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An automatic recording thermobalance for studying the chlorination of plutonium dioxide with phosgene is described. The highly toxic and corrosive nature of these materials imposed restrictions on the construction and operation of the thermobalance. The instrument operates on the deflection balance principle in which the extension of a precision quartz helix spring is measured by a linear variable differential transformer. Experimental results from the gas- solid reaction between phosgene and plutonium dioxide are discussed. (auth)

An autoradiographic technique is described for measuring particle size distributions of inhaled 239PuO2 in alveoli of dogs and rats at various periods of time after exposure. Additional data are presented for the tracheo-bronchial tree of rats and lymphoid tissue of dogs. In rat alveoli, an early (6 hr) decrease in MMD is followed by a rise (2 days) and a second decrease (7 to 32 days). A similar cyclic change in CMD in dog alveoli is found with a different time sequence (1 to 406 days). The implications of these and other observations are discussed.

The AEC Safety Branch advised that the present outlook for a potential mission using four modified SNAP-3 type generators is rather negative. Drop tests of four SNAP-19 intact reentry heat source capsules were conducted at the Tonopah Test Range. A preliminary GE SNAP-27 safety analysis was reviewed. Three arc tunnel tests were conducted at low heat fluxes. Debris were collected on downrange impactors from all tests. The rapid helium depressurization test on fuel microspheres was conducted by Battelle; preliminary examination of the fuel revealed no obvious change in microsphere characteristics.

In the P234-5 Building operation, Task I consists of converting plutonium nitrate solution received from the primary separations plants to a plutonium oxalate slurry. The slurry is filtered and the filter cake is transferred to Task II while the filtrate is treated and returned for further processing in either Recuplex, Redox, or Purex. The basic Task II process consists of calcining the plutonium oxalate cake to form plutonium dioxide. The plutonium dioxide is then fluorinated to form plutonium tetrafluoride which is transferred to Task III for further processing. Various alternate schemes for increasing production have been studied by the Technical and Design Sections during the past several months. The results of these studies are available in references (10) and (11). It is the purpose of this document to describe in detail the new equipment required for replacing Task I and II and to serve as a basis for detailed design of the proposed project.

At the request of NRD (NPR Physics Subsection) a study was initiated to determine the physics characteristics of various plutonium-uranium composites as fuel for the NPR. From this study, the PuO{sub 2}-UO{sub 2} fuel system was selected to receive major attention. The effect of adding a burnable poison, B-10, in intimate contact with the mixed oxide fuel was also is to be considered. The present report summarizes the results of these investigations.

During the thirty years which have elapsed since the discovery of plutonium in 1940 (Seaborg et al., 1946) all aspects of its chemistry have been intensively studied and plutonium is now amongst the best understood elements in the periodic table.

Exposure of inbred mice belonging to an A strain to the inhalation of plutonium dioxide significantly inhibited the capacity of urethane to induce pulmonary adenomas, but tumour size was unaffected. Cell kinetic studies suggested that proliferation of cells comprising the adenomas diminished with time, though the decrease was less evident in irradiated than in non-irradiated animals. Alpha irradiation may act by interfering with the immuno-depressive effect of urethane.

Post-ocean-exposure examinations have been made on plutonium dioxide microspheres recovered after a 5-month exposure on the bottom at a depth of 50 feet off San Clemente Island. These examinations established that approximately 70 percent of the microspheres became encrusted with marine growth. Determination of the distribution of the microspheres and adsorbed activity in the ocean-bottom material was made in addition to post-exposure laboratory dissolution measurements, microscopic examination and X-ray diffraction measurements. (Author)

Previous reports on the chlorination of plutonium dioxide describe numerous small-scale experiments and a few fair-sized batch preparations. The chemistry of chlorination by numerous reagents is covered, but no process had received sufficient study for large-scale preparation of anhydrous plutonium trichloride. The literature search revealed no extensive studies on chlorination rates, exhaust gas filtering, atmospheric requirements, reactor materials, etc. A program was undertaken to select a chlorination process, to develop the necessary information for defining operating conditions and equipment specifications, and then to demonstrate the operation of the process.

The nanoscience field often produces results more mystifying than any other discipline. It has been argued that changes in the plutonium dioxide (PuO2) particle size from bulk to nano can have a drastic effect on PuO2 properties. Here we report a full characterization of PuO2 nanoparticles (NPs) at the atomic level and probe their local and electronic structures by a variety of methods available at the synchrotron.

Etude experimentale de l'elimination de l'americium par evaporation au cours de la reduction carbothermique d'une poudre de PuO 2 a 2 temperatures pour 2 rapports C/PuO 2

Neonatally thymectomized and intact outbred Wistar rats were exposed to plutonium dioxide aerosols, resulting in lung burdens that gave α-radiation doses to the lungs ranging from 100 to 1500 rad. While significant numbers of primary lung tumors were induced by the PuO2, no difference in lung tumor frequencies was observed in thymectomized compared to intact animals. However, thymectomized animals not receiving PuO2 had an obviously increased frequency of extrapulmonary neoplasms. Since thymectomy did not result in any significant effect on lung tumor incidence, T-cell immunodepression probably should not be considered as a factor of risk for all individuals. Yet in animals with lung tumors, staging of cancers delineated an important effect of thymectomy, which was manifested as increased tumor sizes, enhanced tumor invasion, and a greater frequency of regional metastases.

A contained scanning electron microscope (CSEM) was designed and constructed at the Savannah River Laboratory. The facility consists of two stainless‐steel glove boxes with separate compartments for specimen mounting and coating, specimen decontamination, SEM column and sample chamber, and containment of the vacuum pumping systems.

Data on the alveolar deposition of /sup 239/PuO/sub 2/ particles in the mouse are presented. It is shown that alveolar deposition falls with increasing activity median aerodynamic diameter (AMAD) over the range 0.6 to 2.4 microns. In the mouse, any peak in alveolar deposition must occur at an AMAD of less than 1 micron. Information is also provided on the relative lobar concentrations (RLCs) of /sup 239/PuO/sub 2/. The RLC is greatest in the right apical lobe and increases quite sharply with AMAD. The RLCs of the other lobes of the right lung decline with AMAD. The RLC in the left lobe is relatively unaffected by AMAD.

Knowledge of the biological response to inhaled plutonium in animals is necessary in order to understand the changes that might occur in man accidently exposed during the industrial and military handling of this fissionable material. Acute effects were observed in earlier investigations of inhaled (1, 2) and intratracheally injected (3) Pu23902. A deposited dose of 1 Asc/kg caused lymphopenia, respiratory distress, loss of body weight, and finally death within 2 to 4 months postexposure (1). This study was designed to define more clearly the acute syndrome resulting from a single high-level inhalation exposure to plutonium dioxide aerosol. Particular attention was given to the progressive clinicopathologic changes occurring in the exposed animals and their correlation with the tissue changes observed at necropsy. Radiochemical analyses of all urine, feces, and body tissues provided the basis for determining total plutonium deposited and retained, and the amount translocated.