Strontium-90 , nuclear fuel reprocessing

Kuno, Y., Sato, S., Ohno, E., and Masui, J., Rapid determination of strontium-90 in highly radioactive solutions of nuclear fuel reprocessing plant, Anal. Sci., 9,195-198, 1993. 

Markham OD, Hafford DK, Autenrieth RE. 1980. Strontium-90 concentrations in pronghorn antelope bones near a nuclear fuel reprocessing plant. Health Phys 38 811-816. 

There are many examples of the studies on SLM for nuclear applications in the literature. SLMs were tested for high-level radioactive waste treatment combined with removal of actinides and other fission products from the effluents from nuclear fuel reprocessing plants. The recovery of the species, such as uranium, plutonium, thorium, americium, cerium, europium, strontium, and cesium, was investigated in vari-ons extracting-stripping systems. Selective permeation... 

The counting techniques described in this paper are also readily applicable to studies of "hot radioactive waste (z.e.j radioactive waste from reprocessed nuclear fuel). With this type of material, the cesium can be analyzed as 30-y (662-keV y), the RE as 13-y Eu (964-keV and 1408-keV y), strontium as 28-y Sr (after chemical separation and beta counting), and the actinides by group separation and alpha counting. 

Spent fuel from a reactor contains unused uranium as well as plutonium-239 which has been created by bombardment of neutrons during the fission process. Mixed with these useful materials are other highly radioactive and hazardous fission products, such as cesium-137 and strontium-90. Since reprocessed fuels contain plutonium, well suited for making nuclear weapons, concern has been expressed over the possible capture of some of this material by agents or terrorists operating on behalf of unfriendly governments that do not have a nuclear weapons capability. 

Radioactive wastes come directly from nuclear-reactor-fuel reprocessing plants and from industries employing radioactivity for processing work. The dominating elements from nuclear reactor fuels are cesium 137 and strontium 90, with the latter th,e controlling isotope owing to low permissible concentration values (Table 10-2). Rodger cites an example to illustrate the severity of the problem. In the year a.d. 2000 the installed reactor capacity on a world-wide basis is predicted to be 2.2 X 10 Mw. If this system is operated for 50 years, the Sr steady-state level (rate of production = rate of decay) would be 8.6 X 10 curies, which would require 5 per cent of the entire world ocean volume to dilute to the maxi-... 

Storage of spent nuclear fuel poses a major problem because the fission products are extremely radioactive. It is estimated that 20 half-lives are required for their radioactivity to reach levels acceptable for biological exposure. Based on the 28.8-yr half-life of strontium-90, one of the longer-lived and most dangerous of the products, the wastes must be stored for 600 years. Plutonium-239 is one of the by-products present in spent fuel elements. It is formed by absorption of a neutron by uranium-238, followed by two successive beta emissions. (Remember that most of the uranium in the fuel elements is uranium-238.) If the elements are reprocessed, the plutonium-239 is largely recovered because it can be used as a nuclear fiieL However, if the plutonium is not removed, spent elements must be stored for a very long time because plutonium-239 has a half-life of24,000 yr. 

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