Magnetic Fusion Energy Program Research Articles

Unresolved tritium issues in the Magnetic Fusion Energy Program

ABSTRACTThis paper discusses twelve issues involving tritium in the Magnetic Fusion Energy Program that remain to be resolved. The issues are discussed in three broad categories: fuel reprocessing issues, detritiation issues, and tritium handling issues. Where appropriate, suggestions are made concerning routes to resolution of the issues.

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A strategic framework for the magnetic fusion energy program

Fusion is recognized as a sufficiently abundant and environmentally attractive energy source to sustain industrial society in the 21st century and beyond. This paper outlines a strategic framework for the U.S. magnetic fusion program that builds substantially on the high-quality research and the strong scientific and technological basis that has been established during the past two decades.

Wave Heating and the U.S. Magnetic Fusion Energy Program

AbstractThe U.S. Government’s support of the fusion program is predicated upon the long-term need for the fusion option in our energy future, as well as the near-term benefits associated with developments on the frontier of science and high technology. As a long-term energy option, magnetic fusion energy has the potential to provide an inexpensive, vast, and secure fuel reserve, to be environmentally clean and safe. It has many potential uses, which include production of central station electricity, fuel for fission reactors, synthetic fuels, and process heat for such applications as desalination of sea water. This paper presents an overview of the U.S. Government program for magnetic fusion energy. The goal and objectives of the U.S. program are reviewed followed by a summary of plasma experiments presently under way and the application of wave heating to these experiments.

Progress in Fusion Technology in the U.S. Magnetic Fusion Program

The U.S. Fusion Technology Development Program integrates the diverse technology activities within the Office of Fusion Energy. The program contains essentially all the technology activities, both to support the scientific efforts and to resolve a limited number of critical technology feasibility issues. There has been a significant amount of progress in the last few years in the development of reactor-scale fusion technologies. For example, in the area of gyrotron development for radio frequency (RF) heating, 28 gigahertz (GHz) gyrotrons at 200 kW continuous wave (cw) and 60 GHz gyrotrons at 124 kW cw have been operated. Present plans call for continuing development of 100 GHz gyrotrons at higher power levels. In the magnetics area, construction of the Large Coil Test Facility (LCTF) will be completed and initial operations with two coils should begin in 1983. The other four large coils should be delivered to permit full 6 coil torus testing to begin in 1984. The research and development plans for the Magnetic Fusion Energy Program are contained in the Fusion Technology Development Plan (FTDP) which is being distributed. In order to assure that the activities described in the FTDP are consistent with the overall fusion program strategy and to optimizemore » resource allocation recognizing budget constraints, the Fusion Technology Program has prioritized its activities. This paper will review some of the recent progress and future plans in fusion technology in the U.S. Magnetic Fusion Program.« less

The Status of Tritium Technology Development for Magnetic Fusion Energy

The development of tritium technology for the magnetic fusion energy program has progressed at a rapid rate over the past two years. The focal points for this development in the United States have ...

Vacuum applications for the Tritium Systems Test Assembly

The Tritium Systems Test Assembly (TSTA) is a facility which will develop and demonstrate the processes for handling the fuel and exhaust from a magnetic fusion reactor using deuterium and tritium as the fuel. The TSTA facility became operational in mid 1982 and will now proceed to test and evaluate the many subsystems required to purify, separate, circulate, and reuse the deuterium/tritium gas recovered from the reactor vacuum system. At TSTA the reactor will be simulated by a large vacuum vessel into which mixtures of deuterium, tritium, and various impurities (He, CH4, H2O, NH3, C2H2) are injected. This mixture is then exhausted through the vacuum system, reprocessed and prepared for reinjection into the front end. A fusion reactor must have an enormous vacuum system to remove the mixture of fuel and impurites so that the plasma can be replenished with fresh fuel. At TSTA this evacuation is achieved with ‘‘compound’’ cryopumps. These pumps remove the deuterium and tritium by cryocondensation on a 4‐K panel. The helium is removed by cryosorption on a separate refrigerated panel. TSTA will provide the first opportunity to test several models of compound cryopumps with actual mixtures of deuterium, tritium, and helium. This paper will discuss the role TSTA has in the national magnetic fusion energy program with special emphasis on the vacuum system and preliminary experimental results.

