DCL-13-119, Annual Update to Renewal Application and License Renewal Application Amendment Number 47

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Annual Update to Renewal Application and License Renewal Application Amendment Number 47
ML13357A759
Person / Time
Site: Diablo Canyon  Pacific Gas & Electric icon.png
Issue date: 12/23/2013
From: Allen B
Pacific Gas & Electric Co
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
DCL-13-119, FOIA/PA-2016-0438
Download: ML13357A759 (30)
v • d • e


Text

Pacific Gas and Electric Company Barry S. Allen Diablo Canyon Power Plant Site Vice President Mail Code 104/6 P. 0. Box 56 Avila Beach, CA 93424 December 23, 2013 805.545.4888 Internal: 691 .4888 Fax: 805.545.6445 PG&E Letter DCL-13-119 U.S. Nuclear Regulatory Commission 10 CFR 54.21 (b)

ATTN: Document Control Desk Washington, DC 20555-0001 Docket No. 50-275, OL-DPR-80 Docket No. 50-323, OL-DPR-82 Diablo Canyon Units 1 and 2 10 CFR 54.21 (b) Annual Update to the Diablo Canyon Power Plant License Renewal Application and License Renewal Application Amendment Number 47

Dear Commissioners and Staff:

By letter dated November 23, 2009, Pacific Gas and Electric Company (PG&E) submitted an application to the U.S . Nuclear Regulatory Commission for the renewal of Facility Operating Licenses DPR-80 and DPR-82, for Diablo Canyon Power Plant (DCPP) Units 1 and 2, respectively. The application included the license renewal application (LRA) and LRA Appendix E, "Applicant's Environmental Report-Operating License Renewal Stage." As required by 10 CFR 54.21 (b), each year following submittal of the LRA, an amendment to the LRA must be submitted that identifies any change to the current licensing basis (CLB) that materially affects the contents of the LRA, including the Final Safety Analysis Report Supplement.

The LRA update covers the period from October 1, 2012, through September 30, 2013. identifies DCPP LRA changes that are being made to reflect CLB that materially affects the LRA. Enclosure 2 contains the affected LRA pages with changes shown as electronic markups (deletions crossed out and insertions italicized). Enclosure 3 provides the basis for a change to the One-Time Inspection (OTI) aging management program (AMP). Enclosure 4 provides the basis for a clarification to the OTI of ASME Code Class 1 Small Bore Piping AMP. Enclosure 5 provides the basis for eliminating the Fuse Holder AMP.

PG&E makes no new regulatory commitments (as defined by NEI 99-04) in this letter. Changes to existing commitments are contained in the changes to LRA Table A4-1 in Enclosure 2.

If you have any questions regarding this response, please contact Mr. Terence L. Grebel, License Renewal Project Manager, at (805) 458-0534.

A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway

  • Comanche Peak
  • Diablo Canyon
  • Palo Verde
  • San Onofre
  • Wolf Creek

Document Control Desk PG&E Letter DCL-13-119 December 23, 2013 Page 2 I declare under penalty of perjury that the foregoing is true and correct.

Executed on December 23, 2013.

Sincerely, g_7 Barry S. Allen

5. 4!L-Site Vice President crl/50518850 Enclosures cc: Diablo Distribution cc/enc: Brian J. Benney, NRR Project Manager Marc L. Dapas, NRC Region IV Administrator Thomas R. Hipschman, NRC, Senior Resident Inspector Richard A. Plasse, NRC Project Manager, License Renewal A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway
  • Comanche Peak
  • Diablo Canyon
  • Palo Verde
  • San Onofre
  • Wolf Creek

Enclosure 1 PG&E Letter DCL-13-119 Page 1 of 1 Diablo Canyon Power Plant License Renewal Application (LRA) Changes Reflected in the Annual LRA Update Amendment 47 Affected LRA Reason for Change Section Table 2.3.4-4 Updated to reflect plant modifications (review of equipment Table 3.3.2-3 changes).

Table 3.4.2-4 Table 2.3.1-2 Updated to address Pacific Gas and Electric Company Table 2.3.2-1 (PG&E) Letter DCL-10-160, dated December 13, 2010. The Table 2.3.3-8 One-Time Inspection of ASME Code Class 1 Small-Bore Piping aging management program (AMP) will cover piping nominal pipe size less than 4 inches on each Unit.

Section 3.1.2.2.3.1 Errata. Additional change required based on updated pressurized thermal shock analyses results to reflect WCAP-1731-NP and WCAP-17299-NP (Reference PG&E Letter DCL-11-136, "10 CFR 54.21(b) Annual Update to the DCPP License Renewal Application and License Renewal Application Amendment 45," dated December 21, 2011).

Section 3.6.2.1.3 Refer to Enclosure 5 of this letter.

