CP-201001546, Relief Request No. B-11 for the Second 10 Years ISI Interval from 10 CFR 50.55a Inspection Requirements Due to Physical Interferences (Second Interval Start Date: August 13, 2000)

Relief Request No. B-11 for the Second 10 Years ISI Interval from 10 CFR 50.55a Inspection Requirements Due to Physical Interferences (Second Interval Start Date: August 13, 2000)

ML103560596
Person / Time
Site:	Comanche Peak
Issue date:	12/15/2010
From:	Madden F Luminant Power
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
CP-201001546, TXX-10158
Download: ML103560596 (6)

Text

Rafael Flores Luminant Power Senior Vice President P 0 Box 1002

& Chief Nuclear Officer 6322 North FM 56 rafael.flores@Luminant.com Glen Rose, TX 76043 Lum inant 254 897 5550 C 817 559 0403 F 254 897 6652 CP-201001546 Ref. # 10 CFR 50.55a(g)(5)(iii)

Log # TXX-10158 December 15, 2010 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555

SUBJECT:

COMANCHE PEAK NUCLEAR POWER PLANT DOCKET NO. 50-445 RELIEF REQUEST NO. B-11 FOR THE UNIT 1 SECOND 10 YEAR ISI INTERVAL FROM 10 CFR 50.55a INSPECTION REQUIREMENTS DUE TO PHYSICAL INTERFERENCES (SECOND INTERVAL START DATE: AUGUST 13, 2000)

Dear Sir or Madam:

Pursuant to 10 CFR 50.55a(g)(5)(iii), Luminant Generation Company, LLC (Luminant Power) is submitting Relief Request B-11 (see attachment) for Comanche Peak Unit 1 for the second ten year inservice inspection interval. Luminant Power has determined that certain inspection requirements of ASME Section XI are impractical due to physical interferences.

The geometry of the inlet reactor vessel nozzle safe-end to stainless steel piping weld makes the Code required examination coverage requirements impractical. Ultrasonic Testing (UT) of the subject weld was performed during the second interval to the maximum extent practical based on design" configuration restrictions and no indications were detected. Supplemental examination by eddy current technique was also performed and no indications were detected. Pressure test VT-2 visual examinations were also performed with no evidence of leakage identified for the subject component. No undue risk to the public health and safety is presented by this request.

A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway . Comanche Peak - Diablo Canyon

• Palo Verde

• San Onofre. South Texas Project

• Wolf Creek (a),2R~

U. S. Nuclear Regulatory Commission TXX-10158 Page 2 12/15/2010 This communication contains no new licensing basis commitments regarding Comanche Peak Unit 1.

Should you have any questions, please contact Mr. Jack Hicks at (254)897-6725.

Sincerely, Luminant Generation Company LLC Rafael Flores By: 4Aid 2< 2)9,W Fred W. Madden Director, Oversight & Regulatory Affairs Attachment - Relief Request B-11 for Inlet Reactor Vessel Nozzle Safe-end to Stainless Steel piping weld c- E. E. Collins, Region IV B. K. Singal, NRR Resident Inspectors, Comanche Peak Brian Welch, ANII, Comanche Peak Anthony Jones, TDLR

Attachment to TXX-10158 Page I of 4 10CFR 50.55a Request Number B-11 Relief Requested In Accordance with 10CFR50.55a(g)(5)(iii)

- Inservice Inspection Impracticality -

1. ASME Code Component Affected:

Class 1 Risk-Informed Inservice Inspection (RI-ISI) piping welds as shown:

RI-ISI Piping Welds (formerly Code Category B-J)

Code Cat / Item No. Description Weld No.

R-A / R1.20 27.5" inlet RV nozzle safe-end TBX-1-4300-13 to stainless steel piping weld Note: As the methodology in EPRI TR-1 12657 revision B-A does not provide item numbers, the format in ASME Code Case N-578-1 is used for the assignment of these numbers.

2. Applicable Code Edition and Addenda

The applicable ASME Boiler and Pressure Vessel Code (hereafter referred to as the "Code") edition and addenda is ASME Section XI, "Rules for Inservice Inspection of Nuclear Power Plant Components,"1998 Edition through 2000 Addenda as modified by 10CFR50.5 5a(b)(2)(xiv, xv, and xvi).

3. Applicable Code Requirement

ASME Section XI, Figure IWC-2500-8(c) 1998 Edition through 2000 Addenda, requires a volumetric examination of a minimum weld volume of the inner 1/3t (one third of the thickness) extending into the piping base metal for a distance of 1/4" past the edge of the weld crown for NPS 4" and larger. The subject pipe size is 27.5" and Table IWB-2500-1 calls for a surface examination of the weld.

In a letter (NRR 10027) dated September 28, 2001, from the NRC to Comanche Peak Steam Electric Station, Unit No. 1, the NRC approved in a relief request alternative Risk-Informed (RI) - ISI examinations for selected ASME Code Class 1 and 2 piping welds for the second interval. The methodology in EPRI TR-1 12657 Revision B-A is used as the examination method as well as for the selection of welds to be examined.

