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Np. Trace quantities are found in nature from neutron capture reactions by uranium atoms, a fact not discovered until 1951. [2] Twenty-five neptunium radioisotopes have been characterized, with the most stable being 237 Np with a half-life of 2.14 million years, 236 Np with a half-life of 154,000 years, and 235 Np with a half-life of 396.1 days.
neptunium-238: 2.117 182.9 americium-240: 2.117 182.9 lead-203: 2.16138 186.743 plutonium-247: 2.27 196 terbium-153: 2.34 202 neptunium-239: 2.356 203.6 gold-198: 2.695 232.8 fermium-253: 3.00 259 gold-199: 3.169 273.8 radium-224: 3.6319 313.80 radon-222: 3.8235 330.35 uranium-231: 4.16 359 iodine-124: 4.17 360 neptunium-234: 4.4 380 calcium-47 ...
The most important isotopes of these elements in spent nuclear fuel are neptunium-237, americium-241, americium-243, curium-242 through -248, and californium-249 through -252. Plutonium and the minor actinides will be responsible for the bulk of the radiotoxicity and heat generation of spent nuclear fuel in the long term (300 to 20,000 years in ...
It is important to note that a vast number of processes can release radioactivity into the environment, for example, the action of cosmic rays on the air is responsible for the formation of radioisotopes (such as 14 C and 32 P), the decay of 226 Ra forms 222 Rn which is a gas which can diffuse through rocks before entering buildings [6] [7] [8 ...
This page uses the meta infobox {{Infobox isotopes (meta)}} for the element isotopes infobox.. This infobox contains the table of § Main isotopes, and the § Standard atomic weight.
A trace radioisotope is a radioisotope that occurs naturally in trace amounts (i.e. extremely small). Generally speaking, trace radioisotopes have half-lives that are short in comparison with the age of the Earth, since primordial nuclides tend to occur in larger than trace amounts. Trace radioisotopes are therefore present only because they ...
The actinide series is a group of chemical elements with atomic numbers ranging from 89 to 102, [note 1] including notable elements such as uranium and plutonium.The nuclides (or isotopes) thorium-232, uranium-235, and uranium-238 occur primordially, while trace quantities of actinium, protactinium, neptunium, and plutonium exist as a result of radioactive decay and (in the case of neptunium ...
Neptunium is a chemical element; it has symbol Np and atomic number 93. A radioactive actinide metal, neptunium is the first transuranic element. It is named after Neptune, the planet beyond Uranus in the Solar System, which uranium is named after. A neptunium atom has 93 protons and 93 electrons, of which seven are valence electrons.