Table 3.6.1 Table 3.6.2-1 Section A 1. 34 Table A4-1 #15 Section 81.5 Table 82 Section 82.1.34 Section A1.19 Refer to Enclosure 4 of this letter.

Table A4-1 #42 Complete. Procedure NDE VT 3C-1 acceptance criteria was revised to be consistent with ACI 349.3R Chapter 5 detailed quantitative acceptance criteria.

Table A4-1 #69 Complete. Marine growth removal and subsequent inspection of all required areas of the Unit 2 discharge conduits was completed during the 17th refueling outage for Unit 2.

PG&E Letter DCL-13-119 Page 1 of 21 License Renewal Application (LRA)

Amendment 47 Affected LRA Sections, Tables, and Figures Table 2.3.1-2 Table 2.3.2-1 Table 2.3.3-8 Table 2.3.4-4 Section 3.1.2.2.3.1 Table 3.3.2-3 Table 3.4.2-4 Section 3.6.2.1.3 Table 3.6.1 Table 3.6.2-1 Appendix A- Table of Contents Section A 1. 19 Section A 1.34 Table A4-1 #15, 42, 69 Appendix 8 - Table of Contents Section 81 .5 Table 82 Section 82.1.34 Section 2.3 PG&E Letter DCL-13-119 SCOPING AND SCREENING RESULTS MECHANICAL SYSTEMS Page 2 of 21 Table 2. 3. 1-2 Reactor Coolant System Component Type Intended Function Bellows Leakage Boundary (spatial)

  • Pressure Boundary Class 1 Piping <= 4in Pressure Boundary Closure Bolting Pressure Boundary Filter Leakage Boundary (spatial)

Structural Integrity (attached)

Heat Exchanger (RCP Seal Cooler) Heat Transfer Pressure Boundary Heat Exchanger (RPV Support Cooler Plate) Leakage Boundary (spatial)

Structural Support Orifice Pressure Boundary Throttle Piping Leakage Boundary (spatial)

Pressure Boundary Structural Integrity (attached)

Pump Pressure Boundary Rupture Disc Leakage Boundary (spatial)

Tank Leakage Boundary (spatial)

Structural Integrity (attached)

Tubing Leakage Boundary (spatial)

Pressure Boundary Valve Leakage Boundary (spatial)

Pressure Boundary Structural Integrity (attached)

The AMR results for these component types are provided in Table 3.1 .2-2, Reactor Vessel, Internals and Reactor Coolant System -Summary of Aging Management Evaluation - Reactor Coolant System.

Section 2.3 PG&E Letter DCL-13-119 SCOPING AND SCREENING RESULTS MECHANICAL SYSTEMS Page 3 of 21 Table 2.3.2-1 Safety Injection System Component Type Intended Function Class 1 Piping <= 4in Pressure Boundary Closure Bolting Pressure Boundary Expansion Joint Pressure Boundary Filter Pressure Boundary Flow Element Pressure Boundary Throttle Heat Exchanger (SI Pump Lube Oil) Heat Transfer Pressure Boundary Heat Exchanger (SI Pump Seal Water) Heat Transfer Pressure Boundary Indicator Leakage Boundary (spatial)

Structural Integrity (attached)

Liner Sumps Structural Pressure Boundary Orifice Pressure Boundary Throttle Piping Leakage Boundary (spatial)

Pressure Boundary Structural Integrity (attached)

Pump Pressure Boundary Strainer Filter Leakage Boundary (spatial)

Tank Pressure Boundary Thermowell Pressure Boundary Valve Leakage Boundary (spatial)

Pressure Boundary Structural Integrity (attached)

The AMR results for these component types are provided in Table 3.2.2-1 , Engineered Safety Features- Summary of Aging Management Evaluation -Safety Injection System.

Section 2.3 PG&E Letter DCL-13-119 SCOPING AND SCREENING RESULTS MECHANICAL SYSTEMS Page 4 of 21 Table 2.3.3-8 Chemical and Volume Control System Component Type Intended Function Class 1 Piping <= 4in Pressure Boundary Closure Bolting Leakage Boundary (spatial)

Pressure Boundary Demineralizer Leakage Boundary (spatial)

Pressure Boundary Evaporator Leakage Boundary (spatial)

Filter Leakage Boundary (spatial)

Pressure Boundary

Enclosure 2 Section 2.3 PG&E Letter DCL-13-119 SCOPING AND SCREENING RESULTS MECHANICAL SYSTEMS Page 5 of 21 Table 2. 3. 4-4 Condensate System I Component Type I Intended Function

~==nger (Caustic Dilution Hx Section 3.1 PG&E Letter DCL-13-119 AGING MANAGEMENT OF REACTOR VESSEL, INTERNALS, AND REACTOR COOLANT SYSTEM Page 6 of 21 3.1.2.2.3.1 Loss of Fracture Toughness due to Neutron Irradiation Embrittlement TLAA For the Unit 1 reactor vessel, PG&E \Viii implement the revised PTS rule, 10 CFR 50.61a, at least three years prior to exceeding the PTS screening criterion of 10 CFR 50.61. In the e'Jent that the provisions of 10 CFR 50.61 a cannot be met, PG&E 'Nil I implement alternate options, such as flux reduction , as provided in 10 CFR 50.61 .

