Evaluation of neutron irradiated silicon carbide and silicon carbide composites

Newsome, G.A.; Snead, Lance Lewis; Hinoki, Tatsuya; Katoh, Yutai; Peters, D. L.

doi:10.1016/j.jnucmat.2007.05.007

Cited by 140 publications

(53 citation statements)

References 43 publications

(66 reference statements)

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“…More recent results have confirmed the excellent stability of SiC/SiC composites [21]. As shown in Figure 4.6-2, irradiation at 800 ºC resulted in about 0.6% volumetric swelling, with saturation being observed after about 1 dpa.…”

Section: Sic/sic Compositessupporting

confidence: 52%

NGNP Composites R&D Technical Issues Study

2008

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This study identifies potential applications and design requirements for ceramic materials (CMs) and ceramic composite materials (CCMs) in the NGNP high-temperature gas-cooled reactor (HTGR) primary circuit. Components anticipated for fabrication from non-graphite CMs and CCMs are identified along with recommended normal and off-normal operating conditions. The evaluation defines required dimensions and material properties of the candidate materials for normal operating conditions (NOC), anticipated transients, abnormal events, and design basis events. The report also identifies additional activities required for codifying the selected materials. The activities include ASTM Standard and ASME Code development and other work to support NRC licensing of the plant.Evaluation of the NGNP baseline design indicates components requiring either CMs or CCMs depend upon the reactor operating temperatures. For a reactor outlet temperature of 900 o C, four of the five evaluated components would benefit from either CMs or CCMs. Section 4 discusses candidate materials and Section 5 discusses a recommended development and codification process. Although some thermal and mechanical data exist for most of the candidate materials, they all need additional irradiation, thermal, and mechanical testing. Section 5.3 outlines the proposed testing program for CCMs. The recommended program will require an estimated four to six years, not including long-term tests, and cost around $80-120 million. The codification process must take into account the type of material and the geometry of components using either CMs or CCMs. The process requires close integration of the design and the research and development (R&D) program, which has already started by using preliminary control rod component designs as the basis for establishing specimen geometry and test conditions [13][14][15][16]. The remaining time and budget for completing the R&D program need further assessment.Designing the initial NGNP reactor for a lower outlet temperature (e.g., 750 o C) would reduce development risk inherent in the R&D process. Based on the 750 o C outlet temperature evaluation, the study recommends either CMs or CCMs for three of the five evaluated components: control rods, upper core restraint, and lower floor blocks. Designing for an initial lower outlet temperature could greatly reduce schedule and cost risks for the CM and CCM R&D program.

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Section: Sic/sic Compositessupporting

confidence: 52%

NGNP Composites R&D Technical Issues Study

2008

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“…For neutron irradiation the critical temperature for amorphization (i.e. just above this temperature an apparent asymptotic increase in fluence is needed to amorphize crystalline SiC) is about 150°C [49,130]. Above the critical temperature the SiC remains crystalline although point defects are created by the irradiation resulting in significant strain in the substrate.…”

Section: Amorphizationmentioning

confidence: 99%

Diffusion of fission products and radiation damage in SiC

Malherbe

2013

J. Phys. D: Appl. Phys.

104

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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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“…It is generally agreed that a-SiC, undergoes swelling under neutron irradiation, which may not be insignificant even at lower temperatures, making it unsuitable for nuclear applications. In a parallel study by Zunjarrao et al [67], it was observed that pyrolysis to 1150-1650 • C produces β-crystalline silicon carbide from AHPCS, which would be more suitable for nuclear applications [53,54,94]. Finally it should be noted that allylhydridopolycarbosilane, the precursor used in this study, is known for its ultra high purity and ability to form near-stoichiometric SiC, which are favorable attributes for nuclear applications of SiC.…”

