Sodium nuclear properties

The thermal and nuclear properties of sodium (it scatters neutrons without absorbing them) made it the heat exchange fluid of choice for fast-flux reactors in spite of its nasty chemical properties when exposed to air or water. The French Superphenix, a commercial-scale sodium cooled reactor, was beset with technical problems, but demonstrated that fast-flux reactors can produce electric power at the 1000 MW level. 

Sodium is unlike any other cation in its charge and radius. Thus, sodium must be followed by its own nuclear properties (18). Potassium can be replaced, in principle, by thallium(I) and cesium. Both are useful as they have suitable nuclei for NMR studies but thallium has additionally an absorption band at 214 nm which is very ligand-dependent, a readily observable fiuorescence, and a small temperature-independent paramagnetism which can cause marked shifts in the nuclear resonances of ligand nuclei. We (19) have aimed in the first instance to discover if thalhum replaces potassium eflFectively in enzymes. Table VII shows that it does. 

A Thorium-Uranium Exponential Experltnenti C. If. Skeen and W. W. Broum(AI). Because of uncertainties in the knowledge of t nuclear properties of thorium fuel and lattices containing this fuel, an experimental study was made of a thorium based fuel that is to be loaded into the Sodium Reactor Experiment (8RB) in the near future. An exponential experiment was performed with a square-celled lattice of 7-rod elements (l-in. diameter rods) spaced 9.5 in. apart in praphite. The fuel Is a Th-U-23S alloy containing 7.6% uranium by weight which is 93.13 atomic per cent U-235. The feel elements were 5 ft. long. The subcrltical lattice was placed On thd thermal column of a water boiler reactor which served as the source of neutrons for the assembly. 

Extraframework cations are needed in anionic zeolites for charge balance, and for several zeolite topologies their locations are well investigated [281, 282]. Different cations have been investigated by solid state NMR in the past with different NMR properties and different project targets. We restrict this section to a tutorial example on sodium cation motion in sodalite and cancrinite structures [283-285], 23Na has a nuclear electric quadrupole moment, and quadrupolar interaction is useful to investigate jump processes, especially when they are well defined. 

The simplest substances are the elements. They cannot be broken down into simpler constituents by chemical reactions. Ninety-two elements exist in nature although some additional ones can be created experimentally by the techniques of nuclear physics, they exist only for very short periods of time before decaying radioactively. The elements can be arranged in basic groupings based on their properties a fundamental division is into metals (e.g. iron, copper, gold, sodium) and nonmetals (e.g. carbon, oxygen, hydrogen, sulfur). 

Some efforts have been made to design nuclear reactors in which liquid metals are used as heat transfer agents. Liquid sodium is the metal most often suggested. Liquid sodium has many attractive properties as a heat transfer agent, but it has one serious drawback. It reacts violently with water and great care must be taken, therefore, to make sure that the two materials do not come into contact with each other. 

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