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Low strain diameter expansion of internally pressurized Zircaloy-4 tubing at high temperatures

Description: Tests of closed-end, internally pressurized, Zircaloy-4 tubing specimens were utilized to develop low strain creep characteristics as a function of time at temperatures in the range of 1475/sup 0/F to 2000/sup 0/F (802/sup 0/C to 1093/sup 0/C) and hoop stresses in the range of 250 to 2500 psi for use in loss-of-coolant accident (LOCA) analyses. The strain rate above the start of the alpha to beta phase transformation region, approximately 1490/sup 0/F (810/sup 0/C), was found to be sensitive to the test procedure (stress-temperature history). This is believed to result from variations in the metallurgical structure. A prediction model is presented which provides a conservative upper bound to the low strain test data provided in this report and reported in the literature.
Date: March 1978
Creator: White, L.S. & Busby, C.C.
Partner: UNT Libraries Government Documents Department
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Susceptibility of unirradiated recrystallized Zircaloy-4 tubing to stress corrosion cracking

Description: Stress corrosion cracking (SCC) in unirradiated recrystallized Zircaloy-4 internally pressurized tubing specimens in atmospheres containing iodine vapor, cesium, or combinations of iodine and cesium is evaluated experimentally in terms of the effects of internal surface flaw morphology, iodine and cesium concentrations, tubing hydrogen content, test temperature, and test atmosphere water vapor content on the time to failure. The iodine vapor SCC data are analyzed in the framework of a fracture mechanics model. Expressions are developed which relate the iodine SCC threshold stress and lifetime for stresses above threshold to temperature, iodine concentration, and surface flaw geometry.
Date: December 1977
Creator: Polan, N. W. & Tucker, R. P.
Partner: UNT Libraries Government Documents Department
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Cladding corrosion and hydriding in irradiated defected zircaloy fuel rods

Description: Twenty-one LWBR irradiation test rods containing ThO/sub 2/-UO/sub 2/ fuel and Zircaloy cladding with holes or cracks operated successfully. Zircaloy cladding corrosion on the inside and outside diameter surfaces and hydrogen pickup in the cladding were measured. The observed outer surface Zircaloy cladding corrosion oxide thicknesses of the test rods were similar to thicknesses measured for nondefected irradiation test rods. An analysis model, which was developed to calculate outer surface oxide thickness of non-defected rods, gave results which were in reasonable agreement with the outer surface oxide thicknesses of defected rods. When the analysis procedure was modified to account for additional corrosion proportional to fission rate and to time, the calculated values agreed well with measured inner oxide corrosion film values. Hydrogen pickup in the defected rods was not directly proportional to local corrosion oxide weight gain as was the case for non-defected rods. 16 refs., 6 figs., 8 tabs.
Date: August 1985
Creator: Clayton, J. C.
Partner: UNT Libraries Government Documents Department
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Determination of statistically based design limits associated with engineering models.

Description: This report provides a usable reference of methods and procedures for the construction of both one-sided and two-sided ..gamma../P statistical tolerance limits for design application to both linear and nonlinear models in any number of variables.
Date: February 1, 1980
Creator: Ginsburg, H.
Partner: UNT Libraries Government Documents Department
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Thoria powder process development

Description: The development program to identify the critical parameters for the process of converting thorium nitrate solution into thoria powder is described. Thorium oxalate hexahydrate is precipitated from the reaction of thorium nitrate solution with oxalic acid. The resulting thorium oxalate hexahydrate slurry is filter pressed into a cake which is air calcined to form thoria powder. Changes in the critical processing parameters such as free nitric acid content of the thorium nitrate solution, precipitation temperature, and calcining temperature altered the thoria powder characteristics, and thus its capability for being fabricated into fuel pellets. The objective of the powder preparation effort was to obtain thoria powders which could be formed by conventional ceramic fabrication techniques into thoria and thoria-urania pellets of high density and high integrity having a nearly uniform large grain structure.
Date: October 1, 1979
Creator: Hutchison, C.R. & Lloyd, R.
Partner: UNT Libraries Government Documents Department
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Fuel rod-grid interaction wear: in-reactor tests

