Nuclear Fission Product - Radioactivity Over Time

Radioactivity Over Time

Actinides Half-life Fission products
Cm Puƒ Cf Ac№ 10–22 y m is
meta		 Kr Cd₡
Uƒ Pu Cmƒ 29–90 y Cs Sr Sm₡ Sn
ƒ for
fissile		 Cfƒ Amƒ Cfƒ 140 y –
1.6 ky

No fission products
have a half-life in the
range of 91 y – 210 ky
Am Ra№ Bk
Pu Th Cm Am 5–7 ky
4n Cmƒ Cm Puƒ 8–24 ky
Npƒ Uƒ Th№ Pa№ 32–160 ky
Cm 4n+1 U№ 211–348 ky Tc ₡ can capture Sn Se
U Np Pu Cmƒ 0.37–23 My Cs₡ Zr Pd I
Pu № for
NORM		 4n+2 4n+3 80 My 6-7% 4-5% 1.25% 0.1-1% <0.05%
Th№ U№ Uƒ№ 0.7–14 Gy fission product yield

Fission products have half-lives of 90 years (Samarium-151) or less, except for seven long-lived fission products with half-lives of 211,100 years (Technetium-99) and more. Therefore the total radioactivity of fission products decreases rapidly for the first several hundred years before stabilizing at a low level that changes little for hundreds of thousands of years. This contrasts with actinides produced in the open (no nuclear reprocessing) nuclear fuel cycle, a number of which have half-lives in the missing range of about 100 to 200,000 years.

Proponents of nuclear fuel cycles which aim to consume all their actinides by fission, such as the Integral Fast Reactor and molten salt reactor, use this fact to claim that within 200 years, their wastes are no more radioactive than the original uranium ore.

Fission products emit beta radiation, while actinides primarily emit alpha radiation. Many of each also emit gamma radiation.

Read more about this topic:  Nuclear Fission Product

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