NRC 2013-0020, CFR 50.55a Request, Relief Request RR-4L3 Inservice Inspection Impracticality Examination Limitations Due to Configuration Fourth Ten-Year Inservice Inspection Program Interval

CFR 50.55a Request, Relief Request RR-4L3 Inservice Inspection Impracticality Examination Limitations Due to Configuration Fourth Ten-Year Inservice Inspection Program Interval

ML13079A144
Person / Time
Site:	Point Beach
Issue date:	03/19/2013
From:	Mayer L Point Beach
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NRC 2013-0020
Download: ML13079A144 (6)

Text

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March 19,2013 7 POINT Bknbn NRC 2013-0020 10 CFR 50.55a U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Point Beach Nuclear Plant Units 1 and 2 Dockets 50-266 and 50-301 Renewed License Nos. DPR-24 and DPR-27 10 CFR 50.55a Request, Relief Request RR-4L3 lnservice Inspection lmpracticalitv Examination Limitations Due to Configuration Fourth Ten-Year lnservice Inspection Program Interval In accordance with 10 CFR 50.55a, "Codes and Standards," Paragraph (a)(3)(i), NextEra Energy Point Beach, LLC (NextEra) requests that the Nuclear Regulatory Commission (NRC) grant relief from the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (B&PV Code),Section XI, 1998 Edition through 2000 Addenda requirement for 100 percent coverage of the subject weld(s) due to geometric or design configuration, which limited the examination coverage which could be obtained. Relief is requested on the basis that alternative methods will provide an acceptable level of quality and safety.

NextEra requests approval of this request as described in the enclosure prior to December 31,201 3.

Summary of Commitments This submittal contains no new commitments or revisions to existing commitments.

Very truly yours, NextEra Energy Point Beach, LLC

' e Vice President Enclosure Regional Administrator, Region III, USNRC Project Manager, Point Beach Nuclear Plant, USNRC Resident Inspector, Point Beach Nuclear Plant, USNRC PSCW Mr. Mike Verhagan, Department of Commerce, State of Wisconsin NextEra Energy Point Beach, LLC, 6610 Nuclear Road, Two Rivers, WI 54241

ENCLOSURE RELIEF REQUEST RR-4L3 NEXTERA ENERGY POINT BEACH, LLC POINT BEACH NUCLEAR PLANT UNITS 1 AND 2 10 CFR 50.55a REQUEST, RELIEF REQUESTS RR-4L3 INSERVICE INSPECTION IMPRACTICALITY EXAMINATION LIMITATIONS DUE TO CONFIGURATION FOURTH TEN-YEAR INSERVICE INSPECTION PROGRAM INTERVAL ASME Code Component(s) Affected Code Class:

Examination Category: R-A Item Number(s):

==

Description:==

Listed In Table 4L3-1 Applicable ASME Code Edition and Addenda ASME Section XI, 1998 Edition through 2000 Addenda.

Applicable Code Requirement

ASME Section XI requires examination of 100 percent of the weld length as defined in the applicable Code Tables and shown in the applicable Code Figures. The alternative requirements of ASME Section XI, Code Case N-460, approved for use in Regulatory Guide 1.I 47, Revision 16, allows credit for essentially 100 percent coverage of welds provided greater than 90 percent of the required volume has been examined.

10 CFR 50.55a(b)(2)(xv)(A) requires the following examination coverage when applying Supplement 2 to Appendix VIII:

(1) Piping must be examined in two axial directions, and when examination in the circumferential direction is required, the circumferential examination must be performed in two directions, provided access is available.

(2) Where examination from both sides is not possible, full coverage credit may be clamed from a single side for ferritic welds. Where examination from both sides is not possible on austenitic welds, full coverage credit from a single side may be claimed only after completing a successful single-side Appendix Vlll demonstration using flaws on the opposite side of the weld.

10 CFR 50.55a(b)(2)(xvi)(B) requires that examinations performed from one side of a stainless steel pipe weld must be conducted with equipment, procedures, and personnel Page 1 of 5

that have demonstrated proficiency with single side examinations. To demonstrate equivalency to two sided examinations, the demonstration must be performed-to the requirements of Appendix Vlll as conditioned by 10 CFR 50a55a(b)(2)(xvi)(B)and 10 CFR 50.55a(b)(2)(xv)(A).

Impracticality of Compliance Pursuant to 10 CFR 50.55a(g)(5)(iii), relief is requested from the 100 percent coverage of the subject weld(s) due to geometric or design configuration, which limited the examination coverage that can be obtained. Due to Point Beach Nuclear Plant's use of the Risk-Informed in-service inspection (ISI) concept, the welds examined within the Risk Segment were selected in an attempt to gain the highest examination coverage possible. In the case of the welds with limitations, the welds selected were the only welds within that risk segment 1 degradation mechanism.

