CALCULATION OF TEMPERATURE RISE IN DEEPLY BURIED RADIOACTIVE CYLINDERS

Temperatures were calculated relative to the storage of radioactive solid waste as a function of time and radial distance for radioactive solid cylinders in infinite solid media of "average soil," "average rock," and salt. A resistance at the cylinder--infinite medium boundary was included in the form of an air space. For the range of parameters used and withia the practical limits of accuracy, the maximum temperature rise increased linearly with the heat generation rate. The fission product spectrum was not significant in the determination of the maximum temperature rise. Under the pessimistic storage conditions assumed, the storage of cylinders of a practical size appears feasible without excessive temperature rise. A maximum temperature rise of 1000 deg F would be produced with an initial heat generation rate of 1300 to 1600 Btu/hr-ft/ sup 3/ for cylinders with a 5-in. radius, with 350 to 450 Btu/hr-ft/sup 3/ for a 10-in. radius, and with 175 to 210 Btu/hr-ft/sup 3/ for a 15-in. radius, assuming a thermal conductivity of the radioactive cylinder of 0. 1 Btu/hr-ft- deg F. (auth

Student teamwork: developing virtual support for team projects

In the 21st century team working increasingly requires online cooperative skills as well as more traditional skills associated with face to face team working. Virtual team working differs from face to face team working in a number of respects, such as interpreting the alternatives to visual cues, adapting to synchronous communication, developing trust and cohesion and cultural interpretations. However, co-located student teams working within higher education can only simulate team working as it might be experienced in organisations today. For example, students can learn from their mistakes in a non-threatening environment, colleagues tend to be established friends and assessing teamwork encourages behaviour such as “free-riding”. Using a prototyping approach, which involves students and tutors, a system has been designed to support learners engaged in team working. This system helps students to achieve to their full potential and appreciate issues surrounding virtual teamwork. The Guardian Agent system enables teams to allocate project tasks and agree ground rules for the team according to individuals’ preferences. Results from four cycles of its use are presented, together with modifications arising from iterations of testing. The results show that students find the system useful in preparing for team working, and have encouraged further development of the system

THE PERFORMANCE OF AN ADVANCED EXPERIMENTAL STACKED-CLONE CONTACTOR: A HIGH- PERFORMANCE FOR APPLICATION TO VERY HIHGLY RADIOACTIVE SOLUTIONS

A high-performance liquid-liquid extraction contactor, called the stacked-clone contactor, has been developed through the stage of identifying an optimum design of the configuration of the functioning components. The device consists of hydroclones cascaded such that the underflow port of each hydroclone communicates with the overflow of the one below by an underflow chamber. Each stage is comprised of a hydroclone, an underflow chamber, and a pump. The contactor is under development for application with highly radioactive solutions where contact time must be minimized to reduce the degradation of the solvent by radiation damage. Contact times of less than 4.5 sec per theoretical stage have been reached in the experimental model, and contact times of less than 2.5 sec are probable by improving the design to eliminate nonfunctional volume. The throughput of the experimental model was about 4 liters/min at a stage efficiency of 65 to 80%. The stage efficiency and entrainment was relatively independent of throughput. The performance of the contactor was temperature dependent. Although the unit does require pumps at each stage, there is only one control point necessary: the top interface. The simplicity, stability, and rapid response of the contactor promise that it will be a very usable device. The principle of operation and the characteristics of the stacked-clone contactor are discussed. (auth

EQUILIBRIUM CALCULATION IN THE SYSTEM: URANYL NITRATE, NITRIC ACID, WATER, TBP, AND KEROSENE DILUENT USING THE ORACLE DIGITAL COMPUTER

A set of equations was written which allowed the calculation of equilibrium concentrations in the solvent phase of nitric acid and uranyl nitrate, given the initial TBP concentration in the solvent and the aqueous phase concentrations of acid and uranium. An ORACLE subroutine was written based on these equations which will calculate a set of equilibrium values in about 35 milliseconds. The subroutine was incorporated into a short program to calculate equilibrium points. A set of calculated points are presented in graphical form for 5, up to 7 M and uranyl nitrate concentrations up to 0.6 M in the aqueous phase. Since these calculations were based on limited data, it is the purpose of this memo to invite comment on their accuracy. The equations were reworked from a Russian paper by A. M. Rozen and L. P. Khorkhorina, using emperical polynomial fits for some poorly defined parameters, and were based principally on data from J. W. Codding. This project was undertaken to provide a subroutine to calculate equilibria in a general purpose ORACLE program to calculate the performance of multi-stage compound extraction cascades with more than one significant solute. (auth

