Английская Википедия:Fission product yield

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Шаблон:Short description Шаблон:Main

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:

  1. Individual isotope
  2. Chemical element spanning several isotopes of different mass number but same atomic number.
  3. 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 (delayed neutrons), 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 (less than a millionth as much as common fission products) 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 0.2–0.4% of fissions, also produces a third light nucleus such as helium-4 (90%) or tritium (7%).

Mass vs. yield curve

Файл:ThermalFissionYield.svg
Fission product yields by mass for thermal neutron fission of U-235, Pu-239, a combination of the two typical of current nuclear power reactors, and U-233 used in the thorium fuel cycle

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,[1] as nuclei closer to magic numbers are more stable.[2]

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 (time after fission).

Файл:Fission yield volatile 2.png
Yield vs Z. Colors indicate fluoride volatility, 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 100,1,2,3 years after fission, not considering later neutron capture, fraction of 100% not 200%. Beta decay Kr-85Rb, Sr-90Zr, Ru-106Pd, Sb-125Te, Cs-137Ba, Ce-144Nd, Sm-151Eu, Eu-155Gd 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 ("Ordered by yield") gives yields for notable radioactive (with half-lives greater than one year, plus iodine-131) fission products, and (the few most absorptive) neutron poison fission products, from thermal neutron fission of U-235 (typical of nuclear power reactors), computed from [1]Шаблон:Dead link.

The yields in the table sum to only 45.5522%, including 34.8401% which have half-lives greater than one year:

t½ 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

Fission products from U-235

Yield Element Isotope Halflife Comment
6.7896% Caesium Шаблон:Hs 133Cs 134Cs Шаблон:Ntsh 2.065 y Neutron capture (29 barns) slowly converts stable 133Cs to 134Cs, which itself is low-yield because beta decay stops at 134Xe; can be further converted (140 barns) to 135Cs.
6.3333% Iodine, xenon Шаблон:Hs 135I 135Xe Шаблон:Ntsh 6.57 h Most important neutron poison; neutron capture converts 10–50% of 135Xe to 136Xe; remainder decays (9.14h) to 135Cs (2.3 My).
6.2956% Zirconium Шаблон:Hs 93Zr Шаблон:Ntsh 1.53 My Long-lived fission product also produced by neutron activation in zircalloy cladding.
6.1% Molybdenum Шаблон:Hs 99Mo Шаблон:Ntsh 65.94 h Its daughter nuclide 99mTc is important in medical diagnosing.
6.0899% Caesium Шаблон:Hs 137Cs Шаблон:Ntsh 30.17 y Source of most of the decay heat from years to decades after irradiation, together with Шаблон:Chem.
6.0507% Technetium Шаблон:Hs 99Tc Шаблон:Ntsh 211 ky Candidate for disposal by nuclear transmutation.
5.7518% Strontium Шаблон:Hs 90Sr Шаблон:Ntsh 28.9 y Source of much of the decay heat together with Шаблон:Chem on the timespan of years to decades after irradiation. Formerly used in radioisotope thermoelectric generators.
2.8336% Iodine Шаблон:Hs 131I Шаблон:Ntsh 8.02 d Reason for the use of potassium iodide tablets after nuclear accidents or nuclear bomb explosions.
2.2713% Promethium Шаблон:Hs 147Pm Шаблон:Ntsh 2.62 y beta decays to very long lived Samarium-147 (half life>age of the universe); has seen some use in radioisotope thermoelectric generators
1.0888% Samarium Шаблон:Hs 149Sm Шаблон:Ntsh Observationally stable 2nd most significant neutron poison.
0.9%[3] Iodine Шаблон:Hs 129I Шаблон:Ntsh 15.7 My Long-lived fission product. Candidate for disposal by nuclear transmutation.
0.4203% Samarium Шаблон:Hs 151Sm Шаблон:Ntsh 90 y Neutron poison; most will be converted to stable 152Sm.
0.3912% Ruthenium Шаблон:Hs 106Ru Шаблон:Ntsh 373.6 d ruthenium tetroxide is volatile and chemically aggressive; daughter nuclide Шаблон:Chem decays quickly to stable Шаблон:Chem
0.2717% Krypton Шаблон:Hs 85Kr Шаблон:Ntsh 10.78 y noble gas; has some uses in industry to detect fine cracks in materials via autoradiography
0.1629% Palladium Шаблон:Hs 107Pd Шаблон:Ntsh 6.5 My Long-lived fission product; hampers extraction of stable isotopes of platinum group metals for use due to chemical similarity.
0.0508% Selenium Шаблон:Hs 79Se Шаблон:Ntsh 327 ky
0.0330% Europium, gadolinium Шаблон:Hs 155Eu 155Gd Шаблон:Ntsh 4.76 y Both neutron poisons, most will be destroyed while fuel still in use.
0.0297% Antimony Шаблон:Hs 125Sb Шаблон:Ntsh 2.76 y
0.0236% Tin Шаблон:Hs 126Sn Шаблон:Ntsh 230 ky
0.0065% Gadolinium Шаблон:Hs 157Gd Шаблон:Ntsh stable Neutron poison.
0.0003% Cadmium Шаблон:Hs 113mCd Шаблон:Ntsh 14.1 y Neutron poison, most will be destroyed while fuel still in use.
Файл:Fission yield.png
Yields at 100,1,2,3 years after fission, probably of Pu-239 not U-235 because left hump is shifted right, not considering later neutron capture, fraction of 100% not 200%. Beta decay Kr-85Rb, Sr-90Zr, Ru-106Pd, Sb-125Te, Cs-137Ba, Ce-144Nd, Sm-151Eu, Eu-155Gd visible.

