This report focuses on the study of the stabilized pinch program made to increase the plasma temperature and improve the plasma conductivity and containment. One method proposed is the usage of a large toroidal stabilized pinch, which is described here.

The following report presents neutron-flux measurements made with a concentric-cylinder element (Mark II) and includes axial, radial, and peripheral flux distributions.

Abstract: This discussion concerns the operation, construction, and servicing of an alpha rate meter of medium sensitivity (30,000 alpha particles full scale per minute) and good stability. The instrument is equipped with an oscillator which increases both in frequency and loudness as the alpha activity is increased. The oscillator circuit includes an anticipator which causes a change in frequency depending directly upon the rate of change of alpha activity. Maximum sensitivity is approximately 100 millivolts full scale. Grid current varies from 1 to 5 x 10^-14 amperes. A general discussion of time constants and accuracy is included. Tables of stopping power, ionization and alpha activity are appended.

"These notes are intended to serve as a summary of the current knowledge of properties of materials. In the future some need may exist for related information of methods of testing, design and fabrication. This issue presents information on low tin-zirconium alloys with subdivision..."

An inconel loop circulating fluoride fuel (62 1/2 make [unintelligible] NaF, 12 1/2 make [unintelligible] ZrF4, 25 make [unintelligible] UF4, 92 [unintelligible] enriched) was operated at 1485°F with a temperature difference of about 35°F in the Low Intensity Test Reactor for 645 hr. For 475 hr of this time the reactor was at full power, and fission power generation in the loop was 2.7 kw, with a max length power density of 0.4 kw/cc. The total volume of fuel was 1290 cc (5.o kg [unintelligible] and the the flow through the irradiated section was 8.6 fps (Reynolds number 5500). The loop has been disassembled and has been examined by chemical and metallographic analyses. Ne acceleration of corrosion of decomposition of fuel by irradiation was noted, although deposition of fission-product ruthenium was absorbed. Ne mass transfer of Inconel was formed, and the corrosive [unintelligible] was general and relatively light. The average corrosive generation, in the usual form of subsurface yields, was 0.5 [unintelligible], the maximum penetration was 2 to 3 miles.

To insure a full evaluation of the effects of in-reactor loops with respect to all phases of the Plutonium Recycle Program, a separate study of each loop has been undertaken. An initial study was carried out which analyzed the effects of in-reactor loops using the design criteria for the gas loop as a basis. As soon as the design criteria for the H2O high pressure loop became available, a more detailed evaluation was completed for that loop. Recent completion of the scope description of the PRTR fuel element rupture test loop now permits an individual evaluation of this loop.

When it was discovered that two HRT flange bolts of a lot of 16 spares contained serious cracks, a program was launched to (1) determine the cause for the cracking, and (2) find methods for non-destructive testing the remainder of the 672 bolts shipment, a large portion of which had been installed in the HRT. Concurrently, inspection of 8 ferrules removed from an HRT flange revealed hairline cracking in 4 of them. Magnaglo, a magnetic particle inspection method using a fluorescent dye, proved to be the only definitive method for inspecting the bolts. The evidence gathered on the bolts pointed to quench cracking as the cause for the defects. Nothing abnormal was disclosed in regard to the bolt material. The alloy and heat treatment at present prescribed for the HRT bolts and ferrules are considered suitable. However, recommendations are made for plating with zinc, instead of formerly prescribed cadmium, to a thickness of 0.0002 inch, followed by a hydrogen relief treatment and a final bichromate chemical dip.

The feasibility of determining particle sizes in the submicron range by employing an activation analysis - centrifugation method has been demonstrated. It is believed that this method is now applicable to the analysis of thorium oxide for submicron particles. The same techniques are, in most instance, usable in determining particle sized in other sample materials.

Catalysts for use in recombining the gases produced by the radiolytic decomposition of water in thorium oxide slurries under neutron irradiation were investigated in out-of-pile tests using stoichiometric mixtures of hydrogen and oxygen. Most favorable results were obtained with a molybdenum oxide catalyst. Satisfactory rate also were attained with palladium and silver oxides. Copper, nickel, vanadium and chromium compounds were less effective.

A promising nonaqueous process for the recovery of uranium from spent fuel elements is under development at Oak Ridge National Laboratory. This process consists of dissolution of the fuel element in a fluoride melt by hydrofluorination at 600 to 700°C, direct fluorination with fluorine for the production and volatilization of UF6, with further decontamination of the product UF6 from fission product activity being secured in a NaF absorption-desorption step. Good decontamination is obtained in the fluorination step due to the low volatility of most of the fission product fluorides. An over-all decontamination factor greater than 106 with adequate uranium recovery has been demonstrated in laboratory scale tests using a double bed procedure for the NaF step. A pilot plant has been constructed for testing the process with various heterogeneous fuel elements. The engineering and operational features of the pilot plant are described

Thorium and thorium-uranium oxide slurries were irradiation in the Low Intensity Test Reactor (LITR) at temperatures up to 300C in small stirred autoclaves. Stirring was accomplished by means of an electromagnetically operated lunger. Stirrer operations was monitored suing an oscilloscope. Relative slurry viscosities were determined both in and out-of-pile using calibration curves of apparent viscosity versus stirrer rise time. Post-irradiation examination of selected slurries indicated no gross changes occurred in the particulate properties.

A promising scheme for the chemical processing of a thorium breeder reactor of the two-region aqueous homogeneous type consists of the following operations: concentration of insoluble fission and corrosion products from the core system into a small volume of fuel solution, combining this slurry with irradiated thorium oxide slurry taken from the blanket, recovery of D2O by evaporation, dissolution of the thorium and uranium in HNO3, and, after a suitable cooling period, recovery of the uranium and thorium by solvent extraction for return to the reactor. The use of a hydroclone and underflow container arrangement for concentrating insoluble fission and corrosion products under simulated reactor conditions has been successfully demonstrated on dynamic loops. Solids concentration factors greater than 103 were demonstrated, and equilibrium solids concentration in the circulating solution less than 1 ppm was attained in these tests. Present data indicate that proper design and operation will minimize solids deposition in the reactor system and that the insoluble impurities can be effectively removed by the hydroclone. An alternate method of processing the slurry removed from the core system by the hydroclone consists of removing the room temperature insolubles by centrifugation, recovering the uranium from the supernatant by peroxide precipitation, thermal …