Compatibility of interfaces and fibers for SiC-composites in fusion environments

Henager, Charles H.; Kurtz, Richard J.

doi:10.1016/j.jnucmat.2008.12.333

Cited by 3 publications

(2 citation statements)

References 53 publications

(64 reference statements)

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“…SiC and SiC-based composites have been investigated for several years as candidate structural and insulator materials for fusion energy systems [1][2][3][4][5][6][7][8][9][10]. Early SiC-based fibers for SiC-composites were found to be unstable under irradiation [11], but more mature SiC-fibers have emerged as a successful nanocrystalline SiC engineered material polymerized from high-purity polymers and e-beam crystallized [1,12]. SiC-based composites have thus emerged as a promising structural material for fusion energy systems, including first wall and breeder-blanket materials.…”

Section: Introductionmentioning

confidence: 99%

Nanocrystalline SiC and Ti3SiC2 Alloys for Reactor Materials: Annual Report

Henager¹,

Alvine

Roosendaal

et al. 2015

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A new dual-phase nanocomposite of Ti 3 SiC 2 /SiC is being synthesized using preceramic polymers, ceramic powders, and carbon nanotubes (CNTs) designed to be suitable for advanced nuclear reactors and perhaps as fuel cladding. The material is being designed to have superior fracture toughness compared to SiC, adequate thermal conductivity, and higher density than SiC/SiC composites. This annual report summarizes the progress towards this goal and reports progress in understanding certain aspects of the material behavior but some shortcomings in achieving full density or in achieving adequate incorporation of CNTs. The measured thermal conductivity is adequate and falls into an expected range based on SiC and Ti 3 SiC 2. Part of this study makes an initial assessment for Ti 3 SiC 2 as a barrier to fission product transport. Ion implantation was used to introduce fission product surrogates (Ag and Cs) and a noble metal (Au) in Ti 3 SiC 2 , SiC, and a synthesized at PNNL. The experimental results indicate that the implanted Ag in SiC is immobile up to the highest temperature (1273 K) applied in this study; in contrast, significant out-diffusion of both Ag and Au in MAX phase Ti 3 SiC 2 occurs during ion implantation at 873 K. Cs in Ti 3 SiC 2 is found to diffuse during post-irradiation annealing at 973 K, and noticeable Cs release from the sample is observed. This study may suggest caution in using Ti 3 SiC 2 as a fuel cladding material for advanced nuclear reactors operating at very high temperatures. Progress is reported in thermal conductivity modeling of SiC-based materials that is relevant to this research, as is progress in modeling the effects of CNTs on fracture strength of SiC-based materials.

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Section: Introductionmentioning

confidence: 99%

Nanocrystalline SiC and Ti3SiC2 Alloys for Reactor Materials: Annual Report

Henager¹,

Alvine

Roosendaal

et al. 2015

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“…By acting as sinks for radiation-induced point defects, the high density of interfaces in nanolayered metallic composites are postulated to reduce radiation damage (Heinisch et al 2004;Misra et al 2007;Henager et al 2009;Nozawa et al 2009). A detailed understanding of the influence of layer spacing and type of interface on damage tolerance would enable tailoring the interfaces for effective trapping and annihilation of radiation-induced defects.…”

