No abstract available

No abstract available

No abstract available

[en] Gamma-ray spectrometry is a very desirable technique for determining plutonium isotopic abundances because it is nondestructive and adaptable to making rapid in-line analyses. However, the technique has had the shortcoming of not being able to determine the abundance of the /sup 242/Pu isotope. Here a way is described around that shortcoming: a very linear and reactor-independent correlation for calculating the isotopic abundance of /sup 242/Pu from the measured abundances of /sup 239/Pu, /sup 240/Pu, and /sup 241/Pu. 9 refs

[en] Neutron induced fission cross sections of actinides like the Pu-isotopes are of relevance for the development of nuclear transmutation technologies. For ²⁴²Pu current uncertainties are of around 21 %, the target uncertainties in the order of 7 %. Sensitivity studies show that the total uncertainty has to be reduced below 5 %, to allow for reliable neutron physics simulations. This challenging task was performed at the neutron time-of-flight facility nELBE at HZDR, Dresden. Improved experimental conditions and beam power, paired with the right spectral shape of the nELBE neutron source provided excellent conditions to achieve this aim. Within the TRAKULA project, large and homogeneous deposits of ²³⁵U and ²⁴²Pu have been produced successfully. Using them in two consecutively placed fission chambers allows the determination of the neutron induced fission cross section of ²⁴²Pu relative to ²³⁵U. Experimental results are presented and compared to recent experiments and evaluated data. Corrections addressing the neutron scattering are discussed by using results of different neutron transport simulations (Geant 4, MCNP 6 and FLUKA).

[en] A solvent extraction separation scheme using PC-88A extractant for Pu and its application for estimation of Pu in urine matrix in the field of bioassay has been developed. A known amount of ²⁴²Pu tracer is added to urine and the sample is wet oxidised. The Pu is co-precipitated with Ca₂C₂O₄ and oxalate ions are destructed with HCIO₄. The residue is dissolved in 2M HCI, and NaNO₂ is added to adjust the valency to ⁴⁺Pu state. This aqueous phase is filtered and equilibrated with 0.01 M PC-88A/toluene extractant. Pu is stripped into 5% H₂C₂O₄ solution by equilibrating with PC-88A/toluene. Then, the eluate together is added and evaporated with the addition of 8M HNO₃ and concentrated HCIO₄ to destruct oxalate ions and finally the beaker that looks empty-like is cooled and Pu is electro deposited in ammonium oxalate medium and counted in alpha spectrometry

[en] A method is described for electrodeposition of the alpha-emitting nuclides. The effects of electrolyte concentration, chelating reagent, current, pH of electrolyte, and the plating time on the electrodeposition have been investigated in an ammonium oxalate-ammonium sulfate electrolyte containing diethyl triamino pentaacetic acid in order to determine the optimum condition to plate plutonium. An optimized electrodeposition procedure for the determination of plutonium was validate by application to IAEA-Reference soils The chemical yield in the optimized method for electrodeposition step in the environmental sample was about 7% higher than that of a Talvitie's method. The electrodeposition procedure developed with a ²⁴²Pu tracer was also applied analyze the actinides such as thorium, uranium, and americium

[en] Prompt fission of ²⁴²Pu induced by internal conversion in muonic atoms is studied theoretically. We treat the fission mode classically in terms of an elongation and a mass asymmetry coordinate and solve the time-dependent Schroedinger equation for the muon in the Coulomb field of the fissioning nucleus by methods similar to those of time-dependent Hartree-Fock. The muon attachment to the light and heavy fission fragment is calculated as function of the friction coefficient and the fragment mass asymmetry

[en] Membrane based isotope dilution alpha spectrometry (MEM-IDAS) was developed for the determination of plutonium concentration in complex aqueous matrices. A bi-functionalized polyethersulfone membrane was prepared by photo-induced free radical grafting process. The membrane was used for preconcentration of Pu from 3M HNO₃ medium followed by direct quantification of the preconcentrated Pu by IDAS, using ²³⁸Pu spike. Pu concentrations in two unknown samples were determined and the results obtained were in good agreement with the biamperometric data. (author)

[en] Accumulation of americium (²⁴¹Am) and plutonium (^238,242Pu) and their distribution in cell compartments and biochemical components of the biomass of freshwater aquatic plants Elodea canadensis, Ceratophyllum demersum and Myrioplyllum spicatum and aquatic moss Fontinalis antipyretica have been investigated in laboratory experiments. Americium and plutonium taken up from water by Elodea canadensis apical shoots were mainly absorbed by structural components of plant cells (90% for ²⁴¹Am; 89% for ²³⁸Pu and 82-87% for ²⁴²Pu). About 10-18% of isotope activity was recorded in the cytosol fraction. The major concentration (76-92%) of americium was bound to cell wall cellulose-like polysaccharides of Elodea canadensis, Myriophyllum spicatum, Ceratophyllum demersum and Fontinalis antipyretica, 8-24% of americium activity was registered in the fraction of proteins and carbohydrates, and just a minor concentration (<1%) in the lipid fraction. The distribution of plutonium in the biomass fractions of Elodea was similar to that of americium. Hence, americium and plutonium had the highest affinity to cellulose-like polysaccharides of cell walls of freshwater submerged macrophytes. (author)