1,124 Matching Results

Search Results

Advanced search parameters have been applied.

TCT hybrid preconceptual blanket design studies

Description: The conceptual design of a tokamak fusion-fission (hybrid) reactor, which produces electric power and fissile material, has been performed in a cooperative effort between Princeton's Plasma Physics Laboratory (PPPL) and Battelle's Pacific Northwest Laboratories (PNL). PPPL, who had overall project lead responsibility, designed the fusion driver system. Its core consists of a tokamak plasma maintained in the two-component torus (TCT) mode by both D and T beams and having a single null poloidal divertor. The blanket concept selected by PPPL consists of a neutron multiplying converter region, containing natural Uranium Molybdenum (U-Mo) slugs followed by a fuel burning blanket region of molten salt containing PuF/sub 3/. PNL analyzed this concept to determine its structural, thermal and hydraulic performance characteristics. An adequate first wall cooling method was determined, utilizing low pressure water in a double wall design. A conceptual layout of the converter region tubes was performed, providing adequate helium cooling and the desired movement of U-Mo slugs. A thermal hydraulic analysis of the power-producing blanket regions indicated that either more helium coolant tubes are needed or the salt must be circulated to obtain adequate heat removal capability.
Date: January 1, 1978
Creator: Aase, D.T.; Bampton, M.C.C.; Doherty, T.J.; Leonard, B.R.; McCann, R.A.; Newman, D.F. et al.
Partner: UNT Libraries Government Documents Department

Computations of nuclear response functions with MACK-IV

Description: The MACK computer program calculates energy pointwise and multigroup nuclear response functions from basic nuclear data in ENDF/B format. The new version of the program, MACK-IV, incorporates major developments and improvements aimed at maximizing the utilization of available nuclear data and ensuring energy conservation in nuclear heating calculations. A new library, MACKLIB-IV, of nuclear response functions was generated in the CTR energy group structure of 171 neutron groups and 36 gamma groups. The library was prepared using MACK-IV and ENDF/B-IV and is suitable for fusion, fusion-fission hybrids, and fission applications.
Date: January 1, 1978
Creator: Abdou, M A & Gohar, Y
Partner: UNT Libraries Government Documents Department

INTOR impurity control and first wall system

Description: The highlights of the recent INTOR effort on examining the key issues of the impurity control/first wall system are summarized. The emphasis of the work was an integrated study of the edge-region physics, plasma-wall interaction, materials, engineering and magnetic considerations associated with the poloidal divertor and pump limiter. The development of limiter and divertor collector plate designs with an acceptable lifetime was a major part of the work.
Date: April 1, 1983
Creator: Abdou, M.A.
Partner: UNT Libraries Government Documents Department

Key issues of FED/INTOR impurity control system

Description: A key part of the FED/INTOR activity over the past year has focused on examining the critical issues and developing credible physics and engineering solutions for the impurity control system. The primary emphasis of the work was on the edge-region physics, plasma-wall interaction, materials, engineering and magnetic considerations of the poloidal divertor and pump limiter.
Date: October 1, 1982
Creator: Abdou, M.A.
Partner: UNT Libraries Government Documents Department

Important material considerations in INTOR

Description: A number of important material-related problems were identified and analyzed during the Phase-I study for INTOR. The first wall and divertor collector plate are subjected to severe normal and off-normal conditions. A melt layer is predicted to develop in a bare stainless steel wall under plasma disruptions. Graphite tiles will not melt but they introduce other serious uncertainties into the design. The design strategy for the divertor collector plate focused on separating the surface and high heat flux problems and on utilizing a novel mechanical design concept for attaching tungsten tiles to a stainless steel (or copper) heat sink.
Date: January 1, 1981
Creator: Abdou, M.A.; Mattas, R.F. & Smith, D.L.
Partner: UNT Libraries Government Documents Department