Cumulative fission yields

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

Cumulative fission yields per fission for U-235 (%)[4]
Product Thermal fission yield Fast fission yield 14-MeV fission yield
Шаблон:Nuclide 0.00171 ± 0.00018 0.00269 ± 0.00044 0.00264 ± 0.00045
Шаблон:Nuclide 0.00084 ± 0.00015 0.00082 ± 0.00012 0.00081 ± 0.00012
Шаблон:Nuclide 0.0108 ± 0.0004 0.0108 ± 0.0004 0.0174 ± 0.0036
Шаблон:Nuclide 0.0108 ± 0.0004 0.0108 ± 0.0004 0.0174 ± 0.0036
Шаблон:Nuclide 0.1702 ± 0.0049 0.17 ± 0.0049 0.1667 ± 0.0088
Шаблон:Nuclide 1.304 ± 0.012 1.309 ± 0.043 1.64 ± 0.31
Шаблон:Nuclide 0.000285 ± 0.000076 0.00044 ± 0.00016 0.038 ± 0.012
Шаблон:Nuclide 0.286 ± 0.021 0.286 ± 0.026 0.47 ± 0.1
Шаблон:Nuclide 1.303 ± 0.012 1.307 ± 0.043 1.65 ± 0.31
Шаблон:Nuclide 5.73 ± 0.13 5.22 ± 0.18 4.41 ± 0.18
Шаблон:Nuclide 6.502 ± 0.072 6.349 ± 0.083 5.07 ± 0.19
Шаблон:Nuclide 0.00000042 ± 0.00000011 2.90±0.770 × 10−8 0.00004 ± 0.000015
Шаблон:Nuclide 6.498 ± 0.072 6.345 ± 0.083 5.07 ± 0.19
Шаблон:Nuclide 0.0702 ± 0.0067 0.0686 ± 0.0071 0.0548 ± 0.0072
Шаблон:Nuclide 0 ± 0 0 ± 0 0 ± 0
Шаблон:Nuclide 8.70 × 10−10 ± 3.20 × 10−10 0 ± 0 6.20 × 10−8 ± 2.50 × 10−8
Шаблон:Nuclide 0.00042 ± 0.00015 0.000069 ± 0.000025 0.0033 ± 0.0015
Шаблон:Nuclide 6.132 ± 0.092 5.8 ± 0.13 5.02 ± 0.13
Шаблон:Nuclide 6.132 ± 0.092 5.8 ± 0.13 5.02 ± 0.13
Шаблон:Nuclide 3.103 ± 0.084 3.248 ± 0.042 3.14 ± 0.11
Шаблон:Nuclide 0.41 ± 0.011 0.469 ± 0.036 2.15 ± 0.59
Шаблон:Nuclide 0.41 ± 0.011 0.469 ± 0.036 2.15 ± 0.59
Шаблон:Nuclide 0.00106 ± 0.00011 0.0039 ± 0.00091 0.142 ± 0.023
Шаблон:Nuclide 0.000000366 ± 0.000000098 0.0000004 ± 0.00000014 0.00193 ± 0.00068
Шаблон:Nuclide 0.000089 ± 0.000021 0.000112 ± 0.000034 0.027 ± 0.01
Шаблон:Nuclide 0.026 ± 0.0014 0.067 ± 0.011 1.42 ± 0.42
