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- Deposition of Corrosion Products by Cataphoresis
- This report is a record of experimentation conducted intermittently over a period of two years and directed toward preventing deposition of transport corrosion products on fuel elements and other critical components in high-temperature, circulating water nuclear reactor. It includes the postulated mechanism for deposition, a description of experimental equipment, experimental data, results obtained from the experiments, and recommendations for future study.
- Corrosion of Plutonium Alloys in NaK
- A plutonium-aluminum alloy containing 4 atom per cent aluminum showed no attack after exposure to purified NaK for one month at 400 C in the absence of any oxide. The same specimen and other plutonium alloys, including pure plutonium, showed marked deterioration in shorter exposure in the presence of oxide films from a welded stainless steel container. Pure uranium was resistant even in the presence of such oxides.
- Dissolution of Uranium Oxide Arising From Slug Failure
- The purpose of this work was to study reagents which might be effective in dissolving uranium oxide produced during slug failures in water-cooled reactor systems. An aspect of this problem which has subsequently become of primary importance is the solubility or transportability of the oxide in pure water.
- The Use of the Electrical Conductivity of Graphite as a Radiation Damage and Flux Monitor. Implications of the Results to the General Theory of Radiation Damage
- A method for monitoring radiation damage irradiations using the change of the electrical conductivity of graphite is described. Results of monitoring operations in a number of locations are given. An attempt is made to explain the damage rate found in the converter at CP-3. An estimate of the flux spectrum in VT-4 and the converter of CP-3 is made and the damage rate is computed according to theories of Seitz and James. It is found that the experimental results are more in accord with the predictions of Seitz. A number of corrections to James' report, ORNL-307, are noted in an appendix. It is shown that some information about the fast flux spectrum can be inferred from the radiation damage rate.
- Critical Studies with G. E. Type Fuel Elements
- The ZPR-I is a facility to study low power critical assemblies using enriched uranium as fuel, having a light water moderator and an essentially infinite water reflector on all sides. The fuel is held in elements 43" long with a 1" square cross section. Any of these elements may be placed in or removed from any position in the reactor tank. Thus, any desired core configuration may be easily obtained.
- The Electrolytic Refining of Uranium
- This technical report describes work done on the electrolytic refining of natural uranium in fused salt baths composed of various eutectics of alkali metal chlorides in which were dissolved UF, or UCl3.
- Engineering Properties of Diphenyl
- Report issued by the Argonne National Laboratory discussing engineering properties of diphenyl. As stated in the abstract, "data collected from the literature on the vapor pressure, enthalpy, liquid density, and vapor density of pure diphenyl are presented. A Mollier diagram, a temperature entropy diagram, and data on viscosity of diphenyl as a function of temperature are also presented" (p. 5). This report includes tables, and illustrations.
- Chemistry Division, Section C-II, Summary Report For October, November, and December 1952
- This report deals with the (1.1) physical properties of graphite, (1.2) effects of pile irradiation on the properties of graphite, (1.3) effect of irradiation on "ceramic" materials, (1.4) exposure and dosage for radiation damage experiments, (1.5) apparatus for the measurement of the thermal conductivity of solids, (1.6) effects of radiation on ice -- the thermoluminescence of ice, (1.7) investigation of color centers and other optical properties of single crystals. (2.1) radiation chemistry of liquids, (3.1) radiochemical investigation of the spontaneous fission of Cm242, (3.2) radiochemical service, (3.3) on the one-body model of alpha, (4.1) spectrographic analysis, (4.2) chemical analysis, (5.1) the 60-inch cyclotron.
- An Improved Continuous Ether Extractor for the Determination of Uranium in Dissolver Solutions
- An improved continuous ether extractor is described. The modifications include a means of safely disposing of the active raffinate and a means of positivity checking the raffinate for completeness of uranium extraction. The results obtained on synthetic samples and on dissolver solutions are given. This work was undertaken because of a need for the determination of uranium in dissolver solutions with an accuracy of 0.1 per cent. After a review of available methods it was decided that a gravimetric determination would meet the requirements of precision and accuracy.
