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Nuclear

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Reactor technology

Template:Nuclear technology

Types

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Components

Nuclear reactor coolant Neutron moderator

Fission products

Fission product Fission products (by element) Fission product yield Fluoride volatility

Long-lived fission products
v
t
e
Nuclide	t_1⁄2	Yield	Q^{[a 1]}	βγ
	(Ma)	(%)^{[a 2]}	(keV)
⁹⁹Tc	0.211	6.1385	294	β
¹²⁶Sn	0.23	0.1084	4050^{[a 3]}	βγ
⁷⁹Se	0.33	0.0447	151	β
¹³⁵Cs	1.33	6.9110^{[a 4]}	269	β
⁹³Zr	1.61	5.4575	91	βγ
¹⁰⁷Pd	6.5	1.2499	33	β
¹²⁹I	16.1	0.8410	194	βγ
↑ Decay energy is split among β, neutrino, and γ if any. ↑ Per 65 thermal neutron fissions of ²³⁵U and 35 of ²³⁹Pu. ↑ Has decay energy 380 keV, but its decay product ¹²⁶Sb has decay energy 3.67 MeV. ↑ Lower in thermal reactors because ¹³⁵Xe, its predecessor, readily absorbs neutrons.

Medium-lived fission products
v
t
e
Nuclide	t_1⁄2	Yield	Q^{[a 1]}	βγ
	(a)	(%)^{[a 2]}	(keV)
¹⁵⁵Eu	4.74	0.0803^{[a 3]}	252	βγ
⁸⁵Kr	10.73	0.2180^{[a 4]}	687	βγ
^113mCd	13.9	0.0008^{[a 3]}	316	β
⁹⁰Sr	28.91	4.505	2826^{[a 5]}	β
¹³⁷Cs	30.04	6.337	1176	βγ
^121mSn	43.9	0.00005	390	βγ
¹⁵¹Sm	94.6	0.5314^{[a 3]}	77	β
↑ Decay energy is split among β, neutrino, and γ if any. ↑ Per 65 thermal neutron fissions of ²³⁵U and 35 of ²³⁹Pu. 1 2 3 Neutron poison; in thermal reactors, most is destroyed by further neutron capture. ↑ Less than 1/4 of mass-85 fission products as most bypass ground state: ⁸⁵Br → ^85mKr → ⁸⁵Rb. ↑ Has decay energy 546 keV; its decay product ⁹⁰Y has decay energy 2.28 MeV with weak gamma branching.

Actinides and fission products by half-life
v
t
e
Actinides^[1] by decay chain				Half-life range (a)	Fission products of ²³⁵U by yield^[2]
4n (Thorium)	4n + 1 (Neptunium)	4n + 2 (Radium)	4n + 3 (Actinium)	Half-life range (a)	4.5–7%	0.04–1.25%	<0.001%
²²⁸Ra^№				4–6 a		¹⁵⁵Eu^þ
²⁴⁸Bk^[3]				> 9 a
²⁴⁴Cm^ƒ	²⁴¹Pu^ƒ	²⁵⁰Cf	²²⁷Ac^№	10–29 a	⁹⁰Sr	⁸⁵Kr	^113mCd^þ
²³²U^ƒ		²³⁸Pu^ƒ	²⁴³Cm^ƒ	29–97 a	¹³⁷Cs	¹⁵¹Sm^þ	^121mSn
	²⁴⁹Cf^ƒ	^242mAm^ƒ		141–351 a	No fission products have a half-life in the range of 100 a–210 ka ...
	²⁴¹Am^ƒ		²⁵¹Cf^ƒ^[4]	430–900 a
		²²⁶Ra^№	²⁴⁷Bk	1.3–1.6 ka
²⁴⁰Pu	²²⁹Th	²⁴⁶Cm^ƒ	²⁴³Am^ƒ	4.7–7.4 ka
	²⁴⁵Cm^ƒ	²⁵⁰Cm		8.3–8.5 ka
			²³⁹Pu^ƒ	24.1 ka
		²³⁰Th^№	²³¹Pa^№	32–76 ka
²³⁶Np^ƒ	²³³U^ƒ	²³⁴U^№		150–250 ka	⁹⁹Tc^₡	¹²⁶Sn
²⁴⁸Cm		²⁴²Pu		327–375 ka		⁷⁹Se^₡
				1.33 Ma	¹³⁵Cs^₡
	²³⁷Np^ƒ			1.61–6.5 Ma	⁹³Zr	¹⁰⁷Pd
²³⁶U			²⁴⁷Cm^ƒ	15–24 Ma		¹²⁹I^₡
²⁴⁴Pu				80 Ma	... nor beyond 15.7 Ma^[5]
²³²Th^№		²³⁸U^№	²³⁵U^ƒ№	0.7–14.1 Ga	... nor beyond 15.7 Ma^[5]
₡, has thermal neutron capture cross section in the range of 8–50 barns ƒ, fissile №, primarily a naturally occurring radioactive material (NORM) þ, neutron poison (thermal neutron capture cross section greater than 3k barns)

