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Research on the HYLIFE liquid-first-wall concept for future laser-fusion reactors

Description: The experiments were designed to simulate the time period between microexplosions. Extrapolating the results of these small-scale experiments to the large-scale lithium jets, we have tentatively concluded that the lithium jets can be re-established after the microexplosion, and with careful design the jets should not breakup due to instabilities during the relatively quiescent period between microexplosions.
Date: October 1, 1981
Creator: Hoffman, M.A.
Partner: UNT Libraries Government Documents Department

Research on the HYLIFE liquid-first-wall concept for future laser-fusion reactors. Final report No. 4, September 1977-March 1979

Description: It has been proposed to protect the structural walls of a future laser fusion reactor with a curtain or wall of liquid lithium jets. As part of the investigation of this concept, experiments have been performed on planar sheet water jets issuing vertically downward from slit nozzles. The nozzles were subjected to forced harmonic excitation to simulate the vibrational environment of the laser fusion reactor, and experiments were run at both 1 atm and 0.2 atm pressure. Linear temporal stability theory is shown to predict the onset of the unstable regime and the spatial growth rates reasonably well for the cases where the amplitudes of the nozzle excitation are not too large and the waveform is nearly sinusoidal.
Date: March 1, 1979
Creator: Hoffman, M.A.
Partner: UNT Libraries Government Documents Department

Research on the annular lithium jet concept for future laser-fusion reactors. Final report No. 3, Sept 1977--Dec 1978

Description: Experiments have been performed to determine the length for convergence or closure of a vertical, hollow annular water jet due to the action of surface tension forces. The data agree well with theoretical predictions up to a velocity of about 3 m/s. At higher velocities, the convergence lengths are less than predicted and this is attributed to the jet acting as an ejector pump and thereby reducing the air pressure inside the annulus to slightly sub-atmospheric values. The stability of such a jet is also discussed in the light of the fact that no hydrodynamic instabilities have been observed to date. Finally the results of a series of experiments on the flow spreading or splitting due to the presence of wedge-shaped obstacles in the path of the annular jet flow are described.
Date: December 1, 1978
Creator: Hoffman, M.A.
Partner: UNT Libraries Government Documents Department

Research on the HYLIFE liquid-first-wall concept for future laser-fusion reactors. Final report No. 5

Description: It has been proposed to protect the structural walls of a future laser fusion reactor with a curtain or fluid-wall of liquid lithium jets. As part of the investigation of this concept, experiments have been performed on planar sheet water jets issuing vertically downward from slit nozzles. The nozzles were subjected to transverse forced harmonic excitation to simulate the vibrational environment of the laser fusion reactor, and experiments were run at both 1 atm and at lower ambient pressures. Linear temporal stability theory is shown to predict the onset of the unstable regime and the initial spatial growth rates quite well for the cases where the amplitudes of the nozzle vibration are not too large and the waveform is nearly sinusoidal. In addition, both the linear theory and a simplified trajectory theory are shown to predict the initial wave envelope amplitudes very well. For larger amplitude nozzle excitation, the waveform becomes highly nonlinear and non-sinusoidal and can resemble a sawtooth waveform in some cases; these latter experimental results can only be partially explained by existing theories at the present time.
Date: September 1, 1980
Creator: Hoffman, M.A.
Partner: UNT Libraries Government Documents Department

Boiling liquid cauldron status report

Description: The progress made over the past year in assessing the feasibility of the high-temperature, boiling cauldron blanket concept for the tanden mirror reactor is reviewed. The status of the proposed experiments and recently revised estimates of the vapor void fraction in the boiling pool are discussed.
Date: December 28, 1980
Creator: Hoffman, M.A.
Partner: UNT Libraries Government Documents Department

Research on the HYLIFE liquid-first-wall concept for future laser-fusion reactors: liquid jet impact experiments. Final report No. 8

Description: The goal of this initial scoping study was to evaluate the transient and steady state drag of a single bar and of some selected arrays of bars and to determine the momentum removed from impacting liquid slugs. In order to achieve this aim, use has been made of both the published literature and experimental data obtained from a small-scale experimental apparatus. The implications of two possible scaling laws for use in designing the small-scale experiment are discussed. The use of near-universal curves to evaluate the momentum removed during the initial transient period is described. The small-scale apparatus used to obtain steady-state drag data is described. Finally, these results are applied to the HYLIFE fusion reactor.
Date: August 1, 1982
Creator: Hoffman, M.A.
Partner: UNT Libraries Government Documents Department

Research on the HYLIFE liquid-first-wall concept for future laser-fusion reactors. Final report No. 6

Description: Experiments were performed on planar sheet jets of water flowing vertically downward. The nozzles were vibrated transversely to excite the sinuous mode of instability, and the sheet jets were photographed from the edge view to obtain data on the wave growth parameters. The data are compared to a second-order nonlinear theory. Qualitative agreement is obtained with regard to the stabilizing nature of the second-order terms, and reasonably quantitative agreement is obtained on the fall distance for the maximum wave amplitude.
Date: December 1, 1980
Creator: Hoffman, M.A.
Partner: UNT Libraries Government Documents Department

