Radionuclides caesium

However from 1999 till our days, a series of ravishment of ionizing radiation sources occurred on the territory of the district, and in the first place in the town of Krivoi Rog. From 1994 to 1998 only three such incidents were registered in the district, while in 1999 - five, three of which were connected to ravishment. It should be noted that all the stolen sources were of radionuclides caesium - 137. 

Keywords phytoremediation, radionuclides, 137-caesium, 90-strontium, 125-iodine, uranium, radium, uranium mill tailings, biomonitoring... 

Such mass flow may be the primary mechanism by which non-nutritive elements such as these radionuclides are apparently so efficiently concentrated in fruit bodies. However, Gray et al. (1995) demonstrated that even the primordia of basidiocarps forming within mycelia in vitro are strong sinks for caesium. 

Ion-exchange models are commonly used to describe radionuclide sorption onto the fixed-charged sites of materials like clays. Ion exchange will be strongly affected by competition with monovalent and divalent ions such as Na" " and Ca, whereas it will be less dependent on pH over the compositional ranges common for natural waters. Many studies of strontium and caesium sorption by aluminosilicates (e.g., Wahlberg and Fishman, 1962 Tamura, 1972) have been carried out within the framework of ion-exchange theory. Early mechanistic smdies... 

These results are consistent with laboratory measurements of the effects of pH and oxidation state on the leachability of nuclear fuel particles (Kashparov et al, 2000). The increased leachability of the oxidized fuel particles may be due to (i) an increased solubility because of the change in oxidation state (ii) the higher surface area of the highly fractured oxidized particles or (iii) the diffusion of radionuclides (strontium, caesium) to grain boundaries and particle surfaces during the heating and oxidation process. 

Bergman R. (1994) The distribution of radioactive caesium in boreal forest ecosystems. In Nordic Radioecology, the Transfer of Radionuclides through Nordic Ecosystems to Man Studies in Environmental Science. Studies in Environmental Science (ed. H. Dahlgaard). Elsevier, New York, vol. 62, pp. 335-379. 

Radionuclides classified as activation products are created in nuclear reactors and other nuclear devices by the reactions of neutrons with fuel and construction materials. Activation products include the isotopes of the transuranic elements and radioisotopes of hydrogen, carbon, caesium, cobalt, iron, manganese, zinc, and a host of other radionuclides, all of which should be recognised and considered in determining the environmental pathways to human exposure. 

On 7 April 1989, a fire broke out in the stem section of the Komsomolets nuclear submarine. The submarine sank to a depth of 1685 m at 73°43T6"N, 13°15 52"E, near the south-west of Bear Island. The site is about 300 nautical miles from the Norwegian coast. The wreck contains one nuclear reactor and two nuclear warheads, one of which was fractured. The radionuclide inventory includes 1.5 PBq Sr, 2 PBq Cs, about 16 TBq " Pu in the two warheads and 5 TBq of actinides in the reactor s core. During June/July 1994, an international expedition to the Komsomolets site at the request of the Russian Federation was organised. The objectives of the scientific cmise on board the R/V Mstislav Keldysh were to close nine door holes, including torpedo tubes, by capping them with titanium metal cover caps, and to sample and monitor for ambient radioactivity. A series of 280-600 1 sea-water samples collected in profile, a suite of surface sediments and cores and various biota samples were returned to lAEA-MEL for analysis. The results showed that a very limited leakage of caesium and tritium had occurred from the submarine. 

There are assessments predicting the use of reverse osmosis for the processing of the wastes from medical application [36,37] and for the removal of caesium-137 from decontamination wastes after accident in the steel production factory [38]. RO is considered as a method for removal of radioactive pollutants from contaminated water (removal of Cs and °Sr) in the vicinity of atomic power plants [39], as well as for removal of small quantities of radionuclides ( Rn, Ra) from... 

The ability of calixarenes to bind large metal ions with high kinetic stability is important in the search for complexants for radionuclides such as Cs (ti/2 = 30.2 yr) and Sr (ti/2 = 65 d) from the reprocessing of exhausted nuclear fuel. There has been considerable interest in caesium-complexed calix[4]-bis-crowns as selective Cs-carriers. Transport isotherms of trace level Cs through supported liquid membranes containing calix[4]-bis-crowns have been determined as a function of the ionic concentration of the aqueous feeder solutions, and l,3-calix[4]-bis-o-benzo-crown-6 appears to be much more efficient in decontamination than mixtures of crown ethers and acidic exchangers, especially in highly acidic media. " ... 

Caesium is said to behave conservatively that is, the bulk of the radionuclide inventory is associated with the water phase and so transport processes are dominated by the bulk movement of sea water. Plutonium and americium, on the other hand, behave non-conservatively the bulk of their inventory is associated with sediments and the transport processes affecting sediments are very important to their behaviour. The proportion of each nuclide present in the water column as suspended particulate is a simple function of value and suspended sediment load (Sholkovitz, 1983), as indicated in Table 8.2. Thus, for the full range of sediment loadings, water column inventories of Cs are dominated by... 

Effect of the propliylaotic administration of the activated carbon SCN on the concentration of radionuclides, nCi f , in the blood of liquidators (May-June 1986) (adapted from [51 ]). Note that with the exception of iodine and caesium, all the radionuclides are polyvalent transition... 

In addition to the above-mentioned radionuclides, mention should also be made of cobalt 38, cobalt 60, iodine 131, caesium 134, caesium 137 and plutonium 239. 

Bengtsson A, Hansson P (1990) Measures against mercury and caesium in lake fish and wild animals. Project 3. Environmental project Sundsvall-Timra (in Swedish) 29 pp Bergman R, Danell K, Ericsson A, Grip H, Johansson L, Nelin P, Nylen T (1988) Uptake, re-distribution and transport of radionuclides in a forest ecosystem (in Swedish). FOA-rapport E 40040, Sept. 1988, SLU, UmeS... 

Some nuclides are unstable and spontaneously change into other nuclides, emitting energy in the form of radiation, either particulate (e.g. a and P particles) or electromagnetic (e.g. y-rays). This property is called radioactivity, and the nuclide showing it is said to be radioactive. Most nuclides occurring in nature are stable, but some are radioactive, for example, all the isotopes of uranium and thorium. Many other radioactive nuclides (or radionuclides) have been produced artificially, such as strontium-90, caesium-137 and the isotopes of the man-made elements, plutonium and americium. 

To estimate the environmental impact caused by nuclear fuel cycle of the SVBR-75/100, the value of specific radiotoxicity of the produced transuranic elements (neptunium, plutonium, americium and curium) and long-lived fission products (technetium-99, iodine-129 and caesium-135) was taken as a criterion, as a function of the electric energy produced. When this value decreases with energy production, the environmental impact of the nuclear fuel cycle can be considered friendly . The radiotoxicity characteristic adopted was the volume of water necessary to dilute some quantity of radionuclides to the concentrations for which the specific radioactivity of the solution meets the sanitary requirements for drinking water. 

In most cases, the accumulated radionuclide content will consist of activated material such as Co, Co, Cr, Mn and Fe (depending upon the composition and corrosion rates of the material used in the primary circuit). Fission products such as isotopes of iodine, caesium and strontium may be important if failure of fuel cladding occurs. 

Significantly higher specific activity of caesium was detected in the meat of game (in 1986, depending on surface contamination of the territory, the observed values for roe deer meat were 120-600 Bq/kg and 170-660 Bq/kg for deer meat). Contamination of wild Hfe by radionuclides decreases in the order deers > roe deers and fallow deers > mouflons > wild boars (wild pigs) > hares. 

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