Nuclear Fuel Development Status and Prospect Sep. 30, 2014 JEON, Kyeong Lak

Great global challenges of the 21th century Ref. Richard Smalley, Energy & Nanotechnology Conf., Houston, May 3, 2003

Contents Introduction I Basic Issues in Fuel Development II Fuel Development Status in KNF III Fuel Performance IV Nuclear Fuels in Future V Closing Remarks VI

Nuclear Plant v.s. Fossil Plant I. Introduction Nuclear Plant v.s. Fossil Plant Nuclear power reactors based on the fission process are characterized in comparison with fossil plants by High energy density Radiation hazard and decay heat from fission products

Fuel Cost Portion by Electric Power Source Nuclear Fuel Cycle Elements Enrichment 44% Conversion 7% Mining & Milling 33% Fabrication 16% Highly engineered product Specifically designed for reactor type & each fuel load Licensed by the authority in the host country

Nuclear Power Plants in Korea Hanbit Site Wolsong Site Hanul Site Kori Site Seoul Daejeon KNF 1 6 12 W 14x14 (Kori 1) W 16x16 (Kori 2) W 17x17 OPR1000 11 Type In Operation Under Construction Total 4 30 CANDU 23 7 APR1400 Hanul 1, 2, 3, 4, 5, 6 Shin-Hanul 1,2 (Under Construction) Wolsong 1, 2, 3, 4 Shin-Wolsong 1, 2 (Under Construction) Kori 1, 2, 3, 4 Shin-Kori 1,2, 3,4,5,6 (Under Construction) Hanbit 1, 2, 3, 4, 5, 6 6

Construction & Operation of NPPs in Korea Construction (~10 yrs) BOP Design K-E&C (AE) NSSS Design K-E&C (SD) Core Design KNF (ICD) Equip. Mf’g DHIC Construct. (H, D, S….) Test KHNP Fuel Fab. KNF Engineering Construction & Mf’g Operation(~60 yrs) Core Design & Fuel Fab. KNF Maintenance KHNP/KPS Operation KHNP * AE: Architect Engineering SD: System Design ICD: Initial Core Design

Nuclear Fuel Production in KNF 14x14 OFA 16x16 ACE7 17x17 ACE7 16x16 PLUS7 CANDU fuel

Fuel Engineering Overview UO2 Powder Top Nozzle Core Design & Safety Analysis UO2 Pellet Spacer Grids Bottom Nozzle Cladding Tube Fuel Rod Fuel Assembly NPP Operation Support 9

Major Fields in Fuel & Core Design Safety Analysis Fuel Design Nuclear Design Nuclear Physics T/H Design T/H, Fluid Fuel Rod Design Cladding Mat’ls Ceramic FA Mech. Mechanics (Stress,Vib.,FEM,FSI..) Fluid, Thermal

II. Basic Issues in Fuel Development Development Objectives Safety : Thermal Margin DNB Margin LOCA Margin Economy : Burnup Performance High Burnup Long Cycle Reliability : Mechanical Integrity Structural Robustness, Fretting Wear, Irradiation Growth, Corrosion, etc. Debris Filtering Shipping & Handling

Development Phases Licensing In-Pile Tests Out-of-Pile Tests Component & Assembly Design Out-of-Pile Tests In-Pile Tests Licensing Detail Design Manufacturing Process Development Out-of-Pile Tests of Components & Assembly Lead Test Assembly Manufacturing LTA In-Pile Tests Licensing for Commercial Implementation Conceptual Design of Mat’l & Components Scoping tests

PWR Fuel Assembly Fuel Rods : 236 Guide Tubes : 4 Fuel Rods : 264 W type (14OFA,16ACE7,17ACE7) PLUS7(16x16) Fuel Rods : 236 Guide Tubes : 4 Instr. Tube : 1 Top Nozzle : 1 Bot. Nozzle : 1 Zirc. S/G : 9 Inconel S/G : 2 P-Grid : 1 Fuel Rods : 264 Guide Tubes : 24 Instr. Tube : 1 Top Nozzle : 1 Bot. Nozzle : 1 Zirc. S/G : 6+5 Inconel S/G : 2 P-Grid : 1

