Search Results

You are looking at 1 - 10 of 32 items for

  • Author or Editor: A. Dyer x
  • Refine by Access: All Content x
Clear All Modify Search

Abstract  

Organic anion exchange resins, loaded with99Tc pertechnate were incorporated into polymer modified cements and BFS/OPC(9∶1) cements. The composites formed were tested for initial compressive strenghts, underwater and radiation stabilities and leach rates. IAEA standard leach testing was with simulated sea and ground waters. Ground water leaching was also carried out on composites subjected to 1.1 MGy (γ). Polymer modified composites performed better than the BFS/OPC mix under all the conditions studied and, in most cases, were able to encapsulate high resin loading.

Restricted access

Abstract  

The ability of natural and simulated soils to take up radioisotopes of cesium, strontium and ruthenium was examined. Uptakes were assessed by distribution coefficients measured in the presence of different concentrations of Na, Ca, Mg and HN4 cations, and from synthetic groundwaters. Peat was included in similar studies for comparison purposes. Conclusions were drawn as to the effect of soil and ground water compositions on isotope uptake taking into account the results described in Part 1 of this series1 which estimated the distribution coefficients for137Cs,89Sr and106Ru (as chloride or nitrosyl) shown by illite and montmorillonite clays. These, or similar, clays were soil components in this study.

Restricted access

Abstract  

The leaching of137Cs and90Sr from Surrey Earth montmorillonite and Silver Hill illite has been studied. Three forms of the clays, calcined and uncalcined and their composites with cement, were leached with four leachants, deionized water, and simulated sea ground and storage pond waters. Results were expressed as the cumulative fraction of activity leached against the square root of time, and used to compute diffusion coefficients. These suggested that all the leaching processes studied were slow (10−22 to 10−18 m2.s−1).

Restricted access

Abstract  

The ability of two different types of synthetic inorganic ion-exchangers to sorb radioactive cobalt-60 using a batch-type method was studied. The two materials examined were the analogue of the natural titanosilicate penkvilksite-2O (AM-3) and a synthetic antimonysilicate. Ion-exchange experiments were performed with solutions labelled with radioactive cobalt (60Co). The sorption of 60Co onto the two samples materials were compared in terms of distribution coefficient (K d), sorption percentage and cobalt quantity removed in mg per gram weight of the material. Several parameters were investigated viz. contact time, cobalt concentration, and sorbent concentration. It was found that the batch factor and cobalt concentration had a significant influence on the sorption of cobalt onto both of the materials. This was associated with the difference in pH generated by suspensions of the materials in water which was alkaline for the penkvilksite-2O analogue, and acid for the synthetic antimonysilicate.

Restricted access

Cerenkov spectroscopic assay of fission isotopes

I. Assay for90Sr and89Sr in aqueous nitrate solutions in the presence of137Cs

Journal of Radioanalytical and Nuclear Chemistry
Authors:
B. Carmon
and
A. Dyer

Abstract  

The procedure for the assay of90Sr or89Sr in the presence of a weak beta-emitter, such as137Cs is described which could be applicable in studies on the purification and decontamination of aqueous radioactive wastes by ion-exchangers. The influence of colour-quenchers on the counting efficiency of radiostrontium has also been investigated.

Restricted access

Abstract  

The solvents tributylphosphate (TBP) and odourless kerosene (OK) are widely used to extract plutonium(IV) and uranium(V) in nuclear processing plants. Their use depends upon their relatively low affinity for fission products, but small amounts of radioisotopes are taken up by them. To aid disposal/reuse of these solvents it is of use to study ways of removing radioisotopes of Cs and Sr from them. This paper describes simple distribution coefficient (K d ) measurements to test the ability of aluminosilicate zeolites to remove137Cs and90Sr/90Y from TBP, OK and their mixtures.

Restricted access

Abstract  

The solvents tributylphosphate (TBP) and odourless kerosene (OK) are widely used to extract plutonium(IV) and uranium(V) in nuclear processing plants. Although these solvents are chosen because of their low affinity for fission products it is, nevertheless, of value to study ways of removing the small quantities of fission products, such as isotopes of Cs, Sr and Ru, which can be present in the solvents. This paper describes simple distribution coefficients (K d) measurements made to test the ability of the aluminosilicate zeolites to remove106Ru from TBP, OK, and their mixtures.

Restricted access

Abstract  

The characteristics of ion exchange of uranyl and americium, which are -emitting radioactive nuclides, were examined by batch and column methods. SAPO-34 showed good selectivity for uranyl ion at pH 2–3.5, and distribution coefficients of Am3+ and UO 2 2+ increased with equilibrium pH. -irradiation (2 MGy) did not show any significant effect on the uptake of both of actinide ions onto L and SAPO-34. Higher does of -irradiation (up to 10 MGy) created a change of equilibrium pH, and hence uptake, due to radiolysis of water and heat localization generated by -radiation and annealing processes.

Restricted access

Abstract  

Commercially available synthetic hydrous oxides (Ferrox, Zirox, Alumina, Oxti, and Oxtain) have been used to study the sorption of some anionic species from simulated radioactive waste. Results of the analysis showed varying degrees of uptake for the anions in various media solutions. Sorption was most effective in the solution pH 2–7 range following the amphoteric nature of these materials. The presence of competing anions had a marked effect on the sorption properties of the material.

Restricted access

Abstract  

The uptake of sodium, caesium and rubidium onto Los Transcos clay was studied using the batch method. Sodium-22, rubidium-86 and caesium-137 were used as tracers. In most of the experiments cation concentrations used were 0.01 N. Triple distilled and deionized water were used and the grain size of all solid particles was 53 m. In all cases a few hours of shaking was enough to reach the equilibrium. The ion exchange isotherm experiments were performed by using ammonium forms of the clays. Results showed that the ammonium form of Los Trancos clay was selective for Cs and Rb uptake but Na was not prefered. Cation uptake kinetics were complete in 1 h.

Restricted access