ML063040653

Response to Request for Additional Information - Alignment of Inservice Inspection and Containment Inservice Inspection Intervals

ML063040653
Person / Time
Site:	Limerick
Issue date:	10/31/2006
From:	Cowan P Exelon Nuclear
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML063040653 (5)

Text

Exelon Nuclear 200 Exelon Way www.exe1on corp.com r\luclear Kennett Square, PA 19348 10 CFR 50.55a October 31,2006 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 Limerick Generating Station, Units 1 and 2 Facility Operating License Nos. NPF-39 and NPF-85 NRC Docket Nos. 50-352 and 50-353

Subject:

Response to Request for Additional Information Alignment of Inservice Inspection and Containment Inservice Inspection (CISI) Intervals

References:

1) Letter from P. B. Cowan (Exelon Generation Company, LLC) to U. S. Nuclear Regulatory Commission (NRC), dated August 4, 2006

2) Letter from R. V. Guzman (NRC) to C. M. Crane (Exelon Generation Company, LLC), dated October 1 1,2006 In the Reference 1 letter, Exelon Generation Company, LLC (EGC), requested relief from the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, Section XI, "Rules for Inservice Inspection of Nuclear Power Plant Components," on the basis that the proposed alternative provides an acceptable level of quality and safety.

Specifically, relief is being sought to reduce the duration of the Limerick Generating Station, Unit 2 second Inservice Inspection (61)interval in order to create a common IS1 interval for Limerick Generating Station, Units 1 and 2. In addition, relief is requested to reduce the first Containment Inservice Inspection (CISI) interval for Limerick Generating Station, Unit 2, which will permit subsequent CIS1 interval dates to be synchronized with the future IS1 intervals for both units. The net effect of this request is to establish one common interval for both the IS1 and CIS1 Programs at Limerick Generating Station, Units 1 and 2.

In the Reference 2 letter, the U. S. Nuclear Regulatory Commission requested additional information.

Attached is our response to this request.

Should you have any questions concerning this letter, please contact Tom Loomis at (610) 765-5510.

Pamela B. &wan Director - Licensing & Regulatory Affairs Exelon Generation Company, LLC

Attachment:

1) Response to Request for Additional Information cc: S. J. Collins, Regional Administrator, Region I, USNRC S. Hansell, USNRC Senior Resident Inspector, LGS R. Guzman, Project Manager [LGS] USNRC J. Kim, Assistant Project Manager [LGS] USNRC

RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION Response to Request for Additional Information Alignment of Inservice Inspection and Containment Inservice Inspection (CISI) Intervals QUESTION:

1. With respect to the last paragraph of Section 4.0 of the submittal dated August 4, 2006, Reason for Request (page 2 of 6), it is stated that, "Any examination methods unique to and specifically required in the remainder of the LGS, Unit 2 Third Period under the previous ISI

[Inservice Inspection] Interval Code (i.e., American Society of Mechanical Engineers Boiler and Pressure Vessel Code Section XI, 1989 Edition), that will likewise be required in the next ISI Interval, will be scheduled and completed in the First Period of this subsequent interval."

List and discuss the LGS Unit 2 specific items that are within the category of "any examination methods unique to and specifically required in the remainder of the Limerick Generating Station Unit 2 Third Period under the previous ISI interval code, that will likewise be required in the next ISI Interval," and will be scheduled and completed in the first period of the third ISI interval. As applicable, list and clarify those items that are specifically required in the remainder of the LGS, Unit 2 third period under the previous ISI interval code, but will not be scheduled and completed in the first period of the third ISI interval.

Discuss the potential implication of the above with respect to the Exelon Generation Company's (EGC's) stated intent of providing an acceptable level of quality and safety pursuant to Section 50.55a(a)(3)(i) of Title 10 of the Code of Federal Regulations.

RESPONSE

The Limerick Generating Station (LGS), Unit 2 specific items that are "unique to and specifically required" in the remainder of the LGS, Unit 2 third period under the 1989 Edition, no Addenda, of ASME Section XI are provided below in Table 1. These "unique to and specifically required" examinations are those examinations that are specifically required by the Code to be performed at the end of the interval. The exam methods for each unique inspection required under the ASME Section XI 1989 Edition, no Addenda, are shown in Table 1. These inspections will be performed in accordance with the examination method required by the 2001 Edition, 2003 Addenda, of ASME Section XI for the corresponding item number, and credited to the first period of the third interval. For example, the 1989 Edition, no Addenda, of ASME Section XI has a requirement for a visual, VT-2, examination of the extended boundary Class 1 pressure test, under Examination Category B-P, Item Number B15.11. This extended boundary Class 1 pressure test is scheduled for the first period of the third interval (i.e., previously scheduled for the third period of the second interval) for a visual, VT-2, examination in accordance with Examination Category B-P, Item Number B15.10, in the 2001 Edition, 2003 Addenda, of ASME Section XI. Performing these (now first period) exams using the 2001 Edition, 2003 Addenda, of ASME Section XI (i.e., the latest NRC approved version of the ASME code per 10CFR50.55a(b)(2)), as modified by 10CFR50.55a, will ensure an adequate level of quality and safety.

