ML063210266

Meeting Slides with the Palo Verde Nuclear Generating Station Licensee Nuclear Fuel Management Activities

ML063210266
Person / Time
Site:	Palo Verde
Issue date:	11/16/2006
From:	Office of Nuclear Reactor Regulation
To:
Wilkins, L E, NRR/DORL/LPL4, 415-1377
Shared Package
ML063210258	List: ML063210266 ML063230011
References
Download: ML063210266 (40)

Text

Nuclear Fuel Update Palo Verde Nuclear Generating Station November 16, 2006 Meeting with US NRC 1

VERDE PAL O

Nuclear Fuel Management Michael E. Powell, DR Nuclear Fuel Management Yovan Lukic, Principal Engr. Burton A. Grabo, PA Nuclear Fuel Management Nuclear Fuel Management Kathleen C. Parrish, TMA Nuclear Fuel Management Kevin Graham, DL John Hazelbaker, MGR Robert Bandera, DL Nuclear Fuel Services NFM Procurement Nuclear Fuel Analysis Vacant SL Thomas C. Cannon, SL Reactor Engineering Reload Analysis Brian J. Hansen, SL Craig A. Hasson, SL Dry Cask Storage Transient Analysis Rick L. Huffman, SL Fuel Services Jeffrey S. Schmidt, SL Nuclear Analysis 2

VERDE PAL O

Review of 2005-2006 December 2004 Meeting with NRR SG Replacement & Power Uprate Dry Cask Storage Successes SIMULATE Implementation Augmented AORs New Top Grid Design New CEAs & LFA Projects 3

VERDE PAL O

Agenda Today CEA Replacement Dual LFA Program Fuel Performance Dry Cask Storage Update Planned License Submittals 4

VERDE PAL O

CEA Replacement 5

VERDE PAL O

Review of CEA History Felt Metal Wrapped Pellets in Tips CEA Clad Failures Observed - 2001

- Cracks in High Fluence CEA Tips

- Root Cause - IASCC, Inadequate Testing All Full Length CEAs Replaced

- Replaced with Small Pellet Design Lifetime Software Abandoned 6

VERDE PAL O

Determination of New Lifetime Inspection versus Replacement Monitored YGN Inspections

• 5 Cycle Lifetime:

- Vendor Adjusted Software

- Inconel IASCC Threshold Need New CEAs for Fall 2008 7

VERDE PAL O

Design of Future CEAs Want:

- Industry Standard AgInCd

- Extended Tip Region CEDM Weight Restrictions

- AgInCd Tip Region

- Boron Carbide for Remainder Lifetime

- ~20 EFPY Design Lifetime

- ~12 EFPY Experience Base (Hot Cell)

- ~18 EFPY Experience Base (PIE) 8 VERDE PAL O

Analysis & Licensing Impacts AgInCd Tip 75% Worth (vs. 90%) of B4C CEA Misoperation Events Bounded Scram Reactivity Curves Have Margin LOF & SS/SR Being Reanalyzed Tech Spec 4.2.2 Needs Revision 9

VERDE PAL O

Dual LFA Program 10 VERDE PAL O

Specific Fuel Design Goals Materials for Higher Burnup/Duty

- Cladding Oxidation

- Dimensional Stability Preserving/Increasing Operating Margins

- Minimize CRUD

- Increase Thermal Margin Improve Fuel Utilization Overall Robust Design for Flawless Fuel 11 VERDE PAL O

Lead Fuel Assembly Program Fuel Contract Timeline LFAs Needed to Demonstrate New Design

- Observe Performance in Both PV Duty Cycles

- 8 Assembly, 3 Fuel Cycle LFA Programs AREVA and Westinghouse Designs

- M5 (AREVA) and Optimized Zirlo (WEC)

- Mixing Vane Grids and IFMs in Spans 8 & 9

- Gadolinia (AREVA) and IFBA or Gd (WEC) BAs 12 VERDE PAL O

Analysis & Licensing Strategy Explicitly Model LFAs in Core Physics Model Maintain Within > 5% of Limiting Assembly Rod Burnup Will Remain < 60,000 MWD/T Vendors Perform Mechanical, Thermal Hydraulic &

