Additional technological solutions for decreasing waste are described in the paper. Closed-cycle fast reactor technology, such as an Advanced Liquid Metal Reactor (ALMR), has been studied for many years. ALMR uses energetic neutrons to interact with uranium-238 to eventually produce plutonium-239. Through pyrometallurgical processing, a mix of transnuranic elements from the used fuel can be extracted and the uranium can be reused. This process has advantages over PUREX reprocessing, in a counter-proliferation sense, because it does not produce pure plutonium. An alternative to reprocessing or refining is to produce nuclear waste that is self-contained, depleted to the point where it is not a proliferation problem, and can be stored in underground sites without concerns of water leaching or seismic damage. TRISO (tri-structureal isometric) fuel reactors use fuel pebbles that, after spent, are safe to store without cooling, are resistant to water leaching, and contain highly depleted nuclear materials. By employing such overlooked strategies for waste reduction and reopening the search for a permanent storage site the U.S. will be able to develop a more viable nuclear waste disposal program.
While there is a growing consensus that increased investment in nuclear energy is necessary to satisfy future energy needs, the United States currently lacks a suitable permanent storage site for radioactive waste. With more than 103 open-cycle nuclear reactors throughout the country, the issue of nuclear waste storage is a growing concern. Schaffer (2010) assesses the current state of nuclear waste in the U.S. and proposes solutions to developing a viable nuclear waste disposal program. First, the U.S. should reopen the licensing process for the Yucca Mountain waste disposal facility. Additionally, to decrease the amount of waste sent to disposal facilities the U.S. should restart PUREX reprocessing plants. Upon taking these initial steps, the government must continue to search for additionally permanent storage sites and appropriate funds to educate local communities about nuclear waste storage. The Department of Energy (DOE) and the Nuclear Regulatory Commission (NRC) should also issue guidelines and promotions to encourage the industry to build new TRISO-fueled reactors. Finally, further research should focus on innovative technologies that burn nuclear fuel waste. —Carolyn Campbell
Schaffer, M.B., 2011. Toward a viable nuclear waste disposal program. Energy Policy 39, 1382–1388.
Of the 103 operating commercial nuclear power plants in the U.S., all of them are of the open-cycle, batch type. These plants produce long-lived radioactive waste in the form of ceramic-encased low-enriched uranium oxide pellets packed into zirconium-clad rods. With the 1982 Nuclear Policy Act, the U.S. recognized the need for a consolidated storage site, and in 1987 named Yucca Mountain, Nevada as the site for deep underground repositories. However, in response to pressures from Nevada politicians, the DOE has filed a motion to withdraw the license application for Yucca Mountain operations. Due to this decision, the country’s nuclear waste remains stored in on-site tanks and casks, which Schaffer argues is risky, inefficient, and unsustainable. Additionally, as more open-cycle nuclear plants come on line, the problem only gets worse.
Schaffer suggests that there are two main components to solving the open-cycle nuclear waste disposal program. First is the issue of community confidence; in order for a permanent storage site to be developed, community endorsement is required. Therefore, a confidence-enhancing plan should identifying three or four sites instead of just one, specify storage for a nominal period, provide adequate monetary incentives, and disclose the risks and rewards of a nuclear storage site. The second component of a long-term solution for nuclear waste involves reducing the amount of high-level nuclear waste sent to a storage facility. One way to achieve this is through the PUREX (Plutonium and Uranium by Extraction) process in which depleted fuel rods are cut into pieces and dissolved in nitric acid. Uranium, plutonium, and actinides can then be extracted from the resulting liquid. The extracted uranium-235 can be burned in heavy-water moderated reactors or fast-neutron reactors for additional energy, the plutonium-239 can be used to make MOX (mixed oxide uranium and plutonium) fuel, and the actinides can be vitrified in a design that is resistant to water leaching.