This report is a bibliography of studies on the toxicology of polonium with focus on issues addressed by the Atomic Energy Commission, but also includes published literature. Some of the citations contain abstracts and the reports are annotated as to contemporary classification status of reports.

The relative physiological and toxicological properties of americium and plutonium have been studied following their intravenous administration to rats. The urinary and fecal excretion of americium was similar to that of plutonium administered as Pu(N0{sub 3}){sub 4}. The deposition of americium the tissues and organs of the rat was also similar to that observed for plutonium. The liver and the skeleton were the major sites of deposition. Zirconium citrate administered 15 minutes after injection of americium increased the urinary excretion of americium and decreased the amount found in the liver and the skeleton at 4 and 16 days. LD{sub 30}{sup 50} studies showed americium was slightly less toxic when given in the acute toxic range than was plutonium. The difference was, however, too slight to be important in establishing a larger tolerance does for americium. Survival studies, hematological observations, bone marrow observations, comparison of tumor incidence and the incidence of skeletal abnormalities indicated that americium and plutonium have essentially the same chronic toxicity when given on an equal {mu}c. basis. These studies support the conclusion that the tolerance values for americium should be essentially the same as those for Plutonium.

This is the monthly 100 areas technical activities report for the physics group for the month of July 1951. This group was concerned with pile related studies. Work discussed includes neutron attenuation measurements in pile shielding test facilities, studies of physical properties of shielding materials (concrete), work on a xenon generator and separation facility, further development and shielding work for a neutron spectrometer, continued work on a magnetic spectrometer, and counting equipment. Studies of neutron fluxes from exponential piles, and criticality studies are also discussed.

This is a technical progress report for the Research and Development, and 234-5 Metallurgy Groups of the metallurgy-pile technology unit for the period Oct 1951. Numerous reports are attached under the general areas: P-10 alloy development; uranium metallurgy; metallurgy of Hanford structural materials; radiometallurgy, facility development; plutonium metallurgy program; canning development; plant service work; 234-5 metallurgy group, plutonium metallurgy program.

Mound Laboratory is cooperating on a joint development program directed toward the production of polonium-208 by proton irradiation of bismuth. Because of the greater half life of polonium-208 compared with polonium-210 (2.93 years versus 138.4 days), it would be a desirable substitute for polonium-210, At the present time the Electromagnetic Division of Oak Ridge National Laboratory is operating a cyclotron for the production of polonium-208 on an experimental scale. The targets produced are sent to Mound Laboratory for evaluation of the results which have been obtained, as well as for processing of the targets to obtain experimental amounts of the polonium in a purified form. The California Research Corporation is designing the target to be used in the Mark I linear accelerator located at Livermore, California. The overall responsibility for the Mark I design and operation is being handled by the California Research and Development Corporation. Before it is used for the production of polonium-208, the Mark I will be convert d from a deuteron beam, on which it will first operate, to a proton beam. This report describes progress on separation processes of bismuth and polonium, and diffusion of polonium through aluminium.

The current Relox flowsheet proposes precipitation of plutonium peroxide from IIBP solution concentrated by evaporation to 10 g Pu/1 and ca. 5.5 M HNO{sub 3}. Such a solution might have an Al{sup +++} concentration as high as 0.02 M with stainless steel corrosion product concentrations of the order of magnitude of those found in AT solution diluted to 10 g Pu/l. Methods for the precipitation of plutonium peroxide from this type of solution, either with or without partial neutralization of the nitric acid have been described (HW-20053, pp 4-5). Recent work has been devoted to an investigation of the extent to which aluminum, chromium, iron, and contaminating elements are separated from plutonium by peroxide precipitation.

At 11:20 A.M. Tuesday, July 24, 1951, a radium capsule containing 49.6 milligrams of radium became open to the atmosphere t the Kelley-Koett instrument Company, 930 York Street, Cincinnati, Ohio. This radium was contained in a platinum tube and was used for the purpose of calibrating radiation detection instruments. At the time of the accident, the actual chemical composition of the radium salt was not known. On Tuesday morning, July 31, 1951, Mr. W.A. Bigler and Mr. R.A. Miller of the Monsanto Chemical Company, Mound Laboratory, Miamisburg, ohio were sent to the Kelley-Koett Instrument Company for the purpose of recovering as much of the radium as possible and to help in the reduction of the health hazard. This paper details the activities undertaken to survey and decontaminate the area.

A new method for the production of plutonium (IV) fluoride, which is used for the production of metallic plutonium, is described. The method bypasses the oxidation of plutonium(III) oxalate to plutonium(IV) oxide. A production test was executed with favorable yields; the decision to replace the prior method was recommended. This report is from the Hanford Works 234-5 building, March 30, 1951.

Data is presented from the separations technology division, May 14, 1951, to compare plutonium recovery from leaches of N-1 to corresponding hold-up data of plutonium.

