Two-phase flow-regime transitions at elevated pressures for a single-component, trichloromonofluoromethane, were investigated for forced-circulation, upward flow in a vertical, rectangular conduit with internal dimensions of 0.380 by 1.050 inches.

Errata sheet listing corrections to three pages of a report that describes a transistorized automatic counting and recording system built for the determination of foil-activation data.

A total of nine clad plates, containing uranium -5 w/o zirconium 1.5 w/o niobium alloy cores and clad with Zircaloy-II, were rolled in plain carbon steel jackets, heat treated, physically evaluated, and corrosion tested. All these plates were found to be within predetermined dimensional tolerance in width, thickness, length, cladding thickness, and core distribution. Improved control of wielding variables and of the length of the seal pin projecting above the end plugs resulted in the elimination of frequently observed segmented inclusions at the seal pin interfaces.

This seventh Annual Report is a summary of some of the progress in scientific and engineering research and development carried on at Argonne National Laboratory during 1961. As is customary in this series, only those portions of the total program that have reached such a stage that they may be of general interest are recorded. Thus, a comparison with the Annual Reports for 1959 (ANL-6125) and for 1960 (ANL-6275) will reveal the description of a generally different set of scientific activities. A more detailed presentation of any work covered in this report or of the many ANL projects not mentioned may be obtained by perusing the various progress and topical reports issued by the Laboratory during 1961. A list of the publications in the scientific journals during 1961 by Argonne personnel has been given as an Appendix.