Section 3.3 PG&E Letter DCL-13-119 AGING MANAGEMENT OF AUXILIARY SYSTEMS Page 7 of 21 Table 3.3.2-3 Auxiliary Systems- Summary of Aging Management Evaluation- Saltwater and Chlorination System Component Intended Material Environment Aging Effect Aging Management NUREG- Table 11tem Notes Type Function Requiring Program 1801 Vol.

Management 21tem Pulsation L8S GaFeeR Demineralized Loss of material Water Chemistry VIII.S-tD1- 3.4.1 . 16Q4 c Dampener Stainless Water (lnt) (82.1.2) and One-Time +44 Steel Inspection (82.1.16)

Pulsation L8S GaFeeR Plant Indoor Air Less ef E*teFRal Sl:JFfaees VII. ~J-8 15 3.3. 1.§894 8C Dampener Stainless (Ext) mateFiaiNone MeRiteFiR§J PFe§JFam Steel (82.1.2Q) None Section 3.4 PG&E Letter DCL-13-119 AGING MANAGEMENT OF STEAM AND POWER CONVERSION SYSTEM Page 8 of 21 Table 3.4.2-4Steam and Power Conversion System- Summary of Aging Management Evaluation- Condensate System Component . Intended Material Environment Aging Effect Aging Management NUREG- Table 11tem Notes Type Function Requiring Program 1801 Vol.

Management 21tem Heat L8S GaFeeR Plant Indoor Air Less ef E*teFRal S~.:~Ffaees Vll l./-1 OM- 3.4.1. 412-S gc Exchanger Stainless (Ext) mateFiaiNone MeRiteFiRg Pmgmm +-

(Caustic Steel (92.1.20)None Dilution Hx- I Shell)

Heat L8S Stainless Steam (tnt) Cracking Water Chemistry V/1/.A - 10 3.4.1.39 E, 4 Exchanger Steel (82. 1. 2) and One- Time (Caustic Inspection (82. 1. 16)

Dilution Hx -

Shell)

Heat L8S GaFeeR Steam (lnt) Loss of material Water Chemistry VIII.A-1 2& 3.4.1. 37@ AE, 4 Exchanger Stainless (82.1.2) and One-Time (Caustic Steel Inspection (82.1.16)

Dilution Hx-Shell)

Heat- hBS GeppeFAIIey Steam (IRt) Less ef mateFial VVateF Gt:lemistPJ VIII.A 5 3.4 .1.15 G E*SRaRgeF (92.1 .2) aREI GRe +ime (Ga~.:~stie IRspeetieR (92.1.16)

Qil~.:~tieR 1=1*

T,

~ ~~~ ~~ *,

Section 3.6 PG&E Letter DCL-13-119 AGING MANAGEMENT OF ELECTRICAL AND INSTRUMENTATION AND CONTROLS Page 9 of 21 3.6.2.1.3 Fuse Holders {not part of a larger assembly)

Aging Effects Requiring Management The following fuse holders aging effects require management:

  • Embrittlement, cracking, melting, discoloration, swelling, or loss of dielectric strength leading to reduced insulation resistance (IR); electrical failure
  • Electrical Cables and Connections Not Subject to 10 CFR 50.49 EQ Requirements (82.1.24)
  • Fuse Holders (82 .1.34 )

Section 3.6 PG&E Letter DCL-13-119 AGING MANAGEMENT OF ELECTRICAL AND INSTRUMENTATION AND CONTROLS Page 10 of 21 Table 3.6.1 Summary of Aging Management Evaluations in Chapter VI of NUREG-1801 for Electrical Components (Continued)

Item Component Type Aging Effect I Mechanism Aging Management Further Discussion Number Program Evaluation I Recommended 3.6.1.06 Fuse Holders (not part Fatigue due to ohmic heating, Fuse Holders (82 .1.34) No GeRsisteRt \t.titt:l of a larger assembly): thermal cycling, electrical NUREG 1801 .Exception to Fuse holders - metallic transients, frequent NUREG-1801 . Aging effect clamp manipulation, vibration, in NUREG-1801 for this chemical contamination, material and environment corrosion, and oxidation combination is not applicable.

