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Physics Design of the Mixed Spectrum Critical Assembly

Description: Summary: The Mixed Spectrum Superheater (MSSR) is an integral superheater reactor in which boiling occurs in an annular Boiling Water Reactor section and steam in superheated in an unmoderated fast section in the center. A Mixed Spectrum Critical Assembly (MSCA) to be operated at the Vallecitos Atomic Laboratory has been designed to mock up a 75-150 MWe prototype MSSR. The principal experimental measurements aimed at proving the feasibility of the MSSR concept include power distribution, Doppler effect, flooding effects, distribution of reactivity, control rod worths, and the effect of the control system on the power distribution.
Date: August 1963
Creator: Reynolds, A. B.
Partner: UNT Libraries Government Documents Department

High Power Density Development Project: Potter Meter Calibration and Instrumented Fuel Bundle Pressure Drop

Description: Summary: Technical report describing the testing of eight Potter Meters, for metering inlet flow and measuring exit steam qualities in the Consumers Big Rock Point Instrumented Fuel Assemblies, were individually calibrated for flow and pressure drop up to 500 gpm in the low temperature (130 F) fluid flow facility. The flow calibration comparison made with an ASME orifice installation, agreed to within + - 1 percent among seven of the meters, and meter Serial No. 8 was 2.8 percent lower than the others. Pressure drop among the meters was within about 5 percent. Locked rotor pressure drop data was obtained on one meter. A fully instrumented fuel bundle was tested in the low temperature facility and pressure drop data obtained for the tieplates and meters, spacers, and channel rods. A mock-up of the exit end of the instrumented fuel bundles, composed of 1 foot of fuel rods, tieplate, and Potter Meter was tested in the High Pressure Heat Transfer Facility. Data was obtained for single- and two-phase calibration of total flow and exit steam quality in an instrumented bundle. Each meter was operated, for a minimum of 6-8 hours after bearing modifications necessitated by seizure of the rotors, in the High Pressure Facility under conditions of 1000 psi and qualities of about 5-6 percent to verify operation and obtain some run-in time before reactor installation. A total of 655 hours of test and run-in time was made on all eight meters.
Date: July 26, 1963
Creator: Polomik, E. E. & Swan, C. L.
Partner: UNT Libraries Government Documents Department

Nuclear Superheat Quarterly Project Report: Sixteenth Quarter, May-July 1963

Description: From introduction: "This is the sixteenth in a series of quarterly reports which cover the progress and results from the conceptual designs, economic evaluations and research and development work performed by the General Electric Company as part of Contract AT(01-3)-189, Project Agreement No. 13."
Date: August 15, 1963
Creator: Flock, W. L.
Partner: UNT Libraries Government Documents Department

Maritime Loop Irradiation Program for Savannah I Fuel Post-Irradiation Examination of SI5BM Fuel Assembly

Description: Abstract: A stainless steel clad 9-rod assembly fabricated by The Babcock & Wilcox Company was irradiated in a boiling water loop of the General Electric Test Reactor. A post-irradiation examination revealed no significant dimensional changes on the fuel rods. the results of mass spectrometric analysis made of the pelletized UO2 fuel indicated a maximum burnup of 11,500 MWD/tonne was attained by Rod B-4 during the exposure.An x-ray diffraction examination of an unirradiated fuel sample revealed the presence of UN2 and U2N3 phases. Metallographic examination of the irradiated microstructures revealed similar second-phase particles.
Date: November 7, 1963
Creator: Mathay, P. W.
Partner: UNT Libraries Government Documents Department

Fuel Failure Examinations and Analyses in the High Power Density Program

Description: Summary: The High Power Density Project includes a comprehensive fuel development program which has the objective of developing and demonstrating the performance of a nuclear reactor core having a high power density, long fuel life, and low fabrication cost. The fuel program is made up of two principal tasks. Task 1A consists of irradiation tests in the VBWR of Type 304 stainless steel clad, UO2 pellet type fuel rods fabricated by current commercial processes. Task 1B consists of the investigation of lower cost fabrication processes and the irradiation testing of fuel elements fabricated by these processes. Both tasks include the investigation of the feasibility and use of thin-wall stainless steel cladding as a means of improving the neutron economy and fuel cycle costs of stainless steel clad fuel. Irradiation of the Task 1A fuel assemblies in the VBWR was initiated in September, 1960. Subsequently, Task 1B fuel assemblies were inserted in the VBWR as various fabrication processes and design concepts were investigated. Fuel cladding failures have occurred in fuel rods in both Task 1A and 1B. As of this date, cladding failures have occurred in twenty-two rods of approximately 700 fuel rods which have been irradiated. Twenty of the failures occurred in cold worked tubing and two in tubing procured commercially as annealed materials.
Date: September 16, 1963
Creator: Arlt, W. H. & Vandenberg, S. R.
Partner: UNT Libraries Government Documents Department

