Category Archives: Comprehensive nuclear materials

Burnable Poison Materials Property Requirements

Any burnable poison material needs to meet a num­ber of important materials property requirements if it is to be used in nuclear fuel. Such materials must be physically stable under high-temperature conditions, they must not be susceptible to corrosion in the harsh chemical environment, and they must be compatible with the other materials present in nuclear fuel, such as UO2, […]

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Nuclear Applications

Many of the properties that make graphite attractive for a particular application have been discussed above. However, the following characteristics have been ascribed to synthetic, polygranular graphite6 and are those properties that make graphite suitable for its many applications: chemical stability; corro­sion resistance (in a nonoxidizing atmosphere); non­reactive with many molten metals and salts; nontoxic; high electrical and thermal conductivity; […]

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Electrical Resistivity

Electrical resistivity of ZrCx is plotted as a function of temperature in Figure 16. Room temperature resistivity ranges from 60 to 200 pQ cm, depending on C/Zr ratio and microstructure. In an intermediate temperature range from approximately 100 to 2000 K, resistivity increases linearly with temperature.45,46,56,57 Modine et a/58 measured resistivity of single crystal ZrCx (x = 0.89, 0.93, and […]

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UO2 Pellet Production

The flow sheet for UO2 pellet production is shown in Figure 10. The UO2 pellet fabrication process con­sists of mixing the UO2 powder with additives such as binder, lubricant and pore former materials, gran­ulating to form free-flowing particles, compaction in an automatic press, heating to remove the additives, sintering in a controlled atmosphere, and grinding to a final diameter. The […]

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Plutonium distribution (MOX microstructure)

The fresh fuel plutonium concentration and distribu­tion (homogeneous or heterogeneous microstructure) and the induced variations in the local stoichiome­try are supplementary parameters for MOX fuels. The plutonium concentration decreases with burnup whereas it increases in UO2. Therefore, the differ­ences observed in fresh fuels linked to the plutonium effect can be expected to decrease with burnup, at least for homogeneous MOX […]

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B-SiC Properties23

Silicon carbide has a myriad polytypes depending on the varied stacking of closed atomic planes.23 Only CVD SiC material is inherently highly crystalline, pure, and stoichiometric, which is critical to irradia­tion stability. Much emphasis is placed on CVD SiC in this chapter, as it corresponds very closely to the matrix of CVI SiC/SiC. The reader will find further details on […]

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Summary and Outlook

As this review has illustrated, ZrC possesses a combi­nation of thermodynamic, thermal, and mechanical properties that are promising for nuclear fuel appli­cations requiring high-temperature resistance and structural integrity. However, it is also clear that more data are needed. The body of mechanical prop­erty data is limited. The degree of scatter in experi­mental data indicates that methods for fabricating dense, pure, […]

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Summary of How Properties Can Change During Irradiation

Other chapters in this volume present more details on the fundamental nature and aspects ofthe primary damage state in irradiated metals and alloys, and on the detailed effects of irradiation on mechanical properties’ behavior. This chapter simply highlights some changes in microstructure caused by fission or fusion reactor neutron irradiation, and the changes in properties that they cause in 300 […]

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