Radioactive Waste 329Table 16-8. Long-Lived Reactor Fission Products
Isotope Type of emission Half-life Ci produced/MWt-yr
Kr-85
Sr-89
Sr-90
Y-9 1
Zr-95
Nb-95
Ru- 103
Ru- 106
Ag-111
Sn-125
Te- 127
Te- 129
Sb-125
I- 129
1-131
Xe-131
Xe-133
CS-134
CS-137
Ba-140
Ce-141
Ce-144
Pm-147
Pr-143
Nd-147
Pm-148
Eu-156
Betdgamma
Beta
Beta
Beta/garnma
Beta
Betdgamma
Beta
Beta
Beta
Beta
Beta
GaIlUIU
Beta
Beta
Beta
Beta
Betdgamma
Beta
Beta
Beta
Beta
Beta
Beta
Beta
Beta
Gamma
Beta10.6 years
53 days
29 years
58 days
65 days
35 days
40 days
1 year
7.6 days2 years
105 days
33.5 days
1.6 x lo7 years
8.3 days
12 days
5.3 days
2.1 years
30 years
13 days
33 days
13.7 days
286 days2.6 years
42 days
14 days9.4 days11 days500
23,000
2600
33,500
50,000
52,000
40,000
19,000
1300
420
200
580
3000
e200
28,000
270
56,500
2000
3600
45,000
48,000
46,000
38,000
19,000
7600
620
4800make up most of the radioactivity of mW. Table 16-8 lists the relatively long-lived
fission products from a typical reactor.
As can be seen from the Table 16-8, this mixture of fission products has a very high
specific radioactivity. Fission products are beta or gamma emitters, because they are
too small to emit alpha particles. The longest-lived fission products, Cs-137 and Sr-90,
have half-lives of 30 and 29 years, respectively. A large quantity of fission products
containing these two radionuclides could thus be a significant source of radioactivity
for 600 years.
About one fission reaction in 10,000 yields three fission fragments instead of
two; the third fragment is tritium (H-3), which has a 12.3-year half-life. Since tritium
is chemically virtually identical to hydrogen, it exchanges freely with nonradioactive