Additionally, for Examination Categories where 100% of the population is required to be examined by the end of the current third period, the remaining examinations will be performed in accordance with the examination method required by the 2001 Edition, 2003 Addenda, of ASME Section XI, for the corresponding item number, and credited to the first period of the third interval. This method of scheduling will maintain the original sequence of examinations, will not affect the frequency of examinations, and will maintain a rolling 10-year inspection schedule for the successive examination of selected components, in accordance with IWB-2420(a), IWC-2420(a), IWD-2420(a), IWE-2420(a), and IWF-2420(a). This will ensure an adequate level of quality and safety.

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Response to Request for Additional Information Alignment of Inservice Inspection and Containment Inservice Inspection (CISI) Intervals Table 1: Unique Items 1989 Edition, No Addenda 2001 Edition, 2003 Addenda Exam Item Exam Exam Item Exam Comments Category No. Method Category No. Method B-E B4.10 Visual, VT-2 B-P B15.10 Visual, VT-2 Exams required during extended boundary Class 1 pressure test B-P B15.11 Visual, VT-2 B-P B15.10 Visual, VT-2 Extended boundary Class 1 pressure test C-H C7.20 Visual, VT-2 C-H C7.10 Visual, VT-2 EOI Class 2 pressure tests C7.40 Visual, VT-2 C7.10 Visual, VT-2 EOI Class 2 pressure tests C7.60 Visual, VT-2 C7.10 Visual, VT-2 EOI Class 2 pressure tests C7.80 Visual, VT-2 C7.10 Visual, VT-2 EOI Class 2 pressure tests D-A D1.10 Visual, VT-2 D-B D2.10 Visual, VT-2 EOI Class 3 pressure tests D-B D2.10 Visual, VT-2 D-B D2.10 Visual, VT-2 EOI Class 3 pressure tests D-C D3.10 Visual, VT-2 D-B D2.10 Visual, VT-2 EOI Class 3 pressure tests Note: EOI - End-of-Interval There are no items that were specifically required in the remainder of the LGS, Unit 2 third period under the 1989 Edition, no Addenda, of ASME Section XI that will not be scheduled and completed in the first period of the third interval utilizing the examination methodology identified in the 2001 Edition, 2003 Addenda, of ASME Section XI. In accordance with IWB-2420(a),

IWC-2420(a), IWD-2420(a), IWE-2420(a), and IWF-2420(a), the intent is to maintain a rolling 10-year inspection schedule for the successive examination of selected components.

QUESTION:

2. With respect to the third paragraph of page 3 of 6, under Section 4.0, Reason for Request, it is stated that, "...For the IWE portion of the program, the examinations scheduled for the first, second, and third inspection periods Limerick Generating Station, Unit 1 have been completed, and the examinations scheduled for the first and second inspection periods for Limerick Generating Station, Unit 2 have been completed..." As applicable, clarify EGC's intended disposition of the examination items that might have been scheduled for the third inspection period of the first interval containment inservice inspection (CISI) program for the LGS, Unit 2. Also, with respect to the rolling IWL portion of the LGS CISI programs, discuss EGC's recent inspection activities and results, and their key inspection milestones.

RESPONSE

The LGS, Unit 2 CISI specific items that have been scheduled for the LGS, Unit 2 third period under the 1992 Edition, 1992 Addenda, of ASME Section XI, include the following:

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Response to Request for Additional Information Alignment of Inservice Inspection and Containment Inservice Inspection (CISI) Intervals Table 2: Containment Inspections 1992 Edition, 1992 Addenda 2001 Edition, 2003 Addenda Exam Item Exam Exam Item Exam Comments Category No. Method Category No. Method E-A E1.11 Visual, VT-3 E-A E1.11 Visual, VT-3 Periodic MC exam E-A E1.12 Visual, VT-3 E-A E1.12 Visual, VT-3 Underwater exams required at the EOI.

L-A L1.11 Visual, VT-3C L-A L1.11 Visual, VT-3C Periodic CC exam Note: EOI - End-of-Interval The inspections within the examination category and item number scheduled for the third period of the first CISI interval for LGS, Unit 2, which were to be performed in accordance with the 1992 Edition, 1992 Addenda, of the ASME Section XI Code, will be performed in the first period of the second CISI interval for LGS, Unit 2. The examination method for these inspections will be based on the methodology listed in the 2001 Edition, 2003 Addenda, of ASME Section XI (i.e., the latest NRC approved version of the ASME code per 10CFR50.55a(b)(2)), as modified by 10CFR50.55a, which will ensure an adequate level of quality and safety.

IWL examinations, which were to be performed within the first CISI interval in accordance with the 1992 Edition, 1992 Addenda of the ASME Section XI Code, will continue to be performed in accordance with the five (5) year frequency. These inspections will remain on a rolling frequency to ensure that the IWL inspections are performed within the five (5) year allowances as defined in IWL-2400. The examination method used for the 5-year IWL exams, which fall within the second CISI interval will be based on the methodology listed in the 2001 Edition, 2003 Addenda of ASME Section XI (i.e., the latest NRC approved version of the ASME Code per 10CFR50.55a(b)(2)), as modified by 10CFR50.55a, which will ensure an adequate level of quality and safety.

The results of the most recent Unit 2 IWL inspections of concrete revealed no reportable indications. These inspections were completed in March 2005, and the next IWL concrete containment inspections are scheduled to be completed prior to March 2010, in accordance with the requirements of the 2001 Edition, 2003 Addenda, of ASME Section XI, as modified by 10CFR50.55a.

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