In Review

Q&A The Future of Fusion Will nuclear fusion help power the nation’s energy supply? The director of the University’s Laboratory for Laser Energetics says Rochester has set the course for finding out. Interview by Larry Arbeiter

In discussions of the nation’s need to develop safe, clean, renewable power, nu- clear fusion has long been acknowledged as the technology with perhaps the great- est potential payoff. But that recognition comes with the caveat that the necessary breakthroughs may never be achieved. With the recent commissioning of the National Ignition Facility (NIF) at Law- rence Livermore National Laboratory in California, the U.S. government is making a $3.5 billion bet that fusion eventually will be part of the nation’s energy mix. The Omega and Omega EP laser facilities at the University’s Laboratory for Laser En- ergetics reigned as the world’s most power- ful lasers for fusion and high energy density physics research until they were surpassed this year by NIF. The LLE remains the largest user facil- ity for research in this field, with scientists from around the world performing experi- ments at the South Campus site. Founded in 1970 and supported by approximately $70 million annually, mostly from the fed- eral government, the lab and the scores of scientists who conduct research there have LASER VISION: Successful tests of the National Ignition Facility draw on decades of research laid the foundation in laser inertial confine- and development at Rochester, says Robert McCrory, director of the Laboratory for Laser ment fusion research on which the NIF is Energetics since 1983. He is also a professor of physics and of mechanical engineering. built (see sidebar). As director of the LLE since 1983, Rob- ed McCrory for its Lifetime Achievement sign of ignition targets for the NIF. This ert McCrory has had a leading role in de- Award. includes new technologies developed at veloping the nation’s strategy for achieving LLE, such as high efficiency frequency tri- nuclear fusion as a form of energy produc- How has the work at the LLE made the NIF pling and smoothing by spectral dispersion, tion. For his own research on laser-driven possible? which are essential to NIF meeting its per- plasmas and their applications to con- LLE was a significant partner in NIF’s de- formance goals. trolled thermonuclear fusion, McCrory was sign and construction, including coating elected a fellow of the American Physical about half of the large optics. In addition, What do you say to the critics who argue Society and a fellow of the American As- research carried out on the Omega Laser the NIF is perhaps too large and complex sociation for the Advancement of Science, Facility has led to improved understand- to reliably meet its design goals of achiev- and he won the international Edward Tell- ing of inertial confinement fusion and the ing nuclear ignition? er Medal. In 2002, the Hajim School select- results have been incorporated into the de- The NIF is about 50 times larger than the