Section: Radiation Damage Tolerance Of Nanolayered Compositesmentioning

confidence: 99%

Compact X-ray Light Source Workshop Report

Thevuthasan¹,

Evans²,

Terminello³

et al. 2012

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Executive SummaryThis report is the result of a workshop held in September 2011 that examined the utility of a compact x-ray light source (CXLS) in addressing many scientific challenges critical to advancing energy science and technology. The U.S. Department of Energy (DOE) and National Academy of Sciences (NAS) have repeatedly described the need for advanced instruments that "predict, control, and design the components of energetic processes and environmental balance," most notably in biological, chemical, environmental, and materials science. In numerous DOE and NAS reports, direct molecular-scale imaging and timedependent studies are seen as a powerful means to develop an atomistic-level understanding of scientific issues associated with current and future energy and environmental needs, including energy production and storage from both fossil-based and fossil-free sources and cleanup of government and industrial sites worldwide.One of the major enabling capabilities for meeting these needs is a high-brightness x-ray light source. The DOE report, Next-Generation Photon Sources for Grand Challenges in Science and Energy, identifies "spectroscopic and structural imaging of nano-objects (or nanoscale regions of inhomogeneous materials) with nanometer spatial resolution and ultimate spectral resolution" as one of the two aspects of energy science in which current and next-generation x-ray light sources will have the deepest and broadest impact. The report further stresses the power of direct observation in understanding transformational chemical processes. The report also discusses the importance of molecular "movies" of complex reactions that show bond breaking and reforming in natural time scales, along with the intermediate states to understand the mechanisms that govern chemical transformations. Existing accelerator-based x-ray sources have greatly extended capabilities in the time and space domain for scientific investigations in many disciplines. Despite these successes, a number of scientific challenges would benefit greatly from having an x-ray resource that has much of the attractive capability of these large machines but lends itself to operating in conjunction with other characterization tools in a correlative fashion. Such an integrated multiscale and multimodal approach could fully address the fundamental needs expressed by DOE's Office of Biological and Environmental Research (BER) in regards to understanding how genomic information is translated with confidence to redesign microbes, plants, or ecosystems (http://science.energy.gov/).Fortunately, recent advances in laser and super-cooled linear particle accelerator, or linac, technology have enabled development of a long-promised CXLS that uses inverse Compton scattering for generating x-rays. The new CXLS holds the promise of simultaneous energy tuning-from the soft to hard x-ray regime-as well as a pulsed structure closely coupled to the laser pulse duration of pico-to femtoseconds. With a projected brilliance equal to third-generation light sourc...

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Diffusion of fission products and radiation damage in SiC

Malherbe

2013

J. Phys. D: Appl. Phys.

106

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A major problem with most of the present nuclear reactors is their safety in terms of the release of radioactivity into the environment during accidents. In some of the future nuclear reactor designs, i.e. Generation IV reactors, the fuel is in the form of coated spherical particles, i.e. TRISO (acronym for Triple Coated Isotropic) particles. The main function of these coating layers is to act as diffusion barriers for radioactive fission products, thereby keeping these fission products within the fuel particles, even under accident conditions. The most important coating layer is composed of polycrystalline 3C-SiC. This paper reviews the diffusion of the important fission products (silver, caesium, iodine and strontium) in SiC. Because radiation damage can induce and enhance diffusion, the paper also briefly reviews damage created by energetic neutrons and ions at elevated temperatures, i.e. the temperatures at which the modern reactors will operate, and the annealing of the damage. The interaction between SiC and some fission products (such as Pd and I) is also briefly discussed. As shown, one of the key advantages of SiC is its radiation hardness at elevated temperatures, i.e. SiC is not amorphized by neutron or bombardment at substrate temperatures above 350°C. Based on the diffusion coefficients of the fission products considered, the review shows that at the normal operating temperatures of these new reactors (i.e. less than 950°C) the SiC coating layer is a good diffusion barrier for these fission products. However, at higher temperatures the design of the coated particles needs to be adapted, possibly by adding a thin layer of ZrC.

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Compatibility of interfaces and fibers for SiC-composites in fusion environments

Cited by 3 publications

References 53 publications

Nanocrystalline SiC and Ti<sub>3</sub>SiC<sub>2</sub> Alloys for Reactor Materials: Annual Report

Nanocrystalline SiC and Ti<sub>3</sub>SiC<sub>2</sub> Alloys for Reactor Materials: Annual Report

Compact X-ray Light Source Workshop Report

Diffusion of fission products and radiation damage in SiC

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