As Japan's troubles continue, CISAC's Thomas Isaacs discusses the future of the nuclear industry.

CISAC: My understanding is that Three Mile Island set back the industry because afterward there was no appetite for building new reactors.

Thomas Isaacs: It's not clear that it was Three Mile Island. It was certainly in that time frame. Others would say it was a combination of a reduction in the demand for electricity at that time and the emergence of alternative energy sources that were less expensive to get started. You saw less of an appetite not just because of the concern about Three Mile Island -- although that was probably a contributing factor -- but because it just no longer made sense to build new, huge, expensive power plants, particularly nuclear power plants.

CISAC:  Experts now say that what's going on in Japan is worse than Three Mile Island. If so, how might that affect the building of nuclear reactors in the future?

Isaacs: The effects are probably unknown and unknowable now. We'll need to have a much better idea of what actually transpires, and how it is handled by the Japanese. We'll also have to see what the consequences are and what the perceived consequences are, and the ability of the Japanese government and utilities to generate a sense of confidence, which is lacking right now. All of that will have an effect and it will be different for a variety of countries, but it's hard to speculate. My own assumption is that in countries where there is more of a national, organized effort to build nuclear, principally in places like China and India, you might not see as much effect as you might see in countries where nuclear has been much more of a controversial issue, and where the public has much more engagement in the decision-making process. In emerging countries that now have no or very few plants, you might see much more controversy. 

CISAC: What about regulation? Might there be more regulation, both here and in China, India, and elsewhere?

Isaacs: I think we don't know that yet either. You would hope that people would view this as a sobering event -- an opportunity to learn lessons for the future. As a result of Three Mile Island and then Chernobyl we have organizations like the World Association of Nuclear Operators, who come together from all over the world to share lessons learned. This will be an example of a place where you would hope they will take this very seriously -- I'm sure they will -- and they will ask very searching questions about whether our regulations or anybody's regulations are appropriate given what we've experienced. There's no question that the track record for U.S. reactors has been outstanding and getting better over the last 20 to 30 years. Should that lead to a sense of comfort? No. It should lead to a sense that we've always had an obligation to ask ourselves if we're doing everything that makes sense, and we can continue to learn from experience and improve.

CISAC: The issue of nuclear waste is important in this country and elsewhere. How might it fit into what we're seeing in Japan right now?

Isaacs: There is spent nuclear fuel, which is a waste form if it's not reprocessed. That's what would ultimately go into the repository, and that potentially is one of the problems that's causing the release of radioactivity at some of these plants. More broadly, you need to feel confident you know how to handle waste, both in the short term and in the very long term, because it is potentially hazardous for geologic time periods. Most people who work in that business believe that disposing of it in a geologic repository, in a stable geologic formation that has the right characteristics, is a very fine way to solve that problem, and pretty much every country that has decided to move toward nuclear waste disposal has chosen that approach. But from a societal point of view and a political point of view, it's a very tough problem. It's not just the science and technology problem.

As Japan's nuclear troubles continue, CISAC's Alan Hanson discusses the range of scenarios and how to prevent catastrophe.

CISAC: What is the range of events that could happen over the next several days and weeks?

Alan Hanson: The earthquake and resulting tsunami that hit northern Japan last Friday are unprecedented in modern times. These two nearly simultaneous natural disasters did significant damage to the Fukushima nuclear power stations operated by the Tokyo Electric Power Company (TEPCO). Despite this damage, including a total loss of off-site power and emergency backup power, TEPCO personnel have been making a heroic effort to bring the situation under control. To date off-site releases of radiation appear not to have had severe effects to the local population; because of prevailing westerly winds, the radiation releases have not been in the direction of major population centers.

It is impossible to predict the sequence of events that will unfold over the next few days and weeks. Under the best of circumstances, TEPCO will continue to take actions limiting further releases. To do so they must continue to cool the nuclear fuel in two separate regions of each reactor in the two stations; these regions are the reactor core itself and the used fuel storage pool. This means that enough water must be continually injected to keep the fuel covered. More dire circumstances could occur if the nuclear fuel is uncovered for a lengthy period of time. In the reactor core, this could lead to partial or total fuel melting, followed by failure of the primary steel containment due to excessive heat and pressure. Since some fuel has been uncovered for some time intervals, it is believed that partial melting may have already occurred and that the primary containment has been damaged in one or two of the reactors. If used fuel in the storage pools is uncovered, it could lead to fuel cladding failures from high temperatures releasing radioactive gases directly into the atmosphere. In a very unlikely scenario burning of the fuel cladding would release more gases and also particulate matter into the atmosphere. The reactor cores are of immediate concern because that is where the highest temperatures are located. The fuel pools become of greater concern over the intermediate term as water is boiled off or if some other event causes draining of a pool.

CISAC: What can be done to prevent the worst?

Hanson: Both worst-case scenarios described above can be prevented by keeping the nuclear fuel covered with water by any means available including the use of sea water, which has been initiated already. The weather will play an important role, too. As long as winds blow radioactive gases off shore and away from population centers, the public health effects should be minimal; if winds shift and blow toward Japanese cities, the situation would be significantly worse.

CISAC: How can we prevent this sort of thing from happening again?

Hanson: It is too early to speculate about the possibility of future accidents such as this one. Suffice it to say that the combination of a magnitude 9.0 earthquake and a 30-plus foot tsunami is a highly unlikely event. If early reports from the site turn out to be true, the reactors rode out the earthquake reasonably well and all of them shut down in the orderly fashion planned for an earthquake. Without the subsequent tsunami, it is very doubtful that the ongoing crisis at Fukushima would be anywhere near the magnitude we are witnessing. The nuclear industry has a good record of learning from accidents and making the appropriate changes to prevent reoccurrence or to at least mitigate the consequences should something similar happen in the future. Actions will certainly be taken by the industry and regulatory bodies in this vein once the immediate emergency is behind us.