Section: Discussionmentioning

confidence: 60%

“…Raffrey et al [49] found that high cycle efficiency and safety considerations make SiC/SiC materials attractive for use as high performance blankets with LiPb. While the irradiation stability of SiC has always been of concern, it has been established that acceptable properties are expected when the composition of silicon carbide is close to stoichiometric and the microstructure is crystalline [2,[50][51][52][53][54][55]. In a recent study, Hinoki et al found excellent high temperature irradiation resistance for high purity SiC/SiC composites irradiated up to 1600 • C [2].…”

Section: Sic-based Materials In Nuclear Applicationsmentioning

confidence: 99%

“…In a recent study, Hinoki et al found excellent high temperature irradiation resistance for high purity SiC/SiC composites irradiated up to 1600 • C [2]. Moreover, Newsome et al [54] reported insignificant degradation in mechanical properties for high purity silicon carbide after irradiation. They found that the magnitude of volumetric swelling depended on the irradiation temperature and material, and was nearly independent of the irradiation fluence.…”

Section: Sic-based Materials In Nuclear Applicationsmentioning

confidence: 99%

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Novel Processing of Unique Ceramic-Based Nuclear Materials and Fuels

Zhang¹,

Singh²

2008

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Advances in nuclear reactor technology and the use of gas-cooled fast reactors require the development of new materials that can operate at the higher temperatures expected in these systems. These include refractory alloys based on Nb, Zr, Ta, Mo, W, and Re; ceramics and composites such as those based on silicon carbide (SiC f -SiC); carbon-carbon composites; and advanced coatings. Besides the ability to handle higher expected temperatures, effective heat transfer between reactor components is necessary for improved efficiency. Improving thermal conductivity of the materials used in nuclear fuels and other temperature critical components can lower the center-line fuel temperature and thereby enhance durability and reduce the risk of premature failure.Silicon carbide (SiC) is an important ceramic, most commonly used because of its excellent properties such as high strength, high modulus, excellent creep resistance and its high temperature stability. Moreover, crystalline silicon carbide is attracting wide attention as a promising candidate for several applications in nuclear reactors owing to its high thermal conductivity, high melting temperature, good chemical stability, and resistance to swelling under heavy ion bombardment. There have been many efforts to develop SiC based composites in various forms for use in advanced energy systems. However, fabricating SiC based composites by traditional powder processing route generally requires very high temperatures for pressureless sintering. In recent years, with the development of high yield preceramic precursors, the polymer infiltration and pyrolysis (PIP) method has aroused interest for the fabrication of ceramic based materials. Polymer derived ceramic materials offer unique advantages such as ability to fabricate net shaped components, incorporate reinforcements, along with lower processing temperatures, and perhaps most importantly relatively easy control over the microstructure. The raw materials are element-organic polymers whose composition and architecture can be tailored and varied.The primary focus of this work is to use a pyrolysis-based process to fabricate a host of novel silicon carbide-metal carbide/oxide composites, and to synthesize new materials based on mixed-metal (metal/silicon) carbides that cannot be processed using conventional techniques. These mixedcarbide material systems are expected to offer improved material properties for higher-temperature applications. Our fabrication technique resulted in both amorphous and nano-grained SiC matrix composites by controlled pyrolysis of allylhydridopolycarbosilane (AHPCS), the precursor for SiC for our study, under inert argon atmosphere.Cylindrical pellets, φ25 × 25 mm, were fabricated for bulk scale characterization. These samples were analyzed in terms of density and porosity, thermal conductivity, and flexural strength under multiaxial loading conditions. The final composition in the fabricated composite was studied use Xray diffraction (XRD). This was useful in understanding the relative stabil...

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Evaluation of neutron irradiated silicon carbide and silicon carbide composites

Cited by 140 publications

References 43 publications

NGNP Composites R&D Technical Issues Study

NGNP Composites R&D Technical Issues Study

Diffusion of fission products and radiation damage in SiC

Novel Processing of Unique Ceramic-Based Nuclear Materials and Fuels

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