Strontium-90

Strontium-90 Full table
General
symbol	Strontium-90,⁹⁰Sr
Neutrons	52
Protons	38
Nuclide data
Half-life	28.8 years
Decay products	⁹⁰Y
Decay mode	Decay energy
Beta decay	0.546 MeV

Medium-lived fission products
t^½(y)		Yield%	KeV	β
¹⁵⁵Eu	4.76	.0330	252	γ
⁸⁵Kr	10.76	.2717	687	γ
^113mCd	14.1	.0003	316
⁹⁰Sr	28.9	5.7518	2826	β
¹³⁷Cs	30.23	6.0899	1176	γ
^121mSn	43.9	.00003	390	γ
¹⁵¹Sm	90	.4203	77

Strontium-90 (⁹⁰Sr) is a gamma photon emission from the decay of ⁹⁰Y is so weak that it can normally be ignored.

⁹⁰Sr finds extensive use in medicine and industry, as a radioactive source for thickness gauges and for superficial spent nuclear fuel.

⁹⁰Sr is a product of nuclear fallout from nuclear tests. For thermal neutron fission as in today's nuclear power plants, the fission product yield from U-235 is 5.8%, from U-233 6.8%, but from Pu-239 only 2.1%.

Together with cesium isotopes ¹³¹I it was between the most important isotopes regarding health impacts after the Chernobyl disaster. Slightly elevated levels of ⁹⁰Sr may be present in the vicinity of nuclear power plants.

Strontium has biochemical behavior similar to bioassay, most commonly by urinalysis.

In the vicinity of nuclear waste and nuclear test sites, strontium also enters the metabolism of plants in lieu of calcium. For example, specimens of chamisa growing in Bayo Canyon, near Los Alamos, New Mexico, exhibit a concentration of radioactive strontium 300,000 times higher than normal plants. Their roots reach into a nuclear waste treatment area that has been closed since 1963; the radioactive shrubs are "indistinguishable from other shrubs without a Geiger counter" ^[2]. The same happens with the tumbleweed plants at the Hanford Site; "crews armed with pitchforks" are employed to prevent the contaminated plants from spreading ^[2].

Accidental mixing of radioactive sources containing strontium with metal scrap can result in production of radioactive steel. Discarded radioisotope thermoelectric generators are a major source of ⁹⁰Sr contamination in the area of the former Soviet Union.

References

^ Decay data from National Nuclear Data Center at the Brookhaven National Laboratory in the US.
^ ^a ^b Masco, Joseph. The Nuclear Borderlands: The Manhattan Project in Post-Cold War New Mexico. Princeton University Press, 2006.

External links

NLM Hazardous Substances Databank – Strontium, Radioactive

Categories: Radioisotope fuels

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Strontium-90". A list of authors is available in Wikipedia.