Section 3.6 PG&E Letter DCL-13-119 AGING MANAGEMENT OF ELECTRICAL AND INSTRUMENTATION AND CONTROLS Page 11 of 21 Table 3.6.2-1 Electrical and Instrument and Controls- Summary of Aging Management Evaluation- Electrical Components Component Intended Material Environment Aging Effect Aging Management Program NUREG- Table 1

  • Notes  !

Type Function Requiring 1801 Vol. Item Management 21tem Fuse Holder EC Various Plant Indoor Air Fatigue None AgiAg MaAagemeAt PFegFam feF VI.A-8 3.6.1.06 A/, 2 Metals Used (Ext) Fuse HeldeFs (B2.1.34)None for Electrical Contacts - --- --- ---- *-- *-

Standard Notes:

1. Aging effect in NUREG-1801 for this component, material and environment combination is not applicable.

Plant Specific Notes:

2. The fuse holders (not part of a larger assembly) are designed to withstand the ratings of the fuses they house. Thus the fuse holders are protected from thermal fa tigue due to ohmic heating. A walk down confirmed that the fuse holders are located in areas where there is no chemical contamination and the ambient temperature is stable and above the dew point. These fuse holders are not subject to vibration and are not frequently manipulated.

Appendix A FINAL S~FETY ANALYSIS REPORT SUPPLEMENT PG&E Letter DCL-13-119 Page 12 of 21 APPENDIX A- TABLE OF CONTENTS A 1.34 Fuse HoldersNot Used............................ *.....................................A-19 Appendix A PG&E Letter DCL-13-119 FINAL SAFETY ANALYSIS REPORT SUPPLEMENT Page 13 of 21 A1.19 ONE-TIME INSPECTION OF ASME CODE CLASS 1 SMALL-BORE PIPING The One-Time Inspection of ASME Code Class 1 Small-Bore Piping program manages cracking of ASME Code Class 1 piping less than 4 inches nominal pipe size (NPS).

This program is implemented as part of the fourth interval of the DCPP lnservice Inspection (lSI) program.

Diablo Canyon Power Plant will volumetrically examine 10 percent, with a maximum of 25, of the small bore socket welds and 10 percent, with a maximum of 25 of the butt welds within the population of ASME Class-1 piping NPS less than 4 inches on each unit. DCPP may perform opportunistic destructive examination of welds in lieu of volumetric examination with one destructive examination being equivalent to two volumetric examinations. The sample selection methodology will take into account damage mechanisms such as thermal fatigue, vibration induced fatigue, and stress corrosion cracking. DCPP will determine potential damage mechanisms for each weld by using site specific analysis, MRP-146 guidance, and plant operating experience.

The sample selection methodology will take into account damage mechanisms such as thermal fatigue, vibration induced fatigue, and stress corrosion cracking. DCPP will determine potential damage mechanisms for each weld by using site specific analysis, MRP-146 guidance, and plant operating experience. These documents currently show thermal fatigue as the prevalent damage mechanism. Plant operating experience will also be considered for the socket weld examination sample to validate the effectiveness of past corrective actions.

For /\SME Code Class 1 small bore piping, the lSI program requires volumetric examinations on selected butt v1eld locations to detect cracking . VVeld locations are selected based on the guidelines provided In EPRI TR 112657, Revised Risk Informed lnservice Inspection Evaluation Procedure. Volumetric examinations are conducted in accordance with ASME Section XI with acceptance criteria from Paragraph IWB-3000 and IWB-2430. Volumetric examination of these welds will occur The One Time Inspection of /\SME Code Class 1 Small Bore Piping program inspections 'Hill be completed a_nd evaluated within W six years prior to the period of extended operation.

Enclosure 2 Appendix A PG&E Letter DCL-13-119 FINAL SAFETY ANALYSIS REPORT SUPPLEMENT Page 14 of 21 A1.34 NOT USEDFUSE HOLDERS The Fuse Holders program manages thermal fatigue, mechanical fatigue, vibration, chemical contamination, and corrosion of the metallic portions of fuse holders to ensure that fuse holders 'IJithin the scope of license renevJal are capable of performing their intended function .

The fuse holders that perform a license rene'Nal intended function located outside of active devices are tes.ted for deterioration of the metallic clamps using thermography.

These fuse holders VJIII be tested at least once every 10 years. The first test 'Nill be completed prior to the period of extended operation . The acceptance criteria for

  • thermography testing 'Nill be based on the temperature rise above the reference temperature. The reference temperature vJill be ambient temperatures or the baseline temperature data from the same type of connections being tested.

The Fuse Holder program is a ne'.v program that 'Nill be implemented prior to the period of extended operation. Industry and plant specific operating experience 'Nill be evaluated in the development and implementation of this program .

