Fission product yield

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.
Nuclei of a given mass number regardless of atomic number. Known as "chain yield" because it represents a decay chain of beta decay.

Isotope and element yields will change as the fission products undergo beta decay, while chain yields do not change after completion of neutron emission by a few neutron-rich initial fission products, with half-life measured in seconds.
A few isotopes can be produced directly by fission, but not by beta decay because the would-be precursor with atomic number one greater is stable and does not decay. Chain yields do not account for these "shadowed" isotopes; however, they have very low yields because they are far less neutron-rich than the original heavy nuclei.
Yield is usually stated as percentage per fission, so that the total yield percentages sum to 200%. Less often, it is stated as percentage of all fission products, so that the percentages sum to 100%.
Ternary fission, about 0.2% to 0.4% of fissions, also produces a third light nucleus such as helium-4 or tritium.

Mass vs. yield curve

If a graph of the mass or mole yield of fission products against the atomic number of the fragments is drawn then it has two peaks, one in the area zirconium through to palladium and one at xenon through to neodymium. This is because the fission event causes the nucleus to split in an asymmetric manner, as nuclei closer to magic numbers are more stable.
Yield vs. Z - This is a typical distribution for the fission of uranium. Note that in the calculations used to make this graph the activation of fission products was ignored and the fission was assumed to occur in a single moment rather than a length of time. In this bar chart results are shown for different cooling times.
, which is important in nuclear reprocessing: Blue elements have volatile fluorides or are already volatile; green elements do not but have volatile chlorides; red elements have neither, but the elements themselves are volatile at very high temperatures. Yields at 10^0,1,2,3 years after fission, not considering later neutron capture, fraction of 100% not 200%. Beta decay Kr-85→Rb, Sr-90→Zr, Ru-106→Pd, Sb-125→Te, Cs-137→Ba, Ce-144→Nd, Sm-151→Eu, Eu-155→Gd visible.
Because of the stability of nuclei with even numbers of protons and/or neutrons the curve of yield against element is not a smooth curve. It tends to alternate.
In general, the higher the energy of the state that undergoes nuclear fission, the more likely a symmetric fission is, hence as the neutron energy increases and/or the energy of the fissile atom increases, the valley between the two peaks becomes more shallow; for instance, the curve of yield against mass for Pu-239 has a more shallow valley than that observed for U-235, when the neutrons are thermal neutrons. The curves for the fission of the later actinides tend to make even more shallow valleys. In extreme cases such as ²⁵⁹Fm, only one peak is seen.
Yield is usually expressed relative to number of fissioning nuclei, not the number of fission product nuclei, that is, yields should sum to 200%.
The table in the next section gives yields for notable radioactive fission products, and neutron poison fission products, from thermal neutron fission of U-235, computed from .
The yields in the table sum to only 45.5522%, including 34.8401% which have half-lives greater than one year:

t_½ in years	yield
1 to 5	2.7252%
10 to 100	12.5340%
2 to 300,000	6.1251%
1.5 to 16 million	13.4494%

The remainder and the unlisted 54.4478% decay with half-lives less than one year into nonradioactive nuclei.
This is before accounting for the effects of any subsequent neutron capture, e.g.:

¹³⁵Xe capturing a neutron and becoming nearly stable ¹³⁶Xe, rather than decaying to ¹³⁵Cs which is radioactive with a half-life of 2.3 million years
Nonradioactive ¹³³Cs capturing a neutron and becoming ¹³⁴Cs, which is radioactive with a half-life of 2 years
Many of the fission products with mass 147 or greater such as ¹⁴⁷Pm, ¹⁴⁹Sm, ¹⁵¹Sm, and ¹⁵⁵Eu have significant cross sections for neutron capture, so that one heavy fission product atom can undergo multiple successive neutron captures.

Besides fission products, the other types of radioactive products are

plutonium containing ²³⁸Pu, ²³⁹Pu, ²⁴⁰Pu, ²⁴¹Pu, and ²⁴²Pu,
minor actinides including ²³⁷Np, ²⁴¹Am, ²⁴³Am, curium isotopes, and perhaps californium
reprocessed uranium containing ²³⁶U and other isotopes
tritium
activation products of neutron capture by the reactor or bomb structure or the environment
Ordered by yield (thermal neutron fission of U-235)

Cumulative Fission Yields

Cumulative fission yields give the amounts of nuclides produced either directly in the fission or by decay of other nuclides.