Description: Wear of the Zircaloy cladding of LWBR irradiation test fuel rods, resulting from relative motion between rod and rod support contacts, is reported. Measured wear depths were small, 0.0 to 2.7 mils, but are important in fuel element behavior assessment because of the local loss of cladding thickness, as well as the effect on grid spring forces that laterally restrain the rods. An empirical wear analysis model, based on out-of-pile tests, is presented. The model was used to calculate the wear on the irradiation test fuel rods attributed to a combination of up-and-down motions resulting from power and pressure/temperature cycling of the test reactor, flow-induced vibrations, and assembly handling scratches. The calculated depths are generally deeper than the measured depths.
Date: November 1, 1979
Creator: Stackhouse, R. M.
Partner: UNT Libraries Government Documents Department
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Model for incorporating fuel swelling and clad shrinkage effects in diffusion theory calculations

Description: A model has been devised for incorporating into the thermal feedback procedure of the PDQ few-group diffusion theory computer program the explicit calculation of depletion and temperature dependent fuel-rod shrinkage and swelling at each mesh point. The model determines the effect on reactivity of the change in hydrogen concentration caused by the variation in coolant channel area as the rods contract and expand. The calculation of fuel temperature, and hence of Doppler-broadened cross sections, is improved by correcting the heat transfer coefficient of the fuel-clad gap for the effects of clad creep, fuel densification and swelling, and release of fission-product gases into the gap. An approximate calculation of clad stress is also included in the model.
Date: March 1, 1980
Creator: Schick, W.C. Jr.; Milani, S. & Duncombe, E.
Partner: UNT Libraries Government Documents Department
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Effect of fuel chips on cladding stress in zircaloy clad oxide fuel rods

Description: Zircaloy clad oxide fuel rods are subjected to a variety of core power transients. One of these, an up-power transient, can place a severe burden on the fuel rod cladding that would potentially lead to rupture if not properly allowed for during the fuel rod design and plant operation. The cladding stress during such a transient can be increased by the presence of fuel chips between the oxide fuel pellet and the cladding. An analysis procedure based on mechanical tests of fuel and cladding was developed that permits calculation of the stress increase due to chips, so that the stress penalty can be accommodated without unnecessary penalties to fuel rod performance. The method of evaluating the maximum cladding bending tensile stress near the chip is described and test data are presented to support the analysis method.
Date: November 1978
Creator: Yerman, J. F.
Partner: UNT Libraries Government Documents Department
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Nondestructive assay of UO/sub 2/--ThO/sub 2/ fuel pellets using the delayed neutron pellet assay gage

Description: This report describes the use of a delayed neutron pellet assay gage to determine nondestructively the fissile content of fuel pellets during the manufacture of the Light Water Breeder Reactor (LWBR) core. The gage characteristics are described including the nature of the calibration curves and the gage sensitivities to pellet parameters. Statistical methods are derived for analyzing the data to obtain the mean weight percent of total uranium in each blend of fuel material as well as the loading precision of each fuel rod. The fissile loading of each fuel rod was determined to better than 0.25% at the 2 sigma level, and the fissile content of eight fuel compositions in the LWBR core was obtained to better than 0.1%. Use of this gage and the data analysis methods described in this report reduced the need for destructive chemical analysis of fuel pellets by a factor of two.
Date: June 1, 1979
Creator: Emert, C.J.; Milani, S. & Beggs, W.J.
Partner: UNT Libraries Government Documents Department
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Design features of the Light Water Breeder Reactor (LWBR) which improve fuel utilization in light water reactors

Description: This report surveys reactor core design features of the Light Water Breeder Reactor which make possible improved fuel utilization in light water reactor systems and breeding with the uranium-thorium fuel cycle. The impact of developing the uranium-thorium fuel cycle on utilization of nuclear fuel resources is discussed. The specific core design features related to improved fuel utilization and breeding which have been implemented in the Shippingport LWBR core are presented. These design features include a seed-blanket module with movable fuel for reactivity control, radial and axial reflcetor regions, low hafnium Zircaloy for fuel element cladding and structurals, and a closely spaced fuel rod lattice. Also included is a discussion of several design modifications which could further improve fuel utilization in future light water reactor systems. These include further development of movable fuel control, use of Zircaloy fuel rod support grids, and fuel element design modifications.
Date: August 1981
Creator: Hecker, H. C. & Freeman, L .B.
Partner: UNT Libraries Government Documents Department
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Corrosion of Zircaloy-4 tubing in 68OF water

