Development of Direct Drive, High-Gain Capsules for Inertial Fusion: A Materials Challenge

Abstract:The application of Inertial Confinement Fusion to power production requires the development of a high-yield fusion capsule. Theoretical design calculations suggest that a single shell capsule with a uniformly distributed deuterium-tritium (DT) fuel layer on the inside surface could give the desired high-gain performance when directly driven with 0.35 μm laser light. This design requires operation at cryogenic temperatures necessary to condense DT (20-30 K) and a means of levitating the fuel layer inside the capsule. On e recently suggested method for making this capsule is to use a rigid foam matrix to support the condensed DT in a spherical shell configuration. For such a capsule to be successfully fielded, a number of critical materials problems must be solved.

Download Full-text

Fabrication of Hollow Silica Aerogel Spheres for Direct Drive Inertial Confinement Fusion (ICF) Experiments

MRS Proceedings ◽

10.1557/proc-0901-ra05-23-rb05-23 ◽

2005 ◽

Vol 901 ◽

Cited By ~ 1

Author(s):

Reny Richard Paguio ◽

Abbas Nikroo ◽

Jared F Hund ◽

Christopher A. Frederick ◽

Javier Jaquez ◽

...

Keyword(s):

Wall Thickness ◽

Silica Aerogel ◽

Inertial Confinement Fusion ◽

Gelation Time ◽

High Yield ◽

Full Density ◽

Laser Fusion ◽

Inertial Confinement ◽

Direct Drive ◽

Confinement Fusion

AbstractHollow foam spheres are needed for laser fusion experiments on the OMEGA laser facility at the University of Rochester as part of the demonstration of the feasibility of inertial confinement fusion. Previously polymer based foam and aerogel shells have been produced using resorcinol-formaldehyde (R/F) and divinylbenzene (DVB). In this paper we discuss the development of silica aerogel (SAG) shells. SAG may have the increased robustness, which is important in processing these laser targets. SAG shells were fabricated by the microencapsulation method using a triple orifice droplet generator. This technique allows for precise control of the shell diameter and wall thickness. Reduction of the aerogel gelation time is crucial to fabrication of intact shells with high yield. In addition, the proper choice of the components of the different phases of the microencapsulation process is essential for fabrication of intact SAG shells with proper sphericity and wall uniformity. The density of shells fabricated is approximately 100 mg/cc and the diameter ranges from 700–2000 μm, with a wall thickness of 50–200 μm. Development of a full density permeation barrier for retention of the fusion fuel will also be discussed.

Download Full-text

Neutron penumbral imaging of laser-fusion targets

Laser and Particle Beams ◽

10.1017/s0263034600002366 ◽

1991 ◽

Vol 9 (1) ◽

pp. 99-118 ◽

Cited By ~ 23

Author(s):

R. A. Lerche ◽

D. Ress ◽

R. J. Ellis ◽

S. M. Lane ◽

K. A. Nugent

Keyword(s):

Inertial Confinement Fusion ◽

Imaging Technique ◽

High Yield ◽

Laser Fusion ◽

Coded Aperture ◽

Inertial Confinement ◽

Direct Drive ◽

Coded Aperture Imaging ◽

Penumbral Imaging ◽

Confinement Fusion

A camera has been developed that directly measures the deuterium-tritium burn region of laser-driven inertial confinement fusion targets. Images are formed by 14-MeV thermonuclear neutrons emitted from the targets. Our demonstration instrument is based on a coded-aperture imaging technique known as penumbral imaging, and has produced images of high-yield (> 1012 neutrons) direct-drive targets with resolutions of 80 μm. The camera consists of four major components: the penumbral aperture, alignment hardware, detector system, and image analysis software.

