neptunium


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neptunium

 (Np) [nep-too´ne-um]
a chemical element, atomic number 93, atomic weight 237. (See Appendix 6.)

nep·tu·ni·um (Np),

(nep-tū'nē-ŭm),
A radioactive element; atomic no. 93; first element of the transuranian series (not found in nature); 237Np has a half-life of 2.14 × 106 years.
[planet, Neptune]

nep·tu·ni·um

(nep-tū'nē-ŭm)
A radioactive element; atomic no. 93; first element of the transuranian series (not found in nature); 237Np has a half-life of 2.14 × 106 years.
[planet, Neptune]
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References in periodicals archive ?
Since the neptunium isotope that had been located emitted beta particles, it had to gain another unit in atomic number and produce element number 94, which was named plutonium, for the planet Pluto.
This contract is for the renovation of the pool Neptunium in Schaerbeek.
Now a team at Los Alamos (N.M.) National Laboratory has measured how much neptunium it would take to make a bomb--the element's critical mass--with far greater accuracy than ever before.
Nuclear waste, larded with plutonium, americium (more toxic than plutonium), curium, neptunium, radioactive cesium, strontium and iodine, accumulates at 435 reactors around the world.
The highly active liquid waste (HALW) containing the fission products and associated radioactive elements, such as americium, cesium, neptunium, and strontium, is cooled in storage tanks for one to two years.
In 1940 Abelson, who was helping to isolate neptunium (see above), suggested that uranium hexafluoride, with each molecule made up of one uranium atom and six fluorine atoms, was a liquid that was easily evaporated, and the vapors might then be made to pass through tubes or holes.
By selectively separating the actinides, uranium, plutonium, americium, curium and neptunium, you could decrease the time required for waste to return to the safe radiotoxicity level of naturally occurring uranium from 130,000 years to 270 years.
Only 0.2 percent of current stocks are highly radioactive, but some of the material, such as neptunium 237, can remain radioactive for more than two million years, the report noted.
This belonged to element number 61, one of the lanthanides (see 1940, Neptunium and Plutonium).