This progress report discusses the work during the fourth quarter of 1951. During this quarter, "the uranium raw materials program at ORNL has been devoted to studies of uranium chemistry and to the development of processes for deriving uranium and byproducts from various types of ores" (From introduction).

From introduction: "During the second quarter of fiscal year 1952, the Isotope Production and Process Development Department placed primary emphasis on the collection of lithium, iron and calcium isotopes."

From summary: "During 1951 NDA has, at the request of ORNL, been studying the supercritical-water reactor as proposed for aircraft propulsion in Wash-24...This study has concerned itself only with the reactor and shield." The report describes the reactor and the processes involved in developing it. The goal of the development of this reactor is identified as a path to supersonic flight.

From abstract: "The reaction between hydrogen and oxygen with the aid of various catalysts (especially platinum on aluminua) has been studied, and the operating variables such as flow rates, space velocity, temperature, and gas composition have been examined rather extensively. It has been found that hydrogen and oxygen in stoichiometric proportions and mixed with either steam or helium may be made to react to the extent of 99.5% or greater at space velocities up to 30,000 hr-1, or even higher, at temperatures from 100[degrees] to 900[degrees]C, and with mixtures ranging from less than 1% hydrogen to mixtures containing 12% hydrogen and 6% oxygen. Richer mixtures, including undiluted electrolytic gas (H2 + 1/2 O2) have been used with catalysts less active than platinum (e.g. copper, silver, nickel and V2O5) but here the gas mixture is explosive and care must be taken to prevent explosions. The thermal reaction between hydrogen and oxygen diluted with steam has also been investigated at temperatures between 500[degrees] and 800[degrees]C."

Technical reports outlining the controls for the Homogeneous Reactor Experiment (HRE); controls are divided into three principal groups. 1. Reactor. 2. Process or auxiliary. 3. Power generation. These are the classifications designating the primary functions of the controls. [From Introduction]

The first part of this quarterly progress report details reactor theory and design, discussing the aircraft reactor experiment, experimental reactor engineering, reactor physics, and critical experiments. The second part of this report is not included. The third part of this quarterly progress report details materials research, discussing corrosion research, physical properties and heat-transfer research, metallurgy and ceramics, chemistry of high-temperature liquids, and radiation damage. The fourth part of this quarterly progress report details alternate systems, discussing a supercritical water reactor, circulating-moderator-coolant reactors. The fifth part of this quarterly progress report includes appendixes.

This technical report presents "a theoretical study of the motion of gas bubbles in a rotating liquid" in order to "make comparison with experimental data from an investigation concerning the removal of gas bubbles from rotating liquids as descriped in ORNL-630." The report presents a literature review of "motion of gas bubbles in liquids" and provides a "summary of extensive experimental studies at the University of Tennessee." It also presents "an expression for the radial velocity of a gas bubble in a rotating liquid based on principles of mechanics." Finally, this report presents "a method for computing the steady state state [sic] gas hold-up in the HRE reactor core under power producing conditions." (From introduction)

From abstract: "Operation of the 86-inch cyclotron has been continuous except for a three-day interruption caused by a water leak inside the vacuum chamber; monthly output has averaged over 210,000 [mu]a-hr; the average continuous (168-hour week) beam power has been approximately 5.5 kw; and the energy of the beam has been determined to be ~19.4 Mev. No changes due to radiation damage have been detected in Inconel tubes containing UF4-NaF-KF eutectic which were irradited in the 96-inch cyclotron with power inputs up to ~415 watts/cc. The major components of the 63-inch cyclotron have been fabricated and are being tested as the machine is being assembled. On the 22-inch cyclotron a radius-wise examination of the fine structure of the proton beam reveals definite proton orbits. Several grams of very pure uranium 235 have been prepared; the chemical recovery for first-stage separation of U 236 has been established as 97%; and facilities for laboratory-scale separation of plutonium isotopes are being prepared."

Technical report focusing on the Homogeneous Reactor Experiment (HRE) construction, completed 60% as of August 15, 1951. Report also includes alternate systems studies and long range studies of the Homogeneous Reactor Experiment. Technical report is organized in three parts. [From Summary]