Product	Thermal Fission Yield	Fast Fission Yield	14-MeV Fission Yield
	0.00171 ± 0.00018	0.00269 ± 0.00044	0.00264 ± 0.00045
	0.00084 ± 0.00015	0.00082 ± 0.00012	0.00081 ± 0.00012
	0.0108 ± 0.0004	0.0108 ± 0.0004	0.0174 ± 0.0036
	0.0108 ± 0.0004	0.0108 ± 0.0004	0.0174 ± 0.0036
	0.1702 ± 0.0049	0.17 ± 0.0049	0.1667 ± 0.0088
	1.304 ± 0.012	1.309 ± 0.043	1.64 ± 0.31
	0.000285 ± 0.000076	0.00044 ± 0.00016	0.038 ± 0.012
	0.286 ± 0.021	0.286 ± 0.026	0.47 ± 0.1
	1.303 ± 0.012	1.307 ± 0.043	1.65 ± 0.31
	5.73 ± 0.13	5.22 ± 0.18	4.41 ± 0.18
	6.502 ± 0.072	6.349 ± 0.083	5.07 ± 0.19
	0.00000042 ± 0.00000011	2.90 x 10⁻⁸ ± 7.70 x 10⁻⁹	0.00004 ± 0.000015
	6.498 ± 0.072	6.345 ± 0.083	5.07 ± 0.19
	0.0702 ± 0.0067	0.0686 ± 0.0071	0.0548 ± 0.0072
	0 ± 0	0 ± 0	0 ± 0
	8.70 x 10⁻¹⁰ ± 3.20 x 10⁻¹⁰	0 ± 0	6.20 x 10⁻⁸ ± 2.50 x 10⁻⁸
	0.00042 ± 0.00015	0.000069 ± 0.000025	0.0033 ± 0.0015
	6.132 ± 0.092	5.8 ± 0.13	5.02 ± 0.13
	6.132 ± 0.092	5.8 ± 0.13	5.02 ± 0.13
	3.103 ± 0.084	3.248 ± 0.042	3.14 ± 0.11
	0.41 ± 0.011	0.469 ± 0.036	2.15 ± 0.59
	0.41 ± 0.011	0.469 ± 0.036	2.15 ± 0.59
	0.00106 ± 0.00011	0.0039 ± 0.00091	0.142 ± 0.023
	0.000000366 ± 0.000000098	0.0000004 ± 0.00000014	0.00193 ± 0.00068
	0.000089 ± 0.000021	0.000112 ± 0.000034	0.027 ± 0.01
	0.026 ± 0.0014	0.067 ± 0.011	1.42 ± 0.42
	4.276 ± 0.043	4.639 ± 0.065	3.85 ± 0.16
	0.706 ± 0.032	1.03 ± 0.26	1.59 ± 0.18
	2.878 ± 0.032	3.365 ± 0.054	4.11 ± 0.14
	6.59 ± 0.11	6.61 ± 0.13	5.42 ± 0.4
	6.39 ± 0.22	6.01 ± 0.18	4.8 ± 1.4