- Corrosion and Stability Tests on Chemical Poisons in Higher-Temperature Water
- Corrosion-stability tests have been made in static autoclaves at 500 and 600F on solutions of compounds having high neutron cross sections to evaluate their usefulness for shutdown purposes. The only compound tested which appeared to be completely stable in 600F water was boric acid. Limited corrosion data did not show it to cause excessive corrosion of zirconium or stainless steel.
- Preferred Orientation in 300 C Rolled and in Recrystallized Uranium Sheet
- The rolling and recrystallization textures in 300 C rolled uranium sheet were investigated using a Geiger counter diffractometer with the modified Schulz reflection technique. Seven sections of sheet material were used in order to obtain sufficient data for quantitative pole figures by the reflection technique. A special integrating specimen table was used for obtaining and recording the data atomically.
- Reactor Engineering Division Quarterly Report June 1, 1953 through August 31, 1953
- Report issued by the Argonne National Laboratory covering the quarterly report from the Reactor Engineering Division. A summary of reactor programs (including the Power Breeder Reactor (PBR) and the Central Station Water Reactor (CSWR)), designs, development, and experiments are presented. This report includes tables, illustrations, and photographs.
- Comparative Analysis of ANL High Purity Uranium
- In the course of the development at Argonne of high purity uranium metal in ingot form, some questions arose as to the validity of the chemical analyses of some of the impurities (particularly those for carbon, boron, and silicon), with one analytical laboratory reporting concentrations in some instances of an order of magnitude greater than another laboratory. Since the low concentrations of impurities in this material involved, in some cases, the development of modified analytical procedures and standards, it was decided to check these discrepancies by having identically prepared samples analyzed by several AEC and associated laboratories. This report is a compilation of the results obtained.
- The Development of Equipment and Methods for Centrifugally Casting Reactor Fuel Slugs
- This technical report describes the design and construction of equipment and the development of methods for multiple mold, centrifugal casting of reactor fuel slugs. Advantages of the centrifugal casting method over the conventional fabrication methods were found to be (1) fewer operations, (2) fewer and more easily recovered residues, (3) less expensive equipment, and (4) the production of fuel slugs in shapes and in alloys not well adapted to other methods of manufacture. The method consisted of vacuum melting the alloy in stoppered crucibles and bottom pouring into a spinning rotor carrying 16 radially arranged copper molds. The castings so produced were used without further processing, except for cropping the sprue end to obtain the specified length.
- Metallurgy Division Quarterly Report July, August, and September 1953
- This quarterly report discusses ongoing research and experiments at Oak Ridge National Laboratory in the Metallurgy Division. This report discusses water cooled reactors, liquid metal cooled reactors, reactor development metallurgy, basic metallurgy, applied metallurgy, and aqueous corrosion,
- Atomic Energy Commission Division of Reactor Development Reactor Information Meeting. Part VI, Processing; October 7, 8, 9, 1953
- On October 7, 8, and 9, 1953, the Atomic Energy Commission Division of Reactor Development held a reactor information meeting at the Argonne National Laboratory. The objective of the meeting was exchange of information among people actively concerned with the design of reactors for power to the end that the power reactor program would move more speedily and more economically to another milestone of success. In this volume all the papers presented at the meeting are listed. Copies are given of those papers which are available, and references to published reports are indicated where know for those papers not included in this collections. In order to facilitate handling, this volume is being issued in six parts: Part I Power Reactors; Part II Reactor Physics. Critical and Exponential Experiments Measurements; Part III Reactor Components. Reactor Economics Considerations. Reactor Safeguard and Control; Part IV Fuel Element Design and Problems. Corrosion and Chemistry; Part V Heat Transfer; Part VI Processing. The Author Index is being bound and distributed with Part I of this volume.
