Director's Corner

Where do you see your work in a global context? Where do you see it going?

Up until about 1998, we were much more focused on how to improve the reliability and safety of existing power plants. However, we now need to look ahead to innovative ideas for the future. That’s why we’ve organized the Center for Advanced Nuclear Systems. We were probably the first center worldwide to actually concentrate on advanced technologies for future reactors––things like alternative coolants and alternative emissions. Our current focus is to examine new ideas that can improve the reliability and economic viability of nuclear power, and also expand the applications wider than just electricity. I think there will be an opportunity in the next 20 to 25 years to link nuclear energy to the transportation industry. Electricity may also eventually become a more important part of the transportation sector. Right now, in the near-term, this would come more in the form of applying heat in order to make the heavy oils more fluid and more easily transportable, or applying hydrogen to increase their usability for burning. I think globally, and others are beginning to do so as well. For example, two years ago, Tokyo Institute of Technology formed a center of excellence for innovative nuclear technology I believe we will see more and more activities at universities seeking to achieve similar goals.

Do you see nuclear power as transitional energy source or one that is here to stay?

I see nuclear energy as one of a number of energies the world will need. Unlike fossil sources, it doesn’t produce harmful emissions in the form of carbon dioxide. Unlike renewable energy, it is a high-density, concentrated source of power, and doesn’t require the vast amounts of land that are required for the production of energy from solar or wind. Furthermore, not every part of the world is suitable for those renewable sources. Some places are blessed with having a lot of hydropower or solar reception throughout the year. Some are not. Wind blows differently in different parts of the world. 

I do think we will need a backup for our current system and I think that future growth will be in nuclear and renewables. We will see continued use of fossils, because oil and gas are, at the moment, easier to transport and apply. Also, coal is rather abundant in important high-demand places like the United States and China. Because it is in abundance, it will be used. For the last 15 years or so, nuclear energy has accounted for roughly 7% of the total energy production in the world. I expect that will grow. I would be comfortable if that number grew to about 25%. 

Why not more?

There are certain issues inherent to the use of nuclear energy that require resolution. For example, because it is such a sophisticated technology, it is not possible to expect that all countries and communities will be able to assume the necessary maintenance, inspections, and general security procedures. Furthermore, nuclear fuel could be diverted for use in weaponry. So, there will be some limits on the use of that technology, whether it’s at the front end, i.e. enrichment, or at the back end, i.e. reprocessing. 

I think the world will come up with a system where there would be a certain collaboration––perhaps regional, possibly international––in order to keep the strategic materials out of the hands of untrustworthy groups. It would be natural to use a system where there is redundancy––that is, more than one fuel. We certainly don’t want to ever lose a large fraction of the overall energy supply. If you look at today’s energy production, oil, gas, and coal are providing perhaps 8 0% of the energy. Then you have hydro, nuclear, and biomass––mostly wood–– providing the remainder. The other renewables have not grown enough to account for a significant percentage. 

Regarding possible nuclear proliferation dangers, is the problem at the beginning of the creation cycle, or is it later with whatever materials remain?

This has been a matter of worry from day one. The nuclear era began with the development of weaponry. But its potential benefits to humanity were so compelling that the United States­–– beginning with the Eisenhower era Atoms for Peace program in the late 50’s­––led the way in the sharing of this technology. The question has always been how much nuclear know-how can we permit in the commercial world without abetting widespread weapons development. This tension continues to this day. The trend has been, essentially, to ask for all countries to promise not to produce weapons, sign the Nuclear Nonproliferation Treaty, and allow the Intelligent Energy Executive Agency to inspect the plants in order to guarantee peaceful applications. I think we will need an international organization that will provide the fuel initially, and perhaps another organization that takes it at the end. 

Can you discuss some design innovations?

There are ideas for making the plants operate for a very long time before needing refueling. Using today’s water technology, it is feasible to extend the uninterrupted operation of a plant to maybe 15 years. Using fast reactors, you can go even further. The idea is to keep the structure reasonably small. This way, at the end of the lifetime, you can take away the whole reactor and send in a new one. Therefore, the fuel will never be out of the boxes. Many countries are now working on what we call small or medium reactors. But in the final analysis, when you look at the market and what people have been buying, we haven’t seen a big demand for such smaller units, or ones that operate for unusually long times. The Russians have built a small reactor in the neighborhood of 200 megawatts that can be shipped anywhere on a barge. But, I look around the rest of the world and I see many more orders for, and interest in, the large units, which require more frequent refueling. If we can find a way to make the long cycle bottoned -up reactors less costly, maybe demand will increase.

Are they safer, in terms of prevention of terrorism?

I do not think there is a difference. The long cycle reactors need require higher concentration of the the fissionable isotopes at the beginning, but the material is still well bound to the other uranium isotopes. In the reactor, t he fuel becomes very radioactive either way. Anybody who gets close to nuclear fuel is going to suffer quite a dose of radiation. Theoretically, you could say that it is safer if it is never outside the vessel. Nuclear fuel, once irradiatated, is very difficult to handle. You need sophisticated techniques for remote replacement and transportation. It’s not an easy thing to steal.

What are the implications of your work? Is there a downside to this research?

I’m not sure how to answer that. Even if a technology has advantages­––say, in safety or waste reduction––it will not be embraced in the market unless it is also economically attractive. This raises the interesting question of whether to simplify advances so the economics will work out better. Very often, you find that it is possible to improve reliability or safety, but if you increase costs, the technology will not be applied. That’s why it’s always a challenge to improve economics and functionality simultaneously. 

I do not think wider use of nuclear energy has more of a downside than other types of energy. Carbon emissions have a downside that’s well identified. It is less obvious in the case of renewables. But look at the case of the wind farm in Cape Cod. That has stirred passions because people don’t want their views obstructed. There are aesthetic questions when it comes to land use. If we want to supply a big city like Boston with the same amount of electricity it currently uses, do we need to block the land between Route128 and Interstate 495 just to put the solar plates there?

Being prudent about the use of energy is good. Having multiple resources so we are not surprised in the future by unanticipated downsides is good. And, we must continuously examine ways to improve operating conditions. Right now, from one kilogram of fuel, we produce about 50 megawatt- days of energy, that is 1200 megawatt-hours. . If we get to 100 megawatt days per kilogram, we will significantly reduce the amount of space needed for spent fuel storage, by a factor of two. That’s an advantage. However, in the process, you’re going to be subjecting the materials to more damage because they will be withstanding a higher number of neutrons. There is always some challenge to be faced.

Regarding inherent dangers, the U.S. has never allowed a weak reactor containment, building even from the beginning. Our containment requirements are much more stringent than the requirements that precipitated the Chernobyl accident. But since that time, new developments have added to the defenses––both in the fuel inside the core and in the containment building. In some designs, it is now possible to depend only on natural convection of air to keep things cool and safe. I look at it like the airline business. Safety has improved because they’ve learned how to inspect, design, and manage better. Though an accident is a possibility, it is neither a likelihood nor an eventuality. The same goes for nuclear energy.

Interviewed 12/6/06