In this work we present data on transuranium nuclides 238Pu, 239,240Pu, 241Am, 242Cm and 244Cm in effluents discharged to air (activity concentrations and annually discharged activities of individual radionuclides)
from 7 stacks in 2004–2009. In the effluents discharged to air from one stack low activities of transuranium nuclides were
observed throughout the studied period. Transuranium nuclides had been discharged to air from this stack also in previous
years since 1996 when defect in the cladding of a fuel element and consequent contamination of the primary circuit occurred.
In the effluents discharged to air from another stack transuranium nuclides were observed only in some monitoring periods
of studied years. We could not prove the presence of transuranium nuclides in the effluents of the other stacks up to 2006.
The transuranium nuclides in discharged effluents were registered in the second half-year of 2006. In 2007–2008 especially
low activities of 241Am were found in these effluents.
The deposition of transuranium elements in Sweden following the Chernobyl accident was investigated through the analysis of carpets of lichen-and moss-samples and also air-filters and precipitation. The impact of transuranium elements was small compared to that of radiocesium. The deposition of239+240Pu was, as for other actinides, inhomogeneously distributed and ranged from 0.1% to 100% of the inventory in 1986 from nuclear detonation tests. The activity ratio of239+240Pu/137Cs was between 10–3 and 10–6 in comparison to 10–2 for nuclear test fallout. The activity ratios of241Pu,242Cm,238Pu,243+244Am and239+240Pu were about 86, 14, 0.47, 0.14, and 0.13 respectively, but large variations were observed. The results from Sweden were compared with those found in South Finland, Denmark and Southern Europe. The deposition over Scandinavia originated from the initial explosion at Chernobyl, which contained relatively higher amounts of actinide elements than the second emission, which occurred a few days later and was a result of actions taken to bring the fire under control.
An overview of the work carried out on the development of the stripping of transuranium elements which are extracted by trialkyl
phosphine oxide in the actinides-partitioning TRPO process in recent years. Several representative stripping agents and corresponding
processes are introduced in three categories of the management of TRU elements: transmutation, alpha waste conditioning and
Purex-TRPO integrated process.
Authors:A. Berlizov, I. Malyuk, A. Sajeniouk, V. Tryshyn, V. Petrov, A. Savin, S. Abousahl, G. Rasmussen, I. Sadikov, and F. Tashimova
A gamma-spectrometric and radiochemical analysis was carried out of a material (Zr-2.5% Nb alloy) of technological channels
(TC) of Chernobyl Nuclear Power Plant (NPP) power unit No. 2 RBMK-1000 reactor, being under the beginning stage of decommissioning.
Activities of 90Sr, 137Cs, 238Pu, 239+240Pu, 241Am and 244Cm were determined. It was established that the main source of the revealed actinides and fission products was an impurity
of natural thorium and uranium in TC source material on the level of several tenths of ppm. Impurity analysis of TC source
material was performed by neutron activation analysis (NAA) and inductively coupled plasma mass spectrometry (ICP-MS). Fission
product and transuranium element activities measured were compared with the results of prognostic calculations performed with
the help of the NAAPRO code.
Plants and soils from a natural thorium and rare-earth element occurrence (Morro do Ferro, Brazil) were analyzed by alpha spectrometry (Th) and ICP-AES (REE), after pre-concentration of the elements by solvent extraction, co-precipitation and ion exchange procedures. Leaching experiments with humic acid solutions and different soils were performed to estimate the fraction of elements biologically available. High concentrations of the light rare-earth elements (LREE) and of Th, reaching some hundreds of g/g-ash, were measured in plant leaves from the areas of the highest concentration of these elements in soil and in near-surface waters. Chondrite normalized REE plots of plant leaves and corresponding soils are very similar, suggesting that there is no significant fractionation between the REE during uptake from the soil solution and incorporation into the leaves. However, Ce-depletion was observed for some plant species, increasing forSolanum ciliatum in the sequence: leaves<fruits<seeds. Soil to plant concentration ratios (CR's) for Th and the REE, based on the total concentration of these elements in soils, are in the range of 10–3 to 10–2. Leaching experiments confirmed the importance of humic acid complexation for the bio-uptake of Th and REE and further showed that only a very small fraction of these elements in soil is leachable. The implications of these results on the calculated CR's will be discussed.
Authors:M. Galamboš, P. Suchánek, and O. Rosskopfová
The history of sorption and ion-exchange processes starts with the use of natural materials which properties were discovered
coincidentally and ends with the age of polymer and anorganic—or synthetic sorbents specifically made for a particular project.
Its objectives are focused on sorption of anthropogenic radionuclides originating from nuclear power plant operations (fission,
activation, corrosion products and transuranium elements) on bentonites, zeolites, hydroxyapatites, magnetic sorbent, ferrocyanides,
and silica sorbent. Bentonites from Slovak deposits should be used as part of multi-barrier system in deep geological repository
for spent nuclear fuel and high level radioactive waste. Zeolites are used as molecular sieves, catalysts, ion-exchangers,
sorbents, water softeners, in wastewater treatment, in chemistry industry, buildings. Hydroxyapatite is a suitable sorbent
for heavy metals and radionuclides due to its low water solubility, high stability under reducing and oxidizing conditions,
high specific surface area and good buffering properties. The leaching wastes from the Sereď hydrometallurgical plant represent
a large stock of inexpensive, ready-to-use magnetic sorbent for the decontamination of soil or sediments in their common suspensions,
followed by the magnetic separation and sorbent recycling. Insoluble ferrocyanides of nickel are highly selective sorbents
for heavy alkali metals ions, and therefore can be used to separate cesium from liquid radioactve waste. Silica sorbents modified
with imidazole can be used for the separation of cobalt ions from aqueous solution.
The major contributions of G. T. Seaborg to nuclear science, including co-discovery of many isotopes with practical applications in medicine and industry, co-discovery of plutonium and nine more transuranium elements, the actinide hypothesis, and searches for superheavy elements are briefly summarized. His enduring interest in science education, the history of science, and public affairs are also noted.