Interaction of Noble Metal Fission Products with Pyrolytic Silicon Carbide

Fuel particles for the High-Temperature Gas-Cooled Reactor (HTGR) contain layers of pyrolytic carbon and silicon carbide, which act as a miniature pressure vessel and form the primary fission product barrier. Of the many fission products formed during irradiation, the noble metals are of particular interest because they interact significantly with the SiC layer and their concentrations are somewhat higher in the low-enriched uranium fuels currently under consideration. To study fission product-SiC interactions, particles of UO2 or UC2 are doped with fission product elements before coating and are then held in a thermal gradient up to several thousand hours. Examination of the SiC coatings by TEM-AEM after annealing shows that silver behaves differently from the palladium group.

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Irradiation performance of pyrolytic silicon carbide coatings on fissile fuel particles

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100112130 ◽

1984 ◽

Vol 42 ◽

pp. 418-419

Author(s):

R. J. Lauf

Keyword(s):

Silicon Carbide ◽

Fission Product ◽

Fission Products ◽

Carbide Coatings ◽

Fuel Particles ◽

Irradiation Performance ◽

Sic Coatings ◽

Irradiation Behavior ◽

Kinetics Of

Fuel particles for the High Temperature Gas-Cooled Reactor (HTGR) contain a layer of pyrolytic silicon carbide to act as a miniature pressure vessel and primary fission product barrier. Optimization of the SiC coating with respect to fuel performance involves four areas of study: (a) characterization of as-deposited SiC coatings; (b) thermodynamics and kinetics of chemical reactions between SiC and fission products; (c) irradiation behavior of SiC in the absence of fission products; and (d) the combined effects of irradiation and fission product interactions. This paper reports the behavior of SiC deposited on fissile fuel particles and irradiated to fast neutron fluences typical of HTGR fuel at end-of-life.

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Irradiation behavior of pyrolytic silicon carbide

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100074288 ◽

1983 ◽

Vol 41 ◽

pp. 72-73

Author(s):

R. J. Lauf

Keyword(s):

Silicon Carbide ◽

Fission Products ◽

Thermodynamics And Kinetics ◽

Neutron Fluences ◽

Fuel Particles ◽

Sic Coatings ◽

Irradiation Behavior ◽

Kinetics Of ◽

Htgr Fuel

Fuel particles for the High-Temperature Gas-Cooled Reactor (HTGR) contain a layer of pyrolytic silicon carbide to act as a miniature pressure vessel and primary fission product barrier. Optimization of the SiC with respect to fuel performance involves four areas of study: (a) characterization of as-deposited SiC coatings; (b) thermodynamics and kinetics of chemical reactions between SiC and fission products; (c) irradiation behavior of SiC in the absence of fission products; and (d) combined effects of irradiation and fission products. This paper reports the behavior of SiC deposited on inert microspheres and irradiated to fast neutron fluences typical of HTGR fuel at end-of-life.

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Separation of Lanthanide Isotopes from Mixed Fission Product Samples

Separations ◽

10.3390/separations8070104 ◽

2021 ◽

Vol 8 (7) ◽

pp. 104

Author(s):

Leah M. Arrigo ◽

Jun Jiang ◽

Zachary S. Finch ◽

James M. Bowen ◽

Staci M. Herman ◽

...

Keyword(s):

Fission Product ◽

Fission Products ◽

Nuclear Data ◽

Product Analysis ◽

Data Production ◽

Thermal Irradiation ◽

Nuclear Events ◽

Lanthanide Separation ◽

Enriched Uranium ◽

Fission Yields

The measurement of radioactive fission products from nuclear events has important implications for nuclear data production, environmental monitoring, and nuclear forensics. In a previous paper, the authors reported the optimization of an intra-group lanthanide separation using LN extraction resin from Eichrom Technologies®, Inc. and a nitric acid gradient. In this work, the method was demonstrated for the separation and quantification of multiple short-lived fission product lanthanide isotopes from a fission product sample produced from the thermal irradiation of highly enriched uranium. The separations were performed in parallel in quadruplicate with reproducible results and high decontamination factors for 153Sm, 156Eu, and 161Tb. Based on the results obtained here, the fission yields for 144Ce, 153Sm, 156Eu, and 161Tb are consistent with published fission yields. This work demonstrates the effectiveness of the separations for the intended application of short-lived lanthanide fission product analysis requiring high decontamination factors.