The RI-ISI program requires volumetric examination of the subject weld and extends the Code required volume of the inner 1/3t to 1/2" past the edge of the weld crown if no counterbore is present or a distance of 1/4" on either side of the weld counterbore, which ever is greater.

Attachment to TXX-10158 Page 2 of 4 10CFR50.55a Request Number B-11 The Comanche Peak Nuclear Power Plant (CPNPP) second ten-year interval Inspection Program Plan also implements Code Case N-460, which is endorsed by the NRC in revision 15 of Regulatory Guide 1.147, "Inservice Inspection Code Case Acceptability ASME Section XI, Division 1" Code Case N-460 states, in part, when the entire examination volume or area cannot be examined due to interference by another component or part geometry, a reduction in examination coverage on any Class 1 or Class 2 weld may be accepted, provided the reduction coverage for that weld is less than 10 percent.

NRC Information Notice (IN) 98-42, "Implementation of 10CFR50.55a(g) Inservice Inspection Requirements," termed a reduction in coverage of less than 10 percent to be "essentially 100 percent." IN 98-42 states, in part, "The NRC has adopted and further refined the definition of "essentially 100 percent" to mean "greater than 90 percent"...has been applied to all examinations of welds or other areas required by ASME Section XI."

4. Impracticality of Compliance:

The automated examination of the subject piping weld was conducted from the inside diameter (ID) of the pipe. The ID configuration, i.e. counter-bore and root configuration, limited the coverage to 88.99%. The examination was conducted by the contact technique using the WesDyne PARAGON multi-channel data acquisition system, interfaced to a SQUID nozzle scanner. The examination was conducted to the maximum extent practical with the access provided and within the limitation of the component's geometry.

Ultrasonic detection scan for the subject weld was performed from the ID surface using 70 degree L-wave transducers applied in all four scanning directions. This examination interrogated the inner 1/3 thickness volume. An Eddy Current technique was also employed to examine the ID surfaces of this nozzle safe-end to piping weld, in accordance with procedure WDI-STD-146 revision 9. The examination of the volume was conducted with axial scans at a 0.25" increment and the circumferential scans at a 0.080" incremental distance.

All UT data was digitally recorded from baseline to 100% full screen height and evaluated off-line by PDI qualified Level II or III examiners, having certification attachments issued by PDI, relative to procedure PDI-ISI-254-SE-NB revision 1.

5. Burden caused by Compliance:

The design configuration restrictions of the subject components make the Code required examination coverage requirements for the weld volume impractical. Plant modifications or replacements of components designed to allow for complete coverage would be needed to meet the Code requirements. This would cause considerable burden to CPNPP.

Attachment to TXX-10158 Page 3 of 4 10CFR50.55a Request Number B-11

6. Proposed Alternative and Basis for Use:

Proposed Alternative:

The following alternatives are proposed in lieu of the required examination coverage of essentially 100 percent:

1. Ultrasonic testing (UT) of the subject component weld was performed to the maximum extent practical during the second ten-year interval.

2. Supplemental examination by Eddy Current techniques was performed. All areas of limitation were fully examined and no indications were detected.

3. Pressure test VT-2 visual examinations were performed, as required by Code Category B-P, during the second ten-year interval. No evidence of leakage was identified for this component.

Basis for use:

The basis for use of this alternative is it provides the best examination coverage practical within the limitations of the current configuration. The volumetric examination was performed using a system (procedures, personnel, and equipment) qualified in accordance with Appendix VII, Supplements 2 and 10. Due to the possibility that the surface roughness could adversely effect the examination, the vendor performed a supplemental Eddy Current examination to augment the ultrasonic examination and to provide increased sensitivity at the near surface. The supplemental Eddy Current technique, first used in the VC Summer reactor vessel primary nozzle examinations in 2000, has been furthered developed and has been blind tested for the Swedish authority SQC Kvalificeringscentrum AB (SQC NDT Qualification Center) and would have detected ID connected flaws that might have been present.

This technique has also been used to supplement examination of portions of the relevant near-surface volumes during the last twenty domestic pressurized water reactor nozzle-to-pipe examinations, conducted by the vendor.

CPNPP believes that the performance of the partial (88.99%) volumetric examination combined with the supplemental eddy current examination and visual leakage examination provide a level of safety and quality comparable to the Code required examination. There were no indications identified for this weld. There is a high level of confidence in the structural integrity of the weld. CPNPP believes that there is no undue risk to the public health and safety presented by this request.

Attachment to TXX-10158 Page 4 of 4 10CFR50.55a Request Number B-11

7. Duration of Proposed Alternative:

The second ten-year ISI interval for Unit 1 began on August 13, 2000 and ends on August 12, 2010.

8. Precedents:

Wolf Creek Nuclear Power Plant, Letter ET 06-0011, Attachment 4, March 2, 2006