	0 ± 0	0 ± 0	0.00108 ± 0.00048
	0.000038 ± 0.0000098	0.000152 ± 0.000055	0.038 ± 0.014
	0.0313 ± 0.003	0.0365 ± 0.0031	0.047 ± 0.0049
	6.6 ± 0.11	6.61 ± 0.13	5.57 ± 0.41
	0.189 ± 0.015	0.19 ± 0.015	0.281 ± 0.049
	6.61 ± 0.22	6.32 ± 0.18	6.4 ± 1.8
	1.22 ± 0.12	1.23 ± 0.13	2.17 ± 0.66
	0.0000121 ± 0.0000032	0.0000279 ± 0.0000073	0.0132 ± 0.0035
	6.221 ± 0.069	5.889 ± 0.096	5.6 ± 1.3
	6.314 ± 0.095	5.959 ± 0.048	4.474 ± 0.081
	6.315 ± 0.095	5.96 ± 0.048	4.508 ± 0.081
	5.86 ± 0.15	5.795 ± 0.081	4.44 ± 0.2
	5.474 ± 0.055	5.094 ± 0.076	3.154 ± 0.038
	5.474 ± 0.055	5.094 ± 0.076	3.155 ± 0.038
	6.30 x 10⁻⁹ ± 1.70 x 10⁻⁹	1.70 x 10⁻⁹ ± 4.80 x 10⁻¹⁰	0.0000137 ± 0.0000049
	5.475 ± 0.055	5.094 ± 0.076	3.155 ± 0.038
	2.232 ± 0.04	2.148 ± 0.028	1.657 ± 0.045
	2.232 ± 0.04	2.148 ± 0.028	1.657 ± 0.045
	5.00 x 10⁻⁸ ± 1.70 x 10⁻⁸	7.40 x 10⁻⁹ ± 2.50 x 10⁻⁹	0.0000013 ± 0.00000042
	0.000000104 ± 0.000000039	1.78 x 10⁻⁸ ± 6.60 x 10⁻⁹	0.0000048 ± 0.0000018
	1.053 ± 0.021	1.064 ± 0.03	0.557 ± 0.09
	0.4204 ± 0.0071	0.431 ± 0.015	0.388 ± 0.061
	0.000000149 ± 0.000000041	2.43 x 10⁻⁸ ± 6.80 x 10⁻⁹	0.0000058 ± 0.0000018
	0.000061 ± 0.000022	0.0000201 ± 0.0000077	0.00045 ± 0.00018
	0.4204 ± 0.0071	0.431 ± 0.015	0.388 ± 0.061
	0.1477 ± 0.0071	0.1512 ± 0.0097	0.23 ± 0.015
	0.4204 ± 0.0071	0.431 ± 0.015	0.388 ± 0.061
	3.24 x 10⁻¹⁰ ± 8.50 x 10⁻¹¹	0 ± 0	3.30 x 10⁻⁸ ± 1.10 x 10⁻⁸
	0.000000195 ± 0.000000064	4.00 x 10⁻⁸ ± 1.10 x 10⁻⁸	0.0000033 ± 0.0000011
	0.0308 ± 0.0013	0.044 ± 0.01	0.088 ± 0.014

