Key Differences in the Fabrication, Irradiation, and Safety Testing of U.S. and German TRISO-coated Particle Fuel and Their Implications on Fuel Performance

High temperature gas reactor technology is achieving a renaissance around the world. This technology relies on high quality production and performance of coated particle fuel. Historically, the irradiation performance of TRISO-coated gas reactor particle fuel in Germany has been superior to that in the United States. German fuel generally displayed in-pile gas release values that were three orders of magnitude lower than U.S. fuel. Thus, we have critically examined the TRISO-coated fuel fabrication processes in the U.S. and Germany and the associated irradiation database with a goal of understanding why the German fuel behaves acceptably, why the U.S. fuel has not faired as well, and what process/ production parameters impart the reliable performance to this fuel form. The postirradiation examination results are also reviewed to identify failure mechanisms that may be the cause of the poorer U.S. irradiation performance. This comparison will help determine the roles that particle fuel process/product attributes and irradiation conditions (burnup, fast neutron fluence, temperature, and degree of acceleration) have on the behavior of the fuel during irradiation and provide a more quantitative linkage between acceptable processing parameters, as-fabricated fuel properties and subsequent in-reactor performance.

[1]  John T. Maki,et al.  NP-MHTGR Fuel Development Program Results , 2002 .

[2]  W. J. Lackey,et al.  Production of Spherical UO2‐UC2 for Nuclear Fuel Applications Using Thermochemical Principles , 1982 .

[3]  Heinz Nabielek,et al.  Production of carbon monoxide during burn-up of UO2 kerneled HTR fuel particles , 1982 .

[4]  J. Rogers.  Fission Product Transport Processes in Reactor Accidents , 2020 .

[5]  L. Wolf,et al.  Fuel elements of the high temperature pebble bed reactor , 1975 .

[6]  Kazuhiro Sawa,et al.  Fission Product Release Behavior of Individual Coated Fuel Particles for High-Temperature Gas-Cooled Reactors , 2000 .

[7]  R. E. Bullock,et al.  Capsule HRB-15B postirradiation examination report , 1981 .

[8]  H. Huschka,et al.  Coated fuel particles: requirements and status of fabrication technology , 1977 .

[9]  H. Nabielek,et al.  Passive safety characteristics of fuel for a modular high-temperature reactor and fuel performance modeling under accident conditions , 1990 .

[10]  Improved gas distributor for coating high-temperature gas-cooled reactor fuel particles , 1977 .

[11]  O. M. Stansfield.  OPTICAL ANISOTROPY IN PYROLYTIC CARBON AND GRAPHITE. , 1970 .

[12]  Gregory K. Miller,et al.  Consideration of the effects on fuel particle behavior from shrinkage cracks in the inner pyrocarbon layer , 2001 .

[13]  Hans Huschka,et al.  Fuel for pebble-bed HTRs , 1984 .

[14]  Shucai Xu,et al.  Effect of deposition temperature on the properties of pyrolytic SiC , 1995 .

[15]  Nobuyuki Suzuki,et al.  Improvements in Quality of As-Manufactured Fuels for High-Temperature Gas-Cooled Reactors , 1997 .

[16]  R. Bullock.  Fission-product release during postirradiation annealing of several types of coated fuel particles , 1984 .

[17]  Hans Huschka,et al.  Status of qualification of high-temperature reactor fuel element spheres , 1985 .

[18]  Barry Marsden,et al.  Irradiation Damage in Graphite due to Fast Neutrons in Fission and Fusion Systems , 2000 .

[19]  H. Ragoss,et al.  Spherical fuel elements for advanced HTR manufacture and qualification by irradiation testing , 1990 .

[20]  R. L. Beatty,et al.  Stoichiometric Effects on Performance of High-Temperature Gas-Cooled Reactor Fuels from the U-C-O System , 1977 .

[21]  P. Allen,et al.  Nuclear Fuel Coated Particle Development in the Reactor Fuel Element Laboratories of the U.K. Atomic Energy Authority , 1977 .

[22]  H. Nabielek,et al.  High-Temperature Reactor Fuel Fission Product Release and Distribution at 1600 to 1800°C , 1991 .

[23]  Hironobu Kikuchi,et al.  Internal flaws in the silicon carbide coating of fuel particles for high-temperature gas cooled reactors , 1994 .

[24]  H. Nabielek,et al.  Long time experience with the development of HTR fuel elements in Germany , 2002 .

[25]  H. Nabielek,et al.  The Performance of High-Temperature Reactor Fuel Particles at Extreme Temperatures , 1989 .