Software agents to support students working on group projects

This project is designed to develop and apply mechanisms for supporting teamwork, so that students get the most out of their projects, through development of a software system to support students working in team projects online. Online teamwork is problematical for a number of reasons, such as getting acquainted with team members, communications between members and knowing what progress has been made on the project. Possible solutions include software agent technology: intelligent systems to monitor progress across an Internet connection, and offer advice to students. These systems continuously operate in the background on a student’s workstation and act autonomously to suggest ways in which the student team should prepare to start their teamwork, or alter their actions in terms of team progress when the agent detects a need.Within this project an agent prototype has been developed to perform a limited set of functions to help students to get started on their teamwork, and the results of a trial carried out using teams working on projects on campus have informed our further design, and work is in progress on a client-server system for this preparation and supporting role, which will be tried on student teams and evaluated

CHEMICAL TECHNOLOGY DIVISION, UNIT OPERATIONS SECTION MONTHLY PROGRESS REPORT FOR APRIL 1959

A concentration cell electrode was installed in a fritted glass surface and was used to measure the surface KCl concentration while water was being transpired through the surface into a mixed tank of 0.1 M KCl. The results from the first Fluorox run made with crude UF/sub 4/ showed that 85.3% of the theoretical amount of UF/sub 6/ was accounted for, with 17.9% being collected in cold traps and the remainder being consumed in various side reactions. Installation was completed of apparatus to study the electrolytic removal of nickel on an engineering scale from concentrated HRT fuel solution. An extremely low yield stress of 0.02 lb/sq ft was measured for a thoria-urania slurry containing 2.5 wt.% Al/sub 2/O/sub 3/ and spherical particles of 1.7 micron mean diameter. Preliminary data on the rate of uranium sorption on Dowex 21K from sulfate solutions were correlated with a simple spherical diffusion model. Laboratory scale studies to determine the effect of reflux time, HNO/sub 3/ concentration, and air sparge on chloride removal from APPR-type Darex dissolver product showed that an air sparge is definitely beneficial in chloride removal. Preliminary cyclic cleaning tests showed that boiling 25% caustic solution was adequate for cleaning type F (20 micron) porous metal filter elements fouled in the absence of filter aid with siliceous sludge from Darex solvent extraction feed solutions. Sections of unirradiated stainless steel-clad UO/sub 2/, sheared into lengths of 1/2 in., 1 in., 2 in., and 2 3/4 in., were leached free of UO/sub 2/ with 10 M HNO/sub 3/ in 30, 45, 60, and 75 min, respectively. The abrasive blade cost for the removal of inert end adapters from selected reactor assemblies ranges from 12 for the Gas-Cooled Reactor to 19 for Consolidated Edison. A zirconium dissolution was carried to completion at 600 ction prod- C in a NaF-LiF salt mixture containing initially 23 mol per cent ZrF/sub 4/ at an average rate of 1.3 mg/(cm/sup 2/)(min) with an HF feed rate of 2 lb/hr. The thermal conductivity and thermal diffusivity at the center of an 8-in. diameter cake of Darex waste calcined at about 900 ction prod- C were determined as a function of temperature. (For preceding period see CF-59-3-61.) (auth

CHEMICAL TECHNOLOGY DIVISION UNIT OPERATIONS SECTION MONTHLY PROGRESS REPORT, FEBRUARY 1958

The alpha activity for scintillation area measurement was estimated to be 10/sup -6/ of that for the ( alpha ,n) methcd. The UF/sub 6/ recovery during Run FBR-16 was 67.3% of the theoretical recovery for the Fluorox reaction. Hydroclones were used for collection of thoria loop slurries with recoveries exceeding 99%. Flame calcination studies were continued with thoria dispersed in methanol by oxalic acid, using graphite and zirconia reflected burners and acetyleneoxygen flame. Equations for complex ion formation in 4/-H/sub 2/O systems were solved for a few hypothetical solution compositions. A continuous Darex dissolution and stripping run was carried out for 32 hours with chloride removal in the product to 100 ppm. A nine pound section of a fuel element was completely hydrochlorinated in 24 hours with an HCI utilization of 70% and uranium losses to the ZrCl/sub 4/ sublimate of 0.07%. The specific dissolution rate for the fused salt dissolution of Zircaloy-3 was propcrtional to the logarithm of the HF feed rate. One percent of the initial ore resistant t activity and fourteen percent of the initial activity was leached by distilled water from a 900 tained C fired sinter of concentrated fission products in a mix of shale and limestone (Mix 15). (For preceding period see CF- 58-2-139.) (J.R.D.