Actinides


Transmutations in the thorium fuel cycle v t e
														²³⁷Np
														↑
		²³¹U	←	²³²U	↔	²³³U	↔	²³⁴U	↔	²³⁵U	↔	²³⁶U	→	²³⁷U
		↓		↑		↑		↑
		²³¹Pa	→	²³²Pa	←	²³³Pa	→	²³⁴Pa
		↑				↑
²³⁰Th	→	²³¹Th	←	²³²Th	→	²³³Th
Nuclides with a yellow background in italic have half-lives under 30 days Nuclides in bold have half-lives over 1,000,000 years Nuclides in red frames are fissile

in Thorium fuel cycle

Weapons-grade

Isotopes

Table of nuclides Isotope Tritium

Beta-decay stable isobars

↑ Plus radium (element 88). While actually a sub-actinide, it immediately precedes actinium (89) and follows a three-element gap of instability after polonium (84) where no nuclides have half-lives of at least four years (the longest-lived nuclide in the gap is radon-222 with a half life of less than four days). Radium's longest lived isotope, at 1,600 years, thus merits the element's inclusion here.
↑ Specifically from thermal neutron fission of uranium-235, e.g. in a typical nuclear reactor.
↑ Milsted, J.; Friedman, A. M.; Stevens, C. M. (1965). "The alpha half-life of berkelium-247; a new long-lived isomer of berkelium-248". Nuclear Physics. 71 (2): 299. Bibcode:1965NucPh..71..299M. doi:10.1016/0029-5582(65)90719-4.
"The isotopic analyses disclosed a species of mass 248 in constant abundance in three samples analysed over a period of about 10 months. This was ascribed to an isomer of Bk²⁴⁸ with a half-life greater than 9 [years]. No growth of Cf²⁴⁸ was detected, and a lower limit for the β⁻ half-life can be set at about 10⁴ [years]. No alpha activity attributable to the new isomer has been detected; the alpha half-life is probably greater than 300 [years]."
↑ This is the heaviest nuclide with a half-life of at least four years before the "sea of instability".
↑ Excluding those "classically stable" nuclides with half-lives significantly in excess of ²³²Th; e.g., while ^113mCd has a half-life of only fourteen years, that of ¹¹³Cd is eight quadrillion years.

[1] Decay energy is split among β, neutrino, and γ if any.

[2] Per 65 thermal neutron fissions of ²³⁵U and 35 of ²³⁹Pu.

[3] Has decay energy 380 keV, but its decay product ¹²⁶Sb has decay energy 3.67 MeV.

[4] Lower in thermal reactors because ¹³⁵Xe, its predecessor, readily absorbs neutrons.

[5] Decay energy is split among β, neutrino, and γ if any.

[6] Per 65 thermal neutron fissions of ²³⁵U and 35 of ²³⁹Pu.

[neutrons-7] 1 2 3 Neutron poison; in thermal reactors, most is destroyed by further neutron capture.

[8] Less than 1/4 of mass-85 fission products as most bypass ground state: ⁸⁵Br → ^85mKr → ⁸⁵Rb.

[9] Has decay energy 546 keV; its decay product ⁹⁰Y has decay energy 2.28 MeV with weak gamma branching.

[10] Plus radium (element 88). While actually a sub-actinide, it immediately precedes actinium (89) and follows a three-element gap of instability after polonium (84) where no nuclides have half-lives of at least four years (the longest-lived nuclide in the gap is radon-222 with a half life of less than four days). Radium's longest lived isotope, at 1,600 years, thus merits the element's inclusion here.

[11] Specifically from thermal neutron fission of uranium-235, e.g. in a typical nuclear reactor.

[12] Milsted, J.; Friedman, A. M.; Stevens, C. M. (1965). "The alpha half-life of berkelium-247; a new long-lived isomer of berkelium-248". Nuclear Physics. 71 (2): 299. Bibcode:1965NucPh..71..299M. doi:10.1016/0029-5582(65)90719-4.
"The isotopic analyses disclosed a species of mass 248 in constant abundance in three samples analysed over a period of about 10 months. This was ascribed to an isomer of Bk²⁴⁸ with a half-life greater than 9 [years]. No growth of Cf²⁴⁸ was detected, and a lower limit for the β⁻ half-life can be set at about 10⁴ [years]. No alpha activity attributable to the new isomer has been detected; the alpha half-life is probably greater than 300 [years]."

[13] This is the heaviest nuclide with a half-life of at least four years before the "sea of instability".

[14] Excluding those "classically stable" nuclides with half-lives significantly in excess of ²³²Th; e.g., while ^113mCd has a half-life of only fourteen years, that of ¹¹³Cd is eight quadrillion years.

[a 1]

[a 2]

[a 3]

[a 4]

[a 1]

[a 2]

[a 3]

[a 4]

[a 5]

[1]

[2]

[3]

[4]

[5]

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American expansion and division period

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Fission products

Actinides

Isotopes