- Preliminary Report on Corrosion of Low-Uranium, Zirconium-Base Alloys
- Tests were made to determine the effects of heat treatment and composition on the corrosion resistance of low-uranium, zirconium-base alloys to water at 600F. A total of 57 compositions were tested. The zirconium alloys contained up to 9% natural uranium plus small amounts of tin, antimony, lead, bismuth, yttrium, beryllium, germanium, niobium, nickel, and aluminum in various combinations. Data are presented in both tabular and graphical form. The effect of heat treatment on corrosion resistance of zirconium-uranium-tin alloys is partially masked by impurities in alloys made from sponge or bomb-reduced zirconium. In ternary alloys made from crystal bar zirconium, the effect of heat treatment on corrosion resistance is definite, and varies with the composition of the alloy. The range of ternary compositions from approximately % to 6 weight-per cent uranium and from 2 to4 per cent time, are the most attractive fuel element core alloys.
- Physics Division Supplement to Quarterly Report June, July, and August, 1953
- This technical report describes experimental nuclear physics, mass spectroscopy, crystallography, experimental reactor physics, theoretical physics (general), reactor theory, electronic digital computers, and applied mathematics and computations (general).
- Spectroscopy of Uranyl Salts in the Solid State
- From Introduction: "The interpretation of the fluorescence and absorption spectrum of the uranyl ion, indicated in this introduction, is based on the spectroscopic work of Nichols, Howes and co-workers (1914-1919), Dieke and van Heel (1925), Moerman and Kraak (1939), and Freymann and co-workers (1946-1948); on infrared studies (cf., Section 3 below) and Raman spectra; but most of all, on the work of Dieke, Duncan, and co-workers, carried out in 1943-1944 under the Manhattan District program. In the present chapter we will review briefly the earlier investigations in the field of uranyl salt and spectroscopy and give a somewhat more detailed summary of the results of Nichols and Howes and, particularly, of Dieke and co-workers."
- Dimensional Stability of Uranium Powder Compacts Upon Thermal Cycling
- Thermal cycling tests on uranium have shown that the dimensional changes that occur on cycling in the alpha range are directly related to both the texture of the material and its grain size: cold rolled rods generally elongate in the direction of rolling, while the same rods, after a beta-treatment, grow at rates several orders of magnitude lower. This considerable improvement by beta-treatment has been attributed to the texture randomization accompanying the heat-treatment. In the course of this heat-treatment, however, considerable grain growth occurs, which ahs the effect of causing surface roughening on cycling (also referred to as "bumping"); fine grained material generally retains a smooth surface. These observations led to the speculation that the most desirable structure in uranium, from standpoint of dimensional stability, is one that combines both a random texture and a fine grain size. Heat treatment of rolled rod offered no easy method to obtain such a product; powder metallurgical techniques, however, appeared ideally suited for the purpose. To this end, early in 1949, the Sylvania Electric Products Company initiated a program to develop suitable techniques for producing uranium powder compacts having the above-mentioned desired characteristics. Because of the availability of thermal cycling equipment at Argonne, the Metallurgy Division of the Laboratory has undertaken to evaluate the stability of the various experimental compacts produced in the developmental phases of the program. This report contains the results of these evaluations. The data in this report indicate that compacts of nearly theoretical density and fine grain size can be obtained by hot pressing uranium or uranium hydride powders in the high alpha temperature range.
- Eddy Current and Ultrasonic Testing of CP-6 Fuel Elements
- The fuel element to be used in the Savannah River reactors is a natural uranium slug 1.00 in. in diameter and 8 in. long, encased in a 2S aluminum can 1.080 in. O.D. having a wall thickness of 0.035 in. The slug is bonded to the can with an aluminum silicon alloy, using the Hanford Al-Si process.
- Factors Which Affect Formation and Deposition of Transport Corrosion Products in High-Temperature Recirculating Water Loops
- Deposits of corrosion products form on heat transfer surfaces and in radiation flux zones at temperatures around 500F in stainless steel systems operating with circulating water. The report considers the possible harmful effects of such deposits on heat transfer and fluid flow, as well as factors involved in the origin of these corrosion products and in the mechanisms of deposition. The prevention of deposition by chemical, mechanical, and electrostatic methods is discussed.
- The Half-Life of Pu241
- This report describes the first estimation of the beta half-life of Pu241 and was made by determining the beta activity associated with plutonium formed by (d,xn) reactions on U258.
