The following progress report was compiled by the research and development division of the zirconium pilot plant. This report discusses two iodination and deposition runs that were completed as of August 20, 1951, as well as the third iodination run that uses a vaporizer condenser that condenses approximately 40 pounds of zirconium iodide.

The Heavy Water Components Test Reactor (HWCTR) is used to test prototype fuel elements for power reactors that are moderated with heavy water and fueled with natural or slightly enriched uranium. During the initial critical experiments in the HWCTR, it was observed that there were unexpected variations in nuclear reactivity. Investigations revealed that this effect was due to bubble of helium gas appearing and disappearing in the moderator. An examination of the expected operating conditions of the HWCTR and the solubility of helium in D2O showed that it was possible during normal operation for the helium content of the moderator to exceed saturation and thus for helium to appear as bubbles in the moderator. The possibility of helium bubbles appearing in the moderator because of solubility characteristics was eliminated by modifications to the process system so as to maintain the gas content of the moderator appreciably below saturation.

From abstract: "Within the framework of age theory an expression is developed which represents the probability of a neutron being reflected with an energy loss corresponding to age, v, as a function of reflector thickness."

The Model Q-1212C Pulser is a single frequency (60 pps) generator whose output waveform is characterized by a rise-time of less than 4 mµsec and, depending upon the method of termination, an exponential decay having a time constant of 300 or 600µsec. The waveform approximates that produced by a radiation detector. The waveform approximates that produced by a radiation detector. The maximum available output from the instrument is 10 volts, positive or negative polarity, and is continuously adjustable by means of step switches and a 10-turn potentiometer. The potentiometer has a linearity of 0.1%.

During a visit to Professor H.G. Harb at the University of Wisconsin, it was apparent that he had succeeded in obtaining fresh, clean chemisorptive layers of titanium by sublimation and chat that this could be adapted into an effective high vacuum pump. Two previous techniques of obtaining a chemisorptive layer of titanium, namely catholic sputtering and evaporation from the liquid droplet, have been extensively investigated and reported. Each of these seem to have inherent difficulties in stability and continuity of operation that appear to be eliminated or effectively reduced by the sublimation procedure. A development program was started at Brookhaven National Laboratory to investigate the possibilities of each sublimation of titanium as opposed to evaporation from the liquid.

Abstract: "A particularly conventional modified form of Maxwell distribution is chosen. The modified expressions for (a) the energy transfer from the ions to the electrons in a plasma and (b) the brehmestrahlung from the electrons are calculated. Using the expressions some possible steady-state conditions for the ion and electron gases are derived and compared with those for the usual Maxwell distributions."

This is the fifth quarterly report that documents a system of mass flow that can record measurements of homogeneous flow, slurries, highly corrosive fluids and multiphase fluids, additionally considering pressure drops, measuring external to the flow, ruggedness and reliability.

Report discussing the survey work done at the Battelle Memorial Institute with the objective to successfully build a gas-cooled reactor.

The Heavy Water Components Test Reactor (HWCTR) is a pressurized reactor, cooled and moderated with D2O, and has the capability of testing fuel assemblies under operating conditions of coolant flow, temperate, and pressure that are typical of those proposed for modern power reactors. The report contains (1) description of the four systems used for failed element detection, (2) discussion of the laboratory analyses of water samples used a as backup for the fuel failure instruments, (3) description of 3 monitors, Cyclic Air Sampling Monitor, Stack Gas Activity Monitor, Health Physics Building Monitors, (4) normal full power activity readings, (5) discussion of the experience during fuel failure.

This report describes an improved infrared absorption method to analyze aqueous samples and TBP after extraction. The method described in the following pages is the carbon tetrachloride extraction method.

An addendum to report HW-30390 a additional power generation calculation for P, the rate of energy release, in kilowatts, was derived.

From introductory paragraph: "The study of the counting techniques of gamma-emitting radioisotopes is of a great deal of interest to workers in the field of radiochemistry. Of particular interest to the long-lived gamma emitting isotope of yttrium which is commonly prepared by a deuteron bombardment of strontium and is reported to decay by K-capture. This isotope, which is of interest in the fields of biochemistry and metallurgy was tentatively assigned to mass 86. Since a 2.0 hour activity was observed from a neutron irradiation of yttrium, the assignment was considered fixed. Subsequent work indicated a possibility of a long-lived gamma emitting activity arising in the fast neutron irradiation of yttrium. The published data did not agree with theoretical calculations as to the possibility of these two activities being isomers. This work was undertaken to study the characteristics of the radiations from the isotopes; to have data available on the long-lived activity; and, to attempt to fix the mass assignment."

This paper is a preliminary report of experiments being carried out on the compaction of UO₂ powders by swaging within a restraining tube. Various types of UO₂ have been tried with resulting apparent densities as great as 9.89 grams per cubic centimeter.

"A number of mixtures of polymers and multi-unsaturated monomers have been prepared and irradiated. The content of insoluble gel of irradiated samples of these polymer-monomer mixtures has been determined by extraction."

Summary: Two UO2-filled stainless steel clad fuel rods in which fission gas pressure was measured during irradiation have been subjected to post irradiation examination. Results of free gas analysis and metallographic examination are in general agreement with observed pressures reported previously. Calculated fuel surface temperatures based on extent of fuel recrystallization indicate that in a one-half inch diameter fuel rod with 0.014 inch diametral clearance operated at a maximum heat flux of 531,000 Btu/hr-ft, gap conductance increased with increasing heat flux. An analysis of void configuration indicates that pressure is more sensitive to as-fabricated void volume and changes in this volume resulting from fuel expansion than to fuel central temperature. The decreases in effective void volume with increasing fuel temperatures becomes more significant as initial void volume decreases, and excessive fission gas pressures may be developed in fuel rods operated at high fuel temperatures unless adequate expansion volume is provided in fabrication.

The Heavy Water Components Test Reactor (HWCTR) was built for the Atomic Energy Commission by the Du Pont Company to satisfy a need for fuel testing in the AEC's Heavy Water Power Reactor Program. The reactor was designed to provide a realistic test environment for full size fuel candidates. The report contains sections on (1) the containment building, (2) vertical cross section of the reactor vessel, (3) core layout, (4) low power physics tests and comparison with calculations, (5) rod worths, (6) temperature coefficients, (7) flux shapes, and (8) the operating philosophy of a test reactor.

Report discussing a study to obtain a quantitative measurement of the movement and distribution of hydrogen among components such as magnesium metal chips, uranium tetrafluoride, and magnesium fluoride slag, similar to what would occur during a reaction in a thermite bomb.

Abstract. The waveform or character of a refraction arrival has become internationally important because of its use in determining source parameters. An approximate theoretical machine calculation has been made to show the effect of layering above a refractor on the character of the refraction arrival. The method is illustrated with a geologic model taken from the Edwards Plateau area of West Texas. The effect of the Edwards limestone, Comanche, and Trinity formations on the refraction from the Pennsylvanian limestone is computed. The conversion of energy in theses upper layers from compressional to shear plays a significant role in forming the refraction character. An anticlinal structure is introduced into the Pennsylvanian limestone and it is argued that, in a first approximation, the wave in the Pennsylvanian limestone follow the structure, refracting off at the critical angle as before. Now, however, the angle of incidence on the base of the Trinity is a function of the angle of the structure. Since the amplitudes of converted waves depends n this angle, The character of the refraction arrival depends in a predictable way on the angle in the structure where the critical refraction has taken lace. These results are theoretical and only approximate, but …

The object of this study was to determine whether agitation with ultrasonic energy would significantly increase the dissolution rate of nickel in nitric acid.