Studies of tandem mirror confinement (open access)

Studies of tandem mirror confinement

This paper describes a number of physics studies relevant to tandem mirror confinement. We give the basic axial confinement laws and show that T/sub e/ depends critically upon end loss. Sufficient central-cell end loss can stabilize the drift-cyclotron loss-cone mode in the plugs, although the resultant T/sub e/ scaling is too slow for reactors. Minimum-B plugs stabilize flute MHD- and rotation-driven modes; local ballooning sets limits on ..beta.. > or equal to 0.5. Proper magnetic symmetry is important for good drift confinement. For small increases in the total injected power, supplementary ion-cyclotron r.f. heating can halve the neutral-beam energy required to maintain plug densities.
Date: July 10, 1978
Creator: Baldwin, D. E.; Cohen, R. H.; Foote, J. H.; Hall, L. S.; Kaiser, T. B.; Logan, B. G. et al.
System: The UNT Digital Library
Estimates of time-dependence fatigue behavior of type 316 stainless steel subject to irradiation damage in fast breeder and fusion power reactor systems. [Fluence 1--2. 63 x 10/sup 26/ n/m/sup 2/ (E > 0. 1 MeV/ at 593/sup 0/C] (open access)

Estimates of time-dependence fatigue behavior of type 316 stainless steel subject to irradiation damage in fast breeder and fusion power reactor systems. [Fluence 1--2. 63 x 10/sup 26/ n/m/sup 2/ (E > 0. 1 MeV/ at 593/sup 0/C]

Cyclic lives obtained from strain controlled fatigue tests at 593/sup 0/C from specimens irradiated to a fluence of 1 to 2.63 x 10/sup 26/ n/m/sup 2/ (E greater than 0.1 MeV) were compared to predictions based on the method of strainrange partitioning. When appropriate tensile and creep-rupture ductilities were employed reasonably good estimates of the influence of hold periods and irradiation damage on the fully reversed fatigue life of type 316 stainless steel could be made. Ductility values for 20 percent cold-worked type 316 stainless steel specimens irradiated in a mixed spectrum fission reactor were used to estimate fusion reactor first wall lifetime. The ductility values were from irradiations that simulate the environment of the first wall of a fusion reactor. Neutron wall loadings ranging from 2 to 5 MW/m/sup 2/ were used. Results, although conjectural because of the many assumptions, tended to show that 20 percent cold-worked type 316 stainless steel could be used as a first wall material meeting a 7.5 to 8.5 MW-year/m/sup 2/ lifetime goal provided the neutron wall loading does not exceed more than about 2 MW/m/sup 2/. Results were obtained for an air environment, and it is expected that the actual vacuum environment will …
Date: July 10, 1978
Creator: Brinkman, C.R.; Liu, K.C. & Grossbeck, M.L.
System: The UNT Digital Library
Field reversal in mirror machines (open access)

Field reversal in mirror machines

This report discusses some of the physics issues anticipated in field-reversed mirrors. The effect of current cancellation due to electrons is described. An estimate is made of the required impurity level to maintain a field-reversed configuration. The SUPERLAYER code is used to simulate the high-..beta.. 2XIIB results, and favorable comparisons require inclusion of quasilinear RF turbulence. Impact of a quadrupole field on field-line closure and resonant transport is discussed. A simple self-consistent model of ion currents is presented. Conditions for stability of field-reversed configurations to E x B driven rotations are determined.
Date: July 10, 1978
Creator: Pearlstein, L. D.; Anderson, D. V. & Boozer, A. H.
System: The UNT Digital Library
Tandem mirror physics and TMX (open access)

Tandem mirror physics and TMX

The Tandem Mirror Experiment (TMX) is being built at Livermore to test the principles of the new tandem mirror reactor concept. In this concept the fusion plasma is confined in a long solenoid terminated at each end by mirror machines of the magnetic-well type. High density plasmas are maintained in each of the mirror end cells by neutral injection at high energies (up to 1 MeV in a high Q reactor). The usual positive ambipolar potential that automatically develops in each mirror cell serves as an electrostatic barrier that confines ions in the solenoid for many collision times, and the very stable plasmas in these end cells ''anchor'' each flux tube, thereby assuring MHD stability of the system up to betas of order unity in the solenoid. The TMX will test these main features of the tandem mirror idea and will also investigate optimum means of suppressing loss cone instabilities in the end cells based on methods demonstrated in the 2XIIB experiment. The end cells will be similar in size and injected power to 2XIIB, but some injectors will operate at 40 kV. Expected parameters are n tau approximately 10/sup 11/ cm/sup -3/ sec at ion energies of 20 keV …
Date: August 10, 1978
Creator: Fowler, T.K.
System: The UNT Digital Library
Feasibility studies of thermonuclear neutron capture synthesis of SHE (open access)

Feasibility studies of thermonuclear neutron capture synthesis of SHE

A variety of thermonuclear neutron sources and neutron capture targets were investigated for their potential of allowing signigicant production of heavy, perhaps superheavy, isotopes. The neutron sources considered range from inertial confinement microexplosives to (underground) macroexplosives. Optimal capture targets appear to be composites containing uranium and protactinium. 1 figure.
Date: April 10, 1978
Creator: Meldner, H.W.
System: The UNT Digital Library
Microprocessor controlled, personnel thermoluminescence dosimetry reader (open access)