In the case of austenitic piping welds, there are currently no Performance Demonstration Initiative (PDI) qualified single sided examination procedures which have been demonstrated to provide equivalency to dual sided examination procedures. Current technology is not capable of reliably detecting or sizing flaws on the far side of an austenitic weld. PDI Performance Demonstration Qualification Summary (PDQS) certificates for austenitic piping list the limitation that single sided examinations are performed on a "best-effort" basis. The "best-effort" statement is provided in place of a complete single side qualification to demonstrate that the examiner's qualification and any subsequent weld examinations are based upon the application of the best available technology.

Relief is requested from compliance with the 100 percent required examination coverage for piping welds listed in Table 4L3-1 based on configurations limited to single side access. The coverage listed was obtained during the examination with no credit taken for the far side of the weld (i.e., no austenitic weld will have greater than 50 percent coverage).

Generic limitation sketches for austenitic welds are provided in Figure 4L3-1.

Burden Caused by Compliance Compliance would require extensive modification or replacement of components with a design that allows examination from both sides of the weld. This option to meet the 100 percent examination coverage requirement is considered impractical.

Proposed Alternative and Basis for Use The subject welds received a volumetric examination to the maximum extent practical utilizing best available techniques as qualified through PDI. The PDI technique was used to examine the far side of the weld using the search unit angle(s) and frequencies as required by the PDI Generic procedure (PDI-UT-2). Additionally, a visual (VT-2) examination was performed each refueling outage on the applicable system as required by ASME Section XI.

Based on the volumetric examination coverage obtained with acceptable results and the visual (VT-2) examination performed each refueling outage with acceptable results, it is Page 2 of 5

reasonable to conclude that service induced degradation would be detected. Therefore, these proposed alternativesprovide an acceptablelevel of quality and safety by providing reasonable assurance of structural integrity of the subject welds.

Duration of Proposed Alternative Relief is requested for the fourth 10-year inservice inspection interval for Point Beach Nuclear Plant, Units 1 and 2, which began on July 1, 2002 and ended on July 31, 2012.

Precedents Similar relief requests documenting limited examinations have been granted to the following plants:

NRC Letter to Seabrook Station, Dated June 4, 2012, Seabrook Station, Unit 1 -

Second 10-Year Interval lnservice lnspection Program Plan Request for Relief No. 21R-19 (TAC No ME6902), (ML12145A048)

NRC Letter to Seabrook Station, Dated June 4, 2012, Seabrook Station, Unit 1 -

Second 10-Year Interval lnservice Inspection Program Plan Request for Relief No. 21R-20 (TAC No ME6901), (ML12145A170)

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Figure 4L3-1 Typical OD Configuration Pipe to ValveNalve to Pipe Typical OD Configuration PipelCap to Branch ConnectionIBranch Connection to PipelCap No coverage due to configuration geometry Page 4 of 5

Table 4L3-1 Limited Risk-Informed Piping Examinations for the Fourth IS1 Interval Point Beach Unit 1 Component Identification/ Item Damage System Exam Limitation Description Description No. Mechanism Coverage AC-10-SI-1001-19 Intergranular Stress Auxiliary 50%* Examined from pipe side only.

Pipe to Valve 1SI-867B Corrosion Cracking Cooling R1 and Thermal Point Beach Unit 2 Component Identification / Item Damage System or Exam Limitation Description Description No. Mechanism Component Coverage AC-10-SI-2001-17 Intergranular Stress Auxiliary 50%* Examined from pipe side only.

Pipe to Valve 2SI-867B Corrosion Cracking Cooling R1.16 and Thermal Transients Examination Category R-A 1 R1.16 Pressure Retaining Stainless Steel Welds Coverage Limitations and UT Parameters*

Point Beach Unit 1 Weld ID Number Configuration Thickness YO Angle Mode Frequency Comments (Inches) Coverage MHz AC-10-SI-1001-19 10-inch Pipe to >0.50 50* 45" Shear 2.25 Examined from pipe side only due Valve1SI-867B 60" RL 2.0 to configuration.

Point Beach Unit 2 Weld ID Number Configuration Thickness YO Angle Mode Frequency Comments (Inches) Coverage MHz AC-10-SI-2001-17 10-inch Pipe to >0.50 50* 45" Shear 2.25 Examined from pipe side only due Valve2SI-867B 60" RL 2.0 to configuration.

• SO% coverage is the maximum claimed due to limitations of procedure NDE-173 (i.e. PDI-UT-2). The maximum amount of weld volume and base material on the far-side was insonified utilizing the guidance contained within the procedure for single-sided examinations.

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