Search results
Results from the WOW.Com Content Network
A past paper is an examination paper from a previous year or previous years, usually used either for exam practice or for tests such as University of Oxford, [1] [2] University of Cambridge [3] College Collections. Exam candidates find past papers valuable in test preparation.
In contrast, the generic civilian Pressurized water reactor, routinely does (typical for 2015 Generation II reactor) 45 GWd/tU of burnup, resulting in the purity of Pu-239 being 50.5%, alongside a Pu-240 content of 25.2%, [5] [6] The remaining portion includes much more of the heat generating Pu-238 and Pu-241 isotopes than are to be found in ...
Plutonium-241 is a beta emitter with a half-life of 14.3 years, corresponding to a decay of about 5% of 241 Pu nuclei over a one-year period. This decay has a Q -value of 20.78 ± 0.17 keV and a mean of 5.227 ± 0.043 keV , and does not emit gamma rays . [ 1 ]
A 5 kg mass of 239 Pu contains about 12.5 × 10 24 atoms. With a half-life of 24,100 years, about 11.5 × 10 12 of its atoms decay each second by emitting a 5.157 MeV alpha particle. This amounts to 9.68 watts of power. Heat produced by the deceleration of these alpha particles makes it warm to the touch. [12] [13] 238
Plutonium-244 (244 Pu) is an isotope of plutonium that has a half-life of 81.3 million years. This is longer than any other isotope of plutonium and longer than any other known isotope of an element beyond bismuth, except for the three naturally abundant ones: uranium-235 (704 million years), uranium-238 (4.468 billion years), and thorium-232 (14.05 billion years).
The most stable are 244 Pu with a half-life of 80.8 million years; 242 Pu with a half-life of 373,300 years; and 239 Pu with a half-life of 24,110 years; and 240 Pu with a half-life of 6,560 years. This element also has eight meta states; all have half-lives of less than one second.
Lawn mower batteries typically cost between $100 and $300 and last three to five years. The average electric lawn mower, for which a battery typically costs between $100 and $300, lasts for just ...
Plutonium-242 (242 Pu or Pu-242) is the second longest-lived isotope of plutonium, with a half-life of 375,000 years. The half-life of 242 Pu is about 15 times that of 239 Pu; so it is one-fifteenth as radioactive, and not one of the larger contributors to nuclear waste radioactivity.