Nuclear processes have an amazingly diverse range of applications, perhaps the most important being in medicine, where over 1/3 of all procedures in the United States use nuclear techniques. Nuclear processes are used to provide images inside the human body, to detect and measure biochemical processes, and to provide therapy. A major event in 2000 was the FDA approval of the first Monte-Carlo code for use by doctors to design radiation therapy for cancer. Based on nuclear reactor design methods, this new tool now allows doctors to take detailed magnetic resonance imaging data  (another nuclear technique) and predict with great accuracy how to deposit precisely enough radiation to kill cancer tumors without damaging surrounding tissue. Previous crude calculation methods often forced doctors to cause damage to substantial amounts of healthy tissue, or to miss completely killing tumors. Students in NE learn how the principles of engineering physics can be applied to imaging and therapy.

The vision of fission energy is compelling. In the last two decades it has become the world's largest single source of emission-free energy, and it creates a waste stream sufficiently small and compact that we can conceive of isolating this waste permanently from the environment. For fission to provide more energy in the future, our grand challenge is to continue to improve the safety, economic performance, waste minimization, and proliferation resistance of fission power plants.

The U.S. has 103 nuclear power plants providing over 20 % of its electricity; worldwide the number is 433. These plants have helped stabilize electricity costs, particularly with the recent volatility of natural gas prices. Our nuclear plants reduce substantially the amount of carbon dioxide that world-wide electricity use releases to the atmosphere. Nuclear fission is the only non-fossil energy source that has been demonstrated at large scale, and that could be expanded substantially further. Nuclear's current contribution is sufficiently large that every year since 1999 the increases in the operating capacity of existing U.S. nuclear power plants from improving equipment reliability accounted for over half of all carbon-dioxide reductions reported by the U.S. electrical industry.

We now expect most existing U.S. nuclear plants to apply for 20-year license extensions , which means that the existing U.S. nuclear fleet will operate out past 2030. Many of our U.S. plants has been sold by regulated utilities to large owner-operator companies like Excelon and Entergy. Besides encouraging further improvements in reliability and safety, the large technical expertise and financial resources available to these new nuclear-focused companies provides the best possible conditions for new plant orders. Designing the next generation of fission plants is where some of our most interesting work is now, ranging from planning for light water reactors with new passive safety features, to gas-cooled reactors with extremely durable fuel, to lead-cooled reactors that can burn more waste than they generate.

The development of economic fusion energy systems is one of Nuclear Engineering's greatest grand challenges, since such power sources would fundamentally alter the way that humankind interacts with its environment, to the benefit of both humans and nature. In a well-designed fusion power plant, burning one ounce of fusion fuel, plentifully available, makes as much energy as burning 300 tons of coal while making a negligible amount of waste. Worldwide progress toward fusion has been steady and impressive. In the last decade, we have seen magnetic fusion experiments create over 13 million watts of fusion power. In the coming decade, we expect to see the new National Ignition Facility use inertial confinement to ignite fusion fuel, and for the first time reach the fusion conditions needed in an actual inertial
fusion power plant.

UC Berkeley's Nuclear Engineering Department plays a leading role in advancing fusion technology, both toward advanced approaches to magnetic fusion using compact toroidal plasma configurations, as well as collaborations with Lawrence Livermore and Lawrence Berkeley Laboratories to develop inertial fusion systems that can operate at high repetition rates for power production.

Another grand challenge problem that our graduates work on is developing systems for the safe and permanent disposal of radioactive waste.

The most significant milestone in this field occurred with the opening of WIPP, the world's first geologic repository. Located 1/2 mile underground in a 250-million-year-old salt formation in New Mexico, WIPP began emplacing waste contaminated with radioactive transuranic elements in 1999. While the U.S. Department of Energy submitted the license application for the Yucca Mountain Project in 2008 to develop a repository for commercial spent fuel and high level waste from early U.S. military activities, the current Obama administration decided not to continue its development, and established the Blue Ribbon Commission on America's Nuclear Future to explore alternatives for the back-end of the nuclear Fuel cycle. Per Peterson and Senator Pete Domenici co-chair the Reactor and Fuel Cycle Technology Subcommittee of the Commission.

Thus, needs for systems models to assess, compare, and optimize the integrated system of the fuel cycle and geological disposal have been increasing. International collaborations in this field have also been expanding, with active participation by the U.C. Berkeley, Nuclear Research Laboratory.