Шаблон:Nuclide 4.276 ± 0.043 4.639 ± 0.065 3.85 ± 0.16
Шаблон:Nuclide 0.706 ± 0.032 1.03 ± 0.26 1.59 ± 0.18
Шаблон:Nuclide 2.878 ± 0.032 3.365 ± 0.054 4.11 ± 0.14
Шаблон:Nuclide 6.59 ± 0.11 6.61 ± 0.13 5.42 ± 0.4
Шаблон:Nuclide 6.39 ± 0.22 6.01 ± 0.18 4.8 ± 1.4
Шаблон:Nuclide 0 ± 0 0 ± 0 0.00108 ± 0.00048
Шаблон:Nuclide 0.000038 ± 0.0000098 0.000152 ± 0.000055 0.038 ± 0.014
Шаблон:Nuclide 0.0313 ± 0.003 0.0365 ± 0.0031 0.047 ± 0.0049
Шаблон:Nuclide 6.6 ± 0.11 6.61 ± 0.13 5.57 ± 0.41
Шаблон:Nuclide 0.189 ± 0.015 0.19 ± 0.015 0.281 ± 0.049
Шаблон:Nuclide 6.61 ± 0.22 6.32 ± 0.18 6.4 ± 1.8
Шаблон:Nuclide 1.22 ± 0.12 1.23 ± 0.13 2.17 ± 0.66
Шаблон:Nuclide 0.0000121 ± 0.0000032 0.0000279 ± 0.0000073 0.0132 ± 0.0035
Шаблон:Nuclide 6.221 ± 0.069 5.889 ± 0.096 5.6 ± 1.3
Шаблон:Nuclide 6.314 ± 0.095 5.959 ± 0.048 4.474 ± 0.081
Шаблон:Nuclide 6.315 ± 0.095 5.96 ± 0.048 4.508 ± 0.081
Шаблон:Nuclide 5.86 ± 0.15 5.795 ± 0.081 4.44 ± 0.2
Шаблон:Nuclide 5.474 ± 0.055 5.094 ± 0.076 3.154 ± 0.038
Шаблон:Nuclide 5.474 ± 0.055 5.094 ± 0.076 3.155 ± 0.038
Шаблон:Nuclide 6.30 × 10−9 ± 1.70 × 10−9 1.70 × 10−9 ± 4.80 × 10−10 0.0000137 ± 0.0000049
Шаблон:Nuclide 5.475 ± 0.055 5.094 ± 0.076 3.155 ± 0.038
Шаблон:Nuclide 2.232 ± 0.04 2.148 ± 0.028 1.657 ± 0.045
Шаблон:Nuclide 2.232 ± 0.04 2.148 ± 0.028 1.657 ± 0.045
Шаблон:Nuclide 5.00 × 10−8 ± 1.70 × 10−8 7.40 × 10−9 ± 2.50 × 10−9 0.0000013 ± 0.00000042
Шаблон:Nuclide 0.000000104 ± 0.000000039 1.78 × 10−8 ± 6.60 × 10−9 0.0000048 ± 0.0000018
Шаблон:Nuclide 1.053 ± 0.021 1.064 ± 0.03 0.557 ± 0.09
Шаблон:Nuclide 0.4204 ± 0.0071 0.431 ± 0.015 0.388 ± 0.061
Шаблон:Nuclide 0.000000149 ± 0.000000041 2.43 × 10−8 ± 6.80 × 10−9 0.0000058 ± 0.0000018
Шаблон:Nuclide 0.000061 ± 0.000022 0.0000201 ± 0.0000077 0.00045 ± 0.00018
