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Thermonuclear burn in wall-confined plasmas

Description: The one-dimensional initial value problem describing a hot, dense, thermonuclear reacting plasma which is magnetically insulated and contained between cold metal walls has been studied by means of computational simulation. The resulting time evolution of the plasma temperature, number density and magnetic field profiles includes the effects of thermal conduction and radiation energy losses from the plasma, convection, and a detailed treatment of alpha particle heating, as well as ohmic heating and magnetic field diffusion. The results are used to evaluate the net energy gains possible in a shock-heated, magnetically insulated, wall-confined fusion cycle.
Date: January 1, 1979
Creator: Kmetyk, L.N.
Partner: UNT Libraries Government Documents Department

Cavity dimensions for high velocity penetration events: A comparison of calculational results with data

Description: Calculations were performed with the CTH and HULL finite difference wavecodes to evaluate computational capabilities for predicting depth and diameter of target cavities produced in high velocity penetration events. The calculations simulated selected tests in a set of armor penetration experiments conducted by the US Army Ballistic Research Laboratory and reported earlier in the literature. The tests and simulations involved penetration of semi-infinite targets by long rod projectiles over a range of impact velocities from 1.3 to 4.5 km/sec. Comparisons are made between the calculated and measured dimensions of the target cavities, and the sensitivity of the predicted results to target property variations is investigated. 9 refs., 18 figs., 3 tabs.
Date: May 1, 1989
Creator: Kmetyk, L.N. & Yarrington, P.
Partner: UNT Libraries Government Documents Department

Ground shock from multiple earth penetrator bursts: Effects for hexagonal weapon arrays

Description: Calculations have been performed with the HULL hydrocode to study ground shock effects for multiple earth penetrator weapon (EPW) bursts in hexagonal-close-packed (HCP) arrays. Several different calculational approaches were used to treat this problem. The first simulations involved two-dimensional (2D) calculations, where the hexagonal cross-section of a unit-cell in an effectively-infinite HCP array was approximated by an inscribed cylinder. Those calculations showed substantial ground shock enhancement below the center of the array. To refine the analysis, 3D unit-cell calculations were done where the actual hexagonal cross-section of the HCP array was modelled. Results of those calculations also suggested that the multiburst array would enhance ground shock effects over those for a single burst of comparable yield. Finally, 3D calculations were run in which an HCP array of seven bursts was modelled explicitly. In addition, the effects of non-simultaneity were investigated. Results of the seven-burst HCP array calculations were consistent with the unit-cell results and, in addition, provided information on the 3D lethal contour produced by such an array.
Date: August 1, 1990
Creator: Kmetyk, L.N. & Yarrington, P.
Partner: UNT Libraries Government Documents Department

MELCOR 1. 8. 1 assessment: LACE aerosol experiment LA4

Description: The MELCOR code has been used to simulate LACE aerosol experiment LA4. In this test, the behavior of single- and double-component, hygroscopic and nonhygroscopic, aerosols in a condensing environment was monitored. Results are compared to experimental data, and to CONTAIN calculations. Sensitivity studies have been done on time step effects and machine dependencies; thermal/hydraulic parameters such as condensation on heat structures and on pool surface, and radiation heat transfer; and aerosol parameters such as number of MAEROS components and sections assumed, the degree to which plated aerosols are washed off heat structures by condensate film draining, and the effect of non-default values for shape factors and diameter limits. 9 refs., 50 figs., 13 tabs.
Date: September 1, 1991
Creator: Kmetyk, L.N.
Partner: UNT Libraries Government Documents Department

RELAP5 assessment: LOFT turbine trip L6-7/L9-2

Description: The RELAP5 independent assessment project at Sandia National Laboratories is part of an overall effort funded by the NRC to determine the ability of various systems codes to predict the detailed thermal; hydraulic response of LWRs during accident and off-normal conditions. The RELAP5/MOD1 code is being assessed at SNLA against test data from various integral and separate effects test facilities. As part of this assessment matrix, a turbine trip rapid cooldown transient performed at the LOFT test facility has been analyzed. The results show that RELAP5/MOD1 can predict the experimental behavior of LOFT test L6-7/L9-2 in detail. However, careful selection of modeling options and adjustment of boundary conditions within the experimental uncertainties is required.
Date: July 1, 1983
Creator: Thompson, S.L. & Kmetyk, L.N.
Partner: UNT Libraries Government Documents Department