Appendix A PG&E Letter DCL-13-119 FINAL SAFETY ANALYSIS REPORT SUPPLEMENT Page 15 of 21 Table A4-1 License Renewal Commitments Item# Commitment LRA Implementation Section Schedule 15 Implement the Fuse Holders program as described in LRA Section 82.1.34 .Deleted. 82.1.34 Prior to the periea e~

extenaee~eratien .

Deleted.

42 Procedure NDE VT 3C-1 acceptance criteria will be revised to be consistent with ACI 349.3R 82.1.28 Prier te tt-le r;lerieel ef Chapter 5 detailed quantitative acceptance criteria. exteneleel eperat--

Complete.

69 Marine growth removal and subsequent inspection of all required areas of the Unit 2 82.1.32 Pf:ier--k:HA~erieel ef discharge conduit will be completed prior to the period of extended operation. The Unit 2 exter1Gea ~erat.ien .

discharge conduit is currently scheduled to be completed during 2R 17 (2013). Reference Complete.

PG&E Letter DCL-12-124 for Unit 1. - - *- --

Appendix 8 PG&E Letter DCL-13-119 AGING MANAGEMENT PROGRAMS Page 16 of 21 APPENDIX 8- TABLE OF CONTENTS 82.1.34 Not UsedFuse Holders ........................................................................... 144 Appendix B PG&E Letter DCL-13-119 AGING MANAGEMENT PROGRAMS Page 17 of 21 81.5 AGING MANAGEMENT PROGRAMS Fuse Holders (Section 82 .1.34)

Appendix 8 PG&E Letter DCL-13-119 AGING MANAGEMENT PROGRAMS Page 18 of 21 82 AGING MANAGEMENT PROGRAMS NUREG-NUREG-1801 EXISTING APPENDIX 8 1801 PLANT PROGRAM PROGRAM OR NEW REFERENCE NUMBER Xh0 Fl:lse J=leleeFs Fl:lse J=leleeFs New B~ - ~ . 34

Enclosure 2 Appendix 8 PG&E Letter DCL-13-119 AGING MANAGEMENT PROGRAMS Page 19 of 21 82.1.34 Fuse HoldersNot Used Program Description The Fuse Holders program manages thermal fatigue , mechanical fatigue, vibration, chemical contamination and corrosion of the metallic portions of fuse holders to ensure

~hat fuse holders 'IJithin the scope of license rene\val are capable of performing their Intended function. The fuses 'llithin the scope of license renewal at DCPP are not frequently removed or replaced.

Fuse holders are constructed of blocks of rigid insulating material, such as phenolic resins with metallic clamps (clips) that hold each end of the fuse. The clamps, 'IJhich are made of copper alloy, are spring loaded clips that hold the fuse ferrules or blades in place. The insulating phenolic material aging effects are managed under the Electrical Cables and Connections Not Subject to 10 CFR 50.49 Environmental Qualification Requirements program (82.1 .24). NUREG/CR 6763 (NUREG 1760), Aging Assessment of Safety Related Fuses Used in LoV'I and Medium 'lol.fage Applications in Nuclear Pov;er P.tants study determined that fuses are susceptible to aging that can lead to failure, ho\vever, the occurrence is infrequent.

The fuse holders that perform a license rene\val intended function located outside of active devices \Viii be tested for deterioration of the metallic clamps by using ther~ography .. The fuse holder testing will be performed at least once every 10 years.

The f1rst test 'IIIII be completed prior to the period of extended operation.

The acceptance criteria for thermography testing 'Nil I be based on the temperature rise above the reference temperature. The reference temperature \Viii be ambient temperatures or the baseline temperature data from the same type of connections being tested. An engineering evaluation that considers the age and operating environment of the fuse holders \Viii be performed 'Nhen the test acceptance criteria are not met. The engineering evaluation considers the guidance provided in SAND 96 0344, Section 5.2, Maintenance, Sur~eiN-ance, and Gondi#on ,"Aonitorfng Techniques for E't~aluatlon of E *1ectric 1 G '"' 1 an d 19rm:na0ons,

~' a.au.e -r

  • t* th e s1gn11cance
  • *f* of t he test results , the operability of the fuse holder, the reportability of the event, the extent of the concern , the potential root causes , the probability of recurrence , and the corrective actions required.

Corrective actions for conditions that are adverse to quality are performed in accordance 'Nith the Corrective Action Program as part of the QA program. The corrective action process provides reasonable assurance that deficiencies adverse to quality are either promptly corrected or are evaluated to be acceptable.

The Fuse Holders program is an inspection program, no actions are taken as part of this program to prevent or mitigate aging degradation. Trending actions are not included as part of this program because the ability to trend test results is dependent on the specific type of test chosen .