Fuel Rod Fuel Rod Pellet Cladding Tube Plenum Spring Optimization Length, Diameter Fuel Enrichment, Axial Blanket Burnable Absorber Pellet Dish & Chamfer, D/H Grain size, Densification Missing Pellet Surface, PCI/PCMI Property Degradation with Burnup Cladding Tube Corrosion, Creep, Fatigue, Irrad. growth Plenum Spring Optimization Plenum volume, Shipping & handling load End Plug Welding Defect Free & Inspection Variable Pitch Plenum Spring Axial Blanket Advanced Cladding Long Solid End Plug

Mid Grid Improve DNB & LOCA Margin & Low Pressure Drop Optimized Mixing Vane Reduce CIPS Minimize azimuthal temp. distribution Spring & Dimples Fretting Resistance Transverse Stamping Irradiation Growth Anti-Hangup & Tear Resistant Outer Strap Vertical Diagonal (Low ∆P) Conformal I - Spring

※ Vane Shape ※ Vane Pattern No Net Unbalanced Hydraulic Torque No Unbalanced Lateral Force  No Fuel Assembly Vibration Split Vane Side-supported Combined

Intermediate Flow Mixing Grid Improve DNB & LOCA Margin Dimples Fretting wear margin Transverse Stamping Irradiation Growth Important DNB margin zone Active fuel length Power distribution Coolant temp. IFM Grid Mixing vane

Guide Thimble Straight and thick thimble Prevent incomplete RCCA insertion Irradiation Growth Outer Guide tube Dashpot Tube Swaged (Dashpot) Insert Swaged v.s. MONOBLOC Swaged Type Tube-in-Tube

Top Nozzle Removable No loose parts, No screw failure Stainless Steel Casting

Bottom Nozzle Debris Filter Low Pressure Drop with Double Chamfer Stainless Steel Casting

Debris Filter GuardianTM Grid TrapperTM bottom nozzle Protective Grid with DFBN Flow Holes

Fuel Cladding Tube

Poolside Examination FA Length FA Bowing/Twist Spacer Grid Width Controller Inspection Stand X-Y-Z Inspection Table FA to be Inspected DAQ & Analysis FA Length FA Bowing/Twist Spacer Grid Width FR Length FR Diameter FR Bowing FR Oxide Layer Thickness

III. Fuel Development Status in KNF Fuel Development Strategy 고유 핵연료 확보기 (’05~’15) HIPER16, 17 Fuel X-Gen Design Code Technology Innovation Patented Tech. 3rd Gen. Fuel Technology Development (’99~’04) Improved Tech. Joint R&D with W PLUS7 & ACE7 Fuel 2nd Gen. Fuel Technology Initiative (80’s ~ 90’s) Import Proven Tech. Established Tech. 1st Gen. Fuel Fuel Import (70’s ~ 80’s) 0th Gen. Fuel

Technology Transfer from Foreign Venders 1st Generation Fuel Technology Transfer from Foreign Venders PWR Fuel Design & Manufacturing PWR Fuel Design & Mfg Technology Transfer in 1985 Started W Type Fuel Supply from 1989 Started OPR1000 Fuel Supply from 1994 Started Production of Zr Alloy Tubes from 2009 Localized PWR Fuel Components Except Enriched UF6 Feeder Materials of Grid Straps and Bars

Develop Advanced Fuel with Foreign Partner 2nd Generation Fuel Develop Advanced Fuel with Foreign Partner Joint Development Team Was Organized to Develop Design, Mfg Technology, Out-of-Pile Tests and LTA Fabrication 2nd Generation Fuel Includes PLUS7 for OPR 1000 & APR 1400 from 1999 16 and 17ACE7 for W16 and W17 Type Plants from 2001 Status LTA Developments Completed for PLUS7, 16ACE7, and 17ACE7 LTA Irradiation Completed and Hotcell Examination Ongoing PLUS7 : Region Implementation from 2006 16ACE7 : Region Implementation from 2008 17ACE7 : Region Implementation from 2009

Fuel Rod with High Burnup Capability PLUS7 Fuel Rod with High Burnup Capability Reduced Rod Bow Top Inconel Grid Removable Top Nozzle Mid-Grid(9) with Mixing Vanes GT (4) IT (1) Bottom Inconel Grid with High Burnup Capability Spacer Grid Debris Filtering Protective Grid Debris Filtering Bottom Nozzle