Шаблон:Nuclide 0.4204 ± 0.0071 0.431 ± 0.015 0.388 ± 0.061
Шаблон:Nuclide 0.1477 ± 0.0071 0.1512 ± 0.0097 0.23 ± 0.015
Шаблон:Nuclide 0.4204 ± 0.0071 0.431 ± 0.015 0.388 ± 0.061
Шаблон:Nuclide 3.24 × 10−10 ± 8.50 × 10−11 0 ± 0 3.30 × 10−8 ± 1.10 × 10−8
Шаблон:Nuclide 0.000000195 ± 0.000000064 4.00 × 10−8 ± 1.10 × 10−8 0.0000033 ± 0.0000011
Шаблон:Nuclide 0.0308 ± 0.0013 0.044 ± 0.01 0.088 ± 0.014
Cumulative fission yield per fission for Pu-239 (%)[4]
Product Thermal fission yield Fast fission yield 14-MeV fission yield
Шаблон:Nuclide 0.00408 ± 0.00041 0.00346 ± 0.00057 -
Шаблон:Nuclide 0.00135 ± 0.00019 0.00106 ± 0.00016 -
Шаблон:Nuclide 0.0142 ± 0.0007 0.0142 ± 0.0007 -
Шаблон:Nuclide 0.0142 ± 0.0007 0.0142 ± 0.0007 -
Шаблон:Nuclide 0.2192 ± 0.009 0.219 ± 0.009 -
Шаблон:Nuclide 0.574 ± 0.026 0.617 ± 0.049 -
Шаблон:Nuclide 0.00175 ± 0.0006 0.00055 ± 0.0002 -
Шаблон:Nuclide 0.136 ± 0.014 0.138 ± 0.017 -
Шаблон:Nuclide 0.576 ± 0.026 0.617 ± 0.049 -
Шаблон:Nuclide 2.013 ± 0.054 2.031 ± 0.057 -
Шаблон:Nuclide 4.949 ± 0.099 4.682 ± 0.098 -
Шаблон:Nuclide 0.0000168 ± 0.0000045 0.00000255 ± 0.00000069 -
Шаблон:Nuclide 4.946 ± 0.099 4.68 ± 0.098 -
Шаблон:Nuclide 0.0535 ± 0.0066 0.0506 ± 0.0062 -
Шаблон:Nuclide 0 ± 0 0 ± 0 -
Шаблон:Nuclide 3.60 × 10−8 ± 1.30 × 10−8 4.80 × 10−9 ± 1.70 × 10−9 -
Шаблон:Nuclide 0.0051 ± 0.0018 0.0017 ± 0.00062 -
Шаблон:Nuclide 6.185 ± 0.056 5.82 ± 0.13 -
Шаблон:Nuclide 6.184 ± 0.056 5.82 ± 0.13 -
Шаблон:Nuclide 6.948 ± 0.083 6.59 ± 0.16 -
Шаблон:Nuclide 4.188 ± 0.092 4.13 ± 0.24 -
Шаблон:Nuclide 4.188 ± 0.092 4.13 ± 0.24 -
Шаблон:Nuclide 0.0052 ± 0.0011 0.0053 ± 0.0012 -
Шаблон:Nuclide 0.000024 ± 0.0000063 0.0000153 ± 0.000005 -
Шаблон:Nuclide 0.00228 ± 0.00049 0.00154 ± 0.00043 -