Enclosure 2 Appendix 8 PG&E Letter DCL-13-119 AGING MANAGEMENT PROGRAMS Page 20 of 21 NUREG 1801 Consistency The Fuse Holders program is a ne'N program that, v;hen implemented, \Viii be consistent with NUREG 1801,Section XI.E5, Fuse Holders.

Exceptions to NUREG 1801 Enhancements Operating Experience Operating experience has shov;n that loosening of fuse holders and corrosion of fuse clips are aging mechanisms that, if left unmanaged, can lead to a loss of electrical continuity function.

The Fuse Holders program is a ne'N program; therefore, plant specific operating exper~ence to verify the effecti.veness of the program is not available. Industry operating exper~ence that forms the bas1s for these programs is included in the operating exper~e~ce eleme~t of the corresponding NUREG 1801, aging management program descnpt1on. A revle\AJ of plant operating experience for fuse holders has identified instances of loose or corroded fuse holders. Corrective actions taken include plant procedure revisions to verify that fuse holders are tight, adjusting fuse clips, and application of corrosion inhibiting paste or grease. None of these instances involved fuse holders \\'ithin the scope of this program.

As additional industry and applicable plant specific operating experience become available, the operating experience \Viii be evaluated and appropriately incorporated into the program through the DCPP Corrective Action Program and Operating Experience Program. This ongoing revievv of operating experience 'Nill continue throughout the period of extended operation, and the results 'Nill be maintained on site. This process

'Nill confirm the effectiveness of this ne\v license renev1al aging management program by incorporating applicable operating experience and performing self assessments of the program.

The DCPP operating experience findings for this program identified no unique plant specific operating experience; therefore DCPP operating experience is consistent 'Nith NUREG 1801.

Appendix 8 PG&E Letter DCL-13-119 AGING MANAGEMENT PROGRAMS Page 21 of 21 Conclusion The implementation of the Fuse Holders program '.'Jill provide reasonable assurance that aging effects ,_.,ill be managed such that the systems and components 'wfmhin the scope of this program v.(ill continue to perform their intended functions consistent 'Nith the current licensing basis for the period of e}dended operation.

Enclosure 3 PG&E Letter DCL-13-119 Page 1 of 2 One-Time Inspection Pacific Gas and Electric Company (PG&E) revises a statement made in PG&E Letter DCL-10-134, "Response to NRC Letter dated September 28, 2010, Summary of Telephone Conference Call Held on September 2, 2010, Between the U.S. Nuclear Regulatory Commission and Pacific Gas and Electric Company Concerning Responses to Requests for Additional Information Related to the Diablo Canyon Nuclear Power Plant, Units 1 and 2, License Renewal Application," dated October 27, 2010. The revised statement in PG&E's supplemental response to request for additional information (RAI) B2.1.16-1 reads: "A sample of 10 percent of the stagnant locations will be selected for each in-scope system per Unit, with the most susceptible material type using nondestructive examination (NDE) techniques suitable for the specific aging mechanism related to material loss (e.g., visual examination for crevice or pitting corrosion, ultrasonic examination for general wall loss, etc.)."

Basis for Change:

PG&E provided details of the sampling procedure that will be used for the One-Time Inspection (OTI) Program in PG&E Letter DCL-10-073, "Response to NRC Request for Additional Information for the Diablo Canyon License Renewal Application, " dated July 7, 2010. However, the staff was unclear on the basis for the sampling sizes selected for the various aging effects. Based on a discussion with the Nuclear Regulatory Commission (NRC) staff, PG&E agreed to supplement its response to RAI B2.1.16-1 to provide additional information on the basis for the sampling size and criteria for the program.

PG&E provided its supplemental response to RAI B2.1.16-1 in PG&E Letter DCL-1 0-134. In its response, PG&E stated that the OTI Program will verify effectiveness of the Water Chemistry Program at managing material loss by identifying a population for each in-scope system based on the most susceptible material within the system (i.e. carbon steel in feedwater system, stainless steel in chemical and volume control system) at stagnant locations where the full effect of a Water Chemistry Program may not be achieved. A sample of 10 percent of the stagnant locations, with the most susceptible material type suitable for ultrasonic thickness examination will be selected for each in-scope system per Unit. The OTI Program will take credit for volumetric examinations performed under other aging management programs (AMPs), such as flow-accelerated corrosion, when the above criteria is met and the exams are performed within the 10 years prior to the period of extended operation.

PG&E revises the above to state that "A sample of 10 percent of the stagnant locations will be selected for each in-scope system per Unit, with the most susceptible material type using nondestructive examination (NDE) techniques suitable for the specific aging mechanism related to material loss (e.g., visual examination for crevice or pitting corrosion, ultrasonic examination for general wall loss, etc.)."