LOCA Analyses

- AREVA to Assure Non-Limiting

- WEC to Assure Compatibility APS Performs Standard Reload Safety Analyses 13 VERDE PAL O

Analysis & Licensing Strategy (continued)

Safety Limits Preserved by Maintaining LFAs non-Limiting Transient Analyses Explicitly Validated COLSS & CPC Setpoints Explicitly Calculated 10CFR50.46 Exemption for M5 Required

- Expect Exemption for Optimized Zirlo Evaluating Need for Tech Spec Changes 14 VERDE PAL O

4.2.1 Fuel Assemblies Fuel assemblies shall be limited to those fuel designs that have been analyzed with applicable NRC staff approved codes and methods and shown by tests or analyses to comply with all fuel safety design bases A limited number of lead test assemblies that have not completed representative testing may be placed in non-limiting core regions Other cladding material may be used with an approved exemption.

15 VERDE PAL O

2.0 SAFETY LIMITS (SLs) 2.1.1.1 In MODES 1 and 2, Departure from Nucleate Boiling Ratio (DNBR) shall be maintained at > 1.34.

2.1.1.2 In MODES 1 and 2, the peak fuel centerline temperature shall be maintained <

5080°F (decreasing by 58°F per 10,000 MWD/MTU for burnup and adjusting for burnable poisons per CENPD-382-P-A).

16 VERDE PAL O

Palo Verde Fuel Performance 17 VERDE PAL O

Fuel Clad Performance Clad Performance in Uprate Conditions High Burnup Fuel Performance 18 VERDE PAL O

Clad Performance in Uprate Conditions o

3% Power and ~4 F Inlet Temperature New Steam Generators Increased Clad Oxidation Increased Steaming Rates o

- Each 1 F or 1% Power is Worth 10% Steaming Rate

- Higher Source Term from New Steam Generators

- CRUD & AOA Risk 19 VERDE PAL O

Integrated Clad Performance Strategy Advanced Clad Alloy Primary Chemistry CRUD and Oxide Software Three Enrichment Lattice Designs Long Range Fuel Inspection Plan 20 VERDE PAL O

The Two Duty Cycles Typical (U2C13) Core Design Fresh 1x burned 2x burned Reinserts 21 VERDE PAL O

ZIRLOTM Clad Westinghouse Low Tin Zirconium Based Alloy Protect High Duty 2 Cycle Assemblies

- First Implementation in Unit 2 Cycle 11 Licensing Limitations

- Fuel Duty Index & Maximum Oxide Thickness

- Vendor Oxide Software for Core Design Assessment 2R11, 2R12 & 2R13 Inspection Results

- Performance as Expected 22 VERDE PAL O

3 Enrichment Lattice Design Protect High Duty First Burn Assemblies

- First Implementation in Unit 2 Cycle 12 Design Concept - Balance Power & Flow

- In-House Designed Based on APS CRUD Model

- Three Enrichments, Four Pin Types Inspection Results

- 2R12 - No CRUD

- 2R13 - Threshold CRUD 23 VERDE PAL O

Sample Lattice Comparison Previous - 64 Er New - 64 Er 4.05 w/o 4.29 w/o 3.75 w/o 3.99 w/o 3.75 w/o Er 3.79 w/o 3.79 w/o Er 24 VERDE PAL O

Comparison of Average Crud Thickness - Predicted 6.95 7

New Lattice A v e ra g e C ru d 6 Design, Current 5 Source Term T h ic k n e s s in W o rs t 4 2.58 L u m p ed Ch an n el 3

1.25 2 0.5 (m ic ro n s ) 1 0

U2C9 U3C9 U2C11 U2C12 Unit and Cycle 25 VERDE PAL O

High Burnup Fuel Performance High Burnup Fuel Failure Trend Loose Top Grid Cells Top Grid Re-Design 26 VERDE PAL O

