limerick Generating Station, Units 1 and 2 cc:

Regional Administrator - NRC Region I w/attachments NRC Senior Resident Inspector-Limerick Generating Station NRC Project Manager, NRR - Limerick Generating Station Director, Bureau of Radiation Protection, Pennsylvania Department of Environmental Protection

ATTACHMENT Response to DRAFT Supplemental Information Needed for Acceptance of Requested Licensing Action Limerick Generating Station, Units 1 and 2 Docket Nos. 50-352 and 50-353

Response to Draft Request for Supplemental Information Attachment Fourth Interval ISI Relief Requests Page 1 of 2 Docket Nos. 50-352 and 50-353 By letter dated April 13, 2016, Exelon Generation Company, LLC (EGC) submitted relief requests associated with the Fourth 10-Year Interval Inservice Inspection (lSI) program for Limerick Generating Station (LGS), Units 1 and 2. The proposed relief requests would allow LGS to use a risk-informed alternative in accordance with 10 CFR 50.55a(z)(1) for the Fourth Interval Risk-Informed Inservice Inspection (RI-ISI) program that is based on Electric Power Research Institute (EPRI) Tropical Report (TR)-112657, Revision B-A Revised Risk-Informed Inservice Inspection Evaluation Procedure, dated December 1999 as an alternative to the American Society of Mechanical Engineers (ASME)Section XI, Code examination requirements for piping.

The NRC staff has determined that additional information is needed to complete its acceptance review of relief request I4R-01. The specific request for supplemental information is restated below along with EGC's response.

Request for Supplemental Information Please provide the risk results from the risk impact assessment for LGS, Units 1 and 2, that compares the proposed Fourth Interval RI-ISI program to the initial ASME Section XI requirements. The provided results should include both the system level changes in core damage frequency (CDF) and large early release frequency (LERF) and the total change in CDF and LERF. Also, EGC should discuss whether the risk acceptance guidelines of EPRI TR-112657, Revision B-A, are met.

Including the risk results demonstrates that the risk acceptance guidelines of EPRI TR-112657, Revision B-A, are still met for I4R-01.

Response to Request for Supplemental Information Based on the Fourth ISI Interval update of this risk impact assessment, the change in risk from the pre-RI-ISI Section XI Program to the Fourth Interval RI-ISI Program was within the 1.00E-06 and 1.00E-07 acceptance criteria for delta-core damage frequency (Delta - CDF) and delta-large early release frequency (Delta - LERF) as described in Regulatory Guide 1.174, "An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis." The Delta - CDF and Delta - LERF values for LGS, Units 1 and 2, are listed in the following table.

Response to Draft Request for Additional Information Attachment Fourth Interval ISI Relief Requests Page 2 of 2 Docket Nos. 50-352 and 50-353 LGS, Unit 1 LGS, Unit 2 System RISI Delta-CDF Delta-CDF Criteria RISI Delta-LERF Delta-LERF Criteria System RISI Delta-CDF Delta-CDF Criteria RISI Delta-LERF Delta-LERF Criteria CRD 1.00E-14 1.00E-07 1.00E-15 1.00E-08 CRD 1.00E-14 1.00E-07 1.00E-15 1.00E-08 CS 1.51E-10 1.00E-07 6.03E-11 1.00E-08 CS

-1.84E-11 1.00E-07 1.16E-12 1.00E-08 FW

-4.18E-09 1.00E-07

-6.52E-10 1.00E-08 FW

-4.02E-09 1.00E-07

-6.46E-10 1.00E-08 HPCI 5.63E-11 1.00E-07 2.35E-11 1.00E-08 HPCI 2.45E-10 1.00E-07 2.73E-11 1.00E-08 MS 2.14E-09 1.00E-07 1.26E-10 1.00E-08 MS 1.53E-09 1.00E-07 1.06E-10 1.00E-08 RCIC 4.36E-11 1.00E-07 7.45E-12 1.00E-08 RCIC 4.08E-11 1.00E-07 7.42E-12 1.00E-08 RHR 3.57E-10 1.00E-07 1.25E-10 1.00E-08 RHR 1.07E-09 1.00E-07 1.74E-10 1.00E-08 RPV-APP 5.04E-08 1.00E-07 1.01E-09 1.00E-08 RPV-APP 5.03E-08 1.00E-07 1.01E-09 1.00E-08 RR 3.40E-09 1.00E-07 1.10E-10 1.00E-08 RR 6.87E-10 1.00E-07 2.23E-11 1.00E-08 RWCU 5.55E-09 1.00E-07 1.06E-09 1.00E-08 RWCU 9.15E-09 1.00E-07 6.10E-10 1.00E-08 SLC 7.78E-10 1.00E-07 2.53E-11 1.00E-08 SLC

-2.85E-10 1.00E-07

-9.21E-12 1.00E-08 Totals 5.87E-08 1.00E-06 1.90E-09 1.00E-07 Totals 5.87E-08 1.00E-06 1.30E-09 1.00E-07