Enclosure 3 PG&E Letter DCL-13-119 Page 2 of2 In NRC letter "Safety Evaluation Report Related to the License Renewal of Diablo Canyon Power Plant, Units 1 and 2," dated June 2011, the NRC referred to PG&E's October 27, 2010, supplemental response to RAI 82.1.16-1 and indicated that PG&E would conduct a 10 percent inspection of the most susceptible locations (e.g., stagnant flow, low points) for each in-scope system to verify the effectiveness of the Water Chemistry Program in managing loss of material, and cracking of stainless steel components exposed to an environment greater than 140 oF. The safety evaluation report (SER) did not specify an examination technique.

NUREG-1801, Revisions 1 and 2, Program XI.M32 (OTI), Element 3 states that inspection is performed using a variety of NDE methods, including visual, volumetric, and surface techniques.

Therefore, revising the information submitted in PG&E Letter DCL-1 0-134 is acceptable, because removing the specific examination technique (ultrasonic) to allow use of all NDE appropriate to the aging mechanisms for material loss (i.e. pitting or crevice corrosion) is consistent with NUREG-1801, Revisions 1 and 2 and the SER.

Enclosure 4 PG&E Letter DCL-13-119 Page 1 of 2 One-Time Inspection of ASME Code Class 1 Small Bore Piping Pacific Gas and Electric Company (PG&E) proposes to remove the exception to NUREG-1801, "Scope of Program- Element 1," from License Renewal Application (LRA), Section B2.1.19, "One-Time Inspection of ASME Code Class 1 Small Bore Piping."

Basis for LRA Amendment:

PG&E Letter DCL-09-079, "License Renewal Application," dated November 23, 2009, provided an application to the U.S. Nuclear Regulatory Commission (NRC) for the renewal of Facility Operating Licenses DPR-80 and DPR-82, for Diablo Canyon Power Plant (DCPP) Units 1 and 2, respectively. The application included the LRA and Applicant's Environmental Report- Operating License Renewal Stage. The LRA included Section B2.1.19, "One-Time Inspection of ASME Code Class 1 Small-Bore Piping."

LRA Section B2.1.19 proposed the use of risk-informed in-service inspection (RI-ISI) for managing aging of ASME Code Class 1 small bore piping. In using the RI-ISI Program, PG&E took an exception to NUREG-1801 Scope of Program -Element 1, which stated:

NUREG-1801 recommends the use of EPRI Report 1000701, Interim Thermal Fatigue Management Guideline (MRP-24), January 2001, for identifying piping susceptible to potential effects of thermal stratification or turbulent penetration.

The DCPP risk-informed process examination requirements are performed consistent with EPRI TR-112657, Revised Risk-Informed lnservice Inspection Evaluation Procedure, Rev. B, instead of EPRI Report 1000701. Guidelines for identifying piping susceptible to potential effects of thermal stratification or turbulent penetration that are provided in EPRI Report 1000701 are also provided in EPRI TR-112657. The recommended inspection volumes for welds in EPRI Report 1000701 are identical to those for inspection of thermal fatigue in RI-ISI programs; thus, the DCPP risk-informed process examination requirements meet the recommendations of NUREG-1801. The NRC-accepted DCPP's use of EPRI TR-112657 in a letter to PG&E dated November 8, 2001.

By letter dated June 14,2010, the NRC staff issued RAI B2.1.19-1 asking PG&E to justify the proposed deviation from the GALL Report recommendation to perform volumetric examinations of socket welds in ASME Code Class 1 small bore piping.

By PG&E Letter DCL-10-073, " Response to NRC Request for Additional Information for the Diablo Canyon License Renewal Application," dated July 7, 2010, PG&E responded to RAI B2.1.19-1.

Enclosure 4 PG&E Letter DCL-13-119 Page 2 of2 By NRC letter dated September 1, 2010, the NRC staff issued RAI B2.1.19-2 (Follow-up) requesting PG&E to provide the number of socket welds selected for inspection and the sampling methodology and to provide the technical basis for why the sampling is statistically significant and adequate. By PG&E Letter DCL-1 0-126, "Response to NRC Letter dated September 1, 2010, Request for Additional Information (Set 22) for the Diablo Canyon License Renewal Application," dated September 30, 2010, PG&E responded to RAI B2.1.19-2 (Follow-up).

On November 10, 2010, a telephone conference between the NRC and representatives of PG&E was held to obtain clarification on PG&E's response to follow-up RAI B2.1.19-2 that was submitted in PG&E Letter DCL-1 0-126. By PG&E Letter DCL-10-160, "Response to Telephone Conference Call Held on November 10, 2010, Between the U.S. Nuclear Regulatory Commission and Pacific Gas and Electric Company Concerning Responses to Requests for Additional Information Related to the Diablo Canyon Nuclear Power Plant, Units 1 and 2, License Renewal Application,"

dated December 13, 2010, PG&E provided the NRC staff with supplemental information that defines the scope, sample methodology, damage mechanisms, and the time period for inspections.