Шаблон:Nuclide 0.117 ± 0.015 0.138 ± 0.022 -
Шаблон:Nuclide 5.095 ± 0.094 4.92 ± 0.32 -
Шаблон:Nuclide 1.407 ± 0.086 1.31 ± 0.13 -
Шаблон:Nuclide 3.724 ± 0.078 4.09 ± 0.12 -
Шаблон:Nuclide 6.97 ± 0.13 6.99 ± 0.33 -
Шаблон:Nuclide 6.33 ± 0.23 6.24 ± 0.22 -
Шаблон:Nuclide 0.00000234 ± 0.00000085 0.0000025 ± 0.0000012 -
Шаблон:Nuclide 0.00166 ± 0.00056 0.00231 ± 0.00085 -
Шаблон:Nuclide 0.0405 ± 0.004 0.0444 ± 0.0044 -
Шаблон:Nuclide 6.99 ± 0.13 7.03 ± 0.33 -
Шаблон:Nuclide 0.216 ± 0.016 0.223 ± 0.021 -
Шаблон:Nuclide 7.36 ± 0.24 7.5 ± 0.23 -
Шаблон:Nuclide 1.78 ± 0.21 1.97 ± 0.25 -
Шаблон:Nuclide 0.00067 ± 0.00018 0.00115 ± 0.0003 -
Шаблон:Nuclide 6.588 ± 0.08 6.35 ± 0.12 -
Шаблон:Nuclide 5.322 ± 0.059 5.303 ± 0.074 -
Шаблон:Nuclide 5.333 ± 0.059 5.324 ± 0.075 -
Шаблон:Nuclide 5.205 ± 0.073 5.01 ± 0.16 -
Шаблон:Nuclide 3.755 ± 0.03 3.504 ± 0.053 -
Шаблон:Nuclide 3.756 ± 0.03 3.505 ± 0.053 -
Шаблон:Nuclide 0.00000145 ± 0.0000004 0.00000251 ± 0.00000072 -
Шаблон:Nuclide 3.756 ± 0.03 3.505 ± 0.053 -
Шаблон:Nuclide 2.044 ± 0.039 1.929 ± 0.046 -
Шаблон:Nuclide 2.044 ± 0.039 1.929 ± 0.046 -
Шаблон:Nuclide 0.0000056 ± 0.0000019 0.000012 ± 0.000004 -
Шаблон:Nuclide 0.0000118 ± 0.0000044 0.000029 ± 0.000011 -
Шаблон:Nuclide 1.263 ± 0.032 1.275 ± 0.056 -
Шаблон:Nuclide 0.776 ± 0.018 0.796 ± 0.037 -
Шаблон:Nuclide 0.0000168 ± 0.0000046 0.000039 ± 0.000011 -
Шаблон:Nuclide 0.00227 ± 0.00078 0.0051 ± 0.0019 -
Шаблон:Nuclide 0.776 ± 0.018 0.797 ± 0.037 -
Шаблон:Nuclide 0.38 ± 0.03 0.4 ± 0.18 -
Шаблон:Nuclide 0.776 ± 0.018 0.797 ± 0.037 -
Шаблон:Nuclide 0.000000195 ± 0.00000005 0.00000048 ± 0.00000014 -
Шаблон:Nuclide 0.000049 ± 0.000012 0.000127 ± 0.000043 -
Шаблон:Nuclide 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, Шаблон:ISBN.

