Strontium - 90 - wikipedia Strontium - 90 This article is about the chemical isotope. For the band, see Strontium 90 ( band ). Strontium - 90 Full table General Name, symbol Strontium - 90, Sr Neutrons 52 Protons 38 Nuclide data Natural abundance syn Half - life 28.79 years Decay products Y Decay mode Decay energy Beta decay 0.546 MeV Strontium - 90 ( 90 Sr ) is a radioactive isotope of strontium produced by nuclear fission, with a half - life of 28.8 years. It undergoes β decay into yttrium - 90, with a decay energy of 0.546 MeV. Strontium - 90 has applications in medicine and industry and is an isotope of concern in fallout from nuclear weapons and nuclear accidents. Contents 1 Radioactivity 2 Fission product 3 Biological effects 3.1 Biological activity 4 Uses 4.1 Radioisotope Thermoelectric Generators ( RTGs ) 4.2 Industrial applications 4.3 Medical applications 5 Sr contamination in the environment 6 References 7 External links Radioactivity Naturally occurring strontium is nonradioactive and nontoxic at levels normally found in the environment, but Sr is a radiation hazard. Sr undergoes β decay with a half - life of 28.79 years and a decay energy of 0.546 MeV distributed to an electron, an anti-neutrino, and the yttrium isotope Y, which in turn undergoes β decay with half - life of 64 hours and decay energy 2.28 MeV distributed to an electron, an anti-neutrino, and Zr ( zirconium ), which is stable. Note that Sr / Y is almost a pure beta particle source ; the gamma photon emission from the decay of Y is so infrequent that it can normally be ignored. Sr has a specific activity of 5.21 TBq / g. Medium - lived fission products Prop : Unit : t ( a ) Yield ( % ) Q * ( keV ) βγ * Eu 4.76 0.0803 252 βγ Kr 10.76 0.2180 687 βγ Cd 14.1 0.0008 316 β Sr 28.9 4.505 2826 β Cs 30.23 6.337 1176 βγ Sn 43.9 0.00005 390 βγ Sm 96.6 0.5314 77 β Fission product Sr is a product of nuclear fission. It is present in significant amount in spent nuclear fuel and in radioactive waste from nuclear reactors and in nuclear fallout from nuclear tests. For thermal neutron fission as in today 's nuclear power plants, the fission product yield from U-235 is 5.7 %, from U-233 6.6 %, but from Pu - 239 only 2.0 %. Biological effects Biological activity Strontium - 90 is a `` bone seeker '' that exhibits biochemical behavior similar to calcium, the next lighter group 2 element. After entering the organism, most often by ingestion with contaminated food or water, about 70 -- 80 % of the dose gets excreted. Virtually all remaining strontium - 90 is deposited in bones and bone marrow, with the remaining 1 % remaining in blood and soft tissues. Its presence in bones can cause bone cancer, cancer of nearby tissues, and leukemia. Exposure to Sr can be tested by a bioassay, most commonly by urinalysis. The biological half - life of strontium - 90 in humans has variously been reported as from 14 to 600 days, 1000 days, 18 years, 30 years and, at an upper limit, 49 years. The wide ranging published biological half life figures are explained by strontium 's complex metabolism within the body. However, by averaging all excretion paths, the overall biological half life is estimated to be about 18 years. The elimination rate of strontium - 90 is strongly affected by age and sex, due to differences in bone metabolism. Together with the caesium isotopes Cs, Cs, and iodine isotope I it was among the most important isotopes regarding health impacts after the Chernobyl disaster. As strontium has an affinity to the calcium - sensing