CP-201500685, Response to Request for Additional Information for Relief Request 2A3-1, Unit 2, Inservice Inspection for Application of an Alternative to the ASME Boiler and Pressure Vessel Code Section XI Examination Requirements for Class 1 & 2.

Response to Request for Additional Information for Relief Request 2A3-1, Unit 2, Inservice Inspection for Application of an Alternative to the ASME Boiler and Pressure Vessel Code Section XI Examination Requirements for Class 1 & 2.

ML15211A240
Person / Time
Site:	Comanche Peak
Issue date:	07/22/2015
From:	Flores R, Madden F Luminant Generation Co, Luminant Power
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
CP-201500685, TAC MF5813, TXX-15104
Download: ML15211A240 (6)

Text

Senior Vice President P0O Box 1002

____& Rafael Flores Officer Chief Nuclear Luminant 6322 Power North FM 56 RafaeI.Flores@Luminant.com Glen Rose, TX 76043 Luminant 258759 CP-201500685 Ref. # 10CFR50.55a(z)(1)

TXX-15104 July 22, 2015 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555

SUBJECT:

COMANCHE PEAK NUCLEAR POWER PLANT DOCKET NO. 50-446 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION FOR RELIEF REQUEST 2A3-1 FOR UNIT 2 INSERVICE INSPECTION FOR APPLICATION OF AN ALTERNATIVE TO THE ASME BOILER AND PRESSURE VESSEL CODE SECTION XI EXAMINATION REQUIREMENTS FOR CLASS 1 AND 2 PIPING WELDS (2007 EDITION OF ASME CODE, SECTION XI, 2008 ADDENDA THIRD INTERVAL START DATE: AUGUST 3, 2014 THIRD INTERVAL END DATE: AUGUST 2, 2023)

REFERENCES:

1. Letter logged TXX-15032 dated March 4, 2015 from Rafael Flores to the NRC submitting Relief Request No. 2A3-1 Regarding Risk Informed Jnservice Inspection Program for the Class 1 and 2 Piping (Third ISI Interval Start Date: August 3, 2014; Third ISI Interval End Date: August 2, 2023)

2. Email dated June 22, 2015 from Baiwant Singal of the NRC to Timothy Hope of Luminant Power requesting additional information regarding Relief Request 2A3-1 (TAC No. MF5813)

Dear Sir or Madam:

Per Reference 1, Lumninant Generation Company, LLC (Luminant Power) submitted Relief Request 2A3-1 for Comanche Peak Unit 2 for the third ten year inservice inspection interval. Per Reference 2, the NRC provided a request for additional information regarding the subject relief request.

Attached is the Luminant Power response to the request for additional information.

This communication contains no new licensing basis commitments regarding Comanche Peak Unit 2.

U. S. Nuclear Regulatory Commission TXX-15 104 Page 2 of 2 07/22/2015 Should you have any questions, please contact Mr. Jack Hicks at (254) 897-6725.

Sincerely, Luminant Generation Company LLC Rafael Flores BY: redW. Ma~dden ,-°- --

Director, External Affairs Attachment - Response to Request for Information Regarding Unit 2 Relief Request 2A3-1 for Risk-Informed Inservice Inspection of Piping Welds c - Marc L. Dapas, Region IV Balwant K. Singal, NIRK Resident Inspectors, Comanche Peak Robert Free, TDLR Jack Ballard, ANII, Comanche Peak

Attachment to TXX- 15104 Page 1 of 4 COMANCHE PEAK NUCLEAR POWER PLANT UNIT 2 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING RELIEF REQUEST 2A3-1 FOR RISK-INFORMED INSERVICE INSPECTION OF PIPING WELDS (THIRD 10-YEAR ISI INTERVAL START DATE: August 3, 2014)

TAC NO. MF5813 NRC REQUEST 1:

Of the welds not selected for future examinations, did the previous examinations identify any service induced degradation? If service induced degradation was identified, please discuss the degradation mechanism. Please discuss the corrective actions taken to mitigate the degradation?

LUMINANT POWER RESPONSE TO REQUEST 1:

During the Second Interval there were no unacceptable indications identified during the performance of the RI-ISI examinations. Therefore, no new service induced degradation was identified and no corrective actions were required.