Файл:Fission yield.png
Yields at 100,1,2,3 years after fission, probably of Pu-239 not U-235 because left hump is shifted right, not considering later neutron capture, fraction of 100% not 200%. Beta decay Kr-85Rb, Sr-90Zr, Ru-106Pd, Sb-125Te, Cs-137Ba, Ce-144Nd, Sm-151Eu, Eu-155Gd visible.

Ordered by mass number

Decays, even if lengthy, are given down to the stable nuclide.

Decays with half lives longer than a century are marked with a single asterisk (Шаблон:Asterisk), while decays with a half life longer than a hundred million years are marked with two asterisks (Шаблон:AsteriskШаблон:Asterisk).

Yield Isotope
0.0508% style="background:Шаблон:Element color" | selenium-79* style="background:Шаблон:Element color" | bromine-79
0.2717% style="background:Шаблон:Element color" | krypton-85 style="background:Шаблон:Element color" | rubidium-85
5.7518% style="background:Шаблон:Element color" | strontium-90 style="background:Шаблон:Element color" | yttrium-90 style="background:Шаблон:Element color" | zirconium-90
6.2956% style="background:Шаблон:Element color" | zirconium-93 * style="background:Шаблон:Element color" | niobium-93
6.0507% style="background:Шаблон:Element color" | technetium-99* style="background:Шаблон:Element color" | ruthenium-99
0.3912% style="background:Шаблон:Element color" | ruthenium-106 style="background:Шаблон:Element color" | rhodium-106 style="background:Шаблон:Element color" | palladium-106
0.1629% style="background:Шаблон:Element color" | palladium-107* style="background:Шаблон:Element color" | silver-107
0.0003% style="background:Шаблон:Element color" | cadmium-113m style="background:Шаблон:Element color" | cadmium-113** style="background:Шаблон:Element color" | indium-113
0.0297% style="background:Шаблон:Element color" | antimony-125 style="background:Шаблон:Element color" | tellurium-125m style="background:Шаблон:Element color" | tellurium-125
0.0236% style="background:Шаблон:Element color" | tin-126 * style="background:Шаблон:Element color" | antimony-126 style="background:Шаблон:Element color" | tellurium-126
0.9% style="background:Шаблон:Element color" | iodine-129* style="background:Шаблон:Element color" | xenon-129
2.8336% style="background:Шаблон:Element color" | iodine-131 style="background:Шаблон:Element color" | xenon-131
6.7896% style="background:Шаблон:Element color" | caesium-133 style="background:Шаблон:Element color" | caesium-134 style="background:Шаблон:Element color" | barium-134
6.3333% style="background:Шаблон:Element color" | iodine-135 style="background:Шаблон:Element color" | xenon-135 style="background:Шаблон:Element color" | caesium-135* style="background:Шаблон:Element color" | barium-135
6.3333% style="background:Шаблон:Element color" | iodine-135 style="background:Шаблон:Element color" | xenon-135 style="background:Шаблон:Element color" | xenon-136 (essentially stable)** style="background:Шаблон:Element color" | barium-136
6.0899% style="background:Шаблон:Element color" | caesium-137 style="background:Шаблон:Element color" | barium-137
2.2713% style="background:Шаблон:Element color" | promethium-147 style="background:Шаблон:Element color" | samarium-147* style="background:Шаблон:Element color" | neodymium-143
1.0888% style="background:Шаблон:Element color" | samarium-149
0.4203% style="background:Шаблон:Element color" | samarium-151
0.0330% style="background:Шаблон:Element color" | europium-155 style="background:Шаблон:Element color" | gadolinium-155
0.0065% style="background:Шаблон:Element color" | gadolinium-157