- The Manufacture of Internal Blanket and Fuel Blanket Slugs for the Experimental Breeder Reactor
- Surrounding the core of the Experimental Breeder Reactor (EBR) is located the Internal Blanket (see Figure 2 of Reference 1). This blanket is compromised of natural uranium rods jacketed in stainless steel. The active portion of each rod is made up of five natural uranium slugs 0.873" diameter x 4.050" long. The slugs, stacked one of top of another, are held together and protected by a drawn-on stainless steel tube with welded and closures. These internal blanket rods are located inside the external blanket the manufacture of which has been described previously.
- Reactivity as a Function of Irradiation Time in Thermal Reactors
- Equations governing the variation of U235. U238, Pu239, Pu240, and Pu241 have been derived and their solutions plotted as a function of irradiation time. The initial U235 content of the uranium was varied from 0.5% to 2.0%. The range of conversion ratios was from 0.5 to 1.2. The irradiation was from 0 to 20,000 mwd/ton of fuel. Since a range of initial conversion ratios is associated with each value of enrichment, a solution results in a family of curves for each isotope, and, since the range of enrichments is large, the number of curves is quite large. Translation of the isotope curves to reactivity variation necessitates a calculation requiring a modest amount of time for a particular case but a prohibitive amount of time to cover the entire range of possible combinations of enrichment and initial conversion ratios. Reactivity variation as a function of irradiation time has been computed for a natural uranium reactor with an initial conversion ratio ranging from 0.7 to 1.2 and for 3 types of reactors in which there is a considerable current interest. Similar calculations for other reactors can be made by making use of the isotope curves and the calculation technique set forth in this report.
- Roll Cladding of Uranium-Niobium Alloys for Plate Type Fuel Elements
- The feasibility of cladding plate type, corrosion resistant uranium-niobium fuel elements with Zircaloy-II by roll bonding has been demonstrated. Plates with cores of uranium alloyed with 3 w/o and 6 w/o Nb intended for irradiation testing in a high temperature water test loop in the MTR have been finished withing specified tolerances. The preparation of cladding billet core and clad components and the assembly of billets by enclosing cores in welded Zircaloy-II jackets can be readily accomplished with conventional fabrication equipment. Some machining operations and billet evacuations, as used in the preparation of most picture frame billet assemblies have been eliminated. Roll bonds were obtained with reductions of 75% to 80% in thickness. Reductions in excess of 90% in thickness, although not necessary for bonding , can be used for economical productions of long plates. Plates can be made with clad to core bond strengths from 30,000 psi to 60,000 psi. Properly heat treated plates have sufficient ductility to allow cold finishing by rolling, forming, bending, or twisting, with reductions of 20% to 30%. Edge bonds of Zircaloy to Zircaloy have been obtained which were corrosion resistant to 260 C water. End seals which were also corrosion resistant to water at this temperature have been made by shielded arc welding inserts to the clad.
- Reactor Engineering Division Quarterly Report September 1, 1953 through November 30, 1953
- Report issued by the Argonne National Laboratory covering the quarterly report from the Reactor Engineering Division. A summary of reactor programs, designs, development, and experiments are presented. This report includes tables, illustrations, and photographs.
- Metallurgy Division Quarterly Report October, November, and December 1953
- This quarterly report discusses ongoing research and experiments at Oak Ridge National Laboratory in the Metallurgy Division. This report discusses water cooled reactors, liquid metal cooled reactors, reactor development metallurgy, basic metallurgy, applied metallurgy, and aqueous corrosion.
- Chemical Engineering Division Summary Report October, November, and December, 1953
- Progress is reported on (1) experimental breeder reactor program, (2) solvent extraction, (3) fluoride volatilization separation process, (4) elevated temperature separations, (5) denitration of uranyl nitrate in a fluidized bed, (6) development of analytical techniques, (7) processing and utilization of radioactive wastes.
- Five-year climatological summary, July 1949-June 1954, Argonne National Laboratory, DuPage County, Illinois
- Report documenting various meteorological measurements for the purpose of understanding the possible dispersion of radioactive material.