This report describes results of an investigation to determine whether plutonium nitrates and lanthanum compounds were being entrained on the filter aid and filter block of the Nutsche Filters in Cell 2 of Bldg. 231. Leach samples were analyzed for La, Pu, phosphate, fluoride, Pu{sup 240}, and Am. From the data the authors concluded that the holdup on the Nutsche Filter is due to insoluble plutonium compounds either filtered from solution, or more likely, formed on the filter. These compounds would have a relatively low solubility in 25% nitric acid and would dissolve slowly, thus permitting a gradual buildup of material on the filter which was not detected until leaching with 60% nitric acid was instituted.

The Pu in one batch (160 gms) is precipitated in a purification hood and waste supernatant is then transferred to the storage tank in one of the recovery hoods. Under normal process conditions a small amount of Pu remains in the supernatant. However, it is possible, though extremely unlikely, that the entire 160 grams would be transferred to the waste storage tank. The supernatants are transferred to an evaporator where they are concentrated. This evaporator has dimensions approximately the same as those of the storage tank, however, as concentration proceeds, the remaining solution can pass to a geometry more favorable for a chain reaction. There should be definite assurance before evaporation is begun that the amount of Pu in the evaporator does not exceed 160 grams. It is concluded that there is no objection, from a nuclear safety standpoint, to the discontinuance of analysis of the supernatants.

At the request of the ``S`` Division, a study has been made regarding the feasibility of simplifying operations by standardizing the amounts of chemical additions made at the reduction step as is the current practice in the purification operation. The investigation included a study of the following items, which are discussed under separate headings: (1) variation in feed; (2) maximum variation in booster ratios and per cent excess calcium using the method; and (3) chemicals handling and storage procedures. The process reduces plutonium fluoride to the metal.

This summary from the analytical research section, May 1, 1951, briefly describes the analytical method to be utilized in the recovery of plutonium from crucibles program.

This report lists recommendations to be adopted in the process for the reduction of plutonium fluorides by calcium metal in order to save time and money in the Plutonium Finishing Plant. These recommendations regard the standardization of procedures for batch operations. Instead of weighing chemicals to be added to each PuF{sub 4} batch, standard quantities of iodine and calcium would be prepared and stored for later use. The reagents would be added to PuF{sub 4} batches in the 410--430 gram range without further weighing.

In order to change models on the RM Line, a number of equipment items must be either replaced or modified. Some items may not necessarily require replacement depending upon the severity of the change. The attached list of items will require replacement or modification before production can be shifted from the present model to any of the others previously produced at this plant. The equipment is part of the Remote Mechanical A and B lines of the Plutonium Finishing Plant.

The effect made on the RM (Remote Mechanical) Line equipment by an increase in the plant batch size from ca. 300 grams to ca. 375 grams has been studied. Using the process as determined by Production Test 234-3, the volumes for a 300 gram batch and a 375 gram batch are as follows, respectively: volume of plutonium peroxide (alcohol washed, filtered)--1,275 cc., 1,593 cc.; volume of plutonium tetrafluoride (as produced)--617.7 cc., 772 cc.; and volume of reduction charge (tamped)--511 cc., 638 cc. The difficulties encountered with 375 gram batches are discussed.

This report, from the Hanford Plant, May 11, 1951, describes the filtration of process solution resulting from building 231 activities.

A proposal by ``S`` Division that operations be simplified by adding fixed amounts of calcium and iodine in the reduction step as a time saving device has been investigated. Ten test runs in the 410--430 gram range have been compared with twenty normal runs made in this period. The average yields were 98.27% for the normal method and 98.26% for the test runs. No effect on individual yields by the variance in percent calcium and the iodine ratio was observed. Seventy percent of the runs normally fall into the 410--430 gram range. By controlled compositing of the feed batches, it should be possible to increase the percentage of the PuF{sub 4} runs that fall in this range.

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The recuplex Process is proposed by the Process Assistance group of the Separations Technology Unit as a feasible method for the simultaneous and efficient recovery of waste materials in the 234--5 Building and direct coupling of the product steams from the Redox and Bismuth Phosphate Processes to the 235-5 Building operations. Demonstration of the feasibility of the process has been accomplished through the cooperative efforts of the Chemical Research, Chemical Development, and Process Assistance groups of the Separations Technology Unit and LTS described in this document.

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This study was made to evaluate the effects of several operatin variables on the yield at the reduction step in motel fabrication. The original question was whether or not the addition of recycled metal to the charge had an effect on the yield. To circumvent possible masking of such as effect by changes in other operating factors, simultaneous data on the weight of Pu in the powder charge, the % conversion of the powder to PuF{sub 4} in the fluorination step, the firing time, and the maximum temperature were also studied. This permitted estimation of the separate effects of al five factors. The period covered by the data was October through December, 1950.