Application of QUantitative Eels to Analysis of the Titanium Carbide Phase in Austenitic Stainless Steels

The intent of this work is to study the light element (C,N,O) contents, particularly C, of individual particles of the titanium MC carbide phase. Analytical electron microscopy (AEM) studies can employ either electron energy loss spectroscopy (EELS) or x-ray energy dispersive spectroscopy (XEDS) with ultra-thin window detectors to detect these elements, but we will show that because MC contains substantial Mo and C, the former method is best. The alloy studied is, in wt %, a 14 Cr/16 Ni/0.25 Ti modification of normal type 316 austenitic stainless steel. This alloy is the first generation Prime Candidate Alloy (PCA) of its alloy class for the Alloy Development for Irradiation Performance (ADIP) task of the Magnetic Fusion Energy (MFE) program, and the microstructure studied was designed for scoping the resistance of this material to fusion irradiation. The key to this application is stability of the MC phase, and composition is very important to stability. However, such studies cannot be undertaken without the advanced techniques and equipment development of EELS and we will focus on the interfacing of the latter with the metallurgical system studied.

Decision Analysis of Program Choices in Magnetic Fusion Energy Development

This paper describes a methodology based on decision analysis for addressing major program decisions in the development of magnetic fusion energy. The development of this complex technology involves a sequence of funding choices over time among multiple technical approaches and under considerable performance uncertainty. The methodology focuses on the next major facility decision in the U.S magnetic fusion energy program. The decision alternatives include the construction and testing of a major experimental facility based on one of two leading technical approaches (reactor designs), an accelerated program where both approaches are pursued, or delaying another facility until more information is available. Subsequent decisions depend on the first decision and its outcome and involve either further development of the best technical approach or abandonment of the entire research and development program. Analysis of a particular sequence of program decisions takes account of the uncertainties in the ultimate economic performance (cents per kilowatt-hour) of the resulting commercial reactor, the time of commercial availability, and market penetration. Reactor performance is analyzed at a component level and explicitly considers the dependence of component performances based on one technical approach on the respective component performances of alternative approaches. The net benefits of magnetic fusion R&D are assessed by computing the discounted expected cost savings attributable to commercial magnetic fusion energy minus the discounted costs of the R&D program.

Bend strain tolerances of a Nb<inf>3</inf>Sn conductor proposed for use in the magnetic fusion energy program

Bend strain tolerances were studied on a 2869 filament bronze-processed Nb <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> Sn wire conductor in magnetic fields to 8 T. Relative values of the wire's current transfer length to twist pitch were shown to influence the bend-strain tolerance. Low matrix resistivities, associated with Sn-depleted bronzes following heat-treatments of 48 h at 725°C, produce current transfer lengths less than the twist pitch, 10 mm, The resulting bend-strain tolerances, at 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-12</sup> ohm.cm, are improved over those found for shorter heat-treatment times. Results from bend-fatigue experiments were divided into two domains separated by the strain value required to produce compound cracking, <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">\varepsilon\min{f}\max{B}</tex> . Applied bending strains less than <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">\varepsilon\min{f}\max{B}</tex> were found to increase zero strain critical current values and this increase was independent of the number of fatigue cycles. When applying strains large enough to produce cracking in the compound critical currents decreased from their as-reacted values tending to reach a minimum after several fatigue cycles. Evidence exists for a neutral axis shift during bending and slight differences between tensile and bend strain tolerances are accounted for in terms of such a shift.

Magnet development

A review of the status of magnet development for the magnetic fusion energy program is given. Present day machines in the mirror, bumpy torus and tokamak programs are reviewed as are the future requirements for the mirror and tokamak programs. The review is focused on superconducting magnet considerations, but includes the resistive magnetics from TFTR to illustrate the common structural features of all tokamaks.

Neutral Beam Injectors for the Magnetic Fusion Energy Program: Progress and Prognosis for the Future

The attainment of economic, safe fusion power has been described as the most sophisticated scientific problem ever attacked by mankind. The goal of the magnetic fusion program is to develop and demonstrate pure fusion central electric power stations for commercial applications. Neutral beam heating systems are a basic component of the tokamak and mirror experimental fusion plasma confinement devices. The development and application of multimegawatt neutral beam heating systems for PLT, PDX, ISX, TFTR, Doublet-III and MFTF experiments and a plan for developing higher power, longer pulse length, more efficient systems for future application is presented.

Pumping and vacuum requirements for the magnetic fusion energy program

Pumping and vacuum requirements for the magnetic fusion energy program

Pumping and vacuum requirements for the magnetic fusion energy program

The Division of Magnetic‐Fusion Energy (DMFE) in the US ERDA is responsible for the development of the necessary technology for the magnetically confined fusion energy source. The vacuum technology requirements will be met to assure a demonstration power reactor by the end of this century. The objective of this paper is to present an overview of the pumping and vacuum requirements for future technology developement. The fusion‐reactor vacuum subsystems will be discussed with the identification of general operating requirements needed to achieve the desired reacting fusion plasma conditions. A program will be outlined for the development of vacuum technology necessary to support the evolving fusion reactor and auxiliary system designs.