APS News

Fusion Research Runs into Turbulence

By Michael Lucibella

A recent Department of Energy (DOE) advisory committee report about the future of U.S. fusion research has drawn strong criticism from academic researchers feeling squeezed by a tightening fusion budget and a shift in U.S. research priorities.

The Fusion Energy Sciences Advisory Committee (FESAC) issued a report written by its Strategic Plan Panel that highlights a number of top-priority science problems to solve in the next decade. The panel identified new facilities to build, but also a number of reductions and closures at existing facilities. More than fifty scientists, including lab directors, have written to the committee expressing their concern about the directions it recommends, and criticizing how the committee arrived at its conclusions.

The report delivered by the committee offers four different potential budget scenarios ranging from “modest growth” at about 4.1 percent per year over ten years to no growth at all. These funding levels were mandated in a congressional charge to DOE’s Office of Science for a strategic science plan.

“[They are] not optimistic budget scenarios. That had a significant restraining impact on the committee’s deliberations,” said Steven Zinkle, University of Tennessee, who is the vice chair of the FESAC. “That required some pretty severe tradeoffs to be made to keep within that range of budget scenarios.”

The report prioritizes a number of initiatives for the U.S. program, in particular finding materials that can withstand the heat and radiation of long-burning plasmas and finding ways to control “transient events” in confined plasmas that can disrupt containment. “We felt it was important to pick a few of the most important areas where the U.S. has competencies and would have a big impact for where fusion is going [globally],” said Zinkle.

Part of the budget squeeze is the result of a congressional requirement that the U.S. contributions to ITER, the giant tokamak being built in the south of France, not be cut. The current budget for Fusion Energy Sciences is $504 million, with nearly $200 million of that being set aside as a contribution to ITER.

The report recommends shuttering MIT’s Alcator C-Mod tokamak; keeping both the DIII-D at General Atomics and the NTSX-U at the Princeton Plasma Physics Lab running for at least another five years; and then, depending on available funding, running one or possibly both for five more years. In addition, it recommends gearing up to develop a plan for a Fusion Nuclear Science Facility (FNSF, the successor to ITER), a plasma physics computational simulator, and a neutron radiation facility.

The report drew swift criticism from a number of members of the fusion sciences community. Most prominently, fifty researchers from institutions across the country signed an open letter saying the report contains “major flaws” and “glaring deficiencies,” including concerns about the FESAC’s process for drafting the report and its recommendation that somewhat refocuses the U.S. program away from fundamental plasma science.

“It proposes a rather dramatic shift in the program to much more of a technology and engineering focus,” said Martin Greenwald, a scientist at MIT. “That’s all work that needs to be done, but it needs to be done in the context of a viable energy program.”

Miklos Porkolab, director of MIT’s plasma science and fusion center, said also that it was too early to refocus efforts on the more applied sciences that the report emphasizes. “Our approach up to now was to have a physics-based program in fusion until we have a concept that would work, then switch over to an engineering program. We’re not there,” Porkolab said.

However, Zinkle disputes how big of a shift in focus the report recommends. “The vector is changing by about 10 or 15 degrees from the current path…not a 90 degree change,” Zinkle said. “We need to start exploring in a broader scope — all the fusion energy sciences, not just the plasma science activities.”

At MIT, where both Porkolab and Greenwald work , the closure of the Alcator C-Mod in 2015, would be a big setback for the fusion community. The Alcator C-Mod has been one of the top research facilities for high-magnetic field and high plasma pressure since opening in 1991. “We tried in the report to emphasize that it has a tremendous science impact,” Zinkle said. “In order to be responsive to the charge [to FESAC], we imposed some very difficult recommendations.”

This isn’t the C-Mod’s first brush with closure. The tokamak was shut down briefly at the end of 2013 after the president’s budget eliminated funding for the machine, only to be restarted in February after a successful effort by local congressmen to include $22 million for it in the 2014 Congressional Omnibus spending bill.

The FESAC report recommends shuttering the facility and redirecting its scientists and technicians to other areas to maintain their expertise. “It’s not clear how much money you save,” said Porkolab. “If you shut the facilities down, and maintain key staff, you’re only going to save about 10 million dollars.”

The report does recommend the construction of several new facilities. The report calls for FNSF to bridge the knowledge gaps left by ITER on the way to a full-fledged demonstration fusion power plant.

“It is not a clearly defined facility. It’s nowhere close to having [initial project approval],” Zinkle said. “Now is the time to be developing the science basis for what that facility might be.”

However, this recommendation has also drawn criticism from members in the fusion community. “We’re concerned about that because at the moment there’s not a clear consensus as to what this facility would do in a fusion development context,” said John Sarff of the University of Wisconsin, Madison. “The budget scenarios, even the most optimistic ones, are not sufficient to get the necessary fusion technology pieces in place to launch the FNSF.”

The report’s recommendations for the plasma simulator and the neutron radiation facility drew criticism as well, though more for how the recommendations were arrived at. Though not laid out explicitly in the report, it is widely presumed that like many other similar facilities, these two new machines would be located at a national laboratory, likely Oak Ridge.

Scientists were critical because the subgroup of FESAC preparing the report included scientists from national laboratories but not academic labs with fusion programs because of concerns over conflict of interest.

“Historically we haven’t worked that way. When you put panels together you get experts from the field,” Greenwald said, who was a member of the committee for 12 years and chair for six. “It was always understood and you try to balance those [institutional] interests and…as much as you can, get people who can rise above those parochial interests.”

When it came time to adopt the final report, half of the twenty voting members of the entire FESAC committee, both from academic labs with fusion programs and from national labs, were required to recuse themselves from the final vote. The final report was adopted by a vote of six to three in an online meeting of the committee. Other similar reports issued by DOE advisory panels do not usually take such a strict line about conflicts of interest.

“It was a little bit surprising,” Zinkle said. “My understanding is that the general council at the Office of Science…provided guidance on the conflict of interest that was a much more narrow interpretation than would be the case for National Academies committees, for example.”

The timeline was also of concern to the scientists. The 77-page draft was released publicly only the day before the full committee met on September 22. Because of this late release, the committee opted to delay a vote on its adoption until October 10. “If you get the report on Sunday night for a meeting on Monday morning, you’re not in a position to read a long report and give it some thought and formulate your own questions and positions,” Greenwald said.

The relatively short time period was the result of its original congressional charge. The panel’s work needed to be finished in order to be included in a broader strategic plan for the DOE’s Office of Science in January. “The panel definitely would have preferred to have a longer period,” Zinkle said, adding that the chair of the panel twice asked for extensions but was turned down each time.

Zinkle said also that the panel was restricted by the original congressional charge to look only at the four budget options. He said they were not asked to articulate a broad view of the potential future of fusion physics research, which is what a number of scientists say they would have liked to include, but rather to look at the lineup of budget options. “If we had larger budgets, our recommendations would have been different,” Zinkle said. “It’s not an open-ended strategic plan on fusion sciences in the coming decade.”





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