Product	Thermal Fission Yield	Fast Fission Yield	14-MeV Fission Yield
	0.00408 ± 0.00041	0.00346 ± 0.00057	-
	0.00135 ± 0.00019	0.00106 ± 0.00016	-
	0.0142 ± 0.0007	0.0142 ± 0.0007	-
	0.0142 ± 0.0007	0.0142 ± 0.0007	-
	0.2192 ± 0.009	0.219 ± 0.009	-
	0.574 ± 0.026	0.617 ± 0.049	-
	0.00175 ± 0.0006	0.00055 ± 0.0002	-
	0.136 ± 0.014	0.138 ± 0.017	-
	0.576 ± 0.026	0.617 ± 0.049	-
	2.013 ± 0.054	2.031 ± 0.057	-
	4.949 ± 0.099	4.682 ± 0.098	-
	0.0000168 ± 0.0000045	0.00000255 ± 0.00000069	-
	4.946 ± 0.099	4.68 ± 0.098	-
	0.0535 ± 0.0066	0.0506 ± 0.0062	-
	0 ± 0	0 ± 0	-
	3.60 x 10⁻⁸ ± 1.30 x 10⁻⁸	4.80 x 10⁻⁹ ± 1.70 x 10⁻⁹	-
	0.0051 ± 0.0018	0.0017 ± 0.00062	-
	6.185 ± 0.056	5.82 ± 0.13	-
	6.184 ± 0.056	5.82 ± 0.13	-
	6.948 ± 0.083	6.59 ± 0.16	-
	4.188 ± 0.092	4.13 ± 0.24	-
	4.188 ± 0.092	4.13 ± 0.24	-
	0.0052 ± 0.0011	0.0053 ± 0.0012	-
	0.000024 ± 0.0000063	0.0000153 ± 0.000005	-
	0.00228 ± 0.00049	0.00154 ± 0.00043	-
	0.117 ± 0.015	0.138 ± 0.022	-
	5.095 ± 0.094	4.92 ± 0.32	-
	1.407 ± 0.086	1.31 ± 0.13	-
	3.724 ± 0.078	4.09 ± 0.12	-
	6.97 ± 0.13	6.99 ± 0.33	-
	6.33 ± 0.23	6.24 ± 0.22	-
	0.00000234 ± 0.00000085	0.0000025 ± 0.0000012	-
	0.00166 ± 0.00056	0.00231 ± 0.00085	-
	0.0405 ± 0.004	0.0444 ± 0.0044	-
	6.99 ± 0.13	7.03 ± 0.33	-
	0.216 ± 0.016	0.223 ± 0.021	-
	7.36 ± 0.24	7.5 ± 0.23	-
	1.78 ± 0.21	1.97 ± 0.25	-
	0.00067 ± 0.00018	0.00115 ± 0.0003	-
	6.588 ± 0.08	6.35 ± 0.12	-
	5.322 ± 0.059	5.303 ± 0.074	-
	5.333 ± 0.059	5.324 ± 0.075	-
	5.205 ± 0.073	5.01 ± 0.16	-
	3.755 ± 0.03	3.504 ± 0.053	-
	3.756 ± 0.03	3.505 ± 0.053	-
	0.00000145 ± 0.0000004	0.00000251 ± 0.00000072	-
	3.756 ± 0.03	3.505 ± 0.053	-
	2.044 ± 0.039	1.929 ± 0.046	-
	2.044 ± 0.039	1.929 ± 0.046	-
	0.0000056 ± 0.0000019	0.000012 ± 0.000004	-
	0.0000118 ± 0.0000044	0.000029 ± 0.000011	-
	1.263 ± 0.032	1.275 ± 0.056	-
	0.776 ± 0.018	0.796 ± 0.037	-
	0.0000168 ± 0.0000046	0.000039 ± 0.000011	-
	0.00227 ± 0.00078	0.0051 ± 0.0019	-
	0.776 ± 0.018	0.797 ± 0.037	-
	0.38 ± 0.03	0.4 ± 0.18	-
	0.776 ± 0.018	0.797 ± 0.037	-
	0.000000195 ± 0.00000005	0.00000048 ± 0.00000014	-
	0.000049 ± 0.000012	0.000127 ± 0.000043	-
	0.174 ± 0.03	0.171 ± 0.054	-