Analytic and experimental decay heat determinations of 800-MeV proton irradiated aluminum

Description: Postirradiation radiochemistry analysis of 800-MeV proton irradiated ultrahigh purity aluminum has been done with standard gamma-ray counting equipment determining the Na/sup 22/ activity in the activated aluminum. Results are compared to predicted values obtained from CINDER, a general nuclide depletion and fission-product code. This program can be used easily to calculate the activity of materials under arbitrary irradiation, provided that the source terms for the various radionuclides produced are known. The required production cross sections have been calculated by using the nucleon-meson transport code NMTC to determine the nuclear reactions produced by the protons, and the theory of Lindhard et al. to evaluate the resultant damage energy deposited in the target.
Date: October 1, 1981
Creator: Kmetyk, L.N. & Sommer, W.F.
Partner: UNT Libraries Government Documents Department

Analytic method for calculating the time--temperature history of metal foils under pulsed irradiation and a Gaussian beam profile

Description: Utilization of a pulsed radiation source such as the Clinton P. Anderson Meson Physics Facility (LAMPF) for materials science studies requires knowledge of the time--temperature history of a subject metal foil. An analytic solution was derived to a two-dimensional heat flow equation, incorporating the LAMPF time structure and the LAMPF Gaussian beam spot profile. This calculational method is useful in designing experimental systems for materials science studies and can be done on a Hewlett--Packard model 97 desk-top calculator. The results were compared with an equivalent numerical solution of the same two-dimensional heat flow problem done on a digital computer.
Date: May 1, 1979
Creator: Kmetyk, L.N. & Sommer, W.F.
Partner: UNT Libraries Government Documents Department

MELCOR 1.8.3 assessment: CSE containment spray experiments

Description: MELCOR is a fully integrated, engineering-level computer code, being developed at Sandia National Laboratories for the USNRC, that models the entire spectrum of severe accident phenomena in a unified framework for both BWRs and PWRS. As part, of an ongoing assessment program, the MELCOR computer code has been used to analyze a series of containment spray tests performed in the Containment Systems Experiment (CSE) vessel to evaluate the performance of aqueous sprays as a means of decontaminating containment atmospheres. Basecase MELCOR results are compared with test data, and a number of sensitivity studies on input modelling parameters and options in both the spray package and the associated aerosol washout and atmosphere decontamination by sprays modelled in the radionuclide package have been done. Time-step and machine-dependency calculations were done to identify whether any numeric effects exist in these CSE assessment analyses. A significant time-step dependency due to an error in the spray package coding was identified and eliminated. A number of other code deficiencies and inconveniences also are noted.
Date: December 1, 1994
Creator: Kmetyk, L.N.
Partner: UNT Libraries Government Documents Department

Effect of cyclic pulsed temperature on void growth in metals during irradiation

Description: The analysis of Brailsford and Bullough on radiation-produced point defect transport to lattice sinks and the analysis of Ghoniem and Kulcinski of pulsed radiation have been extended to include the effects of radiation-induced temperature oscillations. We have already shown in earlier papers that these temperature pulses enhance void growth if the ambient temperature is below the peak swelling temperature and, conversely, decrease void growth when the ambient temperature is above the peak swelling temperature. When the temperature pulses were suppressed, no difference was seen between void growth under steady and pulsed irradiation. In this paper, we show that the same effects on void growth can be obtained by superposing externally-produced temperature pulses on material under steady irradiation. Calculations have been done for aluminum and molybdenum for sinusoidal temperature pulses of many amplitudes and frequencies.
Date: January 1, 1981
Creator: Kmetyk, L.N.; Sommer, W.F. & Weertman, J.
Partner: UNT Libraries Government Documents Department