The NRC staff evaluated and accepted the supplemental information as documented in "Safety Evaluation Report Related to License Renewal for Diablo Canyon Power Plant, Units 1 and 2," Section 3.0.3.2.9, dated June 2, 2011.

Since the NRC-accepted sample methodology and time period do not reflect that found in the RI-ISI program as proposed in the initial LRA and as accepted by the NRC in the license renewal safety evaluation report, PG&E will no longer credit the RI-ISI program for managing aging of ASME Code Class 1 small bore piping and proposes to remove the Exception to NUREG-1801, "Scope of Program- Element 1,"

from LRA Section B2.1.19.

Enclosure 5 PG&E Letter DCL-13-119 Page 1 of 2 Fuse Holder Program Pacific Gas and Electric Company (PG&E) proposes to eliminate its aging management program (AMP) for fuse holders (NUREG-1801 Program XI.E5) from the Diablo Canyon Power Plant (DCPP) license renewal application (LRA).

PG&E Letter DCL-09-079, "License Renewal Application," dated November 23, 2009, submitted a LRA to the U.S. Nuclear Regulatory Commission (NRC) for the renewal of Facility Operating Licenses DPR-80 and DPR-82, for DCPP Units 1 and 2, respectively.

The LRA included Section B2.1.34, "Aging Management Program for Fuse Holders,"

which states that fuse holders performing a license renewal intended function located outside of active devices will be tested for deterioration of the metallic clamps using thermography. Fuse holder testing will be performed at least once every 10 years, and the first test will be completed prior to the period of extended operation.

The following DCPP stand-alone fuse boxes were evaluated and included in the scope of the fuse holder AMP:

Stand-Alone Fuse Boxes Unit Panel Description In-Scope? Location Located on wall at South end of Unit 1 1 BTD311 Main Cardox Panel y Turbine Building; ambienttemperature is stable Located in the Unit 2, area H, Cable 2 BTH115 Annunciator Terminal Box y Spreading Room; ambient temperature is stable.

NUREG-1801 Program XI.E5 discusses the scope of the fuse holder program:

"This AMP manages fuse holders (metallic clamps) located outside of active devices that are considered susceptible to the following aging effects: increased resistance of connection due to chemical contamination, corrosion, and oxidation or fatigue caused by ohmic heating, thermal cycling, electrical transients, frequent manipulation, or vibration. Fuse holders inside an active device (e.g., switchgear, power supplies, power inverters, battery chargers, and circuit boards) are not within the scope of this AMP."

During the scoping process, it was determined that the only stressor the fuse holders were subject to was loosening of connection caused by thermal cycling. This was a conservative assumption made for all fuse holders in the original scope. The two in-scope fuse holders were walked down and no other stressors, including moisture,

Enclosure 5 PG&E Letter DCL-13-119 Page 2 of 2 chemical contamination, oxidation and corrosion, mechanical stresses, electrical transients, and fatigue from frequent manipulation, were found to affect them.

The possible aging effects for fuse holder metallic clips, including loosening of connection by thermal cycling, are evaluated in EPRI Report 1013475, "Plant Support Engineering: License Renewal Electrical Handbook Revision 1 to EPRI Report 1003057."

Loosening of Connection I Thermal Cycling:

Thermal cycling is a potential aging mechanism that may cause fuse clips or fingers to become annealed and lose their spring force after just one overheating due to a high resistance connection. Annealing of a copper fuse clip may occur at temperatures as low as 93°C, depending on the degree of cold work.

Fuse holders are designed to withstand the ratings of the fuses they house. Thus fuse holders are protected from thermal cycling by their design which prevents the aging effect of fuse clip/finger loosening and requires no aging management program.

PG&E conservatively assumed during the original scoping process that all fuse holders were subject to thermal cycling, and scoped-in the two fuse panels listed above for aging management.

The fuse holder located in the two in-scope fuse panels were walked down and no aging stressors, including moisture, chemical contamination, oxidation and corrosion, thermal fatigue, vibration or mechanical fatigue from frequent manipulation, were found.

Since, the in-scope fuse holders at DCPP are protected from thermal cycling by design as stated in EPRI Report 1003057, and there are no other aging effects that require management, these fuse holders are not subjected to aging mechanisms and do not require aging management.

Because there are no aging effects that require management for fuse holders at DCPP, PG&E proposes to eliminate 82.1.34, Fuse Holders, from the LRA. Markups of the affected LRA sections are located in Enclosure 2 of this letter.

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