In-Core Instrumentation Development Program Quarterly Progress Report June - September 1963

Description: Introduction: The objective of Project Agreement 22 is to determine the feasibility of covering the complete reactor neutron flux start range from 10(3) - 5 x 10(13) nv by using in-core chambers. The counting mode of operating will be used at low neutron fluxes and the root mean square voltage fluctuation mode will be used at high neutron flux levels. Experiments have been run utilizing various ion chambers, gases, gas pressures, voltage, and cables to measure sensitivities and range operating in the counting and RMS voltage modes. Theoretical discussions are presented showing how the RMS voltage is related to individual pulse at both amplifier input and output. Noise is also compared at amplifier output so that the optimum bandwidth can be selected. Spectral shifts with changes in applied voltage causing signal variations have been examined and can be eliminated by appropriate selection of amplifier bandwidth. In the counting mode, all experiments have been conducted with unterminated cable. The chamber has been designed with geometry, gas, and pressure to completely stop fission fragments in the gas and hence maximize the charge generated in the chamber. Cables have been selected to minimize capacity. Various gases, pressures, and voltages have been used to determine that an optimum design has been achieved.
Date: October 1963
Creator: DuBridge, R. A.
Partner: UNT Libraries Government Documents Department

Development of Pulsed Neutron Application to Power Reactor Start-Up Procedures. Sixth Quarterly Progress Report, July 1-September 30, 1963

Description: Activities in a program to develop techniques in the use of pulsed neutron sources to measure shutdown parameters related to large thermal power reactors are reported. The development of pulsed neutron source techniques for large power reactors has led to a new theoretical model recently developed by E. Garelis and J.L. Russell, Jr. The theory is presently based on a bare, one-group model with m-delayed precursors and takes all spatial modes into account. Results indicate, however, that the application of this model is much broader. Experiments were designed and carried out to both verify this new theory and to demonstrate the performance of the experimental hardware in a large power reactor.
Date: October 15, 1963
Creator: Garelis, Edward & Meyer, P.
Partner: UNT Libraries Government Documents Department

High Power Density Development Project: Fourteenth Quarterly Progress Report, July-September 1963

Description: Development of nuclear reactor cores having high power density, long fuel life, and low fabrication costs is the objective of this program sponsored by the AEC. Five tasks are in progress: (1) Task 1A-High Power Density Fuel Development. The number of assemblies has been reduced to seven as a result of the failure of two pellet fuel assemblies. The average burnup of the group operating as of September 1 is 7500 MWD/T. (2) Task 1B-Fuel Fabrication Development. Assembly. Assembly 12S gave positive signals of being a leaker under the multi-type in-core sampler and was declared failed based on the in-core results and visual observation of a cracked rod. Modifications to the instrumented fuel assembly probes were made by removing the failed flow meter rotors to allow continued use of the flux detectors and thermocouples. Flux detectors and thermocouples performed properly after reactor start up. Flux wire tubes were found to be kinked such that their use was prohibited. (3) Task II-Stability, Heat Transfer and Fluid Flow. A series of noise recordings of fluxes, flows, and temperatures has been made at 91 MWt at the Big Rock Point plant. Preliminary analyses of some of the these records were made to obtain noise amplitude as a function of frequency. Thermocouple response tests were performed to verify the temperature measurement obtained during the steady-state noise tests at Big Rock. (4) Task III-Physics Development. Plans for achieving optimum performance from the Big Rock plant are being based on the concept of maintaining a fixed power shape throughout each operating cycle. The desired shape for the present cycle has been computed. Methods of selecting control rod patterns to maintain this shape are being investigated for use in the on-line computer. The computer was put on line during plant startup in August, and is presently performing …
Date: October 1963
Creator: Holladay, R. L.
Partner: UNT Libraries Government Documents Department

Fuel Cycle Program Design and Fabrication of Special Assembly 10-L : Compacted Powder Fuel Rods Clad With 0.127-MM Wall Stainless Steel

Description: Technical report describing sixteen fuel rods clad with thin type 304 stainless steel and filled with vibratory compact powder UO2 that were fabricated and incorporated into a bundle for irradiation testing in the VBWR. The UO2 powders were tested for gas content. N2, CO, and H2 were the principal gases evolved by both type of UO2, but the arc-fused UO2 released about ten times as much gas as the Dyna Pak UO2. The amount of gas released was also a function of particle size and temperature. The gas evolution data were used to design the gas plenum to accommodate the absorbed gases along with the fission gases.
Date: October 1963
Creator: Ogawa, S. Y. & Williamson, N. E.
Partner: UNT Libraries Government Documents Department