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Irradiation Performance of Pyrolytic-Carbon- and Silicon-Carbide-Coated Fuel Particles

Nuclear Applications and Technology ◽

10.13182/nt70-a28686 ◽

1970 ◽

Vol 8 (5) ◽

pp. 417-431 ◽

Cited By ~ 4

Author(s):

P. E. Reagan ◽

E. L. Long ◽

J. G. Morgan ◽

J. H. Coobs

Keyword(s):

Silicon Carbide ◽

Pyrolytic Carbon ◽

Fuel Particles ◽

Irradiation Performance

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Development of High Temperature Gas-Cooled Reactor Fuel for Extended Burnup

18th International Conference on Nuclear Engineering: Volume 6 ◽

10.1115/icone18-29206 ◽

2010 ◽

Cited By ~ 1

Author(s):

Shohei Ueta ◽

Jun Aihara ◽

Masaki Honda ◽

Noboru Furihata ◽

Kazuhiro Sawa

Keyword(s):

High Temperature ◽

Coating Layer ◽

Fission Products ◽

Pyrolytic Carbon ◽

Principal Function ◽

Energy Agency ◽

Triso Fuel ◽

Coating Layers ◽

Test Reactor ◽

Fuel Particles

Current HTGRs such as the High Temperature Engineering Test Reactor (HTTR) of Japan Atomic Energy Agency (JAEA) use Tri-Isotropic (TRISO)-coated fuel particles with diameter of around 1 mm. TRISO fuel consists of a micro spherical kernel of oxide or oxycarbide fuel and coating layers of porous pyrolytic carbon (buffer), inner dense pyrolytic carbon (IPyC), silicon carbide (SiC) and outer dense pyrolytic carbon (OPyC). The principal function of these coating layers is to retain fission products within the particle. Particularly, the SiC coating layer acts as a barrier against the diffusive release of metallic fission products and provides mechanical strength for the particle [1].

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Diffusion of Silver in Single Crystalline 6H-SiC

Fourth International Topical Meeting on High Temperature Reactor Technology, Volume 2 ◽

10.1115/htr2008-58198 ◽

2008 ◽

Author(s):

T. T. Hlatshwayo ◽

N. G. van der Berg ◽

E. Friedland ◽

J. B. Malherbe ◽

P. Chakraborty

Keyword(s):

Silicon Carbide ◽

High Temperature ◽

Nuclear Reactor ◽

Fission Products ◽

Pyrolytic Carbon ◽

Reactor Safety ◽

Fission Fragments ◽

Coated Particle ◽

Nuclear Reactor Safety ◽

Fuel Elements

In a modern high-temperature nuclear reactor, safety is achieved by encapsulating the fuel elements by CVD-layers of pyrolytic carbon and silicon carbide (SiC) to prevent the fission products release. Some studies have raised doubts on the effectiveness of SiC layer as a diffusion barrier to fission fragments due to 110mAg released from the coated particle at high temperatures ranging from 1500°C to 1600°C [1].

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Out-of-reactor studies of fission product-silicon carbide interactions in HTGR fuel particles

Journal of Nuclear Materials ◽

10.1016/0022-3115(84)90166-1 ◽

1984 ◽

Vol 120 (1) ◽

pp. 6-30 ◽

Cited By ~ 31

Author(s):

R.J Lauf ◽

T.B Lindemer ◽

R.L Pearson

Keyword(s):

Silicon Carbide ◽

Fission Product ◽

Fuel Particles ◽

Htgr Fuel

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Consolidation of coated fuel particles with pyrolytic carbon or silicon carbide

Carbon ◽

10.1016/0008-6223(70)90083-7 ◽

1970 ◽

Vol 8 (3) ◽

pp. 400-401 ◽

Cited By ~ 2

Author(s):

E. Gyarmati ◽

H. Nickel

Keyword(s):

Silicon Carbide ◽

Pyrolytic Carbon ◽

Fuel Particles

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A First Principles Study of Palladium Impurities in Silicon Carbide

Advances in Science and Technology ◽

10.4028/www.scientific.net/ast.45.1969 ◽

2006 ◽

Vol 45 ◽

pp. 1969-1973 ◽

Cited By ~ 1

Author(s):

Guido Roma

Keyword(s):

Silicon Carbide ◽

First Principles ◽

Density Functional ◽

Fission Products ◽

Kinetic Properties ◽

Main Task ◽

Functional Theory ◽

And Migration ◽

Fuel Particles ◽

Fission Reactors

The main task of the silicon carbide layer in Triso-coated fuel particles for gas-cooled high temperature fission reactors is to retain fission products. It has been observed that some fission products, and in particular Pd, attack the SiC layer and are supposed to be responsible for corrosion of the material, which could facilitate fission products release. We used first principles calculations based on Density Functional Theory (DFT) in order to investigate the energetic, structural, and kinetic properties of Pd impurities inside SiC; we obtained solution and migration energies in pure SiC and discuss the thermodynamics of a few reactions that could possibly occur for Pd impurities in silicon carbide.

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