As the international ITER project to develop an experimental nuclear fusion reactor eats into research budgets around the world, an advisory panel to the US Department of Energy recommends mothballing at least one of three major experiments and focusing on research necessary to bring ITER online.
The Fusion Energy Sciences Advisory Committee (FESAC) released its report on 22 September at a meeting in Gaithersburg, Maryland. The document outlines a 10-year plan for US nuclear fusion research for various budget scenarios, the most optimistic of which calls for “modest growth”.
Nuclear fusion offers the potential for producing practically limitless energy by smashing heavy atoms of hydrogen into helium inside a burning 100-million-kelvin plasma and capturing the energy released by the reaction — but scientific and engineering challenges remain.
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The report says the US should focus research initiatives on the biggest impediments to ITER’s donut-like design, called a tokamak — how to control the writhing plasma at the reactor’s core, and understanding how it interacts with surrounding material in order to engineer walls that can maintain the reaction.
To free up money, the report recommends ceasing operations at the Alcator C-Mod reactor at the Massachusetts Institute of Technology in Cambridge starting in 2015. Congress cut its funding in 2012, but efforts from Massachusetts lawmakers allowed it to resume operations this year. Depending on budget scenarios, the panel suggests that one other fusion facility — the DIII-D operated by the defense firm General Atomics in San Diego or the National Spherical Torus Experiment in Princeton, New Jersey — could also face the chopping block five years later.
The panel recommends construction of new facilities including a linear system to simulate tokamak conditions, as well as beefing up an existing neutron irradiation source — possibly one at Oak Ridge National Laboratory in Tennessee.
In the future, the report envisions an extensive nuclear fusion research program centered around a national US fusion nuclear science facility, but this would require increased funding.
One thing the committee was not allowed to reconsider was the US commitment to ITER, the international attempt to build an experimental fusion reactor. With its construction soaring in cost to $50 billion — ten times the original figure — and falling 11 years behind schedule, it is the most expensive scientific experiment in history. Its woes have attracted widespread criticism and eaten into research budgets for other fusion experiments around the world.
Some found the report uninspired. “The scale and cost of ITER should give the US community pause,” says Stephen Dean, the head of Fusion Power Associates, an advocacy group in Gaithersburg, Maryland. “There's no evidence in here of a recognition that maybe we ought to try to look for something better.
Others question the closure of MIT’s Alcator C-Mod. “I think there are good reasons for having C-Mod run several more years,” said Dale Smith, former director of the fusion programme at Argonne National Laboratory near Chicago, Illinois.
Although the smallest of the three major US facilities, C-Mod specializes in studying the boundary between the plasma and its reactor walls — one of the “tier 1” research initiatives identified in the report. “We’re kind of at a loss” to explain the discrepancy, said Martin Greenwald, the associate director of MIT’s Plasma Science and Fusion Center. The report is “pretty close” to a death blow for the facility, he said, but he held out hope that the scientific community might rally to its aid.
This article is reproduced with permission and was first published on September 22, 2014.