MELCOR 1.8.2 Assessment: IET direct containment heating tests

Description: MELCOR is a fully integrated, engineering-level computer code, being developed at Sandia National Laboratories for the USNRC, that models the entire spectrum of severe accident phenomena in a unified framework for both BWRs and PWRS. As part of an ongoing assessment program, the MELCOR computer code has been used to analyze several of the IET direct containment heating experiments done at 1:10 linear scale in the Surtsey test facility at Sandia and at 1:40 linear scale in the corium-water thermal interactions (CWTI) COREXIT test facility at Argonne National Laboratory. These MELCOR calculations were done as an open post-test study, with both the experimental data and CONTAIN results available to guide the selection of code input. Basecase MELCOR results are compared to test data in order to evaluate the new HPME DCH model recently added in MELCOR version 1.8.2. The effect of various user-input parameters in the HPME model, which define both the initial debris source and the subsequent debris interaction, were investigated in sensitivity studies. In addition, several other non-default input modelling changes involving other MELCOR code packages were required in our IET assessment analyses in order to reproduce the observed experiment behavior. Several calculations were done to identify whether any numeric effects exist in our DCH IET assessment analyses.
Date: October 1, 1993
Creator: Kmetyk, L. N.
Partner: UNT Libraries Government Documents Department

Evaluation of potential severe accidents during low power and shutdown operations at Grand Gulf, Unit 1: Evaluation of severe accident risks for plant operational state 5 during a refueling outage. Supporting MELCOR calculations, Volume 6, Part 2

Description: To gain a better understanding of the risk significance of low power and shutdown modes of operation, the Office of Nuclear Regulatory Research at the NRC established programs to investigate the likelihood and severity of postulated accidents that could occur during low power and shutdown (LP&S) modes of operation at commercial nuclear power plants. To investigate the likelihood of severe core damage accidents during off power conditions, probabilistic risk assessments (PRAs) were performed for two nuclear plants: Unit 1 of the Grand Gulf Nuclear Station, which is a BWR-6 Mark III boiling water reactor (BWR), and Unit 1 of the Surry Power Station, which is a three-loop, subatmospheric, pressurized water reactor (PWR). The analysis of the BWR was conducted at Sandia National Laboratories while the analysis of the PWR was performed at Brookhaven National Laboratory. This multi-volume report presents and discusses the results of the BWR analysis. The subject of this part presents the deterministic code calculations, performed with the MELCOR code, that were used to support the development and quantification of the PRA models. The background for the work documented in this report is summarized, including how deterministic codes are used in PRAS, why the MELCOR code is used, what the capabilities and features of MELCOR are, and how the code has been used by others in the past. Brief descriptions of the Grand Gulf plant and its configuration during LP&S operation and of the MELCOR input model developed for the Grand Gulf plant in its LP&S configuration are given.
Date: March 1, 1995
Creator: Kmetyk, L.N. & Brown, T.D.
Partner: UNT Libraries Government Documents Department

Launch capabilities to 16 km/s

Description: A systematic study is described that has led to the successful launch of thin flier-plates to velocities of 16 km/s. In this paper, the authors describe a novel technique that has been implemented to enhance the performance of the Sandia Hyper Velocity Launcher (HVL). This technique of creating an impact-generated acceleration reservoir, has allowed the launch of 0.5 mm to 1.0 mm thick titanium (Ti-6Al-4V) and aluminum (6061-T6) alloy plates to record velocities up to 15.8 km/s. These are the highest metallic projectile plate velocities ever achieved for macroscopic masses in the range of 0.1 g to 1 g.
Date: August 1, 1995
Creator: Chhabildas, L.C.; Kmetyk, L.N. & Reinhart, W.D.
Partner: UNT Libraries Government Documents Department

Void growth and swelling for cyclic pulsed radiation

Description: The analysis of Ghoniem and Kulcinski of a single radiation pulse has been extended to include the effects of temperature oscillations and multiple pulses by coupling six simultaneous nonlinear ordinary differential equations for point defect concentrations and sink strengths with a heat equation governing radiation-produced temperature fluctuations. The pulsed irradiation considered is that of the 800 MeV proton beam at the Clinton P. Anderson Meson Physics Facility (LAMPF), and numerical calculations have been done for aluminum and molybdenum. The model material is assumed to have been irradiated to a specific microstructure, and the calculation is begun after the material has returned to thermal equilibrium conditions. Void growth is seen to proceed at a nearly linear rate after initial transients (caused by the assumption of initial thermal equilibrium) in both vacancy concentration and vacancy loop size and number density. The temperature pulses associated with cyclic rather than steady irradiation generally enhance void growth if the ambient temperature is below the material peak swelling temperature, and conversely decreases void growth when the ambient temperature is above peak swelling temperature. The exception seen occurs when the temperature pulse is great enough that thermal emission of vacancies, rather than radiation production, is dominant. 27 figures.
Date: September 1, 1980
Creator: Kmetyk, L.N.; Weertman, J.; Green, W.V. & Sommer, W.F.
Partner: UNT Libraries Government Documents Department