NRC REQUEST 2:

Please identify any augmented inspection programs subsumed in the proposed third 10-year interval RI-ISI program and discuss the reason(s) for any changes. Examples include: augmented program for managing thermal fatigue (NRC Bulletin (BL) 88-11, Generic Letter (GL) 89-08, NRC Information Notice (IN) 93-20, and Materials Reliability Program (MRP)-146), augmented program for addressing stress corrosion cracking (BL 79-17), augmented program to address the requirements of 10 CER 50.55a(g)(6)(ii)(E) that requires implementation of ASME Code Case N-722-1 with conditions, augmented program for piping welds in high energy main steam and main Feedwater piping (NRC NUIREG-0800, Standard Review Plan 3.6.2, and augmented program for inspection of feedwater system piping (NRC BL 79-13).

LUMINANT POWER RESPONSE TO REQUEST 2:

The PI-ISI process has criteria that specifically evaluate the susceptibility of piping to thermal fatigue issues. Therefore, augmented examination programs such as those presented in NRC Bulletin 88-11, Information Notice 93-20, MRP-146 and Bulletin 79-13 are subsumed by the RI-ISI application. This is the same criteria that has been implemented and approved since the initial RI-ISI application in 2001.

The augmented inspection program for flow accelerated corrosion (FAC) per Generic Letter 89-08 is relied upon to manage this damage mechanism and remains a separate program which is not affected or changed by the RI-ISI program. This is the same criteria that has been implemented and approved since the initial RI-ISI application in 2001.

The augmented inspection program for high energy break exclusion piping is a separate program and is not affected or changed by this RI-ISI Relief Request.

CPNPP will meet the criteria of 10CER50.55a(g)(6)(ii)(E) and therefore implement Code Case N-722-1 for the performance of reactor coolant pressure boundary visual inspections.

CPNPP will meet the criteria of 10CFR50.55a(g)(6)(ii)(F) and therefore implement Code Case N-770-1 for the examination of Class 1 piping and nozzle dissimilar-metal butt welds. The Risk Ranking, Element Selection, and Risk Impact Analysis has been changed to reflect the inspection of Primary Water Stress Corrosion Cracking (PWSCC) under Code Case N-770-1 with the applicable welds removed from the RI-ISI Element Selection process.

Attach ment to TXX- 15104 Page 2 of 4 COMANCHE PEAK NUCLEAR POWER PLANT UNIT 2 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING RELIEF REQUEST 2A3-1 FOR RISK-INFORMED INSERVICE INSPECTION OF PIPING WELDS (THIRD 10-YEAR ISI INTERVAL START DATE: August 3, 2014)

TAC NO. MF5813 Portions of the containment spray and residual heat removal systems contain Class 2 piping that is less than 0.375 in. thick. ASME Section XI does not require surface or volumetric examinations on this piping, based on the wall thickness. However, in response to NRC SSER-26, CPNPP committed to performing volumetric examinations on 7.5% of the welds in this "thin wall' piping during each ten year interval. This piping was included in the scope of the RI-ISI application, and therefore is addressed by the RI-ISI program. Consequently, the RI1-ISI program subsumes this augmented inspection program. This is the same criteria that has been implemented and approved since the initial RI-ISI application in 2001.

There are no other augmented examination programs that interface with the RI-ISI program.

NRC REQUEST 3:

The NRC staff notes that the licensee did not specify in P.R 2A3-1 whether it will review and update the proposed third 10-year CPNPP, Unit 2, RI-ISI program on a regular basis (e.g., at least on the basis of the ASME Code periods, more frequently if dictated by any plant procedure to update the probabilistic risk assessment (PRA), or as new degradation mechanisms are identified). Please clarify whether the licensee will implement a monitoring program to review and update the proposed RI-ISI program for the third 10-year 131 interval in accordance with the guidance in NRC Regulatory Guides (RGs) 1.174 and 1.178.

LUMINANT POWER RESPONSE TO REQUEST 3:

Both the original RI-1SI submittal and the resultant NRC Safety Evaluation call for a periodic review and update. The RI-ISI program is a living program requiring feedback of new relevant information to ensure the appropriate identification of high safety significant piping locations. As a minimum, the RI-ISI program will be reviewed and adjusted on an ASME period basis. In addition, significant changes may require more frequent adjustment as directed by NRC Bulletin or Generic Letter requirements, or by industry and plant specific feedback. This is the same criteria that has been implemented and approved since the initial PI-ISI application in 2001.