Prediction of Two-Phase Critical Flow Rate

Description: Technical report of a proposal of an analytical model to predict two-phase critical flow rate. The model is based upon thermal equilibrium, a "lumped" treatment of the two-phase velocity (each phase is represented by a single mean velocity), and upon the neglect of frictional and hydrostatic pressure losses. A comparison, of the proposed predictions with available test results and previous analyses shows that: (1) The present model agrees very well with the published test data. (2) In contrast to all other analyses, the model requires no assumption about the gas void fraction.
Date: October 1963
Creator: Levy, S.
Partner: UNT Libraries Government Documents Department

Design and Fabrication of Pellet Fuel Rods Clad With Thin Wall Stainless Steel

Description: Summary: Stainless steel clad nuclear fuel cycle costs can be reduced to those associated with Zircaloy clad fuel or potentially lower by reducing the thickness of the clad tube wall until performance penalties offset the savings associated with the reduction in parasitic neutron absorption. To demonstrate the feasibility and investigate performance capabilities of thin clad fuel rods for power reactor application an assembly was fabricated with 0.0127 cm (5 mil) thick stainless steel cladding tubes for irradiation testing in the Vallecitos Boiling Water Reactor (VBWR). The fuel bundle was placed in the VBWR and irradiation was begun in November, 1961. The irradiation is scheduled to continue until the target exposure of 2.74 x 10(20) fissions/cc (10,000 MWD/T of uranium) average burnup is reached. Destructive examinations of fuel rods will be performed at regular intervals throughout life to determine fuel rod performance.
Date: February 1964
Creator: Hoffmann, J. P.
Partner: UNT Libraries Government Documents Department

A Uranium Dioxide Fuel Rod Center Melting Test in the Vallecitos Boiling Water Reactor

Description: Technical report describing that as part of the AEC Fuel Cycle Program, tests are being conducted to evaluate the significance of current fuel design limitations that do not permit the maximum fuel temperature to exceed the melting point of UO2. The reliability of prediction of the fuel rod operating conditions that will cause melting of the UO2 was evaluated by means of a calibration test conducted in the Vallecitos Boiling Water Reactor. Conclusions: (a) The central portion of the 3.15-cm diameter uranium dioxide fuel column melted. It appears that the UO2 was molten to a radius of 1.22 cm in the peak power region. The maximum extent of melting probably occurred during the peak power run when the kdT in this region of the rod reached 171 watts cm. The estimated radius of melting from metallographic examination indicates the kdT for sintered UO2 is 89 watts/cm. This supports a calculated estimate for sintered UO2 thermal conductivity published by D. R. deHalas and G. R. Horn. The results of the previous calibration run and subsequent experimental data by Lyons are also consistent with the value. This conclusion is contingent on the interpretation of the post-irradiation crystal structure of the UO2. Insufficient data are available on the mechanisms by which various UO2 crystal structures are formed to permit a positive identification of the extent of melting and correlation with time of operation. No conclusion can be drawn as to whether the thermal conductivity of the UO2 changed with operation. (b) Although extensive UO2 melting occurred, there was no indication of fuel rod clad failure. (c) Axial heat transfer by convection in the molten UO2 was significant.
Date: November 15, 1963
Creator: Williamson, H. E. & Hoffmann, J. P.
Partner: UNT Libraries Government Documents Department

Reactor Safety and Fuel Cycle Economics Considerations for Fast Reactors

Description: Abstract: A core design study of a 10 Mwe fast ceramic reactor is presented. Local reactivity coefficients, safety criteria, accident analyses, and economics are considered. An attempt is made to find a new balance of characteristics by purely geometric devices, i.e., by exploring the sodium : fuel ratio and varying the height : diameter ratio of the core. The use of BeO in the core was also investigated.
Date: November 11, 1963
Creator: Cohen, K. P.; Greebler, P.; McNelly, M. J.; Murphy, P. M.; Sherer, D. B. & Zebroski, E. L.
Partner: UNT Libraries Government Documents Department

Nuclear Superheat Quarterly Project Report: Seventeenth Quarter, August-October 1963

Description: From introduction: "This is the seventeenth in a series of quarterly reports which cover the progress and results from the conceptual designs, economic evaluations and research and development work performed by the General Electric Company as part of Contract AT(01-3)-189, Project Agreement No. 13."
Date: November 15, 1963
Creator: Flock, W. L.
Partner: UNT Libraries Government Documents Department