receptor of parathyroid cells that is similar to that of calcium, the increased risk of liquidators of the Chernobyl power plant to suffer from primary hyperparathyroidism could be explained by binding of strontium - 90. Uses Radioisotope thermoelectric generators ( RTGs ) The radioactive decay of strontium - 90 generates a significant amount of heat, 0.536 W / g in the form of pure strontium metal or approximately 0.256 W / g as strontium titanate and is cheaper than the alternative Pu. It is used as a heat source in many Russian / Soviet radioisotope thermoelectric generators, usually in the form of strontium titanate. It was also used in the US `` Sentinel '' series of RTGs. Industrial applications Sr finds use in industry as a radioactive source for thickness gauges. Medical applications Sr finds extensive use in medicine as a radioactive source for superficial radiotherapy of some cancers. Controlled amounts of Sr and Sr can be used in treatment of bone cancer. It is also used as a radioactive tracer in medicine and agriculture. Sr contamination in the environment Strontium - 90 is not quite as likely as caesium - 137 to be released as a part of a nuclear reactor accident because it is much less volatile, but is probably the most dangerous component of the radioactive fallout from a nuclear weapon. A study of hundreds of thousands of deciduous teeth, collected by Dr. Louise Reiss and her colleagues as part of the Baby Tooth Survey, found a large increase in Sr levels in through the 1950s and early 1960s. The study 's final results showed that children born in St. Louis, Missouri in 1963 had levels of Sr in their deciduous teeth that was 50 times higher than that found in children born in 1950, before the advent of large - scale atomic testing. Commentators on the study said that the fallout was likely to cause increased cases of diseases in those who absorb strontium - 90 into their bones. An article with the study 's initial findings was circulated to U.S. President John F. Kennedy in 1961, and helped convince him to sign the Partial Nuclear Test Ban Treaty with the United Kingdom and Soviet Union, ending the above - ground nuclear weapons testing that placed the greatest amounts of nuclear fallout into the atmosphere. The Chernobyl disaster released roughly 10 PBq, or about 5 % of the core inventory, of strontium - 90 into the environment. The Fukushima Daiichi disaster released 0.1 - 1 PBq of strontium - 90 in the form of contaminated cooling water into the Pacific Ocean. References Jump up ^ `` Table of Isotopes decay data ''. Lund University. Retrieved 2014 - 10 - 13. ^ Jump up to : `` Strontium Radiation Protection US EPA ''. EPA. 24 April 2012. Retrieved 18 June 2012. ^ Jump up to : TOXICOLOGICAL PROFILE FOR STRONTIUM ( PDF ), Agency for Toxic Substances and Disease Registry, April 2004, retrieved 2014 - 10 - 13 Jump up ^ Decay data from National Nuclear Data Center at the Brookhaven National Laboratory in the US. Jump up ^ Delacroix, D. ; Guerre, J.P. ; Leblanc, P. ; Hickman, C. ( 2002 ). Radionuclide and Radiation Protection Data Handbook 2002 ( 2nd ed. ). Nuclear Technology Publishing. ISBN 1 - 870965 - 87 - 6. Jump up ^ `` Livechart - Table of Nuclides - Nuclear structure and decay data ''. IAEA. Retrieved 2014 - 10 - 13. Jump up ^ `` NRC : Glossary -- Bone seeker ''. US Nuclear Regulatory Commission. 