Description: Seamless Zircaloy-4 tubing is utilized as fuel rod cladding in light water reactors. Water corrosion tests at 68OF have been performed to determine the corrosion and hydriding characteristics of Zircaloy-4 tubing, fabricated by cold reduction and finished in two metallurgical conditions: a stress-relief anneal (SRA) and a recrystallization anneal (RXA). These corrosion tests revealed differences in the post-transition corrosion product weight gains of the two materials. A computer corrosion model, designated CHORT, was developed from the test data and ascribes the observed difference in material weight gain to an assumed difference in the periodicity of a postulated cyclic buckling of the oxide.
Date: December 1, 1978
Creator: Marino, G. P. & Fischer, R. L.
Partner: UNT Libraries Government Documents Department
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Summary of the nuclear design and performance of the Light Water Breeder Reactor (LWBR)

Description: This report presents a summary of the nuclear design and expected nuclear performance of the Light Water Breeder Reactor during operation at the Shippingport Atomic Power Station. Performance predictions are presented for core lifetime, breeding margin, power distributions and performance, kinetic and stability parameters, and for core shutdown and reactivity control capability. Also included is a summary of as-built dimensions of core components and of development of breeding parameter equations and sensitivities.
Date: June 1, 1979
Creator: Hecker, H.C.
Partner: UNT Libraries Government Documents Department
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ASBLT: a system of DATATRAN MODULES which process core fuel loading for use in as-built calculations

Description: ASBLT is a computer program consisting of DATATRAN MODULES which was used during the manufacturing phase of LWBR to collect and evaluate as-built data. The program was part of the LWBR fuel rod inspection process and produced sections of module assembly certification reports. ASBLT used fuel pellet, fuel rod and module assembly data to compute core inventories and to supply input to nuclear design programs for as-built core calculations.
Date: February 1, 1979
Creator: Beaudoin, B.R.; Beggs, W.J.; Case, C.R. & Wilczynski, R.
Partner: UNT Libraries Government Documents Department
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Properties of thoria and thoria-urania: a review

Description: Information on the physical, chemical, and mechanical properties of thoria and thoria-urania is reviewed and assessed. The properties discussed are those judged to be important for an understanding of the behavior of these oxides as nuclear fuel materials. Evaluation was made, where possible, of the effects of composition, material variables, temperature, and irradiation exposure. Data were taken from a review of the literature and from both published and unpublished data derived from the Light Water Breeder Reactor (LWBR) Program at the Bettis Atomic Power Laboratory. 30 figs., 23 tables, 163 refs.
Date: June 1, 1978
Creator: Belle, J. & Berman, R.M.
Partner: UNT Libraries Government Documents Department
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PDQ-8 reference manual

Description: The PDQ-8 program is designed to solve the neutron diffusion, depletion problem in one, two, or three dimensions on the CDC-6600 and CDC-7600 computers. The three dimensional spatial calculation may be either explicit or discontinuous trial function synthesis. Up to five lethargy groups are permitted. The fast group treatment may be simplified P(3), and the thermal neutrons may be represented by a single group or a pair of overlapping groups. Adjoint, fixed source, one iteration, additive fixed source, eigenvalue, and boundary value calculations may be performed. The HARMONY system is used for cross section variation and generalized depletion chain solutions. The depletion is a combination gross block depletion for all nuclides as well as a fine block depletion for a specified subset of the nuclides. The geometries available include rectangular, cylindrical, spherical, hexagonal, and a very general quadrilateral geometry with diagonal interfaces. All geometries allow variable mesh in all dimensions. Various control searches as well as temperature and xenon feedbacks are provided. The synthesis spatial solution time is dependent on the number of trial functions used and the number of gross blocks. The PDQ-8 program is used at Bettis on a production basis for solving diffusion--depletion problems. The report describes the various features of the program and then separately describes the input required to utilize these features.
Date: May 1, 1978
Creator: Pfiefer, C J & Spitz, C J
Partner: UNT Libraries Government Documents Department
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Critical heat flux experiments with a local hot patch in an internally heated annulus