Use of the LAMPF accelerator as a fusion materials-radiation facility

Description: Materials for fusion applications will be subjected to radiation that produces large amounts of transmutation product gases such H and He, as well as others. These gaseous products can have a marked influence on material mechanical properties as they affect the microstructural evolution of the material. Previous calculations by others have shown that the 800 MeV proton beam at the Clinton P. Anderson Los Alamos Meson Physics Facility (LAMPF) will produce gaseous transmutation products in amounts near those expected in the fusion environment. This report will survey the LAMPF facility from the standpoint of experiment design, temperature control, available experimental volume and available beam time. Calculations have been made that predict that attainable displacement rates at specific available target stations at LAMPF. Results for W, Mo, Al and stainless steel will be reported.
Date: January 1, 1981
Creator: Sommer, W.F.; Kmetyk, L.N.; Green, W.V. & Damjanovich, R.
Partner: UNT Libraries Government Documents Department

L3 (33) an analytic comparison of the effect of steady state and cyclic pulsed radiation on void growth and swelling

Description: The analysis of Ghoniem and Kulcinski of pulsed radiation was extended to include the effects of temperature oscillations and multiple pulses. Multiple pulses are required before the vacancy concentration stabilizes to an oscillation between limits. Then void growth proceeds at a nearly uniform rate. Point defect recombination plays only a minor role, but temperature oscillations play a significant role.
Date: January 1, 1979
Creator: Kmetyk, L.N.; Sommer, W.F.; Weertman, J. & Green, W.V.
Partner: UNT Libraries Government Documents Department

MELCOR technical assessment at SNL

Description: MELCOR is a fully integrated, engineering-level computer code that models the progression of severe accidents in light water reactor (LWR) nuclear power plants, which is being developed at Sandia National Laboratories for the US Nuclear Regulatory Commission (US-NRC). The entire spectrum of severe accident phenomena, including reactor coolant system and containment thermal/hydraulic response, core heatup, degradation and relocation, and fission product release and transport, is treated in MELCOR in a unified framework for both boiling water reactors (PRWs). The MELCOR computer code has been developed to the point that is now being successfully applied in severe accident analyses, particularly in probabilistic risk assessment (PRA) studies. MELCOR was the first of the severe accident analysis code to undergo a formal peer review process. One of the major conclusions of the recent MELCOR Peer Review was the need for a more comprehensive and more systematic program of MELCOR assessment. This report provides a discussion of this technical assessment.
Date: December 1, 1993
Creator: Kmetyk, L. N. & Tautges, T. J.
Partner: UNT Libraries Government Documents Department

MELCOR 1.8.2 assessment: Aerosol experiments ABCOVE AB5, AB6, AB7, and LACE LA2

Description: The MELCOR computer code has been used to model four of the large-scale aerosol behavior experiments conducted in the Containment System Test Facility (CSTF) vessel. Tests AB5, AB6 and AB7 of the ABCOVE program simulate the dry aerosol conditions during a hypothetical severe accident in an LMFBR. Test LA2 of the LACE program simulates aerosol behavior in a condensing steam environment during a postulated severe accident in an LWR with failure to isolate the containment. The comparison of code results to experimental data show that MELCOR is able to correctly predict most of the thermal-hydraulic results in the four tests. MELCOR predicts reasonably well the dry aerosol behavior of the ABCOVE tests, but significant disagreements are found in the aerosol behavior modelling for the LA2 experiment. These results tend to support some of the concerns about the MELCOR modelling of steam condensation onto aerosols expressed in previous works. During these analyses, a limitation in the MELCOR input was detected for the specification of the aerosol parameters for more than one component. A Latin Hypercube Sampling (LHS) sensitivity study of the aerosol dynamic constants is presented for test AB6. The study shows the importance of the aerosol shape factors in the aerosol deposition behavior, and reveals that MELCOR input/output processing is highly labor intensive for uncertainty and sensitivity analyses based on LHS.
Date: October 1, 1994
Creator: Souto, F. J.; Haskin, F. E. & Kmetyk, L. N.
Partner: UNT Libraries Government Documents Department