Mechanical properties of vapor-deposited thin metallic films: a status report

Description: The mechanical properties of vapor-deposited thin metallic films are being studied in conjunction with the target fabrication group associated with the laser-fusion energy program. The purpose of the work is to gain an understanding as to which metals are structurally best suited to contain a glass microsphere filled with deuterium-tritium (D-T) gas at large internal pressures.
Date: December 17, 1982
Creator: Adler, P.H.
Partner: UNT Libraries Government Documents Department

Technical Support for Combustion 2000 Program

Description: The high-temperature advanced furnace (HITAF) is an important component of the high-performance power system (HIPPS) being developed in the Combustion 2000 program. The purpose of HITAF is to raise superheated steam for the Rankin cycle and to heat the clean working fluid (air) to 1,800-2,400{degree}F for the Brayton cycle. Analytical and experimental investigations are being carried out to design, analyze and assess different concepts for high temperature advanced furnaces capable of heating compressed air to 1,800-2,400{degree}F; to evaluate performance of metallic and ceramic materials for service at elevated temperatures in HITAF environment; and to conduct critical, systems-oriented evaluations of advanced flue-gas cleanup (FGC) technologies appropriate to the low-emission-boiler systems (LEBS).
Date: July 1, 1993
Creator: Ahluwalia, R. K.; Im, K. H.; Natesan, K.; Livengood, C. D. & Schmalzer, D. K.
Partner: UNT Libraries Government Documents Department

Direct determination of radiation damage profiles in the order-disorder alloy Pt/sub 3/Co irradiated with low-energy (500-2500 eV) Ne/sup +/ ions

Description: A new approach was developed, employing the field-ion microscope technique, to determine directly radiation damage profiles in order-disorder alloys; the approach was applied to Pt/sub 3/Co. The experiment consisted of irradiating in situ, at 30/sup 0/K, Pt/sub 3/Co specimens with low-energy (500 to 2500 eV) Ne/sup +/ ions. The specimens were subsequently dissected on an atom-by-atom basis employing the pulse field-evaporation technique. The latter procedure made it possible to determine the change in the Bragg-Williams long-range order parameter (S) as a function of distance from the irradiated surface. The measurement of ..delta..S/sub d/, where the subscript indicates damage, versus distance (x) constituted a radiation damage profile; the depth resolution of this profile was aproximately equal to 2 A. The mean depth of damage (anti x/sub d/) varied from approximately equal to 9 to 20 A and the standard deviation or straggling (..delta..x) varied from approximately equal to 6 to 18 A as the implantation energy was increased from 500 to 2500 eV. The radiation damage profiles have also been used to determine the effective stopping power of Ne in Pt/sub 3/Co.
Date: July 1, 1979
Creator: Aidelberg, J. & Seidman, D. N.
Partner: UNT Libraries Government Documents Department

Free convective laminar flow within the Trombe wall channel

Description: Free convective laminar heat transfer between the channel surfaces of the Trombe wall has been investigated. This study considered the velocity profiles normal and parallel to the direction of fluid flow, the pressure drop due to flow acceleration at the channel entrance, and the effect of a variety of dissimilar but uniform channel surface temperatures for a wide range of flow rates. A finite difference procedure was used to solve the governing equations in dimensionless form using air as the fluid. After comparison with available experimental data, results have been reduced, and several correlations developed to enable important performance characteristics to be estimated given the channel thickness, height, and surface temperatures.
Date: August 1, 1978
Creator: Akbari, H. & Borgers, T.R.
Partner: UNT Libraries Government Documents Department

Plasma-wall interactions in tandem mirror machines

Description: A description is presented of the plasma-surface interactions in thermal-barrier tandem-mirror machines. The thermal-barrier mode of axial confinement is an integral part of a tandem mirror, and it dictates the required plasma conditions, particularly at the surface of the plasma. For this reason, a qualitative discussion of the thermal barrier is presented first in Section 2. A brief description of the experimental configuration used in tandem mirrors to create the thermal barrier is then examined in detail in Section 3; the TMX-U and MFTF-B machines are used as specific examples. In Section 4, the relevant plasma-surface interaction issues are addressed, and experimental results from currently operating tandom mirror machines are included. Section 5 is both a summary and a discussion of future work concerned with plasma-surface interactions in tandem mirrors.
Date: November 1, 1984
Creator: Allen, S.L.
Partner: UNT Libraries Government Documents Department

