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1.
In hypothetical accident scenarios for Light Water reactors, the extent of release of iodine upon irradiation needs to be assessed for the purpose of evaluation of the applicable source term. In this context, an understanding of the behaviour of aqueous cesium iodide solutions subjected to high gamma-ray fluxes acquires significant importance. In the present work, gamma radiolysis of a cesium iodide solution (10–2M I) with and without boron additive is investigated by irradiating with60Co source at ambient temperature. Upon irradiation of the CsI solution, iodine is liberated, and the concentration of iodide in the KOH trap present in the radiolysis vessel increases with dose. The radiolytic products I 3 , IO 3 and H2O2 formed in the irradiated solution are also estimated and G values obtained are reported. G(I 3 ) and G(IO 3 ) are of the order of 10–3 and 10–4, respectively. G(H2O2) decreases with increase in dose. Addition of boron up to 200 ppm, does not appear to alter significantly the release fraction of iodine.  相似文献   

2.
The specific effect due to Gd3+ ion on the radiolysis of aqueous nitrate solutions was determined by measurement of H2, H2O2 and NO 2 radiolytic yields produced by gamma-irradiation of aerated and deaerated solutions of gadolinium, sodium and calcium nitrates in the concentration range of 10–5 to 0.3M. Important O2 consumption in aerated and O2 evolution in deaerated Gd(NO3)2 solutions was found by radiolysis in comparison with the inert cations nitrates. In the former the Gd3+ ion generates an O2 transporter producing an increase in the H2O2 yield and a decrease in the NO 2 yield, while in the latter it enhances the H2 and NO 2 production with respect to the same nitrate concentration of the Na+ solutions.  相似文献   

3.
A mathematical model for the formation of main transient and final radiolysis products generated in tracks of fast electrons and positrons in water and aqueous solutions was constructed and described in terms of equations of inhomogeneous chemical kinetics in part 1 of this study. The model takes into account the reactions of a solute with epithermal electrons, thermal, and hydrated electrons; the ambipolar character of diffusion of charged intratrack particles; and new pathways of the formation of hydrogen and positronium due to the appearance of weakly bound states of electrons. In the present paper, the model was quantitatively fitted to experimental data on both time variation in the yields of radiolytic products (H3O+, e aq , H, OH, OH, H2O2) in pure water and the yields of hydrogen (H2, H), hydrated electron (e aq ) and positronium (Ps) in various dilute and concentrated aqueous solutions.__________Translated from Khimiya Vysokikh Energii, Vol. 39, No. 5, 2005, pp. 330–338.Original Russian Text Copyright © 2005 by Stepanov, Byakov.  相似文献   

4.
Pulse radiolysis was utilized to study the kinetics of the iodine-hydrazine reaction in aqueous solutions containing phosphate buffer in the pH range 5.5 to 7. The reaction rate was found to be proportional to and [I]–1, but did not show simple proportionality to [H+]–1 and was considerably higher than that found earlier when the pH of solutions was adjusted with HClO4 or H3BO3. The results are in a formal agreement with the assumption that in phosphate buffered solutions a complex N2H4. HPO 4 2– is formed, reacting with I2 with a rate constant which is greater than that ascribed earlier to the reaction of N2H4 with I2/Ref. 1/.  相似文献   

5.
6.
A kinetic model of radiation-chemical transformations of nitrogen oxide and nitrites in aqueous solutions is proposed. It includes the previously developed reaction scheme for water and H2, H2O2, and O2 solutions complemented by the reactions of water radiolysis products with NO and NO2. It has been shown that the model describes well experimental data on the decomposition of the compounds and the buildup of products depending on the absorbed dose in aqueous solutions at different pH values.  相似文献   

7.
Reactions of iodination of monosubstituted derivatives of B12H11X2–anion (X = OC(O)CH3, OH, SCN) were studied. The reactions were shown to proceed smoothly to give B12H10(OC(O)CH3)I2–((carboxy)(iodo)[decahydro[I h1551-20-closo]dodecaborate(2–)] anion), B12H10(OH)I2–((hydroxo)(iodo)[decahydro[I h1551-20-closo]dodecaborate(2–)] anion), and B12H10(SCN)I2–((thiocyanato)(iodo)[decahydro[I h1551-20-closo]dodecaborate(2–)] anion) in high yields, irrespective of the solvent used (benzene, H2O–ROH, where R = C2H5, CH2CH2CH3).1  相似文献   

8.
The effects of vitamins B1, B2, and B6 and pyridoxal phosphate on the formation of the final radiolysis products of aqueous ethanol and ethylene glycol solutions were studied. It was found that vitamin B2 and pyridoxal phosphate effectively oxidize R·CHOH species to suppress their recombination and fragmentation reactions, thereby increasing the yields of corresponding oxidation products. Vitamins B1 and B6 are capable of reducing alcohol radicals to the parent molecules and, hence, decreasing the yields of the main radiolysis products.__________Translated from Khimiya Vysokikh Energii, Vol. 39, No. 5, 2005, pp. 325–329.Original Russian Text Copyright © 2005 by Lagutin, Shadyro.  相似文献   

9.
Pulse radiolysis was utilized to study the iodine — hydrazine reaction in aqueous solutions of pH3 to 7, at I concentrations of 0.02 to 0.34M, and a constant ionic strength of 0.35M. The reaction rate was found to be proportional to [H+]–1 and [I]–1. Experimental results support the assumption that the rate-determining step is the reaction of I2 with N2H4 with a rate constant K1.2×107 M–1s–1.  相似文献   

10.
The chain mechanism of oxidation of hydrazine in aqueous solutions saturated with oxygen at pH > 7.5 was established. The yields of radiochemical decomposition of hydrazine increase with a decrease in the absorbed dose rate, an increase in the concentration of hydrazine, and the pH of the solution and attains hundreds of molecules per 100 eV of absorbed energy. It is hypothesized that the chain process includes a stage of formation of the N2H3 radical, its reaction with O2, and the formation of O2 or N2H3O2. The chain propagation reaction is due to the reaction of molecules of N2H4 with N2H3O2 or O2 .Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2450–2453, November, 1989.  相似文献   

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