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Naturally occurring strontium is nonradioactive and nontoxic at levels normally found in the environment, but 90 Sr is a radiation hazard. [4] 90 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 antineutrino, and the yttrium isotope 90 Y, which in turn undergoes β − decay with a half-life of 64 hours and a decay energy ...
Strontium-90 is a commonly used beta emitter used in industrial sources. It decays to yttrium-90, which is itself a beta emitter. It is also used as a thermal power source in radioisotope thermoelectric generator (RTG) power packs. These use heat produced by radioactive decay of strontium-90 to generate heat, which can be converted to ...
But 90 Sr has a 30-year half-life, and 89 Sr a 50.5-day half-life. Thus in the 50.5 days it takes half the 89 Sr atoms to decay, emitting the same number of beta particles as there were decays, less than 0.4% of the 90 Sr atoms have decayed, emitting only 0.4% of the betas. The radioactive emission rate is highest for the shortest lived ...
Source of most of the decay heat from years to decades after irradiation, together with 90 Sr. 6.0507%: Technetium: 99 Tc: 211 ky: Candidate for disposal by nuclear transmutation. 5.7518%: Strontium: 90 Sr: 28.9 y: Source of much of the decay heat together with 137 Cs on the timespan of years to decades after irradiation.
Zirconium-90 mostly forms by successive beta decays out of Strontium-90. A nonradioactive Zirconium sample can be extracted from spent fuel by extracting Strontium-90 and allowing enough of it to decay (e.g. In an RTG). The Zirconium can then be separated from the remaining strontium leaving a very isotopically pure Zr-90 sample.
Strontium-90 and caesium-137, with half-lives of about 30 years, are the largest radiation (including heat) emitters in used nuclear fuel on a scale of decades to ~305 years (tin-121m is insignificant because of the low yield), and are not easily transmuted because they have low neutron absorption cross sections. Instead, they should simply be ...
The alkaline earth metal strontium (38 Sr) has four stable, naturally occurring isotopes: 84 Sr (0.56%), 86 Sr (9.86%), 87 Sr (7.0%) and 88 Sr (82.58%). Its standard atomic weight is 87.62(1). Only 87 Sr is radiogenic ; it is produced by decay from the radioactive alkali metal 87 Rb , which has a half-life of 4.88 × 10 10 years (i.e. more than ...
Strontium-90 has been used by the Soviet Union in terrestrial RTGs. 90 Sr decays by β − decay into 90 Y, which quickly decays again via β emission. It has a lower decay energy than 238 Pu, but its shorter half life of 28.8 years and lower atomic weight yield a power density for pure metal of 0.95 watts per gram. [42] As 90