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Abstract  

Soon after the discovery of the Mössbauer effect, studies were performed on spinels containing various transition metal ions (mostly Fe2+). This method proved very useful for investigating the local symmetry at transition metal ions. In spite of the numerous results, the correct interpretation of the complex quadrupole split spectra is still not given for numerous spinel structures. Since spectra of different shapes were measured for FeAl2O4 and FeCr2O4 by different authors, we performed new measurements on these spinels. The results on FeAl2O4 showed that the statistical distribution of another kind of ions in the positions A may influence the electric field gradient at the Fe2+ ions in the tetrahedral interstices. In FeCr2O4 and in the mixed Fe0.5Mg0.5Cr2O4, the electric field gradient exists at the Fe2+ ions at room temperature indicating that the degeneracy of the orbital doublet of the Fe2+ is removed.

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Summary  

Vanadium-48 was produced with an activity of 222 MBq (6 mCi) by the natTi(d,xn)48V nuclear reactions in the U-120 cyclotron. The energy of the irradiating beam was 13 MeV, its intensity 5 μA, and the metallic Ti target dimension 11’11 mm2 (0.1 mm thickness). For target cooling, circulated water in target backside was used. After 3 cooling days, only 48V and some 46Sc (T 1/2 = 83.8 d), produced by the side nuclear reaction 48Ti(d,α)46Sc were found in the target. For production of the radiotracer of 48V and for the preparation of source for standardization of 48V by 4πβ-γ coincidence, the Ti target was dissolved either in HF or in H2SO4. For both dissolving methods an ion-exchange separation procedure was developed.

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Abstract  

Understanding the characteristics of diffusion is essential in the assessment of radionuclide release through the backfill of waste repository. The diffusion behavior of 3H, 99Tc, 125I, 36Cl and 85Sr in granite, concrete and bentonite was studied in a specially designed diffusion cell. Diffusion coefficients (D, D a) and time-lag (t a) were measured, break-trough curves were plotted and experimental data were interpreted to predict diffusion rates. The results showed that tritium, iodine and chlorine could be considered as non-sorbing tracers, while technetium was weakly and strontium was strongly sorbed (no break-through was observed during the period of the experiments).

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Agrokémia és Talajtan
Authors:
Katalin Sárdi
,
P. Csathó
,
I. Sisák
,
E. Osztoics
,
P. Szűcs
, and
Á. Balázsy
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Journal of Radioanalytical and Nuclear Chemistry
Authors:
P. Ormai
,
A. Fritz
,
J. Solymosi
,
I. Gresits
,
E. Hertelendi
,
Z. Szúcs
,
N. Vajda
,
Zs. Molnár
, and
P. Zagyvai

Abstract  

In the execution of disposal of low and intermediate level radioactive wastes, it is important to evaluate accurately the kind and quantity of each radionuclide in the wastes. For such an evaluation, correlation of non-gamma-emitting nuclides based on gamma-emitting nuclides is recommended and regarded as a practical method. This method necessitates a completion of a highly accurate and reliable nondestructive assay system of gamma-emitting nuclides for practical use. In 1992, in support of the new waste disposal program in Hungary, Paks NPP initiated a waste characterization program to determine the radiological properties of its radwastes. A segmented gamma scanning system has been set up to measure the gamma-emitting nuclides in 200 litre low level drums following in-drum compaction. In the framework of the program a radiochemical analysis sub-program was started to determine the long-lived non-gamma emitting radionuclides, mainly those listed in the US regulatory document (10CFR61). The radionuclides of interest have been3H,14C,90Sr,55Fe,59Ni,99Tc,129I and TRUs. Sample preparation techniques and measurement methods have been selected and used. Newly developed or adopted methods have been tested on real liquid radwaste streams such as concentrates, ion-exchange resin and sludge. The measurements taken so far have revealed brand new information and data on radiological composition of waste of WWER-type reactors. In the next stage of the characterisation program attempt will be made for providing correlation factors between the gamma and non-gamma-emitting radionuclides in different waste streams. Short description of the methods and results on waste inventory are given by highlighting the problem areas.

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