General | |
---|---|
Symbol | 242Pu |
Names | plutonium-242, 242Pu, Pu-242 |
Protons (Z) | 94 |
Neutrons (N) | 148 |
Nuclide data | |
Half-life (t1/2) | 375000 years |
Isotope mass | 242.059 Da |
Decay products | 238U |
Decay modes | |
Decay mode | Decay energy (MeV) |
Isotopes of plutonium Complete table of nuclides |
Actinides[1] by decay chain | Half-life range (a) |
Fission products of 235U by yield[2] | ||||||
---|---|---|---|---|---|---|---|---|
4n | 4n + 1 | 4n + 2 | 4n + 3 | 4.5–7% | 0.04–1.25% | <0.001% | ||
228Ra№ | 4–6 a | 155Euþ | ||||||
248Bk[3] | > 9 a | |||||||
244Cmƒ | 241Puƒ | 250Cf | 227Ac№ | 10–29 a | 90Sr | 85Kr | 113mCdþ | |
232Uƒ | 238Puƒ | 243Cmƒ | 29–97 a | 137Cs | 151Smþ | 121mSn | ||
249Cfƒ | 242mAmƒ | 141–351 a |
No fission products have a half-life | |||||
241Amƒ | 251Cfƒ[4] | 430–900 a | ||||||
226Ra№ | 247Bk | 1.3–1.6 ka | ||||||
240Pu | 229Th | 246Cmƒ | 243Amƒ | 4.7–7.4 ka | ||||
245Cmƒ | 250Cm | 8.3–8.5 ka | ||||||
239Puƒ | 24.1 ka | |||||||
230Th№ | 231Pa№ | 32–76 ka | ||||||
236Npƒ | 233Uƒ | 234U№ | 150–250 ka | 99Tc₡ | 126Sn | |||
248Cm | 242Pu | 327–375 ka | 79Se₡ | |||||
1.33 Ma | 135Cs₡ | |||||||
237Npƒ | 1.61–6.5 Ma | 93Zr | 107Pd | |||||
236U | 247Cmƒ | 15–24 Ma | 129I₡ | |||||
244Pu | 80 Ma |
... nor beyond 15.7 Ma[5] | ||||||
232Th№ | 238U№ | 235Uƒ№ | 0.7–14.1 Ga | |||||
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Plutonium-242 (242Pu or Pu-242) is one of the isotopes of plutonium, the second longest-lived, with a half-life of 375,000 years. The half-life of 242Pu is about 15 times that of 239Pu; so it is one-fifteenth as radioactive, and not one of the larger contributors to nuclear waste radioactivity. 242Pu's gamma ray emissions are also weaker than those of the other isotopes.[6]
It is not fissile (but it is fissionable by fast neutrons) and its neutron capture cross section is also low.