Evaluation of potential severe accidents during low power and shutdown operations at Grand Gulf, Unit 1: Evaluation of severe accident risks for plant operational state 5 during a refueling outage. Main report and appendices, Volume 6, Part 1

Description: Traditionally, probabilistic risk assessments (PRAS) of severe accidents in nuclear power plants have considered initiating events potentially occurring only during full power operation. Recent studies and operational experience have, however, implied that accidents during low power and shutdown could be significant contributors to risk. In response to this concern, in 1989 the Nuclear Regulatory Commission (NRC) initiated an extensive program to carefully examine the potential risks during low power and shutdown operations. Two plants, Surry (pressurized water reactor) and Grand Gulf (boiling water reactor), were selected as the plants to be studied. The program consists of two parallel projects being performed by Brookhaven National Laboratory (Surry) and Sandia National Laboratories (Grand Gulf). The program objectives include assessing the risks of severe accidents initiated during plant operational states other than full power operation and comparing the estimated risks with the risk associated with accidents initiated during full power operation as assessed in NUREG-1150. The scope of the program is that of a Level-3 PRA. The subject of this report is the PRA of the Grand Gulf Nuclear Station, Unit 1. The Grand Gulf plant utilizes a 3833 MWt BUR-6 boiling water reactor housed in a Mark III containment. The Grand Gulf plant is located near Port Gibson, Mississippi. The regime of shutdown analyzed in this study was plant operational state (POS) 5 during a refueling outage, which is approximately Cold Shutdown as defined by Grand Gulf Technical Specifications. The entire PRA of POS 5 is documented in a multi-volume NUREG report (NUREG/CR-6143). The internal events accident sequence analysis (Level 1) is documented in Volume 2. The Level 1 internal fire and internal flood analyses are documented in Vols 3 and 4, respectively.
Date: March 1995
Creator: Brown, T. D.; Kmetyk, L. N.; Whitehead, D.; Miller, L.; Forester, J. & Johnson, J.
Partner: UNT Libraries Government Documents Department

MELCOR 1.8.2 assessment: Surry PWR TMLB` (with a DCH study)

Description: MELCOR is a fully integrated, engineering-level computer code, being developed at Sandia National Laboratories for the USNRC. This code models the entire spectrum of severe accident phenomena in a unified framework for both BWRs and PWRs. As part of an ongoing assessment program, the MELCOR computer code has been used to analyze a station blackout transient in Surry, a three-loop Westinghouse PWR. Basecase results obtained with MELCOR 1.8.2 are presented, and compared to earlier results for the same transient calculated using MELCOR 1.8.1. The effects of new models added in MELCOR 1.8.2 (in particular, hydrodynamic interfacial momentum exchange, core debris radial relocation and core material eutectics, CORSOR-Booth fission product release, high-pressure melt ejection and direct containment heating) are investigated individually in sensitivity studies. The progress in reducing numeric effects in MELCOR 1.8.2, compared to MELCOR 1.8.1, is evaluated in both machine-dependency and time-step studies; some remaining sources of numeric dependencies (valve cycling, material relocation and hydrogen burn) are identified.
Date: February 1, 1994
Creator: Kmetyk, L.N.; Cole, R.K. Jr.; Smith, R.C.; Summers, R.M. & Thompson, S.L.
Partner: UNT Libraries Government Documents Department

Progress in MELCOR development and assessment

Description: MELCOR models the progression of severe accidents in light water reactor nuclear power plants. Recent efforts in MELCOR development to incorporate CORCON-Mod3 models for core-concrete interactions, new models for advanced reactors, and improvements to several other existing models have resulted in release of MELCOR 1.8.3. In addition, continuing efforts to expand the code assessment database have filled in many of the gaps in phenomenological coverage. Efforts are now under way to develop models for chemical interactions of fission products with structural surfaces and for reactions of iodine in the presence of water, and work is also in progress to improve models for the scrubbing of fission products by water pools, the chemical reactions of boron carbide with steam, and the coupling of flow blockages with the hydrodynamics. Several code assessment analyses are in progress, and more are planned.
Date: April 1, 1995
Creator: Summers, R. M.; Kmetyk, L. N.; Cole, R. K., Jr.; Smith, R. C.; Elsbernd, A. E.; Stuart, D. S. et al.
Partner: UNT Libraries Government Documents Department