Influence of the Doppler Effect on the Meltdown Accident

Description: The influence of the Doppler effect in the core disassembly process following a meltdown accident is examined with a Bethe-Tait type model in which the Doppler effect, as well as core disassembly, is considered in the reactor shutdown process. It is shown that a strong negative Doppler effect can radically reduce the explosive energy release in such an accident. (auth)
Date: November 18, 1963
Creator: Wolfe, B.; Friedman, N. & Riley, D.
Partner: UNT Libraries Government Documents Department

Accurate Nuclear Fuel Burnup Analyses; Eighth Quarterly Progress Report, (September - November 1963)

Description: The objective of the Accurate Nuclear Fuel Burnup Analyses program is to develop more accurate methods for burnup analysis for general use than the current method of analysis of Ca-137 or Sr-90. The program will require from three to five years of effort.
Date: December 1, 1963
Creator: Rider, B. F.; Ruiz, C. P.; Luke, P. S., Jr.; Peterson, J. P., Jr. & Smith, F. R.
Partner: UNT Libraries Government Documents Department

Two-Phase Pressure Losses Quarterly Progress Report: Seventh Quarter, August 12, 1963 - November 11, 1963

Description: Technical report describing that the pressure drop along an annular channel with dimensions D(1) = 0.375 inch; D(2) = 0.875 inch, L = 70 inches. Flow was vertical and upward, and only the internal surface was heated. Subcooled conditions existed at the inlet, with two-phase conditions at the exit. Groups of three radial spacer pins on 18-inch centers along the channel, held the inner surface concentric with the outer surface. The single phase loss coefficient for each spacer group is K(8) = 0.21. The single phase friction factor for the annual channel is given by f = 0.16 N(R)(-0.16). The two phase pressure drop increases as the quality increases for G [over] 10(6) = 0.5 ;b/hr ft(2). The effect of heat flux on the pressure drop is very is very slight over the range of fluxes tested (0.55 less than or equal to Q over 10(6).\ less than or equal to 0.8). The two-phase pressure drop gradient in the same annulus, with no heat addition is qualitatively the same as for a 1/4-inch by 1-3/4 inches rectangular channel but is quantitatively greater than for the rectangular channel.
Date: December 2, 1963
Creator: Janssen, E. (Engineer) & Kervinen, J. A.
Partner: UNT Libraries Government Documents Department

AEC Fuel Cycle Program Design and Fabrication of Special Assembly 9-L : Irradiation Performance Test of UO2-Cermet Fuel

Description: Technical report describing a UO2-Mo cermet fuel assembly fabricated for long-term irradiation performance testing in the Vallecitos Boiling water Reactor. The design and fabrication histories of this assembly are described and pre-irradiation data on each individual rod are presented. Molybdenum was added to improve the bulk thermal conductivity of the fuel, so that fuel temperatures would remain comparatively low during high-power level operation of the fuel element. The molybdenum was incorporated into the compacts either as fibers or as a thin coating on individual UO2 particles. Fuel pellets were produced from these materials by vacuum hot pressing. The distribution of the molybdenum in both types of cermet fuels appeared favorable to good heat transfer. The fibers were oriented predominantly in the radial planes of the pellet as a result of the uni-directional compaction during the hot-pressing operation. In the pellets made from the coated particles, a continuous network of molybdenum occurred as a result of the coating welding together during the hot-pressing operation. The test assembly contains eight fuel rods; three contain UO2-Mo cermet, three contain the cermet produced from the coated particles, and two are for reference and contain the conventional sintered UO2 pellet fuel. The nominal outside diameter of the fuel rods is 1.308 cm (0.515 inch), and the clad wall thickness if 0.051 cm (0.020 inch). the cladding material is Type-304 stainless steel. The fuel pellets were all centerless ground to achieve a uniform outside diameter and thereby control the pellet-to-clad diametral clearance within a range of 0.076 to 0.102 mm (0.003 to 0.004 inch). Operation of the fuel rods will be at high specific power levels with surface heat fluxes of about 157 W/cm(2) (~500,000 Btu/h-ft(2)). The assembly was designed for a lifetime of 4.1 x 10(20) fission/cc (15,000 MWD/T) exposure.
Date: March 1964
Creator: Ogawa, S. Y.
Partner: UNT Libraries Government Documents Department

Sodium Mass Transfer. [Part] XI. 1963 Test Run Reports (January - June)