In-sodium creep behavior of alloys M-813 and Nimonic PE16

Description: The in-sodium biaxial creep deformation of internally pressurized tube specimens of alloys M-813 and Nimonic PE16 was measured at 650/sup 0/C under constant stress conditions after 4000 hours of sodium exposure. Each alloy had specimens at two different stress levels, viz., 0 and 165 MPa (24,000 psi). The data showed negative diameter changes at zero stress, which were attributed to material densification associated with precipitation. Although material densification was also seen in comparable in-argon experiments, the in-sodium creep strains at 165 MPa and 650/sup 0/C were much lower than the corresponding in-argon values. The higher creep strains in argon are explained on the basis of two parallel mechanisms involving oxygen, which is present at a low level in sodium (1 ppM) as compared with approximately 1000 ppM in the argon environment. The trends in the current data are consistent with observations by earlier authors. Sodium exposure of Nimonic PE16 also resulted in 4 ..mu..m deep intergranular penetration, which did not have any apparent effect on its biaxial creep behavior.
Date: April 1, 1980
Creator: Anantatmula, R.P. & Gilbert, E.R.
Partner: UNT Libraries Government Documents Department

Modeling and experiments of x-ray ablation of National Ignition Facility first wall materials

Description: This paper discusses results of modeling and experiments on the x-ray response of selected materials relevant to NIF target chamber design. X-ray energy deposition occurs in such small characteristic depths (on the order of a micron) that thermal conduction and hydrodynamic motion significantly affect the material response, even during the typical 10-ns pulses. The finite-difference ablation model integrates four separate processes: x-ray energy deposition, heat conduction, hydrodynamics, and surface vaporization. Experiments have been conducted at the Nova laser facility in Livermore on response of various materials to NIF-relevant x-ray fluences. Fused silica, Si nitride, B carbide, B, Si carbide, C, Al2O3, and Al were tested. Response was diagnosed using post-shot examinations of the surfaces with SEM and atomic force microscopes. Judgements were made about the dominant removal mechanisms for each material; relative importances of these processes were also studied with the x-ray response model.
Date: June 4, 1996
Creator: Anderson, A.T.; Burnham, A.K.; Tobin, M.T. & Peterson, P.F.
Partner: UNT Libraries Government Documents Department

Comparison of elastic--plastic and variable modulus-cracking constitutive models for prestressed concrete reactor vessels

Description: The variable modulus-cracking model is capable of predicting the behavior of reinforced concrete structures (such as the reinforced plate under transverse pressure described previously) well into the range of nonlinear behavior including the prediction of the ultimate load. For unreinforced thick-walled concrete vessels under internal pressure the use of elastic--plastic concrete models in finite element codes enhances the apparent ductility of the vessels in contrast to variable modulus-cracking models that predict nearly instantaneous rupture whenever the tensile strength at the inner wall is exceeded. For unreinforced thick-walled end slabs representative of PCRV heads, the behavior predicted by finite element codes using variable modulus-cracking models is much stiffer in the nonlinear range than that observed experimentally. Although the shear type failures and crack patterns that are observed experimentally are predicted by such concrete models, the ultimate load carrying capacity and vessel-ductility are significantly underestimated. It appears that such models do not adequately model such features as aggregate interlock that could lead to an enhanced vessel reserve strength and ductility.
Date: January 1, 1978
Creator: Anderson, C.A. & Smith, P.D.
Partner: UNT Libraries Government Documents Department

Preliminary evaluation of radiation control coatings for energy conservation in buildings