Download Full-text

Recent progress in quantifying hydrodynamics instabilities and turbulence in inertial confinement fusion and high-energy-density experiments

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2020.0021 ◽

2020 ◽

Vol 379 (2189) ◽

pp. 20200021 ◽

Cited By ~ 2

Author(s):

A. Casner

Keyword(s):

Energy Density ◽

Inertial Confinement Fusion ◽

Fusion Energy ◽

High Gain ◽

High Energy ◽

High Energy Density ◽

Inertial Confinement ◽

Direct Drive ◽

Energy Part ◽

Confinement Fusion

Since the seminal paper of Nuckolls triggering the quest of inertial confinement fusion (ICF) with lasers, hydrodynamic instabilities have been recognized as one of the principal hurdles towards ignition. This remains true nowadays for both main approaches (indirect drive and direct drive), despite the advent of MJ scale lasers with tremendous technological capabilities. From a fundamental science perspective, these gigantic laser facilities enable also the possibility to create dense plasma flows evolving towards turbulence, being magnetized or not. We review the state of the art of nonlinear hydrodynamics and turbulent experiments, simulations and theory in ICF and high-energy-density plasmas and draw perspectives towards in-depth understanding and control of these fascinating phenomena. This article is part of a discussion meeting issue ‘Prospects for high gain inertial fusion energy (part 2)’.

Download Full-text

New target designs for direct-drive ICF

Laser and Particle Beams ◽

10.1017/s0263034699172082 ◽

1999 ◽

Vol 17 (2) ◽

pp. 225-235 ◽

Cited By ~ 9

Author(s):

LEE PHILLIPS ◽

JOHN H. GARDNER ◽

STEPHEN E. BODNER ◽

DENIS COLOMBANT ◽

S.P. OBENSCHAIN ◽

...

Keyword(s):

Inertial Confinement Fusion ◽

High Gain ◽

Fusion Reactors ◽

Inertial Confinement ◽

High Electron ◽

Direct Drive ◽

Confinement Fusion ◽

Density Scale ◽

Enhanced Stability ◽

Scale Length

We describe two approaches to the design of a direct-drive high-gain pellet for inertial confinement fusion reactors that has enhanced stability due to the reduction in the Rayleigh-Taylor growth rate and enhanced thermal smoothing of laser imprint. The first design incorporates an overcoat containing a high-Z element that radiatively heats the ablator during the foot of the laser pulse. The second incorporates a very low density foam ablator that is compressed by a series of transmitted and reflected shocks. Both designs enhance thermal smoothing by developing a very long density scale length and high electron densities in the ablator blowoff.

Download Full-text

One-dimensional hydrodynamic simulations of low convergence ratio direct-drive inertial confinement fusion implosions

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2020.0224 ◽

2020 ◽

Vol 379 (2189) ◽

pp. 20200224 ◽

Cited By ~ 1

Author(s):

R. W. Paddock ◽

H. Martin ◽

R. T. Ruskov ◽

R. H. H. Scott ◽

W. Garbett ◽

...

Keyword(s):

Inertial Confinement Fusion ◽

Fusion Energy ◽

High Gain ◽

Inertial Confinement ◽

Direct Drive ◽

Hydrodynamic Simulations ◽

One Dimensional ◽

Confinement Fusion ◽

High Level ◽

Fusion Implosions

Indirect drive inertial confinement fusion experiments with convergence ratios below 17 have been previously shown to be less susceptible to Rayleigh–Taylor hydrodynamic instabilities, making this regime highly interesting for fusion science. Additional limitations imposed on the implosion velocity, in-flight aspect ratio and applied laser power aim to further reduce instability growth, resulting in a new regime where performance can be well represented by one-dimensional (1D) hydrodynamic simulations. A simulation campaign was performed using the 1D radiation-hydrodynamics code HYADES to investigate the performance that could be achieved using direct-drive implosions of liquid layer capsules, over a range of relevant energies. Results include potential gains of 0.19 on LMJ-scale systems and 0.75 on NIF-scale systems, and a reactor-level gain of 54 for an 8.5 MJ implosion. While the use of 1D simulations limits the accuracy of these results, they indicate a sufficiently high level of performance to warrant further investigations and verification of this new low-instability regime. This potentially suggests an attractive new approach to fusion energy. This article is part of a discussion meeting issue ‘Prospects for high gain inertial fusion energy (part 2)’.

Download Full-text