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Title: Compact toroid fueling for ITER

Abstract

Experimental and theoretical work indicates that deep fueling of ITER may be possible by Compact Toroid (CT) injection. CT velocities sufficient for center fueling of a reactor have been demonstrated in the RACE device. CT injections into the TdeV tokamak have achieved central penetration at 1.4 T, and have increased the particle inventory by more than 30% without disruption. Tests on the MARAUDER device have achieved CT mass-densities suitable for injection into 5 T tokamaks. Techniques for producing multiple-shot CT`s with passive electric switching are being tested on CTIX. The advantages of deep fueling by CT injection include profile peaking to reach ignition, profile control, low tritium inventory and others. In this paper, the CT experimental results are summarized, a conceptual design of a CT fueler for ITER is presented, and the implications on ITER operation and fuel cycle are discussed. 16 refs., 2 figs., 1 tab.

Authors:
;  [1];  [2]
  1. CFFTP, Mississauga (Canada)
  2. Univ. of California, Davis, CA (United States)|[Lawrence Livermore National Lab., CA (United States)
Publication Date:
OSTI Identifier:
196689
Report Number(s):
CONF-950506-
Journal ID: FUSTE8; ISSN 0748-1896; TRN: 96:001398-028
Resource Type:
Journal Article
Resource Relation:
Journal Name: Fusion Technology; Journal Volume: 28; Journal Issue: 3 pt 1; Conference: 5. topical meeting on tritium technology in fission, fusion and isotopic applications, Ispra (Italy), 28 May - 3 Jun 1995; Other Information: PBD: Oct 1995
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION; REACTOR COMPONENTS; DESIGN; THERMONUCLEAR REACTOR FUELING; COMPACT TORUS; ITER TOKAMAK; PELLET INJECTION; FUEL CYCLE

Citation Formats

Gierszewski, P., Raman, R., and Hwang, D. Compact toroid fueling for ITER. United States: N. p., 1995. Web.
Gierszewski, P., Raman, R., & Hwang, D. Compact toroid fueling for ITER. United States.
Gierszewski, P., Raman, R., and Hwang, D. Sun . "Compact toroid fueling for ITER". United States. doi:.
@article{osti_196689,
title = {Compact toroid fueling for ITER},
author = {Gierszewski, P. and Raman, R. and Hwang, D.},
abstractNote = {Experimental and theoretical work indicates that deep fueling of ITER may be possible by Compact Toroid (CT) injection. CT velocities sufficient for center fueling of a reactor have been demonstrated in the RACE device. CT injections into the TdeV tokamak have achieved central penetration at 1.4 T, and have increased the particle inventory by more than 30% without disruption. Tests on the MARAUDER device have achieved CT mass-densities suitable for injection into 5 T tokamaks. Techniques for producing multiple-shot CT`s with passive electric switching are being tested on CTIX. The advantages of deep fueling by CT injection include profile peaking to reach ignition, profile control, low tritium inventory and others. In this paper, the CT experimental results are summarized, a conceptual design of a CT fueler for ITER is presented, and the implications on ITER operation and fuel cycle are discussed. 16 refs., 2 figs., 1 tab.},
doi = {},
journal = {Fusion Technology},
number = 3 pt 1,
volume = 28,
place = {United States},
year = {Sun Oct 01 00:00:00 EDT 1995},
month = {Sun Oct 01 00:00:00 EDT 1995}
}
  • We report the first results of nondisruptive, central fueling of a tokamak by the injection of an accelerated spheromak compact toroid (CT). Interferometry measurements indicate central fueling of the tokamak plasma on a fast time scale ([lt]0.5 ms) with more than 50% of the CT mass used for plasma fueling. The tokamak particle inventory increases by more than 30% without disruption.
  • Reactor particle fueling is one of the issues that remain to be resolved in the development of a tokamak fusion reactor. One of the most promising concepts of reactor fueling is the injection of high-speed compact toroids (CTs). Compact toroid formation and acceleration at the Ring Accelerator Experiment (RACE) device at Lawrence Livermore National Laboratory has shown that CT plasmoid velocities sufficient for center fueling fusion reactors can be achieved by using coaxial accelerators. The Compact Toroid Fueler (CTF) will inject high-speed, dense spheromak plasmoids into the Tokamak de Varennes (TdeV) to examine the feasibility of this approach as amore » fueler for future reactors. Here, a conceptual design study of the particle fueler for TdeV is presented. The issues of CTF design that are considered are formation and relaxation of an axisymmetric CT, optimization of accelerator performance to improve injector electrical efficiency, separation of formation and acceleration phases to improve injector reproducibility, minimization of entrained impurities in the CT, and minimization of neutral gas load to the tokamak following CT fueling. The CTF injector will test theories on CT/tokamak interaction related to reactor fueling. Among the eventual physics questions addressed are the multiple-pulse requirements for future injectors, the bootstrap current enhancement factor, CT fuel confinement times, impurity effects, plasma heating, injector electrical efficiency, and the effect of gas load on the tokamak following CT injection. 28 refs., 5 figs., 3 tabs.« less
  • Pellet injection is the primary fueling technique planned for core fueling of ITER [ITER Technical Basis 2002 ITER EDA Documentation Series (Vienna: IAEA)] burning plasmas. Efficient core plasma fueling with deuterium and tritium D-T is a requirement for achieving high fusion gain and it cannot be achieved with gas fueling. Injection of pellets from the inner wall has been shown on present day tokamaks to provide efficient fueling and is planned for use on ITER. Modeling of the fueling deposition from inner wall pellet injection using the Parks ExB drift model indicates that pellets have the capability to fuel wellmore » inside the separatrix. Gas fueling calculations show very poor neutral penetration due to the high density and wide scrape off layer. Isotopically mixed D-T pellets can provide efficient tritium fueling that will minimize tritium wall loading when compared to gas puffing. Currently the performance of the ITER inner wall guide tube design is under test with initial results indicating that pellet speeds in excess of 300 m/s will lead to fragmented pellets. The ITER pellet injection technology requirements and remaining development issues are discussed along with a plan to reach the design goal for employment on ITER.« less
  • The events which accompany the formation of a compact plasma toroid, i.e., the trapping of the internal field in the plasma during an inversion of the external field at the plasma boundary, are studied. In the absence of a barrier field the rate of loss of the flux frozen in the plasma when the plasma expands to the wall is governed by a wall sheath. The structure of this sheath is studied numerically, and the captured field is calculated. The calculated results are compared with experimental data. The outlook for the use of this method of forming an antiparallel structure,more » without the use of a barrier field near the chamber wall, is evaluated.« less
  • The equilibrium of a compact plasma toroid confined by a poloidal magnetic field in a cylindrical chamber is studied numerically. The measured properties of the configuration, which are of importance for experimental research on compact toroids, are discussed.