16 & 17ACE7 Integral Clamp Top Nozzle (ICTN) Inconel Top Grid IFMs - Reduced Rod Bow Integral Clamp Top Nozzle (ICTN) - No Potential for Loose Parts Enhanced Mid Grids - Thermal Margin - Fretting Margin Fuel Rod - High Burnup - ZIRLOTM Inconel Bottom Grid IFMs Tube-in-Tube - IRI Free Debris Filtering (DFBN, Protective Grid, Long End Cap)) - Increase Debris Filtering

Advanced Fuel Supply Advanced Fuel Project Year 99 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 PLUS7TM Fuel (OPRs & APR1400s) Detail Design Out-of-Pile Tests LTAs In-Reactor Reload Batch Loading 16ACE7TM Fuel (W16x16 Type Plant) Detail Design Out-of-Pile Tests LTAs In-Reactor Reload Batch Loading 17ACE7TM Fuel (W17x17 Type Plants) Detail Design Out-of-Pile Tests LTAs In-Reactor Reload Batch Loading The irradiation data, experiences and VOC will be feedback continuously to PLUS7, ACE7 and further development.

Develop Leading Edge Fuel Technology 3rd Generation Fuel Develop Leading Edge Fuel Technology Utilize Fuel Technologies & Operating Experiences Accumulated through the 1st and 2nd Generation Fuels 3rd Generation Fuel Includes HiPER16 for OPR 1000 & APR 1400 from 2005 HiPER17 for W17X17 Type Plants from 2008 Status Completed LTA Developments for HiPER16 & HiPER17 LTAs In-Reactor Verification 8 LTAs of HiPER16 at Hanul #6 from July 2011 4 LTAs of HiPER17 at Hanbit #2 from Nov. 2014

HiPER 16 HiPER 17 SMART Design Concept High Performance Efficiency Reliability Concepts & Components of HiPER Component / Material HANA Alloy Integrated Top Nozzle Anti Fretting Wear Grid Robust Guide Tube…

Overall Development Schedule Item Year ’05 ’06 ’07 ’08 ’09 ’10 ’11 ’12 ’13 ’14 ’15 ’16 ’17 HiPER 16 Fuel Development Component Development Test Assembly Fabrication Out-of-pile Test & Final Design LTA Fabrication In-Reactor Verification Test HiPER 17 Fuel Development Component Development Test Assembly Fabrication Out-of-pile Test & Final Design LTA Fabrication In-Reactor Verification Test SMART Fuel Development Component Development Test Assembly Fabrication Out-of-pile Test & Final Design Standard Design Approval

IV. Fuel Performance Fuel Failure Rate

PWR Fuel Failure Root Cause 2000-2007 GTRF Corrosion Duty Related Debris Fab. Unknown 2008-2013 U.S. 1995-2005 GTRF Corrosion Others Debris Fab. Unknown 2006-2013 Korea Mechanism Grid-to-Rod Fretting Corrosion Duty Related Debris Fabrication Others Unknown Ref. KHNP-EPRI fuel reliability program workshop, Korea (2013)

Fuel Failure due to Grid-to-Rod Fretting Wear

Debris induced Fuel Failure

V. Nuclear Fuels in Future TMI-2, 1979 Chernobyl, 1986 Fukushima I, 2011

Behavior of Fuel Materials B. Cheng, “Accident Tolerant Fuel Technology”, KHNP-EPRI Fuel Reliability Program Workshop, Daejeon, Sep., 2012.

Accident Tolerant Fuel Cladding Tube SiC Steel(FeCrAl), Mo,…. Coating Ref.: K.A. Terrani et. al, EHPG, Norway (2013) & J. of Nuclear Materials (2012)

Fuel pellets Microencapsulated fuels Higher density fuel (metal, nitride, silicide) Microencapsulated fuels: Fully Ceramic Microencapsulated Fuel Metal Matrix Microencapsulated Fuel Ref.: K.A. Terrani et. al, EHPG, Norway (2013) & J. of Nuclear Materials (2012)

Safe Shutdown & Cooling VI. Closing Remarks Normal Operation Transient Condition Design Basis Accident Beyond-Design Basis Accident Safe Shutdown & Cooling Accident Tolerant High Performance Zero Defect Public Acceptance?

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