Half lives, decay modes, and branching fractions

Half-lives and decay branching fractions for fission products[5]
Nuclide Half-life Decay mode Branching fraction Source Notes
Шаблон:Nuclide 2.9 ± 0.06 m β 1.0 [6] Шаблон:Efn
Шаблон:Nuclide 10.752 ± 0.023 y β 1.0 [7]
Шаблон:Nuclide 4.48 ± 0.008 h IT 0.214 ± 0.005 [6]
β 0.786 ± 0.005
Шаблон:Nuclide 28.8 ± 0.07 y β 1.0 [8]
Шаблон:Nuclide 64.032 ± 0.006 d β 1.0 [8]
Шаблон:Nuclide (7.3 ± 0.9) × 106 d β 1.0 [9]
Шаблон:Nuclide 3.61 ± 0.03 d β 0.025 ± 0.001 [8] Шаблон:Efn
IT 0.975 ± 0.001
Шаблон:Nuclide 34.985 ± 0.012 d β 1.0 [9]
Шаблон:Nuclide (2.111 ± 0.012) × 105 y β 1.0 [6]
Шаблон:Nuclide 39.247 ± 0.013 d β 1.0 [9]
Шаблон:Nuclide 1.018 ± 0.005 y β 1.0 [9]
Шаблон:Nuclide 30.1 ± 0.3 s β 1.0 [9]
Шаблон:Nuclide 55 ± 5 y β 0.224 ± 0.02 [6]
IT 0.776 ± 0.02
Шаблон:Nuclide 2.7238 ± 0.0002 d EC 0.0241 ± 0.0012 [6]
β 0.9759 ± 0.0012
Шаблон:Nuclide 60.2 ± 0.03 d β 1.0 [6]
Шаблон:Nuclide 2.7584 ± 0.0006 y β 1.0 [9]
Шаблон:Nuclide (5.89 ± 0.23) × 109 d β 1.0 [9]
Шаблон:Nuclide 8.0233 ± 0.0019 d β 1.0 [7]
Шаблон:Nuclide 20.87 ± 0.08 h β 1.0 [8] Шаблон:Efn
Шаблон:Nuclide 6.57 ± 0.02 h β 1.0 [6]
Шаблон:Nuclide 11.930 ± 0.016 d IT 1.0 [7]
Шаблон:Nuclide 5.243 ± 0.001 d β 1.0 [6]
Шаблон:Nuclide 2.19 ± 0.01 d IT 1.0 [6]
Шаблон:Nuclide 9.14 ± 0.02 h β 1.0 [6]
Шаблон:Nuclide 15.29 ± 0.05 m β 0.003 ± 0.003 [6] Шаблон:Efn
IT 0.997 ± 0.003
Шаблон:Nuclide 2.063 ± 0.003 y EC 0.000003 ± 0.000001 [9] Шаблон:Efn
β 0.999997 ± 0.000001
Шаблон:Nuclide 30.05 ± 0.08 y β 1.0 [9]
Шаблон:Nuclide 12.753 ± 0.004 d β 1.0 [7]
Шаблон:Nuclide 1.67850 ± 0.00017 d β 1.0 [7]
Шаблон:Nuclide 32.508 ± 0.010 d β 1.0 [8]
Шаблон:Nuclide 285.1 ± 0.6 d β 1.0 [9]
Шаблон:Nuclide 17.28 ± 0.05 m β 1.0 [6]
Шаблон:Nuclide 10.98 ± 0.01 d β 1.0 [6]
Шаблон:Nuclide 2.6234 ± 0.0002 y β 1.0 [6]
Шаблон:Nuclide 41.29 ± 0.11 d IT 0.042 ± 0.007 [6]
β 0.958 ± 0.007
Шаблон:Nuclide 5.368 ± 0.002 d β 1.0 [6]
Шаблон:Nuclide 2.2117 ± 0.0021 d β 1.0 [6]
Шаблон:Nuclide 1.1833 ± 0.0017 d β 1.0 [6]
Шаблон:Nuclide 90 ± 6 y β 1.0 [6]
Шаблон:Nuclide 1.938 ± 0.010 d β 1.0 [9]
Шаблон:Nuclide (4.941 ± 0.007) × 103 d β 0.279 ± 0.003 [9] Шаблон:Efn
EC 0.721 ± 0.003
Шаблон:Nuclide (3.1381 ± 0.0014) × 103 d EC 0.00018 ± 0.00013 [9] Шаблон:Efn
β 0.99982 ± 0.00013
Шаблон:Nuclide 4.753 ± 0.016 y β 1.0 [9]