Attachment to TXX-15104 Page 3 of 4 COMANCHE PEAK NUCLEAR POWER PLANT UNIT 2 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING RELIEF REQUEST 2A3-1 FOR RISK-INFORMED INSERVICE INSPECTION OF PIPING WELDS (THIRD 10-YEAR ISI INTERVAL START DATE: August 3, 2014)

TAC NO. MF5813 NRC REQUEST 4:

In Section 4.0 of the NRC safety evaluation report of EPRI TR-112657, Revision B-A, "Revised Risk-Informed Inservice Inspection Evaluation Procedure," (ADAMS Accession No. ML013470102), the NRC staff concluded that a licensee requesting to implement an RI-ISI program pursuant to 10 CFR 50.55a(z)(1) may incorporate into its application, by reference, the program described in EPRI TR-112657, Revision B-A, together with appropriate plant specific information, provided that the application includes, among other items, a summary of the risk impact of the changes to the ISI program.

The licensee stated in its application dated March 4, 2015 that a new risk impact analysis was performed, and that the revised RI-ISI program continues to represent a risk reduction when compared to the last deterministic ASME Code,Section XI, inspection program.

To demonstrate that the acceptance criteria of EPRI TR-112657, Revision B-A, for change in CDF and LERF per system are met, please provide tabulated values for the system level changes in CDF and LERF (i.e., the changes in CDF and LERF compared between the ASME Code 1SI program and the CPNPP, Unit 2, third 10-year RI-lSI program). For an example, please refer to Tables 3.6.1 and 3.6.2 of Luminant letter dated February 15, 2001 (ADAMS Accession Number ML010520269) requesting relief from the ASME Code,Section XI examination requirements for inservice inspection of Class 1 and 2 piping welds for CPNPP, Units 1 and 2.

LUMINANT POWER RESPONSE TO REQUEST 4:

See the table on the foliowing page for the results of the current risk impact analysis for CPNPP Unit 2.

The applicable "CDF Impact" and "LERF Impact" values are those with Probability of Detection (POD) included.

Attachment to TXX-15104 Page 4 of 4

____________ -CPNPP Unit 2 Bounding Estim~ate of Risk Impoact Based on Best E~stimate Failure Rates RsUpeBon FalrPoeta Bet POD Improvement Inspection CDF Impact LERF Impact Rik oudppr alue otntal BetFactors Locations Syst - 1R 1TEstimate1 _ ____ ______ ______ ____