JEFF-3.1

Joint Evaluated Fission and Fusion File, Incident-neutron data,
http://www-nds.iaea.org/exfor/endf00.htm, 2 October 2006;
see also A. Koning, R. Forrest, M. Kellett, R. Mills, H. Henriksson,
Y. Rugama, The JEFF-3.1 Nuclear Data Library, JEFF Report 21,
OECD/NEA, Paris, France, 2006,.

not U-235 because left hump is shifted right, not considering later neutron capture, fraction of 100% not 200%. Beta decay Kr-85→Rb, Sr-90→Zr, Ru-106→Pd, Sb-125→Te, Cs-137→Ba, Ce-144→Nd, Sm-151→Eu, Eu-155→Gd visible.

Ordered by mass number

Half lives, decay modes, and branching fractions

Nuclide	Half-life	Decay mode	Branching fraction	Source	Notes
	2.9 ± 0.06 m	β⁻	1.0	ENSDF
	10.752 ± 0.023 y	β⁻	1.0	BIPM-5	-
	4.48 ± 0.008 h	IT	0.214 ± 0.005	ENSDF	-
	4.48 ± 0.008 h	β⁻	0.786 ± 0.005	ENSDF	-
	28.8 ± 0.07 y	β⁻	1.0	LNHB	-
	64.032 ± 0.006 d	β⁻	1.0	LNHB	-
	x 10⁶ d	β⁻	1.0	IAEA-CRP-XG	-
	3.61 ± 0.03 d	β⁻	0.025 ± 0.001	LNHB
	3.61 ± 0.03 d	IT	0.975 ± 0.001	LNHB
	34.985 ± 0.012 d	β⁻	1.0	IAEA-CRP-XG	-
	x 10⁵ y	β⁻	1.0	ENSDF	-
	39.247 ± 0.013 d	β⁻	1.0	IAEA-CRP-XG	-
	1.018 ± 0.005 y	β⁻	1.0	IAEA-CRP-XG	-
	30.1 ± 0.3 s	β⁻	1.0	IAEA-CRP-XG	-
	55 ± 5 y	β⁻	0.224 ± 0.02	ENSDF	-
	55 ± 5 y	IT	0.776 ± 0.02	ENSDF	-
	2.7238 ± 0.0002 d	EC	0.0241 ± 0.0012	ENSDF	-
	2.7238 ± 0.0002 d	β⁻	0.9759 ± 0.0012	ENSDF	-
	60.2 ± 0.03 d	β⁻	1.0	ENSDF	-
	2.7584 ± 0.0006 y	β⁻	1.0	IAEA-CRP-XG	-
	x 10⁹ d	β⁻	1.0	IAEA-CRP-XG	-
	8.0233 ± 0.0019 d	β⁻	1.0	BIPM-5	-
	20.87 ± 0.08 h	β⁻	1.0	LNHB
	6.57 ± 0.02 h	β⁻	1.0	ENSDF	-
	11.930 ± 0.016 d	IT	1.0	BIPM-5	-
	5.243 ± 0.001 d	β⁻	1.0	ENSDF	-
	2.19 ± 0.01 d	IT	1.0	ENSDF	-
	9.14 ± 0.02 h	β⁻	1.0	ENSDF	-
	15.29 ± 0.05 m	β⁻	0.003 ± 0.003	ENSDF
	15.29 ± 0.05 m	IT	0.997 ± 0.003	ENSDF
	2.063 ± 0.003 y	EC	0.000003 ± 0.000001	IAEA-CRP-XG
	2.063 ± 0.003 y	β⁻	0.999997 ± 0.000001	IAEA-CRP-XG
	30.05 ± 0.08 y	β⁻	1.0	IAEA-CRP-XG	-
	12.753 ± 0.004 d	β⁻	1.0	BIPM-5	-
	1.67850 ± 0.00017 d	β⁻	1.0	BIPM-5	-
	32.508 ± 0.010 d	β⁻	1.0	LNHB	-
	285.1 ± 0.6 d	β⁻	1.0	IAEA-CRP-XG	-
	17.28 ± 0.05 m	β⁻	1.0	ENSDF	-
	10.98 ± 0.01 d	β⁻	1.0	ENSDF	-
	2.6234 ± 0.0002 y	β⁻	1.0	ENSDF	-
	41.29 ± 0.11 d	IT	0.042 ± 0.007	ENSDF	-
	41.29 ± 0.11 d	β⁻	0.958 ± 0.007	ENSDF	-
	5.368 ± 0.002 d	β⁻	1.0	ENSDF	-
	2.2117 ± 0.0021 d	β⁻	1.0	ENSDF	-
	1.1833 ± 0.0017 d	β⁻	1.0	ENSDF	-
	90 ± 6 y	β⁻	1.0	ENSDF	-
	1.938 ± 0.010 d	β⁻	1.0	IAEA-CRP-XG	-
	x 10³ d	β⁻	0.279 ± 0.003	IAEA-CRP-XG
	x 10³ d	EC	0.721 ± 0.003	IAEA-CRP-XG
	x 10³ d	EC	0.00018 ± 0.00013	IAEA-CRP-XG
	x 10³ d	β⁻	0.99982 ± 0.00013	IAEA-CRP-XG
	4.753 ± 0.016 y	β⁻	1.0	IAEA-CRP-XG	-