Description: Radiation Control Coatings (RCCs) applied to external building surfaces can reflect about 85 percent of the solar heating from the surfaces of buildings. Since in warm climates, solar heating is the primary source of heat gain through walls and roofs, RCC technology represents an alternative or adjunct to conventional thermal control methods (e.g., thermal insulation) for opaque building components. The primary objectives of this project were to: (1) obtain solar and infrared reflectance data for representative RCC products, (2) evaluate test methods for measurement of the radiative properties of RCCs, (3) calculate the changes in heat flow attributed to RCCs in flat roof applications in several geographic locations, and (4) compare field tests and calculated thermal performance of an RCC in a flat roof configuration. Data are presented for the radiative properties of five commercially available RCC products as determined by several test methods. The potential energy benefits of RCCs are presented for flat roofs in both warm and cold climates.
Date: February 1, 1992
Creator: Anderson, R. W.
Partner: UNT Libraries Government Documents Department

Preliminary evaluation of radiation control coatings for energy conservation in buildings

Description: Radiation Control Coatings (RCCs) applied to external building surfaces can reflect about 85 percent of the solar heating from the surfaces of buildings. Since in warm climates, solar heating is the primary source of heat gain through walls and roofs, RCC technology represents an alternative or adjunct to conventional thermal control methods (e.g., thermal insulation) for opaque building components. The primary objectives of this project were to: (1) obtain solar and infrared reflectance data for representative RCC products, (2) evaluate test methods for measurement of the radiative properties of RCCs, (3) calculate the changes in heat flow attributed to RCCs in flat roof applications in several geographic locations, and (4) compare field tests and calculated thermal performance of an RCC in a flat roof configuration. Data are presented for the radiative properties of five commercially available RCC products as determined by several test methods. The potential energy benefits of RCCs are presented for flat roofs in both warm and cold climates.
Date: February 1, 1992
Creator: Anderson, R.W. (Anderson (Robert W.) and Associates, Inc., Boulder City, NV (United States))
Partner: UNT Libraries Government Documents Department

Using infrared thermography for the study of heat transfer through building envelope components

Description: Heat transfer through building envelope components is typically characterized by one number, the conductance. Such a characterization is best suited for homogeneous samples since it does not quantify or illustrate spatial variations within a sample. However, the growing use of advanced wall and window insulations with existing framing materials has increased the importance of understanding spatial heat transfer effects within building envelope components. An infrared thermography laboratory has been established to provide detailed quantitative and qualitative information on the spatial heat transfer effects of building envelope materials. The use of this facility for more effective product development and more accurate product development and more accurate product characterization is discussed.
Date: November 1, 1991
Creator: Arasteh, D.; Beck, F.; Griffith, B.; Acevedo-Ruiz, M. (Lawrence Berkeley Lab., CA (United States)) & Byars, N. (California Polytechnic Univ., San Luis Obispo, CA (United States). Dept. of Engineering Technology)
Partner: UNT Libraries Government Documents Department

Super-insulating gas-filled panels

Description: This paper presents the design, materials characteristics, and thermal performance of a new insulating material. Development of this material is motivated by the need for non-CFC based high performance insulations with applications for refrigerator/freezer and building walls. This super insulating gas filled panel technology achieves R-values of between 8 hr-ft{sup 2}-F/Btu per inch and 15 hr-ft{sup 2}-F/Btu per inch (one to two times that of CFC blown foams and two to four times that of fiberglass insulations) at estimated costs of $0.40--$1.50/in-ft{sup 2}. Prototypes have been built using commercially available materials and components, tested by the developers, and sent to an independent laboratory for independent thermal performance testing. 2 refs., 4 figs., 1 tab.
Date: August 1, 1990
Creator: Arasteh, D.; Griffith, B. & Selkowitz, S.
Partner: UNT Libraries Government Documents Department

Hierarchies Without Symmetries from Extra Dimensions

Description: It is commonly thought that small couplings in a low-energy theory, such as those needed for the fermion mass hierarchy or proton stability, must originate from symmetries in a high-energy theory. We show that this expectation is violated in theories where the Standard Model fields are confined to a thick wall in extra dimensions, with the fermions ''stuck'' at different points in the wall. Couplings between them are then suppressed due to the exponentially small overlaps of their wave functions. This provides a framework for understanding both the fermion mass hierarchy and proton stability without imposing symmetries, but rather in terms of higher dimensional geography. A model independent prediction of this scenario is non-universal couplings of the Standard Model fermions to the ''Kaluza-Klein'' excitations of the gauge fields. This allows a measurement of the fermion locations in the extra dimensions at the LHC or NLC if the wall thickness is close to the TeV scale.
Date: March 22, 1999
Creator: Arkani-Hamed, Nima
Partner: UNT Libraries Government Documents Department