- Plutonium Production Analysis - Graphical Method
- In the a study of plutonium production, the analytical solutions of the various isotope production equations are difficult and time consuming when spatial variation of the flux is considered. In an effort to reduce the time and labor required to determine the integrated production of a given thermal reactor, a graphical method of analysis is presented. The method is based on the assumption that the reactor may be divided into a relatively small number of regions such that the flux in each of these regions may be assumed constant. The production of the given isotope for each region is then read from the appropriate graph. The total production is obtained by adding the productions of all the regions.
- Techniques for X-Ray Examinations of End-Weld Closures and Can-to-Cap Brazes on CP-6 Type Fuel Elements : Final Report -- Metallurgy Program 7.7.7
- A fuel element assembly in which a uranium slug is bonded to an impact extruded aluminum can by means of aluminum-silicon eutectic, and in which the can is capped with a thin aluminum disc, brazed and welded to the can, may contain,(a) imperfections common to brazed and welded metal sections, and (b) inhomogeneities arising from oxidation of uranium, and alloy formation between uranium, aluminum and silicon.
- Physics Division Supplement to Quarterly Report September, October, and November, 1953
- This technical report describes experimental nuclear physics, mass spectroscopy, crystallography, experimental reactor physics, theoretical physics (general), reactor theory and electronic digital computers.
- Metallurgy Division Quarterly Report January, February, and March 1954
- This quarterly report discusses ongoing research and experiments at Oak Ridge National Laboratory in the Metallurgy Division. This report discusses water cooled reactors, liquid metal cooled reactors, reactor development metallurgy, basic metallurgy, applied metallurgy, and aqueous corrosion.
- Summary of Meteorological Data Taken at Argonne National Laboratory, Du Page County, Illinois, July 1952 Through June 1953
- Report issued by the Argonne National Laboratory discussing meteorological data collected between 1952 and 1953. Wind, temperature, pressure, and precipitation studies are presented. This report includes tables, illustrations, and a map.
- Reactor Engineering Division Quarterly Report: December 1, 1953 Through March 30, 1954
- Report issued by the Argonne National Laboratory covering the quarterly report from the Reactor Engineering Division. A summary of reactor programs, designs, development, and experiments are presented. This report includes tables, illustrations, and photographs.
- Chemical Engineering Division Summary Report January, February, and March, 1954
- Progress is reported on (1) direct cycle boiling reactor studies, (2) solvent extraction, (3) fluoride volatilization separation process, (4) elevated temperature separations, (5) fluidization studies, (6) development of analytical techniques, (7) processing and utilization of radioactive wastes.
- Preliminary Hazard Summary Report on the Boiling Experiment Reactor (BER)
- Experiments performed by the Laboratory with the Borax Reactor at the National Reactor Testing Station have demonstrated that a boiling reactor possesses inherent safety characteristics which have not previously been included in the estimation of reactor hazards. Other operating characteristics of Borax were also sufficiently attractive to justify the development of boiling reactors for package power and central station power plant applications. Accordingly, a proposal was made to the Atomic Energy Commission that Argonne design, construct and operate a pilot-scale boiling reactor (BER) as part of the Commission's five year program for development of power reactors. Tentative approval for this project has been granted. The primary objective of the BER is to establish the feasibility of operating a boiling reactor in conjunction with a turbine generator on a scale which can be extrapolated to large sizes. A preliminary evaluation of hazards is hereby submitted for the purpose of determining site requirements for a 20 mw reactor of this type. Because the construction of the reactor would be expedited and its usefulness as an operating experiment greatly enhanced, it is suggested that the reactor should be constructed at the DuPage site of the Laboratory. If the inherent features of safety of the boiling reactor are shown to provide a sufficient reduction in exclusion area to permit construction in a metropolitan areas, a sizeable improvement in the possibility of industrial power will have been made. It is in this sprit that this preliminary evaluation is presented.
- Environmental Radioactivity at Argonne National Laboratory. Report for the Year 1953
- The radioactive content of samples of rain, surface water, soil, plants, and material from the beds of surface waters (bottom silt) which were collected and analyzed during 1953 are given in this report. Samples were collected form the Laboratory site, at locations with 25 miles, and at places 100 miles from the Laboratory. Since Laboratory waste water is discharged into Sawmill Creek, water from the this stream was analyzed daily. Other samples were collected from the Laboratory site periodically, and collections from the off-site locations were made at approximately quarterly intervals. Most of the results were obtained by counting total alpha and beta activity; selected samples were analyzed for specific nuclides and elements. The total activity measurements provided a rapid means of determining general levels of radioactivity which could be compared between samples and indicated which samples should be analyzed in more detail. Radioactive contamination attributable to Laboratory operations was found only in water and bottom silt taken from Sawmill Creek below the outfall of Laboratory waste water (below site).
