The growth of alpha-rolled uranium rods on thermal cycling has been shown to depend on both preferred orientation and grain size. Preferred orientation appears to be a necessary condition for growth to occur; the extent of the growth depends upon the sharpness and type of texture developed and on the grain size. The highest growth rates occur in specimens with highly developed textures coupled with small grain sizes. The growth rates increase with cycling level, particularly in specimens of large grain size.

The thermal cycling growth and the accompanying metallographic changes were studied in 300 [degree] C rolled uranium rods up to 3000 cycles. The growth rate was found to decrease at the higher cycling levels. Project-grade material developed substantial porosity during cycling; high purity material showed no evidence of porosity.

Measurement of radioactive carry-over was made on borax III operating at 300 psig and at power levels ranging from 4 to 14 mv. Decontamination factors of from 1.5 x 104 (at 14 mv) were obtained. These data are in essential agreement with those predicted by previous laboratory experimental work.

The EBWR loading requires a total of 888 plates. It is anticipated that approximately 1000 plates will have to be produced to obtain the number of acceptable plates required for the loading. To the end of this quarter, 568 cladding billet cores acceptable with respect to chemical composition and physical soundness had been cast; this number represents 78% of the total number of cores cast. Approximately 75% of the Zircaloy-II stock required has been rolled, and about 55% of the cladding components required have been finished. The anticipated number of 495 cladding billets required for the thin (0.210") natural and enriched plates have been assembled, welded, sealed, and jacketed in steel. A total of 310 cladding billets have been rolled to fuel plates; of this number, 142 have been completely finished, and the remaining 168 are in the finish processing stages. The stability of the equipment for measuring the clad thickness of EBWR fuel plates has been improved by placing the phototube and the anthracene scintillator crystals in an insulated box with a temperature regulation of the order of 0.1°F.

The purpose of this program was to develop techniques and methods for producing fuel elements for the Experimental Boiling Water and Experimental Breeder Reactors. Methods for fabricating large tubes, flat plates, and small pins were investigated. The tube and plates contained U-5 w/o Zr-1.5 w/o Nb alloy and were designed for the EBWR. The pins contained U-2 w/o Zr alloy and were designed for the EBR. Cladding and end seal material of Zircaloy-2 was required for the water-cooled EBWR elements. Unalloyed zirconium was specified for cladding on the sodium-cooled EBR elements.

Physics calculations have been made for various combinations of the four types of fuel assemblies to be used in the EBWR core. Two thicknesses of plates, 0.205 in. and 0.274 in., including the two 0.020-in. cladding layers, are to be made of both natural U and U containing 1.44% U235. A total of 148 assemblies, 74 natural and 74 enriched, are to be fabricated with six identical plates each. Various configurations of these fuel assemblies will be used to (1) change the critical size of the core, (2) change the power distribution in the core, and (3) change the amount of reactivity corresponding to a given stream volume in the core. The physics calculations show that uncertainties in critical mass are adequately covered by the number and variety of fuel assemblies and that the possible changes in core characteristics with the different fuel assemblies should provide valuable information about the factors affecting maximum power density and stability in a boiling water reactor.

Additional runs have been made in the six-inch, continuous-flow mixing chamber to study the rate of mass transfer between isobutanol and water. These runs were inconclusive because the effluents were mutually saturated. A new four-inch cell has been designed and is being fabricated; this will permit a reduction in the time available for mass transfer. Consideration has been given to other liquid pairs which may transfer more slowly than isobutanol-water. The system nitrobenzene-ethylene glycol appears attractive.

Methods of producing extremely clean surfaces on rolled Zircaloy-2 strip have been investigated. It has been found that the finer abrasives, 400 mesh or finer, are more effective than coarse types because of their ability to penetrate pits and crevices more readily. Two such cleanings, with an intermediate 35 v/o HNO3-5 v/o HF pickle, resulted in a microscopically clean surface. Ultrasonic inspection of the EBWR fuel plates has been completed during this quarter. Approximately 95% of the plates were found acceptable. All subassemblies manufactured from the EBWR plates met dimensional specifications and passed 9-day corrosion tests at 290°C (550°F). All thoria-urania pellets for the loading of Borax-IV have been pressed, loaded into tube plates, and fabricated into subassemblies. The total number of subassemblies made was 82, of which 72 were fuel plates and 10 were blanket plates, more than sufficient for the loading. The reactor has gone critical using this loading.

