The goal of this study was to develop an iron-based alloy, similar to Type 316 stainless steel in mechanical and corrosion properties but with a reduced chromium content or, ideally, no chromium. A total of twenty-six 225-g ingots and ten 2.5 to 12 kg ingots of various compositions in the Fe-Si-Mn-Ni-C system were prepared. All ingots contained from 5 to 11 w/o silicon and drew their corrosion resistance primarily from this component. The composition ranges of the remaining major alloying elements were (in w/o) 0-24 Mn, 0-35 Ni, and 0.08 to 0.95 C. Most of the alloys were reduced to sheet, demonstrating the hot fabricability of these high-silicon alloys. The mechanical and corrosion properties of these alloys are attractive. Tensile tests showed yield strengths of 303 to 379 Mpa (44 to 55 ksi), ultimate tensile strengths of 731 to 882 MPa (106 to 128 ksi), and elongations of 34 to 77%. Air oxidation rates were lower than those of 300-series stainless steels at 1000 C. Salt water corrosion rates for these alloys fall between those of stainless steels and plain carbon steels and are 5 to 10 times lower than the rates for plain carbon steels.

This report describes the fabrication of a new boron-copper neutron absorbing material that was developed to meet the upgrading needs of the Intense Pulsed Neutron Source (IPNS) at Argonne National Laboratory. To increase the intensity of the neutron beams from the IPNS, the target uranium was changed from depleted uranium to uranium enriched to 77.5% U-235. To keep the multiplication factor, k(sub eff) (number of fissions in one generation/number of fissions in preceding generation) at a safe level, a new neutron absorber material was needed. The previous materials, boral and cadmium, could not meet the new requirements and a search of the literature showed that no currently available material was acceptable.

Report describing the fabrication of Doppler Helices, which were 1/8 inch diameter x 12 foot long uranium core completely enclosed within a thin metal jacket and wound into a spring or helix shape.

Radioactive krypton-85 is used as a tracer to detect pinhole failures in GCFR cladding. High-purity helium (99.99% pure) that contains 0.3 ppm krypton-85 is used to pressurize the tubular test specimens, and a Geiger-Mueller counter is used to detect the krypton-85 in the helium environmental gas as it leaves the test chamber. Under the least favorable conditions of temperature and specimen pressure, it is estimated that the smallest pinhole failure that could be detected within 60 sec would have an orifice diameter of 0.0102 cm. Using lead shielding around the Geiger-Muller counter to reduce background radiation, the electronics associated with the krypton-85 detector will terminate a biaxial creep test at krypton-85 activity levels above 20 counts/minute.