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Plutonium-238 (238 Pu or Pu-238) is a radioactive isotope of plutonium that has a half-life of 87.7 years. Plutonium-238 is a very powerful alpha emitter ; as alpha particles are easily blocked, this makes the plutonium-238 isotope suitable for usage in radioisotope thermoelectric generators (RTGs) and radioisotope heater units .
For instance, 3.6 kg of plutonium-238 undergoes the same number of radioactive decays per second as 1 tonne of plutonium-239. Since the morbidity of the two isotopes in terms of absorbed radioactivity is almost exactly the same, [ 55 ] plutonium-238 is around 275 times more toxic by weight than plutonium-239.
By 1986, the estimated cost had blown out to $3.8 billion (equivalent to $9 billion in 2023) and the reactor was still unfinished. Meanwhile, the estimated total cost of the entire project had increased from $4.1 billion in 1973 (equivalent to $10 billion in 2023) to $24 billion in 1986 (equivalent to $57 billion in 2023).
Nuclear fission splits a heavy nucleus such as uranium or plutonium into two lighter nuclei, which are called fission products. Yield refers to the fraction of a fission product produced per fission. Yield can be broken down by: Individual isotope. Chemical element spanning several isotopes of different mass number but same atomic number.
U-232 hazards, a result of its highly radioactive decay products such as thallium-208, are significant even at 5 parts per million. Implosion nuclear weapons require U-232 levels below 50 PPM (above which the U-233 is considered "low grade"; cf. "Standard weapon grade plutonium requires a Pu-240 content of no more than 6.5%."
The presence of the isotope plutonium-240 in a sample limits its nuclear bomb potential, as 240 Pu has a relatively high spontaneous fission rate (~440 fissions per second per gram; over 1,000 neutrons per second per gram), [20] raising the background neutron levels and thus increasing the risk of predetonation. [21]
Assembly of the core of Experimental Breeder Reactor I in Idaho, United States, 1951. A breeder reactor is a nuclear reactor that generates more fissile material than it consumes. [ 1 ] These reactors can be fueled with more-commonly available isotopes of uranium and thorium, such as uranium-238 and thorium-232, as opposed to the rare uranium ...
Authors Krey and Hardy estimated the total quantity of plutonium contamination outside of Rocky Flats's boundaries to be 2.6 Ci (36 grams or 1.3 ounces), [53] while Poet and Martell estimated the value to be 6.6 Ci (92 grams or 3.2 ounces). The study also noted that plutonium levels just outside the boundaries of the plant were hundreds of ...