Though nuclear power produces electricity with little in the way of carbon dioxide emissions, it, like other energy sources, is not without its own set of waste products. And in the case of nuclear power, most of these wastes are radioactive. Some very low level nuclear wastes can be stored and then disposed of in landfill-type settings. Other nuclear waste must remain sequestered for a few hundred years in specially engineered subsurface facilities; this is the case with low level waste, which is composed of low concentrations of long-lived radionuclides and higher concentrations of short-lived ones. Intermediate and high-level waste both require disposal hundreds of meters under the Earth's surface, where they must remain out of harm's way for thousands to hundreds of thousands of years (IAEA, 2009). Intermediate level wastes are not heat-emitting, but contain high concentrations of long-lived radionuclides. High-level wastes, including spent nuclear fuel and wastes from the reprocessing of spent fuel, are both heat-emitting and highly radioactive.
Today, 437 nuclear reactors are in use around the world in 31 countries. In addition, more than 60 countries have expressed an interest in acquiring nuclear power for electricity production in the future (IAEA, 2010). Each reactor will produce its own wastes. Yet no repository exists for the disposal of high-level nuclear waste anywhere in the world. Even the topic of storing waste continues to be a minor priority in the planning stages. But this lack of foresight does not come without consequences: Reactor sites can be overburdened with spent fuel without a clear plan for dealing with this material in a timely manner. This is the case right now in South Korea, where the country's utility foresees a crisis in the next 10 years as the storage at all of the country's four nuclear plants fills up. The United Arab Emirates, which broke ground on its first nuclear facility on March 14, 2011 and is set to bring four nuclear reactors online beginning in 2017, has yet to announce storage as a priority. Hans Blix, former head of the International Atomic Energy Agency and current chairman of the UAE's International Advisory Board notes, "The question of a final disposal plan is still open and more attention should be spent on deciding what to do" (DiPaola, 2011).
When it comes to the severity of an accident at a nuclear facility, there may be little difference between those that occur at the front end of the nuclear power production and those at the back end: An accident involving spent nuclear fuel can pose a threat as disastrous as that posed by reactor core meltdowns. In particular, if spent fuel pools are damaged or are not actively cooled, a major crisis could be in sight, especially if the pools are packed with recently discharged spent fuel.
So why, if the danger is comparable to that at the front end, is there so little foresight and planning regarding the back end of the fuel cycle? Certainly for nuclear engineers, there are more rewards for reactor design than waste disposal. The nuclear industry in general has focused on electricity production, and few players in the field of electricity generation writ large put much time and effort into clean-up of their waste products -- just think about the coal and natural gas industries and the production of mine wastes, ash ponds, waste water from gas extraction, and, of course, carbon dioxide. Put bluntly, money is made on the front end, not on the back end. But the reality, as South Korea is now realizing, is that a lack of planning for waste streams may cause the front end to collapse, halting the production of nuclear energy. This planning should include a medium-term strategy for spent fuel storage prior to the long-term plan for spent fuel or high-level waste disposal.
Japan's Fukushima Daiichi plant has seven spent fuel pools -- one at each reactor and a large, additional, joint pool -- as well as dry cask storage for spent fuel on site. Initially, Japan had planned a short period of spent fuel storage at the reactor site prior to reprocessing, but Japan's reprocessing facility has suffered long delays (it was expected to begin operations in 2007, but is still not open), causing spent fuel to build up at reactor sites. In light of the country's nuclear disaster, a major lesson can be learned related to the back end of the fuel cycle: specifically, that careful planning, not ad hoc solutions, is necessary for spent nuclear fuel. A strategy for dealing with nuclear waste is essential to a successful nuclear power program, and it is best enacted early in the planning of a nuclear power program.
Before the repository.
The full contents of this article are available in the July/August issue of the Bulletin of the Atomic Scientists and can be found here.