High Temperat ure Gas React ors The Next Generat ion ? Prof essor - PowerPoint PPT Presentation

High Temperat ure Gas React ors The Next Generat ion ? Prof essor Andrew C Kadak Massachuset t s I nst it ut e of Technology Argonne Nat ional Laborat ory J uly 14, 2004 1

Fundamentals of Technology • Use of Brayton vs. Rankine Cycle • High Temperature Helium Gas (900 C) • Direct or Indirect Cycle • Originally Used Steam Generators • Advanced Designs Use Helium w/wo HXs • High Efficiency (45% - 50%) • Microsphere Coated Particle Fuel 2

History of Gas Reactors in US • Peach Bottom (40 MWe) 1967-1974 - First Commercial (U/Thorium Cycle) - Generally Good Performance (75% CF) • Fort St. Vrain ( 330 MWe) 1979-1989 (U/Th) - Poor Performance - Mechanical Problems - Decommissioned 3

4 Fort St. Vrain

Different Types of Gas Reactors • Prismatic (Block) - General Atomics - Fuel Compacts in Graphite Blocks • Pebble Bed - German Technology - Fuel in Billiard Ball sized spheres • Direct Cycle • Indirect Cycle • Small Modular vs. Large Reactors 5

6 GT-MHR Module General Arrangement

7 GT-MHR Combines Meltdown-Proof Advanced Reactor and Gas Turbine

8 Flow through Power Conversion Vessel

TRISO Fuel Particle -- “Microsphere” Fuel Pebble (60mm) • 0.9mm diameter Matrix Graphite • ~ 11,000 in every pebble Microspheres 10 9 microspheres in core • • Fission products retained inside microsphere Microsphere (0.9mm) • TRISO acts as a pressure vessel • Reliability – Defective coatings during manufacture – ~ 1 defect in every fuel pebble 9

10 Fuel Components with Plutonium Load

11 Comparison of 450 MWt and 600 MWt Cores

PBMR Thermal Cycle Generator compressor LP Turbo- compressor HP Turbo- Reactor Sea water 7160 kPa 5267 kPa Demin OUT 802.5°C 678.6°C 8954 kPa Water Power 482.4°C 193.1 kg/sec Discharge 21°C 135°C Turbine 8663 kPa 40°C Demin to Seawater 900°C Helium outlet 33.2°C 2994 kPa 2920 kPa 495.8°C Exchanger Helium 7002 kPa Heat outlet 5616 kPa 97.7°C 31.6°C Recuperator Precooler Intercooler 1.48 m 3 /sec 18°C Helium inlet Heliu KEY 198.4 kg/sec Sea water 2942 kPa 143.8°C m IN Demin water Wate 1.26 m 3 /sec 49°C r as at Oct 2002 circ pump 12

Main Power System CBCS T/G Power output: 400MWt 165 MWe LPT Coolant: Helium Coolant pressure: 9 MPa Reactor HPT Outlet temperature: 900°C Net cycle efficiency: >41% Recuperator CCS Pre-cooler Inter-cooler 13

14 Integrated Plant Systems

Differences Between LWRS • Higher Thermal Efficiencies Possible • Helium inert gas - non corrosive • Minimizes use of water in cycle • Utilizes gas turbine technology • Lower Power Density • Less Complicated Design (No ECCS) 15

Advantages & Disadvantages Advantages Disadvantages • Higher Efficiency • Poor History in US • Lower Waste Quantity • Little Helium Turbine Experience • Higher Safety Margins • US Technology Water • High Burnup Based - 100 MWD/kg • Licensing Hurdles due to different designs 16

Advanced Nuclear Energy Plants (Generation IV) • Competitive with Natural Gas • Demonstrated Safety • Proliferation Proof • Disposable High Level Waste Form • Used Internationally to Meet CO 2 Build-Up in the Environment 17

International Activities Countries with Active HTGR Programs • China - 10 MWth Pebble Bed - 2000 critical • Japan - 40 MWth Prismatic • South Africa - 250 MWth Pebble - 2006 • Russia - 290 MWe - Pu Burner Prismatic 2007 (GA, Framatome, DOE, etc) • Netherlands - small industrial Pebble • Germany (past) - 300 MWe Pebble Operated • MIT - 250 MWth - Intermediate Heat Exch. 18

Pebble Bed Modular Reactor South Africa • 165 MWe Pebble Bed Plant - ESKOM • Direct Helium High Temperature Cycle • In Licensing Process • Schedule for construction start 2006/7 • Operation Date 2010 • Commercial Reference Plant 19

20 15 MWe Research Reactor AVR: Jülich

21 300 Mwe Demonstration Reactor THTR: Hamm-Uentrop

Modular High Temperature Gas Reactor Russia • General Atomics Design • 290 MWe - Prismatic Core • Excess Weapons Plutonium Burner • In Design Phase in Russia • Direct Cycle • Start of Construction - 2007 22

High Temperature Test Reactor Japan • 40 MWth Test Reactor • First Critical 1999 • Prismatic Core • Intermediate Heat Exchanger • Currently in Testing for Power Ascension 23