Microprocessor controlled, personnel thermoluminescence dosimetry reader

Using a DEC LSI-11 microprocessor, a thermoluminescence dosimetry reader for personnel dosimetry has been developed. This microprocessor provides system control, accumulates data for temporary storage on a cassette, and later outputs the data to a large computer. The microprocessor also provides a human/system interface through a computer terminal. A programmable high-voltage supply and a light-emitting diode are used in the reader system to automatically control photomultiplier tube gain.
Date: October 10, 1978
Creator: Hunt, Gerald F.
System: The UNT Digital Library
Enhancement of methane production in the anaerobic digestion of sewage sludges (open access)

Enhancement of methane production in the anaerobic digestion of sewage sludges

The effect of powdered activated carbon on stressed anaerobic digesters utilizing a sewage sludge substrate was evaluated. The addition of carbon resulted in increased methanee production and greater process stability. The degree of enhancement appeared to be proportional to carbon concentration over the dose range studied (500-10,000 mg/l). A maximum increase in methane production of about 150% was observed at the highest carbon dose. The effect of 1500 mg/l carbon, 4000 mg/l coal, and 4000 mg/l flyash on relatively unstressed digesters was also examined. Units using a sewage sludge substrate were operated at 10 and 20 day SRT's. A 12% increase in methane production was observed in a carbon dosed digester functioning at a 10 day detention time. Enhancement was not evident with carbon at a 20 day SRT. No significant improvement in methane production was obtained in any of the digesters using coal or flyash as additives. Using the experimental data, a technique was developed for estimating the efficiencies of the methane forming and acid forming steps in the anaerobic digestion process. The results indicated that in stressed systems both stages of the digestion process were enhanced by the addition of powdered carbon. In the relatively unstressed systems, when …
Date: May 10, 1978
Creator: Spencer, R. R.
System: The UNT Digital Library
Heat transfer from internally-heated molten UO/sub 2/ pools. [PWR; BWR] (open access)

Heat transfer from internally-heated molten UO/sub 2/ pools. [PWR; BWR]

Experimental measurements of heat transfer from internally heated pools of molten UO/sub 2/ have been obtained for two cell sizes: 10 cm x 10 cm and 20 cm x 20 cm. The experiments with the large cell have supported a previous conclusion from early small data that the measured downward heat fluxes are higher than would be expected on the basis of considerations of thermal convection. A convective model underpredicts the downward heat fluxes by a factor of 2.5 to 4.5 for all but one early experiment. Arbitrary assumptions of increased thermal conductivity do not account for the discrepancy. A single model based on internal thermal radiation heat transfer is able to account for the high values. The model uses the optically thick Rosseland approximation. Because of this, it is tentatively concluded that thermal radiation plays a dominant role in controlling the heat transfer from internally heated molted fuel.
Date: October 10, 1978
Creator: Stein, R. P.; Baker, L., Jr.; Gunther, W. H. & Cook, C.
System: The UNT Digital Library
U. S. Mirror Program (open access)

U. S. Mirror Program

The mirror approach is now the principal alternate to the tokamak in the U.S. magnetic fusion energy program. The program is now focused on two new concepts that can obtain high values of Q, defined as the ratio of fusion power output to the neutral beam power injected to sustain the reaction. These are the tandem mirror and field reversed mirror concepts. Theoretically both concepts should be able to attain Q = 5 or more, as compared with Q approximately 1 in previous mirror designs. Success with either or both of these approaches would point the way toward fusion power plants with many attractive features. The linear geometry of mirror systems offers a distinct alternative to the toroidal tokamak. As a direct consequence of this difference in geometry, it is generally possible to build mirror systems in smaller units of modular construction that can probably be made to operate in steady-state. During the next 5 years the main mirror facilities in the U.S. will be the 2XIIB (renamed Beta II); a tandem mirror experiment caled TMX; and the Mirror Fusion Test Facility (MFTF) scheduled to be completed in 1981 at a cost of $94 million. As a background for discussing …
Date: August 10, 1978
Creator: Fowler, T. K.
System: The UNT Digital Library
Reduction of irradiation-induced creep by point defect trapping (open access)

Reduction of irradiation-induced creep by point defect trapping

The theory of point defect trapping was applied to predict the effect of solutes on the steady-state dislocation climb creep rate. Vacancy loops generated in the cascades of point defect production by heavy particles were included. It is shown that the effect of vacancy loops on the creep rate is mathematically equivalent to a simultaneous reduction in the vacancy trapping rate at solutes as well as in the free point defect generation rate and recombination coefficient. These parameters are reduced by the ratio of the sink strength without vacancy loops to the total sink strength. Solute trapping and vacancy loops do not reduce the unperturbed creep rates by more than an order of magnitude for the parametric range considered.
Date: July 10, 1978
Creator: Mansur, L. K. & Wolfer, W. G.
System: The UNT Digital Library
Overview of the M. A. I. T. analysis system (machine analysis of the internal threat). [Collusion and illicit use of access] (open access)

Overview of the M. A. I. T. analysis system (machine analysis of the internal threat). [Collusion and illicit use of access]

The problem of the internal threat epitomized by the tactics of collusion and illicit use of access has been structured into a data processing format. The format procedures and analysis are objective; the flexibility of the method allows the security analyst to input his judgment and opinions into the code. By so doing he can interact and determine the effects of interacting with the safeguard system.
Date: April 10, 1978
Creator: NiCastro, J.R.
System: The UNT Digital Library