Three—Materials Compatibility

A compatibility chart only considers two-component mixtures. Consider also whether any interactions among three materials are hazardous e.g., one acting as a catalyst for the reaction of two others. 

The use of lithium as a solid compound, a pure melt, or a molten alloy is required for tritium breeding in at least the first generation of fusion reactors. Three fusion reactor concepts are discussed with emphasis on material selection and material compatibility with lithium. Engineering details designed to safely handle molten lithium are described for one of the example concepts. Tritium recovery from the various breeding materials is reviewed. Finally, two aspects of the use of molten Li-Pb alloys are discussed the solubility of hydrogen isotopes, and the influence of the alloy vapor on heavy ion beam propagation. 

The next sections describe three reactor studies with emphasis on the lithium-structure compatibility. HYLIFE is a liquid metal wall (LMW) ICF reactor considered here for electricity production. It has also been adapted to fissile fuel production ( 5). The Tandem Mirror Reactor (TMR) Cauldron Blanket Module is an MCF concept designed to produce hydrogen. The TMR Heat Pipe Blanket Module is designed to produce either hydrogen or electricity. All three studies emphasize materials compatibility with lithium. Tritium recovery techniques and two aspects of lead-lithium liquids are also discussed. 

Three primary materials questions will need to be answered by research to confirm the viability of using these materials for these applications. These include testing for materials compatibility with molten salt and sulfuric acid as a part of these materials compatibility studies now under way in the DOE nuclear hydrogen program, to confirm material corrosion performance, and studies of helium permeation in appropriate small test articles. 

By considering Eqs. 3.1 and 3.2, three clear requirements for SOFC anode materials can be derived. First, oxygen anion cOTiductivity is required to transport the reactant oxygen anions to the reaction site. Secmid, the anode must selectively facilitate the desired electrocatalytic oxidatimi of the fuel. Third, facile electrical conductivity is required to transport the product electrons from the reaction site to the current collector wire. These material requirements are in additirm to considerations of materials compatibility and stability during cell fabricatirm and operation, porosity in the electrode for fuel and product gas-phase diffusion, structural integrity, tolerance to impurities in the fuel and anode materials, and redox stability in case of accidental oxidation. 

This section will briefly describe the principles and problems of three of the most successful systems under development in the USA and elsewhere. The demonstration of several new practical batteries based on quite different chemistry should be recognized as a considerable achievement. Many of the problems now relate to techniques of manufacture or materials compatibility over a long period of time. In the final part, we have attempted to summarize the status of secondary batteries in the mid 1980s. 

Open-Arc Furnaces. Most of the open-arc furnaces are used in melting and refining operations for steel and iron (Fig. 1). Although most furnaces have three electrodes and operate utilizing three-phase a-c power to be compatible with power transmission systems, d-c furnaces are becoming more common. Open-arc furnaces are also used in melting operations for nonferrous metals (particularly copper), slag, refractories, and other less volatile materials. 

Tanl . Coatings for Hquid cargo tanks ate selected according to the materials that the tanks (qv) ate to contain. Tank coatings protect the cargo from contamination and must be compatible with the material carried. Epoxy systems ate most frequendy selected because they perform well with both aqueous and organic products. A carefully appHed three-coat epoxy system having a dry-film thickness of 225—300 pm can be expected to last for 12 years. 

In the formulation of PVC compounds it is not uncommon to replace some of the plasticiser with an extender, a material that is not in itself a plasticiser but which can be tolerated up to a given concentration by a polymer-true plasticiser system. These materials, such as chlorinated waxes and refinery oils, are generally of lower solubility parameter than the true plasticisers and they do not appear to interact with the polymer. However, where the solubility parameter of a mixture of plasticiser and extender is within unity of that of the polymer the mixture of three components will be compatible. It may be shown that... 

The in vitro biocompatibihty of wound dressings in regards to fibroblasts has been assessed and compared with three commercial wound dressings made of collagen, alginate and gelatin. Methylpyrrolidinone chitosan and collagen were found to be the most compatible materials [305,306],... 

In MBE grown GaAs three dominant electron traps are usually observed Ml at c - 0.17 eV, M3 at c - 0.28 eV and M4 at c - 0.45 eV. Exposure of MBE grown material to a hydrogen plasma for 30 minutes at 250°C completely passivates these three deep levels as shown in Fig. 10 (Dautremont-Smith et al., 1986). After five minute anneals at 400°C or 500°C, the passivation remains complete while the shallow donors are fully reactivated. A five minute annealing at 600°C partially restores the electrical activity of M3. Therefore the thermal stability of the neutralization of deep levels in MBE material is much higher than in other materials and is compatible with most technological treatments. 

In LC the mobile phase is a liquid and so has a density some three orders of magnitude greater than in GC. The denser mobile phase has a much greater solubilising capacity for compatible solutes, permitting higher molecular weight materials to be separated without... 

Aneuploidy, which indicates a deviation from the euploid number of chromosomes, is the term used to describe the loss or gain of specific chromosomes. Two major types of aneuploidy are observed trisomy (three copies of a specific chromosome) and monosomy (one copy of a specific chromosome). Monosomies and trisomies are usually caused by nondisjunction (the failure of the two members of the chromosome pair to disjoin or separate) during meiosis (Fig II-3-2). All autosomal monosomies are lethal, but trisomies of three different autosomes (13,18, and 21) are compatible with survival to term in at least some cases. This difference illustrates the fact that the body tolerates extra genetic material more successfiiUy than a loss of genetic material. 

---