Report on UCRL progress in general physics research and accelerator operation and development.

The report includes summary reports in five areas (1) High-speed computer program, (2) Mathematical methods, (3) ILLIAC use and operations, (4) IBM 650 use and operation, and (5) General laboratory information.

From abstract: "The rate of hydrolysis of TBP and the effect of the hydrolysis products in the Purex Process have been studied. Hydrolytic conditions may be encountered in the process which would lead to formation of dibutyl phosphoric acid, causing significant losses of tetravalent plutonium in stripping. This situation may be easily alleviated by reducing and stripping the plutonium in the trivalent state."

The effects of oxidation and irradiation on the microsurface structure of pile graphite have been investigated by measuring the surface area and pore size distribution of several samples. The results obtained for both oxidized and irradiated graphite samples indicate that changes in surface characteristics which occur are determined by the flux, temperature of irradiation, and gaseous atmosphere in which the radiation takes place.

Abstract: "Because of the radiation hazards inherent in processing large volumes of radioactive solutions by solvent extraction techniques, there is need for a system with small hold-up which can be contained within a minimum of shielding and yet which is versatile enough to be used as a research tool. A system utilizing a miniature mixer-settler has been constructed and its successful operation by remote means demonstrated. The unit is semiportable and employs a number of novel features of value in studying a wide variety of solvent extraction flowsheets. Data on the distribution of nitric acid between water and tributyl phosphate (in kerosene) are included as a demonstration of the operability of the unit."

This report follows a study that was aimed at the collection of experimental data needed to estimate the maximum safe temperatures and dispersed UO2 contents for MoSi2--UO2 fuel elements exposed to air.

Development of nuclear reactor cores having high power density, long fuel life, and low fabrication costs is the objective of this program sponsored by the AEC. Five tasks are in progress: (1) Task 1A-High Power Density Fuel Development. The number of assemblies has been reduced to seven as a result of the failure of two pellet fuel assemblies. The average burnup of the group operating as of September 1 is 7500 MWD/T. (2) Task 1B-Fuel Fabrication Development. Assembly. Assembly 12S gave positive signals of being a leaker under the multi-type in-core sampler and was declared failed based on the in-core results and visual observation of a cracked rod. Modifications to the instrumented fuel assembly probes were made by removing the failed flow meter rotors to allow continued use of the flux detectors and thermocouples. Flux detectors and thermocouples performed properly after reactor start up. Flux wire tubes were found to be kinked such that their use was prohibited. (3) Task II-Stability, Heat Transfer and Fluid Flow. A series of noise recordings of fluxes, flows, and temperatures has been made at 91 MWt at the Big Rock Point plant. Preliminary analyses of some of the these records were made to obtain …

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Technical report covering classified activities of the Department of Reactor Science and Engineering since its inception in January, 1949. This if focused on the research, evaluation, and redesign of the reactor as well as the tests on various reactor components and engineering design to correct structural defects as they have become evident through reactor use.

The reactor equipment cell is expected to be completed by February 15. While filled with water, the tank was inspected for leaks, and the few leaks found will have been repaired by February 15. All orders for construction materials placed prior to this quarter have been received. New requisitions issued during the quarter total $16,000. Work orders were issued, and fabrication of all low-pressure-system components was begun in the ORNL shops. The thermal shield around the reactor vessel was specified as a 2-ft-thick cylindrical concrete wall. With this shield, the fast-neutron flux in the equipment area will be reduced to 7 x 109 neutrons/cm2/sec, the slow flux to 4 x 107 neutrons/cm2/sec, and the gamma intensity to less than 105 r/hr. The possible blast effects from a rupture of the pressure vessel were studied and are judged to be sufficient to justify the inclusion of a 1.5. to 2-in.-thick blast shield around the pressure vessel. The blast shield eliminates the danger of damaging the leak tight equipment-cell liner. Pressures in the reactor equipment cell, as a result of vessel failure, were calculated in order to arrive at a safe design pressure for the reactor equipment cell. For the case of …