Alloy development for irradiation performance. Quarterly progress report for period ending December 31, 1979

Description: Progress is reported concerning preparation of a materials handbook for fusion, creep-fatigue of first-wall structural materials, test results on miniature compact tension fracture toughness specimens, austenitic stainless steels, Fe-Ni-Cr alloys, iron-base alloys with long-range crystal structure, ferritic steels, irradiation experiments, corrosion testing, and hydrogen permeation studies. (FS)
Date: April 1, 1980
Creator: Ashdown, B. G.
Partner: UNT Libraries Government Documents Department

Liquid nitrogen cooled liners for 2XIIB

Description: Liquid-nitrogen-cooled liners have been installed in the neutral-beam source tanks of 2XIIB. The installation has resulted in improvements in vacuum pumping, although testing is not complete. The liners are stainless-steel-flooded-type liners, using spot-welded-and-inflation construction. The natural-convection flow system must keep the liners cold during the high heat loads imposed during Ti gettering.
Date: October 17, 1977
Creator: Atkinson, D.P. & Calderon, M.O.
Partner: UNT Libraries Government Documents Department

Activation analyses for different fusion structural alloys

Description: The leading candidate structural materials, viz., the vanadium alloys, the nickel or the manganese stabilized austenitic steels, and the ferritic steels, are analysed in terms of their induced activation in the TPSS fusion power reactor. The TPSS reactor has 1950 MW fusion power and inboard and outboard average neutron wall loading of 3.75 and 5.35 MW/m{sup 2} respectively. The results shows that, after one year of continuous operation, the vanadium alloys have the least radioactivity at reactor shutdown. The maximum difference between the induced radioactivity in the vanadium alloys and in the other iron-based alloys occurs at about 10 years after reactor shutdown. At this time, the total reactor radioactivity, using the vanadium alloys, is about two orders of magnitude less than the total reactor radioactivity utilizing any other alloy. The difference is even larger in the first wall, the FW-vanadium activation is 3 orders of magnitude less than other alloys' FW activation. 2 refs., 7 figs.
Date: January 1, 1991
Creator: Attaya, H. & Smith, D.
Partner: UNT Libraries Government Documents Department

US--ITER activation analysis

Description: Activation analysis has been made for the US ITER design. The radioactivity and the decay heat have been calculated, during operation and after shutdown for the two ITER phases, the Physics Phase and the Technology Phase. The Physics Phase operates about 24 full power days (FPDs) at fusion power level of 1100 MW and the Technology Phase has 860 MW fusion power and operates for about 1360 FPDs. The point-wise gamma sources have been calculated everywhere in the reactor at several times after shutdown of the two phases and are then used to calculate the biological dose everywhere in the reactor. Activation calculations have been made also for ITER divertor. The results are presented for different continuous operation times and for only one pulse. The effect of the pulsed operation on the radioactivity is analyzed. 6 refs., 12 figs., 1 tab.
Date: September 1, 1990
Creator: Attaya, H.; Gohar, Y. & Smith, D.
Partner: UNT Libraries Government Documents Department

Defect production and electronic stopping for light ions in metals

Description: A method for determining effective electronic stopping powers in metals is presented. The method involves measuring damage rates in thin films as a function of ion energy. The experimental results are compared with predictions based on Monte Carlo computer simulations. Results are presented for H, D, He, and Li projectiles on Cu, Ag, and Ni. The implication of these results for defect production is discussed.
Date: January 1, 1979
Creator: Averback, R.S.; Benedek, R.; Merkle, K.L. & Thompson, L.J.
Partner: UNT Libraries Government Documents Department