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Interest in dosimetry procedures in the context of a large‐scale processing situation exceeds the purely documentary aspects of this report. The numerous combinations afforded by the various types, strengths and configurations of irradiation sources and the possibilities for various conveyors and other facility design factors impacting on irradiation logistics render a completely general treatment of dosimetry procedures in such instances almost impossible. While the exact combination of these various factors represented by the irradiation facilities at NARADCOM may be duplicated nowhere else, the dosimetry procedures documented in this report offer both experience and solutions that might be more generally useful. Therefore, this report complements and supplements more general discussions found in the literature and cited in the text.

The radiolysis of aqueous FeSOrCuS04-HzSOc solutions has been studied at dose rates up to ~3 x 1027 eV L-1 sec-1 (~5 x 1010 rads sec-l). G(Fea+), which equals -0.7 at low irradiation intensities, increased to -4 with increasing dose rate, acidity, and the extent of oxygenation. This increase is significantly reduced for systems containing higher concentrations of Cu2+. Kinetic analysis of the results showed that the increase in G(Fe*+) values at the higher radiation intensities is due to the reactions H + H + Hz, H + HOz -% HzOz, and OH + HOz + HzO3, and good agreement between calculated and experimental values is obtained using the following rate constant values (in 1. mol-' sec-1) : k~ = 1.4 X lolo, = 2.0 X 1O1O, k~ = 1.1 X lolo, and k14 (for H + OH -HzO) = 2.0 X lolo. Our studies show also that (1) some of the hydrogen atoms are produced in primary radiolytic processes together with solvated electrons, (2) hydrogen sesquioxide, produced by the recombination of OH and HOz radicals, is capable of oxidising four equivalents of Fez+ even in the presence of excess Cu2+ ions and therefore the oxidation of Fez+ by H@a does not proceed via processes which regenerates the HOg radical, and (3) radiation-produced hydrogen peroxide is partially decomposed during the pulse, particularly at the higher intensities. kl2 kl6 IntroductionThe radiation chemistry of F~SO~-CUSOCHZSO~ solutions has been examined by a number of investigators.2-6 In most cases, these studies have been carried out either to elucidate the reactions which take place a t relatively low radiation intensities or to evaluate the application of such systems as dosimeters.In this paper, we report on a study of the radiolysis of the FeS04-CuS04-HzS04 system in the dose rate range up to -3 X loz7 eV 1.-' sec-l (-5 X 1O1O rads sec-l). At such high radiation intensities, radical recombination reactions compete efficiently with radical-solute reactions,6-1' and as a result, G(Fe3+) increases with increasing dose rate. Because of the rather low G value (-0.7) of this system at low dose rates, the relative increase in ferric yield is large, and is consequently convenient for studying the reaction kinetics in the high-intensity radiolysis of aqueous sys tems.

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