7 May 2014. Retrieved 2014 - 10 - 13. Jump up ^ Tiller, B.L. ( 2001 ), `` 4.5 Fish and Wildlife Surveillance '', Hanford Site 2001 Environmental Report ( PDF ), DOE, retrieved 2014 - 01 - 14 Jump up ^ Driver, C.J. ( 1994 ), Ecotoxicity Literature Review of Selected Hanford Site Contaminants ( PDF ), DOE, doi : 10.2172 / 10136486, retrieved 2014 - 01 - 14 Jump up ^ `` Freshwater Ecology and Human Influence ''. Area IV Envirothon. Retrieved 2014 - 01 - 14. Jump up ^ `` Radioisotopes That May Impact Food Resources '' ( PDF ). Epidemiology, Health and Social Services, State of Alaska. Retrieved 2014 - 01 - 14. Jump up ^ `` Human Health Fact Sheet : Strontium '' ( PDF ). Argonne National Laboratory. October 2001. Retrieved 2014 - 01 - 14. Jump up ^ `` Biological Half - life ''. HyperPhysics. Retrieved 2014 - 01 - 14. Jump up ^ Glasstone, Samuel ; Dolan, Philip J. ( 1977 ). `` XII : Biological Effects ''. The effects of Nuclear Weapons ( PDF ). p. 605. Retrieved 2014 - 01 - 14. Jump up ^ Shagina, NB ; Bougrov, NG ; Degteva, MO ; Kozheurov, VP ; Tolstykh, EI ( 2006 ). `` An application of in vivo whole body counting technique for studying strontium metabolism and internal dose reconstruction for the Techa River population ''. Journal of Physics : Conference Series. 41 : 433 -- 440. ISSN 1742 - 6588. doi : 10.1088 / 1742 - 6596 / 41 / 1 / 048. Jump up ^ Boehm BO, Rosinger S, Belyi D, Dietrich JW ( August 2011 ). `` The Parathyroid as a Target for Radiation Damage ''. New England Journal of Medicine. 365 ( 7 ) : 676 -- 678. PMID 21848480. doi : 10.1056 / NEJMc1104982. Retrieved 19 August 2011. Jump up ^ Harris, Dale ; Epstein, Joseph ( 1968 ), Properties of Selected Radioisotopes ( PDF ), NASA Jump up ^ Standring, WJF ; Selnæs, ØG ; Sneve, M ; Finne, IE ; Hosseini, A ; Amundsen, I ; Strand, P ( 2005 ), Assessment of environmental, health and safety consequences of decommissioning radioisotope thermal generators ( RTGs ) in Northwest Russia ( PDF ) ( StrålevernRapport 2005 : 4 ), Østerås : Norwegian Radiation Protection Authority Jump up ^ `` Power Sources for Remote Arctic Applications '' ( PDF ). Washington, DC : U.S. Congress, Office of Technology Assessment. June 1994. OTA - BP - ETI - 129. Jump up ^ `` Nuclear Fission Fragments ''. HyperPhysics. Retrieved 18 June 2012. Jump up ^ Schneir, Walter ( April 25, 1959 ). `` Strontium - 90 in U.S. Children ''. The Nation. 188 ( 17 ) : 355 -- 357. Jump up ^ Hevesi, Dennis. `` Dr. Louise Reiss, Who Helped Ban Atomic Testing, Dies at 90 '', The New York Times, January 10, 2011. Accessed January 10, 2011. Jump up ^ `` II : The release, dispersion and deposition of radionuclides '', Chernobyl : Assessment of Radiological and Health Impacts ( PDF ), NEA, 2002 Jump up ^ Povinec, P.P. ; Aoyama, M. ; Biddulph, D. ; et al. ( 2013 ). `` Cesium, iodine and tritium in NW Pacific waters -- a comparison of the Fukushima impact with global fallout ''. Biogeosciences. 10 ( 8 ) : 5481 -- 5496. Bibcode : 2013BGeo... 10.5481 P. ISSN 1726 - 4189. doi : 10.5194 / bg - 10 - 5481 - 2013. External links NLM Hazardous Substances Databank -- Strontium, Radioactive Retrieved from `` https://en.wikipedia.org/w/index.php?title=Strontium-90&oldid=800540061 '' Categories : Fission products Isotopes of strontium Radioisotope fuels Radioactive contamination Talk Contents About Wikipedia Чӑвашла Čeština فارسی Français 한국어 Bahasa Indonesia Interlingua Italiano Nederlands 日本 語 Português Русский Simple English Suomi தமிழ் 中文 Edit links This page was last edited on 14 September 2017, at 04 : 48. 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Question: the element 90sr undergoes beta decay to form which isotope
Answer: yttrium-90