6 ROCHESTER REVIEW November–December 2010 Adam Fenster

3_RochRev_Nov10_Review.indd 6 10/28/10 10:24 PM In Review

Omega laser facility but was built upon the reasons that nuclear fission power plants Incoming Hydrogen experience gained from Omega, and from were successfully developed was the re- laser beams isotope fuel the Nova laser at Lawrence Livermore be- search carried out by the Navy to develop target (about 1 mm in fore that. The innovations in the laser ar- nuclear-powered vessels under Admiral diameter) chitecture incorporated in the NIF make it [Hyman] Rickover. This was the precur- possible for it to meet its design goals. It’s sor to the nuclear power industry. We are worth noting that the new Omega EP laser at a similar stage now with inertial confine- was built using these same innovations and, ment fusion, which is in the development while much smaller (4 beams compared to stage. After a successful demonstration of 192 on NIF), is operating reliably. The ini- ignition on the NIF, a significant inertial fu- tial performance of the NIF is very encour- sion energy program will likely begin with Core aging. The Lawrence Livermore team, with the goal of demonstrating a nuclear fusion Ablating undergoes its national partners, did a masterful job of power plant by the middle of this century. plasma exerts fusion and pressure on core burns completing the project. In fact, the Project A National Academy of Sciences and Na- Management Institute named the NIF as tional Academy of Engineering study will IGNITION: Heated by the 192 laser beams its Project of the Year in October, selecting begin late in 2010 to assess the potential of at NIF, the surface of the target fuel NIF from three finalists drawn from world- inertial fusion energy. ablates, squeezing the remaining fuel wide nominees. The other finalists were the into a dense core—which undergoes monumental Cowboys Stadium, the NFL’s Some financial and environmental activ- nuclear fusion. superstructure in Dallas, and the Norton ists are complaining that the NIF may not Brownsboro Hospital, a facility featuring reach all of its deadlines on time, and the latest in health care technology, in Lou- should therefore be penalized or reconsid- Laboratory Stars isville, Ky. ered. How do you respond to them? Nuclear fusion, the release of energy that Achieving nuclear fusion ignition in the lab- occurs when the nuclei of hydrogen atoms Why should we spend so much money and oratory is difficult, and there is a significant are fused together, is something of the energy to try to achieve fusion when we national research program to demonstrate holy grail of energy production. Potentially already have nuclear power in the form of ignition. But this is a research program, not providing manyfold as much energy as fission-based reactors? an engineering project, and we cannot pro- nuclear fission, which releases energy by It is true that nuclear fission is in wide- vide a definitive date by which ignition will splitting apart the nuclei of heavy atoms spread use in the U.S. and worldwide. be achieved. The deadlines are goals that like uranium or plutonium, nuclear fu- There is sufficient fuel so that nuclear fis- we hope to reach, but in a research pro- sion not only would produce enormous sion could play a significant role in meeting gram, new discoveries can influence how amounts of energy efficiently, but it also the nation’s carbon-free energy needs over the goals are met. This can make things take would create a thousandth of the radioac- the next century. However, no new nuclear more, or sometimes less, time than original- tive waste created by fission. While one of fission plants have been built in the U.S. in ly anticipated. While the date that ignition the isotopes needed to power the reaction the past decades. This is, in large part, due will be demonstrated cannot be guaranteed, must be manufactured in a reactor, the to the public’s fears about nuclear fission, I am confident that ignition can be achieved other can be found in water. the possibility that there could be a melt- in the next few years. So far the only power plants using fusion down and concerns about how to store the as a routine source of energy are stars, spent radioactive fuel, and difficult regula- If ignition is soon achieved, and assuming which have the advantage of enormous tory and licensing requirements. The U.S. we and other nations continue to pursue mass to create the millions of degrees and was planning for long-term storage at Yuc- the long-term challenge, how far off is the hundreds of billions of atmospheres of ca Mountain and spent over $8 billion on it, payoff likely to be? pressure needed to overcome the powerful but that has been abandoned. By contrast, After the demonstration of ignition, an in- electric repulsion that exists between the nuclear fusion offers the advantages of an ertial fusion energy program could begin positively charged hydrogen nuclei. essentially unlimited supply of fuel—con- with the goal of demonstrating a nuclear So how do you recreate in a lab a pro- tained in water—no risk of meltdown, and fusion power plant by the middle of the cess that happens naturally only in stars? very little radioactive waste. Fusion also century. If that is successful, nuclear fu- That’s the goal of the National Ignition avoids many of the nuclear proliferation sion could meet a significant fraction of the Facility—to compress and heat pellets of dangers and concerns associated with fis- nation’s electricity needs by the end of the hydrogen fuel sufficiently to induce a fu- sion reactors. century. This will require the continued sion reaction that generates more energy support of the federal government over the than was required to begin it. Scientists With all of the advantages of fusion, why next few decades. It is unlikely that private refer to that as thermonuclear “ignition.” are there hundreds of nuclear fission industry will become a significant player While achieving ignition doesn’t guaran- power plants but not a single one powered until after a prototype power plant has been tee the feasibility of limitless, clean fusion by fusion? demonstrated.r power, it’s perhaps the largest single step Achieving fusion ignition in the labora- on a path to a new role for nuclear power. tory is much more difficult than making Larry Arbeiter is associate vice president for —Scott Hauser a nuclear fission plant work. One of the University Communications.

November–December 2010 ROCHESTER REVIEW 7

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