24 High Temperature Test Reactor

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High Temperature Reactor China • 10 MWth - 4 MWe Electric Pebble Bed • Under Construction • Initial Criticality Dec 2000 • Intermediate Heat Exchanger - Steam Cycle 26

27 First Criticality Dec.1, 2000 HTR- 10 China

Modular Pebble Bed Reactor MIT/INEEL • Pebble Bed Design • 120 MWe • Intermediate Heat Exchanger Helium/Helium • Similar Core Design to ESKOM • Balance of Plant Different 28

Project Objective Develop a sufficient technical and economic basis for this type of reactor plant to determine whether it can compete with natural gas and still meet safety, proliferation resistance and waste disposal concerns. 29

Modular High Temperature Pebble Bed Reactor • 110 MWe • On-line Refueling • Helium Cooled • Modules added to meet demand. • “Indirect” Cycle • No Reprocessing • 8 % Enriched Fuel • High Burnup 90,000 • Built in 2 Years MWd/MT • Factory Built • Direct Disposal of • Site Assembled HLW 30

What is a Pebble Bed Reactor ? • 360,000 pebbles in core • about 3,000 pebbles handled by FHS each day • about 350 discarded daily • one pebble discharged every 30 seconds • average pebble cycles through core 15 times • Fuel handling most maintenance-intensive part of plant 31

FUEL ELEM ENT DESIGN FOR PBM R 5mm Graphite layer Coated particles imbedded in Graphite Matrix Dia. 60mm Pyrolytic Carbon 40/1000mm Silicon Carbite Barrier Coating Fuel Sphere 35/1000 Inner Pyrolytic Carbon 40/1000mm Porous Carbon Buffer 95/1000mm Half Section Dia. 0,92mm Coated Particle Dia.0,5mm Uranium Dioxide Fuel 32

Core Neutronics • Helium-cooled, graphite moderated high-temp reactor • ~360,000 fuel balls in a cylindrical graphite core • central graphite reflector • graphite fuel balls added and removed every 30 s • recycle fuel balls up to 15 times for high burnup 33

34 MPBR Side Views

MPBR Core Cross Section A Pebble Bed Core B Pebble Deposit Points C Inner Reflector D Outer Reflector E Core Barrel F Control Rod Channels G,H Absorber Ball Channels I Pebble Circulation Channels J Helium Flow Channels K Helium Gap L Pressure Vessel 35

36 Flowpath Helium Reactor Unit

Fuel Handling & Storage System Fresh Fuel Container Damaged Graphite Return Sphere Fuel Return Container Fuel/Graphite Discrimination system Spent Fuel Tank 37

Fuel Handling System Reactor Vessel in this Area - Not shown Used Fuel Fresh Fuel Storage Storage Tanks 38

MPBR Specifications Thermal Power 250 MW Core Height 10.0 m Core Diameter 3.5 m Pressure Vessel Height 16 m Pressure Vessel Diameter 5.6 m Number of Fuel Pebbles 360,000 Microspheres/Fuel Pebble 11,000 Fuel UO 2 Fuel Pebble Diameter 60 mm Fuel Pebble enrichment 8% Uranium Mass/Fuel Pebble 7 g Coolant Helium Helium mass flow rate 120 kg/s (100% power) 520 o C/900 o C Helium entry/exit temperatures Helium pressure 80 bar Mean Power Density 3.54 MW/m 3 Number of Control Rods 6 Number of Absorber Ball Systems 18 39

Features of Current Design Thermal Power 250 MW Gross Electrical Power 132.5 MW Net Electrical Power 120.3 MW Plant Net Efficiency 48.1% (Not take into account cooling IHX and HPT. if considering, it is believed > 45%) Helium Mass flowrate 126.7 kg/s Core Outlet/Inlet T 900°C/520°C Cycle pressure ratio 2.96 Power conversion unit Three-shaft Arrangement 40

Indirect Cycle with Intermediate Helium to Helium Heat Exchanger Current Design Schematic 800 ° C 520 ° C 69.7 ° C 280 ° C 126.7kg/s 8.0MPa 7.75MPa HPT MPC2 HPC 52.8MW 26.1 MW 26.1MW Reactor core 799.2 C 6.44 MPa Intercooler 900 ° C 7.73MPa 69.7 C 4.67MPa IHX LPT LPC MPC1 52.8MW 26.1 MW 26.1MW 509.2 ° C 522.5 ° C 7.59MPa 350 ° C 7.89MPa 30 C 7.90MPa 719. ° C 125.4kg/s 2.71MPa Bypass 5.21MPa Valve Circulator Inventory control PT 136.9MW Precooler Generator 326 ° C 96.1 ° C 105.7kg/s 511.0 ° C 2.73MPa 2.75MPa 115 ° C Recuperator 1.3kg/s 69.7 ° C Cooling RPV 1.3kg/s 41

Features of Current Design Thermal Power 250 MW Gross Electrical Power 132.5 MW Net Electrical Power 120.3 MW Plant Net Efficiency 48.1% (Not take into account cooling IHX and HPT. if considering, it is believed > 45%) Helium Mass flowrate 126.7 kg/s Core Outlet/Inlet T 900°C/520°C Cycle pressure ratio 2.96 Power conversion unit Three-shaft Arrangement 42