- Testing of Fuel Element Parts and Assemblies by the Radiographic Method
- Concurrently with the production of canned uranium slugs for pile operation there arises the problem of nondestructive testing so that no slug which may fail structurally during operation be placed in the pile. The ultimate goal of any such testing program is to devise nondestructive testing methods which will eliminate defective slugs. A secondary goal of the testing program is to learn as much as possible about the construction of the canned slug so that the mechanisms of failure can be understood. Radiography, an increasingly useful nondestructive test method, offered one possible way of investigating this area.
- Quarterly Progress Report on Reactor Development: 4000 program
- Report issued by the Argonne National Laboratory discussing progress made on reactor development. Progress made on the core, pressure vessel and shield, and the power plant are presented. This report includes tables, and illustrations.
- A Physical Determination of the Conversion Ratio of the Experimental Breeder Reactor
- Report issued by the Argonne National Laboratory discussing the Experimental Breeder Reactor (EBR). Descriptions and methods of the EBR are presented. This report includes tables, and illustrations.
- The Regeneration Factor as a Function of Time in a Th232 - U235 Thermal Reactor
- This technical report is concerned with a theoretical investigation of the variation of the regeneration factor [gamma] in a Th232 - U235 thermal reactor. The abundances of the significant isotopes in the thorium-uranium cycle have been derived as a function of irradiation time at constant reactor power. The change in [gamma] as a function of irradiation time at constant power was calculated for combinations of enrichment and resonance escape probability considered likely to exist in a thermal reactor. The effect upon [gamma] of the the absorption cross section of 91Pa233 and of the fission products has been shown.
- Differential Thermal Analysis of Irradiated Diamond and Silicon Carbide
- It was demonstrated by differential thermal analysis (DTA) that: 1. Catastrophic amounts of energy can be stored in diamond. 2. Even at low irradiations, the release takes place over serval hundred degrees, indicating a spectrum of activation energies. 3. At higher irradiations, the stored energy release is considerably less than the increased energy contents and seems not to have been completely released even at the highest temperatures reached. 4. There is some indication of an increased heat capacity below the temperature of stored energy release. It was shown by DTA that large amounts of energy can be stored in silicon carbide on irradiation. The release was found to be spread out over a greater range of temperatures than in diamond and indicated a larger and higher group of activation energies. Catastrophic release was not achieved. The amount of stored energy released over the range of temperatures used was 140 cal/g in a sample irradiated in a water-cooled test hole at HEW for an exposure of 265 Mwd/aT.
- IsotopesProduction Reactor: Summary of Complete Design
- Report describing an Isotope Production Reactor, which may be of interest to industrial groups studying the possibilities of entering the radioactive isotopes production field. Detailed drawings and specifications for the construction of the reactor are included.
- Soluble Poisons in Reactor Control
- Theoretical and experimental investigations of the use of soluble poisons (neutron absorbers) to supplement mechanical control rods are summarized. Experimental evaluation of poisons of interest includes in-pile and out-of-pile tests simulating anticipated reactor operating conditions. Other phases of the investigation included methods of poison injection, removal, and cleanup of poison-diluted reactor systems, as well as studies to evaluate possible application of soluble poison control in existing and proposed reactors.
- Argonne National Laboratory Annual Report: 1956
- 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.
- The Process Equipment and Protective Enclosures Designed for the Fuel Fabrication Facility: Facility #350
- 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.
- Effects of Preferred Orientation and Grain Size On Dimensional Stability of Uranium on Thermal Cycling and Irradiation : Final Report -- Metallurgy Program 5.1.7
- 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.
- Summary Report of the Hazards of the Internal Exponential Experiment (ZPR-V)
- 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.