Description: Technical report describing how corrosion data and exposure effects were obtained by subjecting metallic samples, during programmed test runs to flowing sodium in 6 test loops fabricated with various combinations of three selected materials, Type 316 stainless steel, 2 1/4 Cr-1 Mo alloy steel, and 5 Cr-1/2 Mo-1/2 Ti alloy steel. Information produced by each test run, including operational and metallurgical data and analyses, is presented. Data are shown in tables, graphs, and drawings.
Date: February 1964
Creator: Lockhart, R. W.
Partner: UNT Libraries Government Documents Department

In-Core Instrumentation Development Program Quarterly Progress Report September - December 1963

Description: Introduction: The objective of Project Agreement 22 is to determine the feasibility of using in-core ion chambers to cover the complete reactor neutron flux startup range from 10(4) -5 - 10(13) nv using in-core ion chambers. The counting mode of operation will be used at low neutron flux levels and the RMS voltage fluctuation mode (Campbell Theorem) will be used at high neutron flux levels. The June-September Progress Report (GEAP-4386) shows how the RMS voltage mode can be used, discusses counting problems with long cable and ways of maximizing signal levels. This report discusses primarily the effect of gamma on counting with in-core ion chambers and the range of neutron flux measurable in the RMS voltage mode. Readers are referred to GEAP-4386 for a summary of all previous progress to attain the objective of PA-22.
Date: January 1964
Creator: DuBridge, R. A.
Partner: UNT Libraries Government Documents Department

High Power Density Development Project: Fifteenth Quarterly Progress Report, October-December 1963

Description: Development of nuclear reactor cores having high power density, long fuel life, and low fabrication costs is the objective of this program sponsored by the AEC. Five tasks are in progress: (1) Task 1A-High Power Density Fuel Development. All fuel irradiation has been terminated with the final shutdown of the VBWR. The high burnup average achieved by a single assembly in the group is 10,000 MWD/T (assembly 1F). Twenty-one of the original 24 assemblies have failed or are suspected of failure. Profilometer tests rung on HPD assembly 2E, Rod B, indicate that localized clad deformation occurs during operation. (2) Task 1B-Fuel Fabrication Development. Assembly. All fuel irradiation has been terminated with the final shutdown of the VBWR. The highest average burnup achieved by a single assembly in the group was assembly 4S with 8400 MWD/T. All assemblies in the group have failed or are suspected of failure. The Phase I developmental fuel continues to be irradiated in the Big rock Point reactor with the lead assembly having reached 1500 MWD/T. Fifteen phase II developmental assemblies are being construction for insertion at Big Rock Point in March. Engineering is underway to provide one instrumented assembly probe and two spare flowmeters for use in phase II testing. Flowmeter bearing are being redesigned to minimize crud access and changes of bearing seizure. (3) Task II-Stability, Heat Transfer and Fluid Flow. Phase I of the reactor performance tests has now been completed. These tests consisted of core performance, control rod oscillator, pressure transient, and flow tests. Reduction of the data from these tests has begun, and preliminary results have been prepared for use by the Consumers Power Company in relicensing for Phase II. (4) Task III-Physics Development. Power distribution calculations have been performed for the proposed 84-bundle, 75 MWe core and for the high …
Date: January 1, 1964
Creator: Hollady, R. L.
Partner: UNT Libraries Government Documents Department

Accurate Nuclear Fuel Burnup Analyses; Ninth Quarterly Progress Report, (December 1963 - February 1964)

Description: The objective of the Accurate Nuclear Fuel Burnup Analyses program is to develop more accurate methods for burnup analysis for general use than the current method of analysis of Ca-137 or Sr-90. The program will require from three to five years of effort.
Date: March 1, 1964
Creator: Rider, B. F.; Peterson, J. P., Jr.; Ruiz, C. P. & Smith, F. R.
Partner: UNT Libraries Government Documents Department

Design and Fabrication of Fuel Rods Containing Sintered UO2 Extrusions - Assembly 11L

Description: The extrusion forming of ceramic powders may be economically interesting in the field of nuclear fuel fabrication. When applied to the forming of rod-type uranium dioxide fuel, extrusion processes have been able to produce cylindrical bodies with length-to-diameter ratios much greater than those of the conventional die-pressed pellets. Furthermore, after being sintered, the extrusions have exhibited densities at least as high as those of sintered pellets. Thus, extrusion forming may offer reductions in handling during fabrication and, at the same time, provide a fuel with improved performance characteristics by decreasing the number of discontinuities in the fuel column. This report reviews the production of these extrusions, sets forth some of their characteristics, describes the materials and processes employed in cladding them, and records the pre-irradiation data pertaining to the finished fuel rods and fuel assembly. Irradiation of the fuel assembly in the VBWR was initiated on July 17, 1962.
Date: February 1964
Creator: Megerth, F. H.
Partner: UNT Libraries Government Documents Department
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