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001-es BibID:BIBFORM018705
Első szerző:Dombovári Péter
Cím:Accumulation of uranium on austenitic stainless steel surfaces / Péter Dombovári, Péter Kádár, Tibor Kovács, János Somlai, Krisztián Radó, István Varga, Renáta Buják, Kálmán Varga, Pál Halmos, János Borszéki, József Kónya, Noémi M. Nagy, László Kövér, Dezső Varga, István Cserny, József Tóth, Lajos Fodor, Attila Horváth, Tamás Pintér, János Schunk
Dátum:2007
ISSN:0013-4686
Megjegyzések:The surface contamination by uranium in the primary circuit of PWR type nuclear reactors is a fairly complex problem as (i) different chemical forms (molecular, colloidal and/or disperse) of the uranium atoms can be present in the boric acid coolant, and (ii) only limited pieces of information about the extent, kinetics and mechanism of uranium accumulation on constructional materials are available in the literature. A comprehensive program has been initiated in order to gain fundamental information about the uranium accumulation onto the main constituents of the primary cooling circuit (i.e., onto austenitic stainless steel type 08X18H10T (GOSZT 5632-61) and Zr(1%Nb) alloy). In this paper, some experimental findings on the time and pH dependences of U accumulation obtained in a pilot plant model system are presented and discussed. The surface excess, oxidation state and chemical forms of uranium species sorbed on the inner surfaces of the stainless steel tubes of steam generators have been detected by radiotracer (alpha spectrometric), ICP-OES and XPS methods. In addition, the passivity, morphology and chemical composition of the oxide-layers formed on the studied surfaces of steel specimens have been analyzed by voltammetry and SEM-EDX. The experimental data imply that the uranium sorption is significant in the pH range of 4-8 where the intense hydrolysis of uranyl cations in boric acid solution can be observed. Some specific adsorption and deposition of (mainly colloidal and disperse) uranyl hydroxide to be formed in the solution prevail over the accumulation of other U(VI) hydroxo complexes. The maximum surface excess of uranium species measured at pH 6 (Gamma(sample) = 1.22 mu g cm(-2) U congruent to 4 x 10(-9) mol cm(-2) UO2(OH)(2)) exceeds a monolayer coverage. (c) 2006 Elsevier Ltd. All rights reserved.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
uranium
stainless steel
accumulation
Megjelenés:Electrochimica Acta. - 52 : 7 (2007), p. 2542-2551. -
További szerzők:Kádár Péter Kovács Tibor Somlai János Radó Krisztián Varga István Buják Renáta Varga Kálmán Halmos Pál (kémikus) Borszéki János Kónya József (1937-) (vegyész) Nagy Noémi, M. (1960-) (vegyész, angol szakfordító) Kövér László (1949-) (fizikus) Varga Dezső Cserny István (fizikus) Tóth József (fizikus) Fodor Lajos Horváth Attila Pintér Tamás Schunk János
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