Flawless Fuel New Agreement with Westinghouse

- Identify and Investigate All Failures

- Incentive for Flawless Fuel

- Reconstitute Failed Assemblies Sipping in Containment UT in Spent Fuel Pool 27 VERDE PAL O

High Burnup Fuel Failure Trend Mid 90s, Clean Cores Cycle After Cycle Ten Failed First Burn Pins in U2C9 One Failed End Cap Weld (U1C9)

Nine Indications Starting with U2C9 Five of Nine Cycles with 1 or 2 Indications Three Identified Grid-Rod Fretting Failures No Current Operating Failures 28 VERDE PAL O

Loose Top Grid Cells PV1P Fabrication Campaign Root Causes

- Bias in Grid Construction Tolerances

- Force-Fit of 20 mil Oversize Guide Tube

- Rod Pushing Table Mis-Alignment

- Weaknesses in Inspection/QA Process 29 VERDE PAL O

Top Grid Re-Design Zirc-4 to Inconel 625 Wavy strip to Straight Strip Cantilever Spring Cut-out Double Back-up Arch Accommodation of Expanded Guide Tube Grid to Guide Tube Attachment Change to Top Nozzle (UEF) 30 VERDE PAL O

Dry Fuel Storage Update ISFSI in Production 4 Years 47 Casks on the Pads Doses Consistently Under 50 mR Need NAC Amendment #5 12/07 31 VERDE PAL O

Planned License Submittals 32 VERDE PAL O

Planned License Submittals TS 3.1.6 Shutdown CEA Insertion Limits (2006)

TS 5.6.5 Core Operating Limits Report (Summer 2007) 10CFR50.46 Exemption for M5 (Summer 2007)

TS 2.1.1 Fuel Safety Limits (Summer 2007)

TS 4.2.2 CEA Design (Fall 2007)

Revised Inlet Flow Uncertainties (Fall 2007)

Potential CEA Ejection with RAVE Methodology (2008) 33 VERDE PAL O

Shutdown CEA Insertion Limits Current T.S. Allows Insertion to 144.75 Withdrawn Safety Analysis Only Covers Insertion to 147.75

- Sufficient Additional Shutdown Margin Verified

- Guide Tube Wear Program Controlled to 147.75 Shutdown Margin is Monitored per Core Data Book T.S. 3.1.6 rewritten to 147.75 withdrawn Submitted to NRC Summer 2006 (Requested 6/07) 34 VERDE PAL O

Core Operating Limits Report Inconsistent CEA Drop Reference Currently Processing Changes

- Remove CESSAR References

- Add 3990 MW Power Uprate References

- Add Topical Report of 2nd Tier References Expected Submittal Date: Summer 2007 35 VERDE PAL O

M5 Clad Exemption Fall 2008 Insertion of AREVA LFAs M5 Already in Use M5 Not Listed in 10CFR50.46 Expected Submittal Date: Summer 2007 36 VERDE PAL O

TS 2.1.1 Safety Limits Potential TS Submittal to Allow for LFAs TS 2.1.1.1 DNBR

- Allow for Alternate CHF Correlation TS 2.1.1.2 Centerline Melt Temperature

- Allow for Alternate Burnable Absorbers Potential Submittal Date: Summer 2007 37 VERDE PAL O

TS 4.2.2 CEA Design Tech Spec 4.2.2 states:

The control section for the full strength CEAs shall be boron carbide with Inconel Alloy 625 cladding Needs to include AgInCd Expected Submittal Date: Fall 2007 38 VERDE PAL O

Revised Inlet Flow Uncertainties PV DNBR Limit Allows Statistical Combination of Inlet Flow Distribution Uncertainties

- Within DNBR Limit or via Deterministic Penalties Re-Analysis of Experimental Data

- Reduced Uncertainties

- Reduced DNBR Penalties Potential Submittal Date: Fall 2007 39 VERDE PAL O

CEA Ejection with RAVE Current CEA Ejection AOR Precludes Fresh Fuel Under Lead Bank Considering RAVE Analysis

- Core Design Flexibility

- Improves Worth for Axial Control

- Margin for New Criteria Potential Submittal Date: 2008 40 VERDE PAL O