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Abstract  

Quantitative measurement of both bulk and localized oxygen concentrations is of importance in the study of oxidation kinetics. We describe the combined application of two nuclear techniques, fast neutron activation analysis and (d, p) nuclear microprobe, to the determination of oxygen concentrations and surface profiles for steam-oxidized Zircaloy-4 cladding specimens. Results of measurements using these techniques are presented.

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Abstract  

The kinetic parameters of the formation of single-strand breaks (ssb) induced by OH radicals in presence of oxygen and that of the decay of peroxyl radicals of the polynucleotide have been found to be very similar. The conclusion that the decay of the peroxyl radicals is involved in the rate-determining step of ssb formation is confirmed for poly(U) by a study of the effect of ethanol on ssb formation under conditions of laser pulse excitation. The kinetics of the formation of ssb for poly(U) is complex but is consistent with a first order followed by more complex reactions. This kinetics is compatible with a pathway to ssb formation assuming H abstraction from the sugar moiety by base peroxyl radicals as the rate-determining step in the beginning of the overall reaction.

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Abstract  

Lanthanides are common fission products and the ability to separate and quantify these elements is critical to rapid radiochemistry applications. Published lanthanide separations using Eichrom Ln Spec resin utilize an HCl gradient. Here it is shown that the efficacy and resolution of the separation is improved when a nitric acid gradient is used instead. The described method allows parallel processing of many samples in 1.5 h followed by 60 min counting for quantification of 9 radioisotopes of 7 lanthanide elements.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: M. D'Agostino, E. Kamykowski, F. Kuehne, G. Padawer, E. Schneid, R. Schulte, M. Stauber, and F. Swanson

Abstract  

A review is presented summarizing several nondestructive bulk and surface analysis nuclear techniques developed in the Grumman Research Laboratories. Bulk analysis techniques include 14-MeV-neutron activation analysis and accelerator based neutron radiography. The surface analysis techniques include resonant and non-resonant nuclear microprobes for the depth profile analysis of light elements (H, He, Li, Be, C, N, O, and F) in the surface of materials. Emphasis is placed on the description and discussion of the unique nuclear microprobe analytical capabilities of immediate importance to a number of current problems facing materials specialists.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: M. Douglas, J. Friese, L. Greenwood, O. Farmer, M. Thomas, T. Maiti, E. Finn, S. Garofoli, P. Gassman, M. Huff, S. Schulte, S. Smith, K. Thomas, and P. Bachelor

Abstract  

Quantitative measurement of fission and activation products resulting from neutron irradiation of fissile materials is of interest for applications in environmental monitoring, nuclear waste management, and national security. Based on established separation processes involving co-precipitation, solvent extraction, and ion-exchange and extraction chromatography, we have optimized a proposed sequence of separation steps to allow for the timely quantification of analytes of interest. We have recently evaluated this scheme using an irradiated sample to examine the adequacy of separations for measurement of desired analytes by gamma spectrometry. Here we present the radiochemical separations utilized and the yields and purity obtained.

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