The long-term future of safe, reliable, and ample nuclear power may involve a transition from fission to fusion, says professor Per Peterson, chair of the College of Engineering's Nuclear Engineering department. Historically, nuclear fusion - smashing two hydrogen isotopes together to release energy - has been something of a holy grail in power generation. Its promise is an effectively limitless fuel supply with orders of magnitude less inventory of radioactive material, drastically reducing the risk of a nuclear accident.
As stated in President Bush's recent National Energy Policy report, "Fusion - the energy source of the sun - has the long-range potential to serve as an abundant and clean source of energy."
Harnessing the same energy that powers the sun is not without its scientific hurdles though. But at one of only two nuclear engineering departments in the west, Peterson and his team are off with a running start with an approach called "inertial fusion," compressing fuel to extraordinarily high densities and igniting it.
The first step is demonstrating that fusion fuel can be crushed and heated to temperatures of 100 million degrees that are needed so the isotopes rapidly react to generate energy. A scientific demonstration of this approach to inertial confinement fusion is expected to be achieved by 2009 in the $3 billion National Ignition Facility, a massively powerful 192-beam laser array under construction at Lawrence Livermore National Laboratory. The aim is to fire a pulse of 1.8 megajoules of laser energy at less than a pinhead of fusion fuel to drive the release of 20 megajoules of energy, the equivalent of burning a pound of coal.
"Once you've demonstrated scientific feasibility of getting more energy out than you put in, all that's left is whether you can engineer a plant that can do the same thing several times a second," Peterson says.
And that's where the lion's share of the Department of Nuclear Engineering's inertial fusion research is focused. Recent breakthroughs include development of a novel liquid blanket to protect the fusion chamber's walls from the fusion explosions at its core. Combined with drivers in development at Lawrence Berkeley National Laboratory that confine the fuel from escaping as it heats, much the way stars use gravity in fusion reactions, Peterson believes that an experimental facility capable of operating at high repetition rates - and producing enough energy for 200,000 homes - could be under construction early in the next decade.
Meanwhile, even as they tackle the tough problems of nuclear fusion, the Nuclear Engineering Department is also developing approaches to further enhance safety and reduce waste generation in fission power plants. This work includes approaches that may enable plants to actually consume more high-level waste than they generate by recycling and burning radioactive waste as part of the fission process.
The continuing improvement in operation of current plants over the last decade, and recognition that new generations of nuclear plants will be better yet, are altering the climate for nuclear power, Petersen says. In the latest public opinion poll on nuclear energy, conducted by Bisconti Research, 66 percent of Americans agree that new nuclear power plants should be built, a 24 percent increase since October of 1999, Petersen points out.
(For more on Berkeley's fusion research see the 2001 issue of Forefront magazine, available from the College of Engineering Public Affairs Office.)
Department of Nuclear Energy: www.nuc.berkeley.edu
Inertial Fusion Energy: A Tutorial on the Technology and Economics: www.nuc.berkeley.edu/thyd/icf/IFE.html
National Energy Policy Report: www.whitehouse.gov/energy
U.S. Public Opinion Poll on Nuclear Energy from Bisconti Research: www.nuc.berkeley.edu/html/hot/news_events/newspaper_articles/bisconti.html
