In a study of the nuclear and physical properties of the concrete shield of the ORNL Graphite Reactor measurements were made of the fast-neutron fluxes in a hole through the shield. These fluxes were not incinded in the formal report of the study (ORNL-2195) since several uncertainties associated with the measurements made the absolute values unreliable. The attenuation curves at one energy may be reasonably accurate, however. (auth)

Speciments of iodide zirconium, Zircaloy-2, Zr-15Nb, iodide titanium, TMCA-45 titanium, A-110AT titanium, and 430 stainless steel were corroded in a highpressure recombiner loop. Analyses were performed to determine the amount of hydrogen pickup. The titanium materials and iodide zirconium showed very high hydrogen pickups, while the zirconium alloys and the 430 stainless steel absorbed smaller amounts of hydrogen Metallographic examination of the specimens showed that recrystallization occurred in all but the Ar-15Nb specimens. There seems to be little difference in the extent of recrystallization and grain growth whether the in the recombiner section at 430 to 500 deg C. Recrystalliplained or correlated in any way with the amount of f hydrogen sion that occured. Since hydrogen is known to seriously embrittle zirconium and titanium, it is recommended that crystal-bar zirconium and titanium alloys not be used as materials of construction in environ ments sinmilar to that of the High Pressure Recombiner Loop. (auth)

A comprehensive program has been initiated at the University of California Radiation Laboratory to give practical aid to the physicists and technicians carrying out track measurements. Attention has been given to stack alignment, coordinate read-out, grain-density measurement, multiple-scattering measurements, and data recording. (A. C.)