[en] This article summarizes NUREG/CR-3950 (PNL-5210, Vol. 8), Fuel Performance Annual Report for 1990, published in November 1993. This thirteenth annual report provides a brief description of fuel performance during 1990 in commercial nuclear power plants and an indication of trends. Brief summaries of fuel design changes, fuel surveillance programs, fuel operating experience, fuel failure trends and problems, and high-burnup fuel experience are provided in this article. 23 refs., 4 figs., 10 tabs

[en] This volume describes the fuel rod material and performance models that were updated for the FRAPCON-3 steady-state fuel rod performance code. The property and performance models were changed to account for behavior at extended burnup levels up to 65 Gwd/MTU. The property and performance models updated were the fission gas release, fuel thermal conductivity, fuel swelling, fuel relocation, radial power distribution, solid-solid contact gap conductance, cladding corrosion and hydriding, cladding mechanical properties, and cladding axial growth. Each updated property and model was compared to well characterized data up to high burnup levels. The installation of these properties and models in the FRAPCON-3 code along with input instructions are provided in Volume 2 of this report and Volume 3 provides a code assessment based on comparison to integral performance data. The updated FRAPCON-3 code is intended to replace the earlier codes FRAPCON-2 and GAPCON-THERMAL-2. 94 refs., 61 figs., 9 tabs

[en] Fuel behavior models have recently been updated within the U.S. Nuclear Regulatory Commission steady-state FRAPCON code used for auditing of fuel vendor/utility-codes and analyses. These modeling updates have concentrated on providing a best estimate prediction of steady-state fuel behavior up to the maximum burnup level s of current data (60 to 65 GWd/MTU rod-average). A decade has passed since these models were last updated. Currently, some U.S. utilities and fuel vendors are requesting approval for rod-average burnups greater than 60 GWd/MTU; however, until these recent updates the NRC did not have valid fuel performance models at these higher burnup levels. Pacific Northwest Laboratory (PNL) has reviewed 15 separate effects models within the FRAPCON fuel performance code (References 1 and 2) and identified nine models that needed updating for improved prediction of fuel behavior at high burnup levels. The six separate effects models not updated were the cladding thermal properties, cladding thermal expansion, cladding creepdown, fuel specific heat, fuel thermal expansion and open gap conductance. Comparison of these models to the currently available data indicates that these models still adequately predict the data within data uncertainties. The nine models identified as needing improvement for predicting high-burnup behavior are fission gas release (FGR), fuel thermal conductivity (accounting for both high burnup effects and burnable poison additions), fuel swelling, fuel relocation, radial power distribution, fuel-cladding contact gap conductance, cladding corrosion, cladding mechanical properties and cladding axial growth. Each of the updated models will be described in the following sections and the model predictions will be compared to currently available high burnup data

[en] Experiments characterizing the coaxial helicity source and helicity injection current drive on the Prototype Helicity Injected Tokamak (Proto-HIT) have been performed. Toroidal currents over 30 kA can be sustained for times much greater than the plasma resistive times. The coaxial source operates with a large toroidal field that greatly enhances the source impedance, allowing a high rate of helicity injection (high source voltage) at a low source current (high efficiency), with results showing good agreement with a simple analytical model. (author). 23 refs, 5 figs, 1 tab

[en] Department of Energy contractors responsible for the safe operation of non-reactor nuclear facilities need to establish maximum inventory limits on both radioactive and hazardous materials stored, used, or processed at their facilities. These contractors need to ensure that established maximum limits are not exceeded. This necessity is derived from the requirement to demonstrate that a non-reactor facility can by safely operated during normal and abnormal conditions. The 222-S Laboratory has established that a maximum of 800 core equivalent samples (CES)may be stored at the Laboratory. Using the CES definition one can determine the maximum allowed curies pre radionuclide permitted. These estimates were made using a variation on a statistical technique called smoothed-bootstrapping. Smoothed- bootstrapping is a method analogous to Monte Carlo simulation using a smoothed empirical probability distribution. This report discusses the application of the smoothed bootstrap technique to predicting the curie inventory retained in the numerous waste tank samples for the radionuclides of concern and the uncertainty associated with such a prediction

[en] A steady-state tokamak fusion reactor requires current drive. Presently studied tokamak current-drive experiments (neutral beam, electron cyclotron, and lower hybrid) drive tail particles and have a power efficiency approximately five times that of ohmic. However, at reactor conditions their efficiency relative to ohmic decreases to approximately 10^-3. Helicity injection current drive utilizes plasma relaxation processes to drive current carried by the bulk population, allowing efficiency to remain near ohmic for reactor conditions. Magnetic helicity, K, is a measure of toroidal and poloidal flux linkage, proportional to their product. Thus tokamak helicity is proportional to the plasma current I_p, which decays on resistive time scales. The Prototype Helicity Injected Tokamak (Proto-HIT) experiment (R = 0.35 m, a = 0.25 m, annular thin-walled flux conserver) formed and sustained 30 kA of plasma current solely by coaxial helicity injection. The helicity injector behavior agrees with a force balance model. Surface conditioning by titanium gettering increases the toroidal current and the injector impedance, in agreement with helicity balance

[en] The Large S Experiment (LSX) began its first series of experiments in October 1990. As the largest FRC ever in operation in the world, LSX has already successfully demonstrated FRC formation using ''low voltage'' technology. Configuration lifetimes are ∼300 μsec. Initial results at low voltages, and with a non-ideal crowbar, have resulted in final magnetic fields of 0.3-0.5 T. Electron temperatures are estimated in the 40-200 eV range, depending on fill pressure. Plans for the on-going University/Spectra collaboration effort are outlined. This paper describes some of the first results coming from LSX, while concentrating on radiation observations made by a variety of instruments. (author) 7 refs., 3 figs

[en] This annual report, the thirteenth in a series, provides a brief description of fuel performance during 1990 in commercial nuclear power plants. Brief summaries of fuel design changes, fuel surveillance programs, fuel operating experience and trends, fuel problems high-burnup fuel experience, and items of general significance are provided . References to additional, more detailed information, and related NRC evaluations are included where appropriate

[en] This report is the fourteenth in a series that provides a compilation of information regarding commercial nuclear fuel performance. The series of annual reports were developed as a result of interest expressed by the public, advising bodies, and the US Nuclear Regulatory Commission (NRC) for public availability of information pertaining to commercial nuclear fuel performance. During 1991, the nuclear industry's focus regarding fuel continued to be on extending burnup while maintaining fuel rod reliability. Utilities realize that high-burnup fuel reduces the amount of generated spent fuel, reduces fuel costs, reduces operational and maintenance costs, and improves plant capacity factors by extending operating cycles. Brief summaries of fuel operating experience, fuel design changes, fuel surveillance programs, high-burnup experience, problem areas, and items of general significance are provided