Top DOE Fusion Panel Recommends More Money; More Emphasis on IFE.

Fusion energy sciences should have a budget of $300 million per year, with a slight increase in the proportion of funding going to inertial fusion energy (IFE) programs compared to magnetic fusion energy (MFE) programs, DOE's Fusion Energy Sciences Advisory Committee (FESAC) recommended.

FESAC met Sept. 8-9 to complete recommendations on fusion program priorities and balance.

FESAC adopted the report and presented it to Martha Krebs, director of DOE's Office of Science, after making several relatively minor changes to the draft report.

Panel Made 'Hard Choices'

Krebs praised FESAC for making some "hard choices' and expressed admiration for the many scientists in the magnetic fusion energy (MFE) and inertial fusion energy (IFE) communities who worked together effectively over the past year forging the report.

One of the key recommendations in the FESAC report is that, even at the present $222 million level of funding, some $5 million should be shifted from MFE into IFE, with a resulting distribution of $207 million for MFE and $15 million for IFE.

However, the committee told Krebs, there are "exciting opportunities to move forward in both MFE and IFE approaches," and therefore "we urge the department to move towards our $300 million budget case in a timely manner."

In the $300 million case, FESAC recommended $250 million for MFE and $50 million for IFE.

The committee also considered an intermediate case of $260 million, with $230 million going to MFE and $30 million going to IFE.

In June, FESAC issued an outline of Opportunities in the Fusion Energy Sciences Program that said "achievement of a more integrated national program in MFE and IFE [should be] a major programmatic and policy goal in the years ahead."

Four MFE Goals Proposed

With respect to magnetic fusion, FESAC urged DOE to accept four goals or "thrusts" as a way to implement existing higher-level goals of the fusion program:

(1) "Advance fundamental understanding of plasma, the fourth state of matter, and enhance predictive capabilities, through comparison of well-diagnosed experiments, theory and simulation;

(2) "Resolve outstanding scientific issues and establish reduced-cost paths to more attractive fusion energy systems, by investigating a broad range of innovative magnetic confinement configurations;

(3) "Advance understanding and innovation in high-performance plasmas, optimizing for projected power-plant requirements; and participate in a burning plasma experiment; and

(4) "Develop enabling technologies to advance fusion science; pursue innovative technologies and materials to improve the vision for fusion energy; and apply systems analysis to optimize fusion development."

The MFE program "is currently reasonably well balanced among its programmatic sub-elements," FESAC said. The program "properly emphasizes steady-state, externally controlled configurations, such as the advanced tokamak and spherical torus."

However, to maintain a proper balance, "care must be taken to also maintain an emphasis on pulsed and/or self-organized concepts," the committee cautioned.

Recommendations Support MFE Goals

FESAC made four recommendations for the MFE program, corresponding to the four goals:

(1) "Strengthen theory and computation as a very cost effective means to advance fusion and plasma science, taking advantage of advances in computation science and technology. Strengthen activities in general plasma science and encourage research on near-term applications of plasma science and technology;

(2) "Pursue an aggressive portfolio of confinement concepts through increased effort in the proof-of-principle area, and through strengthening of the concept exploration program;

(3) "Focus the moderate-pulse advanced tokamak program, including U.S. collaboration on leading international facilities, and to a lesser degree the spherical torus program, towards a five-year assessment point; and prepare for participation in a burning plasma experiment; and

(4) "Revitalize the technology program to provide for continued innovation in this area because of its overall importance to the success of fusion science and fusion energy and applications. Utilize systems studies to identify attractive fusion energy concepts and affordable development paths."

FESAC said approximately two-thirds of the additional resources, relative to the administration's proposed FY 2000 budget, should be divided about equally between support for goals (2) and (3).

However, the committee said, "it is also a high priority to increase support for achieving goals (1) and (4), with somewhat greater emphasis on (4), especially under small budget increases."

IFE Objectives Identified

FESAC identified the two central objectives of the IFE program as:

(1) Advancing the fundamental understanding and predictability of high energy density plasmas; and

(2) Developing the science and technology of attractive rep-rated IFE power systems leveraging from the single-shot work in the [DOE Defense Inertial Confinement Fusion] program."

FESAC noted that, at the present time, "two approaches are the most advanced and have the greatest potential of meeting near term IFE requirements."

One approach uses indirect drive targets, heavy-ion drivers, and chambers with first walls protected from neutrons by a thick liquid layer. The other approach uses direct drive targets, either a krypton fluoride (KrF) or diode-pumped solid-state laser, and a dry wall chamber."

Other IFE Configurations Seen

However, "it is important to emphasize that there are other possible combinations of drivers and chambers, as well as other approaches including z-pinches, fast ignition targets, and light ions," the report said.

FESAC's recommended IFE program of $50 million per year (in the $300-Million scenario) "would prepare three driver candidates for an IRE (Integrated Research Experiment) stage, develop the necessary chamber and target technology and pursue some limited efforts at the concept exploration level."

At the $30-million funding level (in the $260-million scenario), the program would emphasize the heavy-ion driver option and associated chamber/target technology, while maintaining reduced efforts on advanced laser options.

At lower levels, the FESAC recommended "mounting an adequate, albeit delayed, program to develop the ion-beam option, while reducing funding for the laser option."

FESAC Reviews MFE Proposals

FESAC also reviewed priorities for three new MFE "Proof of Principle" (PoP) proposals that received technical reviews earlier: the Reversed Field Pinch (RFP), University of Wisconsin; the Compact Stellarator (CS), Princeton Plasma Physics Laboratory; and the Magnetized Target Fusion (MTF) concept, Los Alamos National Laboratory.

"The RFP is ready for PoP designation, but a more focused sequential approach should be implemented," FESAC said.

However, the committee concluded that, "CS is not ready at this time for PoP designation because of one important technical concern," but the panel believed this concern "will likely be addressed in the near future."

MTF also "is not ready at this time for PoP designation," FESAC said. However, the panel recommended a three-year continuation of the MTF concept exploration program at approximately the present level of effort to produce and translate the required target plasma for the experiment.

The draft report can be accessed at Web sites: http://fire.pppl.gov/ or http://vlt.ucsd.edu/.

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