Description: Critical heat flux experiments were conducted for upflow of water in a vertical 84 inch annular flow channel, 0.303 inch heated I.D. and 0.500 inch unheated O.D. Test data were obtained at pressures from 1200 to 2000 psia, mass velocities from 0.25 x 10/sup 6/ to 2.8 x 10/sup 6/ lb/hr-ft/sup 2/ and inlet temperatures ranging from 200 to 600/sup 0/F. Three different test sections were employed with (1) axially uniform heat flux over the 84 inch length to serve as a no-hot-patch data base, (2) axially uniform heat flux over 82 inches with a 1.5 heat flux ratio hot patch over the last two inches, and (3) axially uniform heat flux over 82 inches with a 2.25 heat flux ratio hot patch over the last two inches.
Date: February 1, 1979
Creator: Mortimore, E.P. & Beus, S.G.
Partner: UNT Libraries Government Documents Department
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Summary of the hydraulic evaluation of LWBR

Description: The principal hydraulic performance features of the Light Water Breeder Reactor are summarized in this report. The calculational models and procedures used for prediction of reactor flow and pressure distributions under steady-state and transient operating conditions are described. Likewise, the analysis models for evaluation of the static and dynamic performance characteristics of the hydraulically-balanced and hydraulically-buffered movable-fuel reactivity-control system are outlined. An extensive test program was conducted for qualification of the subject LWBR hydraulic evaluation models. The projected LWBR hydraulic performance is shown to fulfill design objectives and functional requirements.
Date: April 1, 1981
Creator: Stout, J.W.; Lerner, S.; McWilliams, K.D. & Turner, J.R. (eds.)
Partner: UNT Libraries Government Documents Department
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Fission gas release from ThO/sub 2/ and ThO/sub 2/--UO/sub 2/ fuels

Description: Fission gas release data are presented from 51 fuel rods irradiated as part of the LWBR irradiations test program. The fuel rods were Zircaloy-4 clad and contained ThO/sub 2/ or ThO/sub 2/-UO/sub 2/ fuel pellets, with UO/sub 2/ compositions ranging from 2.0 to 24.7 weight percent and fuel densities ranging from 77.8 to 98.7 percent of theoretical. Rod diameters ranged from 0.25 to 0.71 inches and fuel active lengths ranged from 3 to 84 inches. Peak linear power outputs ranged from 2 to 22 kw/ft for peak fuel burnups up to 56,000 MWD/MTM. Measured fission gas release was quite low, ranging from 0.1 to 5.2 percent. Fission gas release was higher at higher temperature and burnup and was lower at higher initial fuel density. No sensitivity to UO/sub 2/ composition was evidenced.
Date: August 1, 1978
Creator: Goldberg, I.; Spahr, G. L.; White, L. S.; Waldman, L. A.; Giovengo, J. F.; Pfennigwerth, P. L. et al.
Partner: UNT Libraries Government Documents Department
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Densification related pellet diameter shrinkage in low burnup thoria-base fuels

Description: In-reactor densification of ThO/sub 2/ and ThO/sub 2/--UO/sub 2/ fuel of low burnup and low power operation (hence low temperature) was assessed by measuring fuel pellet diameter changes. Pellet diameter changes ranged from nil in a large grain, low temperature thoria pellet (98.9 percent theoretical density) to -1.06 percent in a small grain, moderate temperature ThO/sub 2/-30 w/o UO/sub 2/ pellet (93.8 percent theoretical density). A correlation was established between quantity of small pores (<2.3 ..mu..m diameter) and as-fabricated fuel grain size. An empirical equation, based on densification (pore closure) plus fuel swelling, was formulated for pellet diameter change as a function of initial grain size and fuel burnup.
Date: September 1, 1978
Creator: Spahr, G.L.
Partner: UNT Libraries Government Documents Department
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Water cooled breeder program summary report

