The cooling pools at nuclear reactors are used for varying periods of time to store the spent nuclear fuel.5 For the Wolf Creek Nuclear Plant that I visited, the cool­ing pool will hold the fuel for 40 years of reactor life, but what happens after that? Other reactors are older and already have faced the problem of what to do with the used fuel rods in the short term. The short-term solution to storage of used fuel is to place them in an inert gas in steel containers encased in concrete and stored on-site at the reactor (Figure 9.3). This is called dry cask storage, which is currently being used at many nuclear reactors, and this is what will happen at

Wolf Creek Nuclear Plant after the cooling pool is filled. According to the Nuclear Regulatory Commission (NRC), about 80% of the cooling pools at nuclear reac­tors are at capacity, so dry cask storage is necessary. This only happens after the used fuel rods have been stored in cooling pools for at least five years to allow them to cool off and for some of the most radioactive elements to decay away. The heat has dissipated enough that normal airflow around the casks is sufficient to cool them. The steel containers and concrete casks shield the radiation, so it is not dangerous to be close to the casks (6).

An average-sized 1,000 megawatt nuclear reactor produces about 20 tons of spent nuclear fuel each year that has to be stored in cooling pools for a few years. Each cask typically holds about 10 tons, so the total waste from a reactor is about 2 casks per year (7). Since uranium and transuranics are heavier than lead,6 this is not a large volume. In fact, it has been calculated that the yearly waste from a typical nuclear power plant would fit in the back of a pickup (though of course it would crush it!) (8). Recall from Chapter 3 that the 280 MWe Rawhide coal-fired power plant produces 70,000 tons of fly ash annually. Thus, a 1,000 MWe coal-fired power plant would produce about 250,000 tons of fly ash or sludge waste annually. And, of course, this does not include the approximately 8 million tons of carbon dioxide (CO2) produced annually by a 1,000 MWe coal plant.

Another striking statistic is that all of the waste generated by all 104 nuclear power plants in the United States through 2010 would fill a football field to a depth of about 7 yards if all of the used fuel assemblies were laid out end to end and side to side (9). Of course, estimates like these are not realistic, because that is not how spent nuclear fuel can be stored. To be more realistic, the total amount of spent nuclear fuel generated in the United States annually is about 2,000 tons, which would require about 5 acres for dry cask storage (10).

Dry cask storage was never meant to be a long-term solution, but it has great merit as an intermediate solution over the next 50-100 years. The casks are stored on-site at nuclear reactors within the secure part of the reactor site. There is little concern about terrorist attacks because the casks are very sturdy and the spent nuclear fuel within them is useless for making bombs because of all of the fission products. While nuclear reactors normally have dry cask storage on site, there could also be several centralized depots in various states where spent nuclear fuel from numerous reactors could be stored. According to the NRC, which has to license the dry cask storage facilities, 33 states currently have dry cask storage sites. Dry cask storage—either on-site or in centralized depots—can provide a safe and secure method to handle spent nuclear fuel for the next century and can reduce the need for an immediate solution to the long-term problem of waste storage (7, 11). Furthermore, the longer the spent nuclear fuel is stored in dry casks, the more the radioactivity and heat decays, so the ultimate disposal becomes simpler and less expensive.

But is this just kicking the can down the road? What is to be done about the long-term storage of spent nuclear fuel for thousands or hundreds of thousands of years? Is this really the Achilles’ heel of nuclear power, as so many anti-nuclear activists claim it is? It is clear to me that the problem of long-term waste storage is primarily a political problem, not a scientific or engineering problem. Politics is the reason that the United States does not currently have a solution to long-term storage.