Plutonium thermal properties

Due to the tailored properties of liquid phase sintered silicon carbide (LPSSiC) it is used as dewatering elements in the paper machinery and as rings for highly stressed gas seals. It is a price competitive alternative to silicon nitride materials and outperforms alumina and tungsten carbide materials. In addition, LPSSiC is proposed as neutral matrix in ceramic matrix composites containing plutonium to burn the world s stockpiles of military plutonium in thermal or fast reactors [278]. 

Any particular fuel cycle might employ some, or all of these features, as needed. In addition, advanced characterization techniques will help to elucidate the relationship between fuel properties and fuel performance for advanced fuels. Examples of such innovative techniques include the measurement of thermal diffusivity, porosity, density, or the oxygen potential of irradiated fuel, use of advanced techniques for measuring the diffusion coefficient of fission gases (Hocking et al. 1998), and methods to accurately determine plutonium distribution in MOX fuel. 

If the approach is used to evaluate the properties of barriers to the proliferation of nuclear materials at all stages of the fuel cycle, it is possible to show that when excessive plutonium is used for the fuel makeup of fast reactors (which are gradually being substituted for thermal reactors running on uranium), the proliferation risk in the system can be reduced considerably since the extent of uranium mining and separation activities decreases. 

The limitations of motallurgical knowledge at present lead to the conclusion that tantalum will be one of the be.st container materials for those plutonium alloys. The high-temperature strength properties and the heat-transfer properties of tantalum are excellent moreover, it is weldable. The parasitic capture cross section of tantalum would be intolerable in an epithermal or thermal power breeder reactor and, although relatively large in a fast spectrum, its effect on neutron economy in a fast reactor can be made small, if not minor, by careful design. 

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