Шаблон:Noteslist

Ordered by thermal neutron absorption cross section

Barns Yield Isotope t½ Comment
Шаблон:Nts 6.3333% Шаблон:Hs 135I 135Xe Шаблон:Ntsh 6.57 h Most important neutron poison; neutron capture rapidly converts 135Xe to 136Xe; remainder decays (9.14 h) to 135Cs (2.3 My).
Шаблон:Nts 0.0065% Шаблон:Hs 157Gd Neutron poison, but low yield.
Шаблон:Nts 1.0888% Шаблон:Hs 149Sm 2nd most important neutron poison.
Шаблон:Nts 0.0003% Шаблон:Hs 113mCd Шаблон:Ntsh 14.1 y Most will be destroyed by neutron capture.
Шаблон:Nts 0.4203% Шаблон:Hs 151Sm Шаблон:Ntsh 90 y Most will be destroyed by neutron capture.
Шаблон:Nts
60,900
0.0330% Шаблон:Hs 155Eu 155Gd Шаблон:Ntsh 4.76 y Both neutron poisons.
Шаблон:Nts 2.2713% Шаблон:Hs 147Pm Шаблон:Ntsh 2.62 y Suitable for radioisotope thermoelectric generators with annual or semi-annual refueling.
Шаблон:Nts 2.8336% Шаблон:Hs 131I Шаблон:Ntsh 8.02 d
Шаблон:Nts
140
6.7896% Шаблон:Hs 133Cs 134Cs
2.065 y
Neutron capture converts a few percent of nonradioactive 133Cs to 134Cs, which has very low direct yield because beta decay stops at 134Xe; further capture will add to long-lived 135Cs.
Шаблон:Nts 6.0507% Шаблон:Hs 99Tc Шаблон:Ntsh 211 ky Candidate for disposal by nuclear transmutation.
Шаблон:Nts 0.6576% Шаблон:Hs 129I Шаблон:Ntsh 15.7 My Candidate for disposal by nuclear transmutation.
Шаблон:Nts 6.2956% Шаблон:Hs 93Zr Шаблон:Ntsh 1.53 My Transmutation impractical.
Шаблон:Nts 0.1629% Шаблон:Hs 107Pd Шаблон:Ntsh 6.5 My
Шаблон:Nts 0.2717% Шаблон:Hs 85Kr Шаблон:Ntsh 10.78 y
Шаблон:Nts 5.7518% Шаблон:Hs 90Sr Шаблон:Ntsh 28.9 y
Шаблон:Nts 0.3912% Шаблон:Hs 106Ru Шаблон:Ntsh 373.6 d
Шаблон:Nts 6.0899% Шаблон:Hs 137Cs Шаблон:Ntsh 30.17 y
0.0297% Шаблон:Hs 125Sb Шаблон:Ntsh 2.76 y
0.0236% Шаблон:Hs 126Sn Шаблон:Ntsh 230 ky
0.0508% Шаблон:Hs 79Se Шаблон:Ntsh 327 ky

References

  1. Шаблон:Cite web
  2. Шаблон:Cite journal
  3. Purkayastha, B. C., and G. R. Martin. "The yields of 129I in natural and in neutron-induced fission of uranium." Canadian Journal of Chemistry 34.3 (1956): 293-300.
  4. 4,0 4,1 Шаблон:Cite web
  5. Шаблон:Cite web
  6. 6,00 6,01 6,02 6,03 6,04 6,05 6,06 6,07 6,08 6,09 6,10 6,11 6,12 6,13 6,14 6,15 6,16 6,17 6,18 Evaluated Nuclear Structure Data File, http://www-nds.iaea.org/ensdf/, 26 January 2006.
  7. 7,0 7,1 7,2 7,3 7,4 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.
  8. 8,0 8,1 8,2 8,3 8,4 Laboratoire National Henri Becquerel, Recommended Data, http://www.nucleide.org/DDEP_WG/DDEPdata.htm, 16 January 2006.
  9. 9,00 9,01 9,02 9,03 9,04 9,05 9,06 9,07 9,08 9,09 9,10 9,11 9,12 9,13 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, Шаблон:ISBN.

External links