1. U.S. HTGR Activities - Status Syd Ball Oak Ridge National Laboratory – USA IAEA Workshop on HTGR Safety & Market Potential Beijing, China September 27–30, 2004

2. O AK R IDGE N ATIONAL L ABORATORY U. S. D EPARTMENT OF E NERGY 2 Gen-IV VHTR Builds Upon Near Term Gas-Cooled Reactors

3. O AK R IDGE N ATIONAL L ABORATORY U. S. D EPARTMENT OF E NERGY 3 Modular Helium Reactor (MHR) Provides A Next Generation Nuclear Plant (NGNP) Option for VHTR Based on prismatic (GT-MHR) design High temperature source for range of process heat applications High Temperature considerations -Advanced particle coatings for FP retention at elevated temperatures -Advanced fuel materials (carbides, nitrides, cermets,etc) -Fuel element design for reduced temperature drop - fuel to coolant -Control materials and design -Structural materials -Heat exchanger / recuperator materials and design Fuel compact Coating (Nb,C,..) Moderator Coolant Passage Central Cooling Channels Cooling channels in moderator Fuel compacts Coolant channels Moderator Fuel Compact Annular Cooling Channels Kernel: UO 2 /ThO 2 UCZrC Buffer: Pyro Carbon Pyro Carbon Coating Coating: SiC,ZrC,NbC

4. O AK R IDGE N ATIONAL L ABORATORY U. S. D EPARTMENT OF E NERGY 4 The PBMR in the USA  RSA: PBMR = National Strategic Project, available to the world via a demonstration plant at Koeberg, ~2010  Plans Design Certification Pre-application package to the U.S. NRC ~2006  Developing consensus standards for HTGRs on safety, materials, ISI, etc.  Formal entry in Gen-IV, the U.S. NGNP program with Westinghouse [lead], PBMR (Pty) Ltd, Sargent & Lundy, Air Products, & others

5. O AK R IDGE N ATIONAL L ABORATORY U. S. D EPARTMENT OF E NERGY 5 The GT-MHR-Pu Program Began in 1993 as a “Private” General Atomics and MINATOM Agreement  Objective: Dispose of excess weapons Pu (1 t/yr) and produce electricity, district heat for Seversk (4 modules)  Private (GA) funding was matched by MINATOM  Framatome and Fuji Electric joined later  Current U.S. Program now directed and supported by the DOE/NNSA Office of Fissile Materials Disposition.  Conceptual & Preliminary Designs completed in 1997/2002; Currently in the Final Design stage  Prime Russian Contractor: OKBM (Nizhny Novgorod)  Major program: Also provides designs and technology for commercial MHR and NGNP (~500 RF workers)

6. O AK R IDGE N ATIONAL L ABORATORY U. S. D EPARTMENT OF E NERGY 6 Coated Particle Fuel Fabrication Fuel Qualification Analysis Methods Development & Validation Coated Particle Fuel Fabrication Fuel Qualification Analysis Methods Development & Validation Fuel Performance Modeling Post Irradiation Examination & Safety Testing Fuel Supply Program Participants INEEL, ORNL, BWXT, GA AGR Program Elements Fission Product Transport & Source Term Fuel and Materials Irradiation

7. O AK R IDGE N ATIONAL L ABORATORY U. S. D EPARTMENT OF E NERGY 7 Kernels Needs are Being Met - Process will Evolve in the Future Internal Gelation Processes 1970’s1980’s2000’s TCESi-OilAir (forming media) ORNL LDRD AGR: UCO AGR: UO 2 (microwave) 10 kg 350 mm 2 kg 500  m (BWX) 3.5 kg 350  m continuous in the future batch processing

8. O AK R IDGE N ATIONAL L ABORATORY U. S. D EPARTMENT OF E NERGY 8 Attempting to Improve the Standard TRISO Coating Process * Proper tradeoff of Pyrocarbon Permeability vs. Isotropy * Possibility of isothermal coating sequence, lower SiC deposition temperature Modern I&C, automation. “push-button coating”

9. O AK R IDGE N ATIONAL L ABORATORY U. S. D EPARTMENT OF E NERGY 9 Process Modeling - Define conditions for high quality coatings - Understand scale-ups from small coaters Fluid-Bed Chemical Vapor Deposition Modeling: Hydrodynamics Heat and Mass Transfer Chemical Reactions New Computational Tools (MFIX) and Methods permit better modeling than in the past. Inlet Gas Solids Gas Contacting movie

10. O AK R IDGE N ATIONAL L ABORATORY U. S. D EPARTMENT OF E NERGY 10 Computer Modeling Provides a More Efficient Way to Improve Nuclear Fuel Coating Processes Coating at high- temperature (1300- 1500 °C) in batch spouted bed reactor Particles cycle thru deposition and annealing zones where complex chemistry occurs Challenge is to maintain optimal temperatures, species, residence times in each zone Outer Pyrolitic C Si-C Inner Pyrolitic C Amorphous C Kernel Example Simulation Results Spouted Bed Coater Detailed predictions of gas- solids mixing from MFIX CFD code Dark blue – gas Red – solid Light blue - entrained solids White arrows - solids flux Circulation cell clearly visible Adding heat & mass transfer, chemistry for complete performance Results critical to scaling from lab to production, improved process control ORNL contacts: Stuart Daw, Sreekanth Pannala, Charles Finney MFIX CFD code (http://www.mfix.org) Coated Fuel Particle 0.5-1 mm particles for gas- cooled reactors Coating traps fission products Required failure rate < 1 in 10 5 UO 2 C or SiC reactant gas Deposition Zone Annealing Zone Spout Center Wall

11. O AK R IDGE N ATIONAL L ABORATORY U. S. D EPARTMENT OF E NERGY 11 Preliminary Evaluation of High-Resolution X-ray Techniques Show Great Promise 1-2  m resolution Radiograph of 300  m diameter ZrO 2 TRISO ~5  m resolution Imaging of this quality would be adequate for non-destructive measurement of coating thickness and identifying coating defects: Can see more detail Replace destructive methods

12. O AK R IDGE N ATIONAL L ABORATORY U. S. D EPARTMENT OF E NERGY 12 Summary  “Official” U.S. Program centered around the Gen-IV’s NGNP (=MHTGR); emphasis on H 2  Nearer-term electric power plants “getting started” – MHR (prism, ~ RF designs of Pu burner) and PBMR (pebble, ~ Koeberg demo)  Smaller programs in progress for fuel & materials development; studies for safety (accident analysis) and licensing