In view of current work on the Columbia River by the Biology Division and Development Division of the Health Instrument Divisions and the contemplated studies of the US Public Health Service Group new at Hanford, it was suggested that the groups review their programs related to studies of the Columbia River. The work carried out by the Control Functions Section of the Health Instrument Division in this respect is reviewed in outline form. Some of the studies are jointly carried out by the Control Functions Section and the Methods Group of the Environmental Hazards Section. The principal purpose for monitoring the Columbia River is to evaluate any radiation hazards that might exist as the result of discharging radioactive effluent into the river from the Hanford pile areas. The miscellaneous special studies conducted so supplement the routine monitoring program are pointed at into the river to better understand the effects of this radioactive contamination on the environment of the river and/or any drinking water supplies using the Columbia river as a source of supply. 1 fig.

This is a progress report of the production reactors on the Hanford Reservation for the month of April 1951. This report takes each division (e.g., manufacturing, medical, accounting, occupational safety, security, reactor operations, etc.) of the site and summarizes its accomplishments and employee relations for that month.

The fission and spallation reactions caused in uranium by bombardment with high energy protons (340 t o 350 MeV) were investigated. The reaction products were separated from the target by chemical processes and identified by their radioactive properties. The relative yields of the observed fission products were measured, and the results plotted as a function of mass number. Several of the spallation products were identified and their yields estimated. An attempt was made to determine the most probable atomic number for a nuclide of given mass formed directly from fission. Studies were made of the relative yields along several isobaric chains as a function of atomic number. From these data predictions of the mass and charge of the fissioning nucleus are made.

This volume presents the quarterly results of that portion of the research and development which is directed towards establishing new techniques and instruments and towards improving present methods for determining levels of radioactivity accurately and safely. The locally developed amplifier of high gain and of wide dynamic range has been shown to provide plateaus suitable for the simultaneous counting of alpha and beta particles. Commercially available amplifiers have failed to exhibit suitable plateaus when used under the same conditions. This locally developed amplifier in conjunction with the Nuclear Instruments PC1 chamber has made it possible to estimate beta energies down to 0.02 million electron volt, which is to be compared to a former lower limit of 0.1 million electron volt. A fast neutron survey meter must be simple, lightweight, portable and efficient and must provide discrimination against gamma rays. The first step, which is the design of a suitable detecting device has been successfully completed as good efficiency and good discrimination against gamma rays have been achieved. The necessary electronic circuits must now be engineered to provide the requisite simplicity lightweight and portability.

The work presented in this volume concludes the research on methods for the recovery of purified radium from K-65 residues. The completion of a final report and an engineering study of the proposed process are underway. The preliminary treatment of the K-65 residues with 15% sodium hydroxide was checked and found to give 84% removal of lead and 40% removal of silica. The combined sodium hydroxide, sodium carbonate treatment for removing additional amounts of lead and achieving a preliminary conversion of the radium-barium silfates to carbonates has been studied at 170 deg C under pressure as well as at 100 deg C as previously used. A marked improvemont was found with the use of higher temperatures. Alternate methods were studied for removing the residual lead content in place of precipitation with hydrogen sulfide. Precipitation of insoluble hydroxides was found to remove about 90% of the lead present. The over-all recovery of radium in the residues treatment has been checked and found to be better than 98%. The work on the separation of radium from barium by fractional precipitation of the chromates has shown that in actual practices the results are in good agreement with the results calculated from the observed …

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The slow neutron transmission of several samples of plutonium is being investigated with the Columbia Neutron Velocity Spectrometer. The spectrometer, which has been described previously (Rainwater et al., Phys. Rev. 71, 65 (1947)), was recently improved, recalibrated, and the operational factor reevaluated (CUD-59). Results reported here were obtained by the procedure described in that report.

It is concluded that austenitic stainless steels in the fully solution- heat-treated state will give satisfactory service in concentrated UNH solutions. (M.H.R)

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This report is based on studies conducted for the Atomic Energy Commission.

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A systematics is given of all transitions for odd A nuclei for which sufficiently reliable data are available. The allowed or forbidden characters of the transitions are correlated with the positions of the initial and final odd nucleon groups in the nuclear shell scheme. The nuclear shells show definite characteristics with respect to parity of the ground states. The latter is the same as the one obtained from known spins and magnetic moments in a one-particle interpretation.

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A meeting was held on May 17 to review possible alternate designs of horizontal rods for 105-C. The system used on ``C`` must operate satisfactorily at an anticipated graphite temperature of 380 C (760 F) with the possibility expressed by the Technical Division that this temperature limitations may be raised if satisfactory new pile atmospheres can be developed. The design will be based on a maximum graphite growth of 3 inches at a distance of 3 feet from the edge of the graphite block. This value ignores the anticipated favorable results from graphite coring, and is greater than the growth expected in ``C`` based on experience with present reactors. A satisfactory rod end seal configuration is required for these conditions. It was decided that a round control rod with external seal would be recommended to meet these conditions.

Studies were continued on processes for the separation and purification of Ac/sup 227/ from neutron-irradiated Ra and for the deposition of Ac on various metal surfaces. (For preceding period see MLM-519.) (C.W.H.)