Part I. Experimental Reactors: The design has been completed for all the major high-pressure and low-pressure components except the reactor pressure vessel. Contained in this report are the most recent revisions of the low-pressure-system flow sheet, a description of important details of the reactor cell, and the final design of the main heat exchangers, the inner dump tanks and separator. the recombiner and recombiner-condenser, and the outer dump tank and reflux condenser. Part II. Thorium Breeder Reactor: An analysis of the relative effects of major process variables on the economics and characteristics of two-region thorium breeder reactors is nearing completion, and the results to date are presented in this report. From these results most of the major reactor characteristics have been determined; they are reported with certain other engineering studies pertinent to the early phases of the program. Part III. Corrosion: One loop was removed from service and cross sectioned for inspection of the internal surfaces. This loop was of type 347 stainless steel pipe and had a cumulative operating time of more than 12,000 hr with uranyl sulfate solutions varying in concentration from 0.004 to 1.34 m. No excessive or localized corrosion attack was noted except in one highly …