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The amount of 206 Pb will increase accordingly while that of 238 U decreases; all steps in the decay chain have this same rate of 3 × 10 6 decayed particles per second per mole 238 U. Thorium-234 has a mean lifetime of 3 × 10 6 seconds, so there is equilibrium if one mole of 238 U contains 9 × 10 12 atoms of thorium-234, which is 1.5 × 10 ...
The 4n+2 chain of uranium-238 is called the "uranium series" or "radium series". Beginning with naturally occurring uranium-238, this series includes the following elements: astatine, bismuth, lead, mercury, polonium, protactinium, radium, radon, thallium, and thorium. All are present, at least transiently, in any natural uranium-containing ...
All three isotopes are radioactive (i.e., they are radioisotopes), and the most abundant and stable is uranium-238, with a half-life of 4.4683 × 10 9 years (about the age of the Earth). Uranium-238 is an alpha emitter, decaying through the 18-member uranium series into lead-206. The decay series of uranium-235 (historically called actino
The decay-chain of uranium-238, which contains radium-226 as an intermediate decay product. 226 Ra occurs in the decay chain of uranium-238 (238 U), which is the most common naturally occurring isotope of uranium. It undergoes alpha decay to radon-222, which is also radioactive; the decay chain ultimately terminates at lead-206.
Radon-222 (222 Rn, Rn-222, historically radium emanation or radon) is the most stable isotope of radon, with a half-life of approximately 3.8 days. It is transient in the decay chain of primordial uranium-238 and is the immediate decay product of radium-226.
Uranium-238 is the most stable isotope of uranium, with a half-life of about 4.463 × 10 9 years, [7] roughly the age of the Earth. Uranium-238 is predominantly an alpha emitter, decaying to thorium-234. It ultimately decays through the uranium series, which has 18 members, into lead-206. [17]
The tailings contain mainly decay products from the decay chain involving Uranium-238. [1] Uranium tailings contain over a dozen radioactive nuclides, which are the primary hazard posed by the tailings. The most important of these are thorium-230, radium-226, radon-222 (radon gas) and the daughter isotopes of radon decay, including polonium-210.
The decay chain of uranium-238 to uranium-234 and eventually lead-206 involves emission of eight alpha particles in a time (hundreds of thousands of years) short compared to the half-life of 238 U, so that a sample of 238 U in equilibrium with its decay products (as in natural uranium ore) will have eight times the alpha activity of 238 U alone ...