PROPERTIES OF FUELS FOR HIGH-TEMPERATURE REACTOR CONCEPTS

A compilation was prepared to aid design engineers in the selection of potential fuels for advanced hightemperature reactors. Available data are included on critical properties for all fuels believed to be potentially capable of operating at surface temperatures of at least 650 deg C. Fuels of recent interest with this capability are included even though sufficient data for their final evaluation are not yet available. The compilation is broken down into sections devoted to particular types of fuels. Property data for all these materials are arranged in a standardized format designed for rapid consultation. In addition to these data sheets, a master table that permits comparison of all fuels covered in the compilation on the basis of four properties considered essential in an initial fuel evaluation is presented. Also, a compilation of appropriate conversion units has been included for the design engineer's convenience. (J.R.D.

PROPERTIES OF FUELS FOR HIGH-TEMPERATURE REACTOR CONCEPTS

A compilation was prepared to aid design engineers in the selection of potential fuels for advanced hightemperature reactors. Available data are included on critical properties for all fuels believed to be potentially capable of operating at surface temperatures of at least 650 deg C. Fuels of recent interest with this capability are included even though sufficient data for their final evaluation are not yet available. The compilation is broken down into sections devoted to particular types of fuels. Property data for all these materials are arranged in a standardized format designed for rapid consultation. In addition to these data sheets, a master table that permits comparison of all fuels covered in the compilation on the basis of four properties considered essential in an initial fuel evaluation is presented. Also, a compilation of appropriate conversion units has been included for the design engineer's convenience. (J.R.D.

THE EFFECT OF IMPURITIES ON IRON-CHROMIUM-YTTRIUM ALLOYS

A study was made of the effect of carbon, manganese, oxygen, palladium, and sulfur on the structure and fabricability of iron-35 wt.% chronium-1 wt.% yttrium alloy. Using a vacuum-induction melting technique each of the additives except oxygen was introduced to 1-lb remelts of a single 15-lb master alloy. The master alloy and remelts were made under similar melting, pouring, and casting conditions. Oxygen was introduced as Fe/sub 2/0/sub 2/ by inertelectrode arc melting to avoid extraneous, uncontrolled contamination stemming from crucible contact. Photomicrographs were prepared of as-cast metal illustrating structural variations. Ingots obtained were fabricated to 0.050-in. sheet at 2000 deg F to compare fabrication characteristics with those of the control ingot containing no additives. As a qualitative measure of metal soundness and ductility, a portion of each of the 0.050-in. sheets was further reduced at room temperatare to 3-mil foil. During melting at 2900 to 3000 deg F under controlled conditions, the amount of yttrium present in the charge was reduced roughly 50% by reaction with the alumina crucible. Sulfide, added as FeS, and oxide additions also lowered the amount of yttrium retained in ingots. The maximum amount of sulfur retained in an alloy of nominal composition iron-35 wt.% chromium--1 wt.% yttrium--500 ppm sulfur was found to be about 80 ppm, and an alloy containing this amount of sulfur seemed to show slightly improved fabrication characteristics. None of the impurities investigated affected the fabrication characteristics or the quality of the finished product sufficiently to be considered detrimental from this point of view. (auth