Description: The purpose of the Department of Energy Water Cooled Breeder Program was to demonstrate pratical breeding in a uranium-233/thorium fueled core while producing electrical energy in a commercial water reactor generating station. A demonstration Light Water Breeder Reactor (LWBR) was successfully operated for more than 29,000 effective full power hours in the Shippingport Atomic Power Station. The reactor operated with an availability factor of 76% and had a gross electrical output of 2,128,943,470 kilowatt hours. Following operation, the expended core was examined and no evidence of any fuel element defects was found. Nondestructive assay of 524 fuel rods determined that 1.39 percent more fissile fuel was present at the end of core life than at the beginning, proving that breeding had occurred. This demonstrates the existence of a vast source of electrical energy using plentiful domestic thorium potentially capable of supplying the entire national need for many centuries. To build on the successful design and operation of the Shippingport Breeder Core and to provide the technology to implement this concept, several reactor designs of large breeders and prebreeders were developed for commercial-sized plants of 900--1000 Mw(e) net. This report summarizes the Water Cooled Breeder Program from its inception in 1965 to its completion in 1987. Four hundred thirty-six technical reports are referenced which document the work conducted as part of this program. This work demonstrated that the Light Water Breeder Reactor is a viable alternative as a PWR replacement in the next generation of nuclear reactors. This transition would only require a minimum of change in design and fabrication of the reactor and operation of the plant.
Date: October 1, 1987
Partner: UNT Libraries Government Documents Department
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Nuclear analysis and performance of the Light Water Breeder Reactor (LWBR) core power operation at Shippingport

Description: This report presents the nuclear analysis and discusses the performance of the LWBR core at Shippingport during power operation from initial startup through end-of-life at 28,730 EFPH. Core follow depletion calculations confirmed that the reactivity bias and power distributions were well within the uncertainty allowances used in the design and safety analysis of LWBR. The magnitude of the core follow reactivity bias has shown that the calculational models used can predict the behavior of U/sup 233/-Th systems with closely spaced fuel rod lattices and movable fuel. In addition, the calculated final fissile loading is sufficiently greater than the initial fissile inventory that the measurements to be performed for proof-of-breeding evaluations are expected to confirm that breeding has occurred.
Date: April 1, 1984
Creator: Hecker, H.C.
Partner: UNT Libraries Government Documents Department
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FLASH-6: simulation of top injection emergency core cooling heat transfer tests

Description: Data from top injection ECCS tests conducted at Columbia University have been analyzed as part of an effort to qualify the FLASH-6 computer program for performing post-blowdown heat transfer calculations for the LWBR Safety Analysis. These experiments, which employed a full-scale fuel assembly with electrical heater rods to simulate an inlet rupture for a pressurized water reactor, provided test conditions and rod cooling mechanisms quite similar to those encountered in the postulated LWBR cold leg break loss-of-coolant accident. Clad temperature predictions were obtained using both the modified Dittus-Boelter and the Dougall-Rohsenow correlations to evaluate beyond CHF heat transfer coefficients. Overall comparisons using the FLASH calculated flow rates indicated that the rod temperature calculations were conservative using either of the heat transfer correlations because virtually none of the coolant was calculated to penetrate the heated test assembly. Heat transfer model comparisons were also performed by adjusting the calculation so that coolant was injected directly into the top of the rod bundle to simulate the experimentally observed flow conditions. Once this downflow was forced, conservative temperature predictions were obtained using the Dougall-Rohsenow correlation, whereas the modified Dittus-Boelter beyond CHF option yielded non-conservative results.
Date: May 1, 1977
Creator: Lincoln, F. W.
Partner: UNT Libraries Government Documents Department
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Model to estimate the local radiation doses to man from the atmospheric release of radionuclides

Description: A model was developed to estimate the radiation dose commitments received by people in the vicinity of a facility that releases radionuclides into the atmosphere. This model considers dose commitments resulting from immersion in the plume, ingestion of contaminated food, inhalation of gaseous and suspended radioactivity, and exposure to ground deposits. The dose commitments from each of these pathways is explicitly considered for each radionuclide released into the atmosphere and for each daughter of each released nuclide. Using the release rate of only the parent radionuclide, the air and ground concentrations of each daughter are calculated for each position of interest. This is considered to be a significant improvement over other models in which the concentrations of daughter radionuclides must be approximated by separate releases.
Date: April 1, 1977
Creator: Rider, J. L. & Beal, S. K.
Partner: UNT Libraries Government Documents Department
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