Thermal hydraulic study of the ESPRESSO blanket for a Tandem Mirror Reactor

Description: This paper deals primarily with the thermal-hydraulic design and some critical thermomechanical aspects of the proposed ESPRESSO blanket for the Tandem Mirror Fusion Reactor. This conceptual design was based on the same physics as used in the MARS study.
Date: February 1, 1986
Creator: Raffray, A.R. & Hoffman, M.A.
Partner: UNT Libraries Government Documents Department

Heat pipes for use in a magnetic field

Description: A heat pipe configuration is described for use in a magnetic field environment of a fusion reactor. Heat pipes for operation in a magnetic field when liquid metal working fluids are used are optimized by flattening of the heat pipes having an unobstructed annulus which significantly reduces the adverse side region effect of the prior known cylindrically configured heat pipes. The flattened heat pipes operating in a magnetic field can remove 2 to 3 times the heat as a cylindrical heat pipe of the same cross sectional area.
Date: April 29, 1981
Creator: Werner, R.W. & Hoffman, M.A.
Partner: UNT Libraries Government Documents Department

Water-cooled U-tube grids for continuously operated neutral-beam injectors

Description: A design for water-cooled extractor grids for long-pulse and continuously operated ion sources for neutral-beam injectors is described. The most serious design problem encountered is that of minimizing the thermal deformation (bowing) of these slender grid rails, which have typical overall spans of 150 mm and diameters on the order of 1 mm. A unique U-tube design is proposed that offers the possibility of keeping the thermal bowing down to about 0.05 mm (about 2.0 mils). However, the design requires high-velocity cooling water at a Reynolds number of about 3 x 10/sup 4/ and an inlet pressure on the order of 4.67 x 10/sup 6/ Pa (677 psia) in order to keep the axial and circumferential temperature differences small enough to achieve the desired small thermal bowing. It appears possible to fabricate and assemble these U-tube grids out of molybdenum with high precision and with a reasonably small number of brazes.
Date: November 5, 1979
Creator: Hoffman, M.A. & Duffy, T.J.
Partner: UNT Libraries Government Documents Department

Gas-cooled, Li/sub 2/O moderator/breeder canister blanket for fusion-synfuels

Description: A new integrated power and breeding blanket is described. The blanket incorporates features that make it suitable for synthetic fuel production. It is matched to the thermal and electrical requirements of the General atomic water-splitting process for producing hydrogen. The fusion reaction is the Tandem Mirror Reactor (TMR) using Mirror Advanced Reactor Study (MARS) physics. The canister blanket is a high temperature, pressure balanced, cross-flow heat exchanger contained within a low activity, independently cooled, moderate temperature, first wall structural envelope. The canister uses Li/sub 2/O as the moderator/breeder and helium as the coolant. In situ tritium control, combined with slip stream processing and self-healing permeation barriers, assures a hydrogen product essentially free of tritium. The blanket is particularly adapted to synfuels production but is equally useful for electricity production or co-generation.
Date: March 24, 1983
Creator: Werner, R.W. & Hoffman, M.A.
Partner: UNT Libraries Government Documents Department

Optimizing the heat pipe for operation in a magnetic field when liquid-metal working fluids are used

Description: A novel method for reducing the magnetohydrodynamic (MHD) pressure drops in the liquid metal flow in a heat pipe wick is described. By flattening the heat pipe, the eddy current return path in the metallic heat pipe wall is inreased significantly, thereby increasing the effective wall resistance. This, in turn, reduces the magnitude of the MHD pressure drop. The same principle can also be applied to flows of liquid metal coolants in a magnetic field.
Date: May 18, 1981
Creator: Werner, R.W. & Hoffman, M.A.
Partner: UNT Libraries Government Documents Department

Analysis of the steady-state operation of vacuum systems for fusion machines

Description: A computer code named GASBAL was written to calculate the steady-state vacuum system performance of multi-chamber mirror machines as well as rather complex conventional multichamber vacuum systems. Application of the code, with some modifications, to the quasi-steady tokamak operating period should also be possible. Basically, GASBAL analyzes free molecular gas flow in a system consisting of a central chamber (the plasma chamber) connected by conductances to an arbitrary number of one- or two-chamber peripheral tanks. Each of the peripheral tanks may have vacuum pumping capability (pumping speed), sources of cold gas, and sources of energetic atoms. The central chamber may have actual vacuum pumping capability, as well as a plasma capable of ionizing injected atoms and impinging gas molecules and ''pumping'' them to a peripheral chamber. The GASBAL code was used in the preliminary design of a large mirror machine experiment--LLL's MX. (auth)
Date: November 1, 1975
Creator: Roose, T.R.; Hoffman, M.A. & Carlson, G.A.
Partner: UNT Libraries Government Documents Department