CaRak isk Cat Risk Cat D j Rank Failure Rate S Xl I-S None S XIl I-S Delta w/ POD wlo POD w/ POD w/o POD RCS -2 High 1.98E-03 1.65E-03 TASCS, TT Medium 2.00E-07 0.3 0.9 0.5 4 2 -2 -2.38E-10 3.96E-10 -198E-10 3.30E-10 RCS 2 High 1.98E-03 165E-03 TASCS Medium 2.00E-07 0.3 0.9 0.5 1 6 5 -2.02E-09 -9.90E-10 -1.68E-09 -8.25E-10 RCS 2 Higqh 1.98E-03 165E-03 TT Medium 2.OOE-07 0.3 0.9 0.5 4 0 -4 4.75E-10 7.92E-1D 3.96E-10 6.60E-10 TT Medium RCS 2 (2) High (High) 1.98E-03 165E-03 (PWSCC) (Medium) 2.00E-07 0.3 0.9 0.5 1 0 -1 1.19E-10 1.98E-f0 9.90E-11 1.65E-19 RCS 4 Medium 1.00E-04  !.00E-05 None Low 1.00E-08 0.5 0.5 0.5 49 30 -19 9.50E-12 9.50E-12 9.50E-13 9.50E-13 RCS 4 (2) Medium) 100E-0  !.00E-05 NoneCC Lowium 1.0E-C8 0.5 0.5 0.5 12 0 -12 6.00E-12 6.00E-12 6.00E-13 6.00E-13 RCS 5a Medium 1.00E-04 IO00E-05 TASCS Medium 2.00E-07 0.3 0.9 0.5 5 2 -3 -6.O0E-12 3.O0E-11 -6.00E-13 3.00E-12 RCS 5a Medium 1.00E-04 1.00E-05 TT Medium 2.00E-07 0.3 0.9 0.5 2 6 4 -9.60E-11 -4.00E-11 -9.60E-12 -4.00E-12 Medium TT Medium RCS 5a (5a) (Medium) 1.OOE-04 I.00E-05 (PWSCC) (Medium) 2.00E-07 0.3 0.9 0.5 1 0 -1 6.00E-12 1.00E-11 6.00E-13 l00E-12 RCS 6a Low 1.OOE-06 1.00E-07 None Low 1.OOE-08 0.5 0.5 0.5 0 0 0 no change no change no change no chan qe RCS 7a Low 1.00E-06  !.00E-07 None Low 1.00E-08 0.5 0.5 0.5 0 0 0 nochange nochange nochange nochange RCS Total _____________ ____-1.74E-09 4.12E-10 -1.39E-09 3.32E-10 CVCS Sa Medium 1.OOE-04 1.00E-05 TT Medium 2.O0E-07 0.3 0.9 0.5 q0 0 0 0.00E+00 0.OOE+00 0.OOE+00 0.OOE+00 CVCS 6a Low 1.OOE-06 1.00E-07 None Low lOO.0E-08 *"0.5 0.5 0.5 5 0 -5 negligible negligible negl~igible negqligible CVCS 6b Low 1.00E-06 1.00E-07 TT Medium 2.00E-07 0.3 0.9 0.5 0 0 0 no change no change no change no changqe CVCS 7a Low 1.00E-06 tO00E-07 None Low t.00E-08 0.5 0.5 0.5 0 0 0 no change no changqe no changqe no changqe CVCS Total _________0.OOE+OO O.OOE+O0 O.OOE+O0 O.OOE+00 SIS 4 Medium 1.00E-04 tO0E-05 None Low IOOE-08 0.5 0.5 0.5 4 10 6 -3.OOE-12 -3.OOE-12 -3.OOE-!3 -3.O0E-13 SIS 6a Low 1.OOE-06 1.00E-07 None Low 1.OOE-08 0.5 0.5 0.5 33 7 -26 1.30E-13 1.30E-13 1.30E-14  !.30E-14 SIS 6b Low 1.OOE-06 1.00E-07 IGSCC Medium ZO2.0E-07 *"0.5 0.5 0.5 2 2 0 0.OOE+00 0.O0E+00 0.00E+00 0.OOE+00 SIS 7a Low 1.0OE-06 1.00E-07 None Low 1.00E-08 0.5 0.5 0.5 6 0 -6 negqli~gible negligible negligqible negqligible SIS Total _______________________-2.87E-12 -2.87E-12 -2.87E-13 -2.87E-13 RHRS 4 Medium 1.0OE-04 1.00E-O5 None Low 1.O0E-08 0.5 0.5 0.5 17 13 -4 2.OOE-12 2.OOE-12 2.00E-13 2.00E-13 RHRS 6a Low 1.OOE-06  !.00E-07 None Low 1.O0E-08 0.5 0.5 0.5 0 0 0 no changqe no changqe no change no changqe RHRS Total ____________2.OOE-12 2.OOE-12 2.OOE-13 2.OOE-13 CSS 4 Medium 1.00E-04 1.00E-05 None Low I.00E-08 0.5 0.5 0.5 13 2 -11 5.50E-12 5.5OE-12 5.50E-13 5.50E-13 CSS 6a Low 1.00E-06 1.00E-05 None Low 1.00E-08 0.5 0.5 0.5 3 0 -3 negligqible negligible negligible negligible CSS 7a Low 1.00E-06 t00E-07 None Low  !l00E-08 0.5 0.5 0.5 14 0 -14 negligible negligible negligible negligible CSS Total ___ ____________ ____ __________5.50E-12 5.50E-12 5.50E-13 5.50E-13 FWS 6b (4) Medium 1.00E-04 l.00E-05 TFASCS Medium 2.00E-07 0.3 0.9 0.5 3 0 -3 negligible negligible negligible negligible FWS 7a (4) Low 1.OOE-06 1.00E-07 None(FAC) Low(High) l.00E-08 0.5 0.5 0.5 14 0 -14 negligible negligible negligible negligible FWS Total ________________0.OOE+OO O.O0E+OO O.00E+00 0.O0E+O0 MSS 7a Medium 1.O0E-04 l00E-05 None(FAC) Low(High) 1.00E-08 0.5 0.5 0.5 0 0 0 negligible negligible negligible negligible MSS Total ____ _______________negligible negligible negligible negligible AFW 6a (3) Medium 1.00E-04  !l00E-05 None (FAC) Low(High) l00E-08 0.5 0.5 0.5 7 0 -7 negligible negligible negligible negligible AFW Total _________ ______________negligible negligible negligible negligible Grand Total ___________ __________-1.74E-09 4.16E-10 -1.39E-09 3.32E-10