BIPM-5	M.-M. Bé, V. Chisté, C. Dulieu, E. Browne, V. Chechev, N. Kuzmenko, R. Helmer, A. Nichols, E. Schönfeld, R. Dersch, Monographie BIPM-5, Table of Radionuclides, Vol. 2 - A = 151 to 242, 2004.
LNHB	Laboratoire National Henri Becquerel, Recommended Data, http://www.nucleide.org/DDEP_WG/DDEPdata.htm, 16 January 2006.
IAEA-CRP-XG	M.-M. Bé, V.P. Chechev, R. Dersch, O.A.M. Helene, R.G. Helmer, M. Herman, S. Hlavác, A. Marcinkowski, G.L. Molnár, A.L. Nichols, E. Schönfeld, V.R. Vanin, M.J. Woods, IAEA CRP "Update of X-ray and Gamma-ray Decay Data Standards for Detector Calibration and Other Applications", IAEA Scientific and Technical Information report STI/PUB/1287, May 2007, International Atomic Energy Agency, Vienna, Austria,.
ENSDF	Evaluated Nuclear Structure Data File, http://www-nds.iaea.org/ensdf/, 26 January 2006.

β- decay branches of 0.9982 ± 0.0002 to Kr-85m and 0.0018 ± 0.0002 to Kr-85.

ENSDF branching fractions: 0.944 ± 0.007 for IT and 0.056 ± 0.007 for β-.

β- decay branch of 0.0288 ± 0.0002 to Xe-133m.

Branching fractions were averaged from ENSDF database.

Branching fractions were adopted from ENSDF database.

Branching fractions were adopted from LNHB data.

Ordered by thermal neutron neutron absorption cross section

Popular movies

The Hunger Games (film) - 2012 American dystopian action thriller science fiction-adventure film directed by Gary Ross and based on Suzanne Collins’s 2008 novel of the same name. It is the first insta...
untitled Captain Marvel sequel - part of Marvel Cinematic Universe....
Killers of the Flower Moon (film project) - Killers of the Flower Moon - film project in United States of America. It was presented as drama, detective fiction, thriller. The film project starred Leonardo Dicaprio, Robert De Niro. Director of...
Five Nights at Freddy's (film) - Five Nights at Freddy's - film published in 2017 in United States of America. Scenarist of the film - Scott Cawthon....

Popular books

Book of Revelation - The Book of Revelation is the final book of the New Testament, and consequently is also the final book of the Christian Bible. Its title is derived from the first word of the Koine Greek text: apok...
Book of Genesis - account of the creation of the world, the early history of humanity, Israel's ancestors and the origins...
Gospel of Matthew - The Gospel According to Matthew is the first book of the New Testament and one of the three synoptic gospels. It tells how Israel's Messiah, rejected and executed in Israel, pronounces judgement on ...
Michelin Guide - Michelin Guides are a series of guide books published by the French tyre company Michelin for more than a century. The term normally refers to the annually published Michelin Red Guide , the oldest...
Psalms - The Book of Psalms , commonly referred to simply as Psalms , the Psalter or "the Psalms", is the first book of the Ketuvim , the third section of the Hebrew Bible, and thus a book of th...
Ecclesiastes - Ecclesiastes is one of 24 books of the Tanakh , where it is classified as one of the Ketuvim . Originally written c. 450–200 BCE, it is also among the canonical Wisdom literature of the Old Tes...
The 48 Laws of Power - non-fiction book by American author Robert Greene. The book...

Popular television series

The Crown (TV series) - historical drama web television series about the reign of Queen Elizabeth II, created and principally written by Peter Morgan, and produced by Left Bank Pictures and Sony Pictures Tel...
Friends - American sitcom television series, created by David Crane and Marta Kauffman, which aired on NBC from September 22, 1994, to May 6, 2004, lasting ten seasons. With an ensemble cast sta...
Young Sheldon - spin-off prequel to The Big Bang Theory and begins with the character Sheldon...
Modern Family - American television mockumentary family sitcom created by Christopher Lloyd and Steven Levitan for the American Broadcasting Company. It ran for eleven seasons, from September 23...
Loki (TV series) - upcoming American web television miniseries created for Disney+ by Michael Waldron, based on the Marvel Comics character of the same name. It is set in the Marvel Cinematic Universe, shar...
Game of Thrones - American fantasy drama television series created by David Benioff and D. B. Weiss for HBO. It...
Shameless (American TV series) - American comedy-drama television series developed by John Wells which debuted on Showtime on January 9, 2011. It...