Radionuclides Likely to be Found in Nuclear Reactors and Spent Fuel

RadionuclideActivity in Heavy Metals of Spent Fuel
[MBq Kg-1 (Ci ton-1) 180 days post-shutdown]a
LWRbLMFBRb
Activation Products
58CoN/AN/A
60CoN/AN/A
Fission Products
90Sr3.4 x 106 (8.3 x 104)3.9 x 106 (9.5 x 104)
91Y6.2 x 106 (1.5 x 105)8.8 x 106 (2.1 x 105)
95Zr9.9 x 106 (2.4 x 105)1.9 x 107 (4.6 x 105)
99Tc590 (14)1,300 (33)
106Ru1.4 x 107 (3.5 x 105)6.6 x 107 (1.6 x 106)
129I1.3 (0.033)4.2 (0.10)
131I7.9 (0.19)19 (0.47)
134Cs9.4 x 105 (2.3 x 104)2.9 x 106 (7.0 x 105)
137Cs4.5 x 106 (1.1 x 105)1.0 x 107 (2.5 x 105)
144Ce3.2 x 107 (7.9 x 105)5.7 x 107 (1.4 x 106)
Neutron Capture Products
239Pu1.4 x 104 (330)2.6 x 105 (6,300)
240Pu2.0 x 104 (480)3.4 x 105 (8,300)
241Pu4.4 x 106 (1.1 x 105)2.9 x 107 (7.1 x 105)
241Am6,800 (170)9.5 x 105 (2.3 x 104)
aRadionuclides are those with the highest activity 180 days post-shutdown (Knief, 1992).
bLWR = light water reactor
 LMFBR = liquid metal fast-breeder reactor


Source: Management of Persons Contaminated with Radionuclides: Scientific and Technical Bases (NCRP Report No. 161, Volume II, Table 17.4, page 403), National Council on Radiation Protection and Measurements, Bethesda, MD, 2010; Reprinted with permission of the NCRP, http://NCRPpublications.org)