Report issued by the Argonne National Laboratory discussing the design and construction of equipment for reactor fuels. As stated in the summary, "the report describes the development, prototype construction, methods of testing, and leak detection of a modular hood design to be used in housing equipment and processes for the Argonne National Laboratory Fuel Fabrication Facility" (p. 9). This report includes tables, illustrations, and photographs.

Report issued by the Argonne National Laboratory discussing the variety of work done at the laboratory during the year of 1956. This report includes tables, illustrations, and photographs.

Report issued by the Argonne National Laboratory discussing single-phase water loop systems. As stated in the introduction, "the principal objective of this study was to determine the reliability of the calculations based upon numerical solutions of finite-difference energy and flow equations" (p. 9). This report includes tables, illustrations, and photographs.

Physical calculations have been performed for various combinations of the four types of fuel assemblies to be used in the EBWR core. Two thicknesses of plates (0.205 in. and 0.274 in., including two 0.020-in. cladding layers) are to be made of both natural uranium and uranium containing 1.44% U235. Any given fuel assembly contains six identical plates. A total of 148 assemblies, 74 natural and 74 enriched, are to be fabricated. Various configurations of these fuel assemblies can be used to (1) change the critical size of the core, (2) change the power distribution in the core or (3) change the amount of reactivity corresponding to a given steam volume in the core. Physics calculations show that any uncertainties in the required critical mass are adequately covered by the number and variety of fuel assemblies, and that the changes in core characteristics possible with the different fuel assemblies should provide valuable information about the factors affecting maximum power density and stability in a boiling reactor.

This report is essentially a procedural account of the fabrication of certain enriched ZPR-III fuel plates for use in the ANL fast critical experiments at Arco, Idaho. A total of 208.92 kilograms of fully enrich, unalloyed uranium was processed. Of this amount 202.74 kilograms was received in the form of Oak Ridge type reduction buttons and 6.18 kilograms as pressed-powder plates. The completed fabrication consisted of 720 rectangular fuel plates having the nominal dimensions 3in. x 2in. x 1/8in. Their combined weight of 159.21 kilograms represents 76.22% of the weight of enriched material processed. The final distribution of the enriched material was as follows: [figure not transcribed].

The table of sin θ and sin2 θ, to five decimal places for every hundreth of a degree from 2°-87°, has been prepared for the use of Professor W. H. Zachariasen in his X-ray diffraction studies. [Tables not transcribed]

The Internal exponential Exponential Experiment (ZPR-V) will be constructed by loading up to 49 of the fuel cans, containing up to 155 kg of U235, of the present Fast Exponential Experiment in a 22-in. square iron tank, surrounded by an annular thermal region of fully enriched light water lattice 10 to 15 cm thick. This assembly will be placed in a 5-ft diameter tank which will, in turn, be located in the 10-ft diameter ZPR-II tank, the annular space between the outer tanks containing water for shielding. The new experiment will be a well-shielded, strongly coupled fast-thermal system. It will be possible to make measurements that cannot be made on the present Fast Exponential Experiment. One category of such determinations is the study of reactivity effects produced in the fast core, including control scheme studies and danger coefficient and oscillator measurements of such effects as Doppler coefficients and effect of lumping and streaming. The higher flux and excellent shielding will make beam studies of energy spectrum practical. Additional foil activations will be possible. Characteristics of mixed fast-thermal systems, which are of potential importance as power breeders, can be studied.

The gastight steel building (400,000 cu ft) in which all radioactive components are to be housed has been completed by the Graver Tank Company. This structure was tested for strength at 18.75 psig (20% above design pressure) and then tested for leaks. No leaks were found in soap bubble testing of all welded seams. Continuous measurements of temperature and pressure over a ten-day period showed the leakage, if any, to be less than the 500 cu/ ft/day at 15 psig specified. The gastight cylinder was, therefore, accepted. General construction work by the Sumner Sollitt Company on the remainder of the plant has begun.

A preliminary design study, Phase I of the ALPR project, has been made in accordance with the Army Reactors Branch specifications for a nuclear "package" power plant with a 200-260-kw electric and 400 kw heating capacity. The plant is to be installed at the Idaho Reactor Testing Station as a prototype for remote arctic installations. The "conventional" power plant as well as the exterior reactor components are described in the accompanying report and cost estimate by Pioneer Service and Engineering Company, Architect-Engineers for the project."Nuclear" components of the reactor are designed by Argonne National Laboratory as described in the present report.