In-situ MHD energy conversion for fusion. [R]

Description: An advanced concept, in-situ MHD conversion, is described for converting fusion energy to electricity. Considerable cost savings can be realized because of the conversion of thermal energy to electricity achieved in the blanket by means of magnetohydrodynamic (MHD) generators. The external disk generator, also described, is another application of the MHD idea, which may have certain advantages over the in-situ scheme for advanced-fuel tokamaks. The feature that makes these schemes fusion-specific is the novel use of the electro-magnetic radiation naturally emitted by the plasma. The synchrotron radiation can be used either to heat the nonequilibrium MHD plasma, or possibly improve its stability. A Rankine cycle with cesium-seeded mercury as a working fluid is used in either case. Performance predictions by a quasi-one-dimensional model are presented. An experiment to determine the effect of microwave radiation on channel performance is planned.
Date: June 1, 1986
Creator: Campbell, R.B.; Logan, B.G. & Hoffman, M.A.
Partner: UNT Libraries Government Documents Department

Cost study of the ESPRESSO blanket for a Tandem Mirror Reactor

Description: A detailed cost study of the ESPRESSO blanket concept for the Tandem Mirror Fusion Reactor (TMR) has been performed to complement the thermal-hydraulic parametric study and to help narrow down the choice of parameters for the final design. The ESPRESSO blanket consists of a number of structurally independent ring modules. Each ring module is made up of a number of mutually pressure-supporting canisters containing arrays of breeder tubes. Two separate helium coolant flows are used: a main flow to cool the tube bank and a cooler first wall flow.
Date: February 1, 1986
Creator: Raffray, A.R.; Hoffman, M.A. & Gaskins, T.
Partner: UNT Libraries Government Documents Department

Thermal analysis of a helium-cooled, tube-bank blanket module for a tandem-mirror fusion reactor

Description: A blanket module concept for the central cell of a tandem mirror reactor is described which takes advantage of the excellent heat transfer and low pressure drop characteristics of tube banks in cross-flow. The blanket employs solid Li/sub 2/O as the tritium breeding material and helium as the coolant. The lithium oxide is contained in tubes arranged within the submodules as a two-pass, cross-flow heat exchanger. Primarily, the heat transfer and thermal-hydraulic aspects of the blanket design study are described in this paper. In particular, the analytical model used for selection of the best tube-bank design parameters is discussed in some detail.
Date: January 10, 1983
Creator: Werner, R.W.; Hoffman, M.A. & Johnson, G.L.
Partner: UNT Libraries Government Documents Department

Heat-pipe liquid-pool-blanket concept for the Tandem Mirror Reactor

Description: The blanket concept for the tandem mirror reactor described in this paper was developed to produce the medium temperature heat (approx. 850 to 950 K) for the General Atomic sulfur-iodine thermochemical process for producing hydrogen. This medium temperature heat from the blanket constitutes about 81% of the total power output of the fusion reactor.
Date: October 1, 1981
Creator: Hoffman, M.A.; Werner, R.W. & Johnson, G.L.
Partner: UNT Libraries Government Documents Department

Microwave superheaters for fusion

Description: The microwave superheater uses the synchrotron radiation from a thermonuclear plasma to heat gas seeded with an alkali metal to temperatures far above the temperature of material walls. It can improve the efficiency of the Compact Fusion Advanced Rankine (CFAR) cycle described elsewhere in these proceedings. For a proof-of-principle experiment using helium, calculations show that a gas superheat ..delta..T of 2000/sup 0/K is possible when the wall temperature is maintained at 1000/sup 0/K. The concept can be scaled to reactor grade systems. Because of the need for synchrotron radiation, the microwave superheater is best suited for use with plasmas burning an advanced fuel such as D-/sup 3/He. 5 refs.
Date: October 16, 1987
Creator: Campbell, R.B.; Hoffman, M.A. & Logan, B.G.
Partner: UNT Libraries Government Documents Department

Sodium Loop Safety Facility W-2 experiment fuel pin rupture detection system. [LMFBR]

Description: The objective of the Sodium Loop Safety Facility (SLSF) W-2 experiment is to characterize the combined effects of a preconditioned full-length fuel column and slow transient overpower (TOP) conditions on breeder reactor (BR) fuel pin cladding failures. The W-2 experiment will meet this objective by providing data in two technological areas: (1) time and location of cladding failure, and (2) early post-failure test fuel behavior. The test involves a seven pin, prototypic full-length fast test reactor (FTR) fuel pin bundle which will be subjected to a simulated unprotected 5 cents/s reactivity transient overpower event. The outer six pins will provide the necessary prototypic thermal-hydraulic environment for the center pin.
Date: May 1, 1980
Creator: Hoffman, M.A.; Kirchner, T.L. & Meyers, S.C.
Partner: UNT Libraries Government Documents Department