[en] The data extracted from numerous irradiation tests were used to derive amoeba endurance parameters for UO₂. The data do not yet allow an unambiguous definition of the controlling mechanism, which may be due to either gaseous or solid-state diffusion processes. Adequate data on the amoeba effect are available for design of a steam-raising high-temperature gas-cooled reactor using UO₂ fuel

[en] A survey of data relevant to the assessment of amoeba failure parameters is presented. The data which can be extracted from the various sources were used to derive amoeba endurance parameters which were also compared to ones from other sources. The governing mechanism is discussed. (author)

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[en] The title complex were prepared from no-carrier-added sup(99m)Tc-TcOsub(4)sup(-) and the air-sensitive reducing ligand DMPE under argon in ethanol-water. At acidic pH [Tc(III)Clsub(2) dmpesub(2)]sup(+) was formed, while alkaline pH led to the formation of 95% yield in less than 1 hour, otherwise the [Tc(V)Osub(2)dmpesub(2)]sup(+) intermediate was present. Electrophoresis demonstrated the unit positive charge and reversed-phase ion-pair HPLC provided separation and identification of sup(99m)Tc-products by direct comparison with known sup(99m)Tc-complexes. In rats the sup(99m)Tc-complexes were excrated by kidneys and liver and reached high heart/blood but only low heart/lung and heart/liver ratios. In dogs satisfactory myocardial scintigrams were obtained in spite of high liver activity. (author)

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[en] Synthesis of the inactive compounds was carried out with a modification of the method of Callery and Lofgren. After ⁹⁹Tcsup(m) labelling, radiochemical purity control was performed with ITLC, TLC, PC and HPLC. The kinetic behaviour of diethyl-IDA (de-IDA) and p-butyl-IDA (pb-IDA) and also their ability for sequential imaging was compared in 8 jaundiced patients (serum bilirubin: 3-25 mg/dl). Blood clearance curves were biexponential with half-times for the fast component of 4.1 and 4.9 min for de-IDA and pb-IDA respectively. Cumulative urinary excretion was higher for de-IDA. pb-IDA demonstrated a slower liver uptake and elimination. Thus on sequential images pb-IDA proved to exhibit relatively prominent hepatic uptake compared with de-IDA, whereas gall bladder filling and intestinal excretion were delayed, and depiction of the biliary system failed in 5 patients using pb-IDA. The delayed imaging characteristics using pb-IDA offer no diagnostic advantage over de-IDA. Misinterpretation of the scintigrams may occur more often with pb-IDA especially if the observation time is not adequately prolonged. The data of the authors indicate that de-IDA seems to be superior to pb-IDA in its diagnostic usefulness, also in patients with severe hyperbilirubinaemia. (author)

[en] The presence of gaseous chemical impurities in the primary coolant of an HTR requires that materials compatibility aspects are considered for HTR designs and particularly so in the case of advanced systems such as direct cycle gas turbine and process heat versions where core exit helium gas temperatures will be in range of 800-1,000⁰C. Materials selection is required for primary circuit components such as heat exchangers, liners for hot ducts, insulation, and turbine discs and blades. In this paper the environmental conditions are considered and the selection and application of high temperature alloys, carbon fibre based composite materials and ceramics is discussed. (orig.)