Highlights
– Reactors’ full storage capacities lead to a push for above ground storage containers
– NRC rules containers as secure and safe structures in event of accident or terror attack
– Long-term storage solution delays generate interest for alternative storage methods
In nuclear reactors across the country, spent nuclear fuel storage pools are increasingly reaching capacity. Specifically, the nation’s storage pools hold 56,000 tons of spent fuel, while an additional 2,000 tons are generated annually (Source). This increase has caused several nuclear reactors to design and install Independent Spent Fuel Storage Installations (ISFSI). On these sites, spent fuel, cooled for at least one year, can be stored in dry cask storage containers. The ISFSI utilize tested and safe, robust sealed concrete and steel structures to store the spent fuel. However, environmentalists and anti-nuclear groups are raising concerns that above ground facilities could become a target for terrorists.
With almost 170 million Americans living within 75 miles of temporary nuclear waste storage sites in 39 states, the safety concerns are well founded (Source). Currently, the US Nuclear Regulatory Commission (NRC) conducts continuous security evaluations and ensures that the dry cask units are vetted through a rigorous testing process. Despite these safety measures, there will likely be greater pressure for the US government to undertake alternative methods for a long-term solution to the nation’s fading storage pool capacity by implementing spent fuel reprocessing and permanent geological disposal.
Sparking Debate in Diablo Canyon
While nuclear reactors remain some of the most secure and fortified structures in the US, an anti-nuclear group, Mothers for Peace, legally called for the NRC to evaluate environmental and safety concerns for above ground storage facilities in the event of a terrorist attack. The group specifically focused on a proposed plan by Diablo Canyon Nuclear Power Plant to install steel storage cylinders to store highly radioactive used reactor fuel. As a result of a legal challenge, the US Court 9th Circuit ordered federal agencies to study the effects of terrorism on reactors and storage houses. However, the NRC ruled that Diablo’s above ground storage units are considered safe. Some of the threat assessment’s key findings include:
• ISFSI are required to maintain physical barriers, surveillance, intrusion detection, security patrols, augmented security forces and weapons, and heightened cooperation with local law enforcement and military.
• Spent fuel dry casks are designed to withstand the impact of severe accidents including the “impact of a tornado-generated missile such as a 4000-pound automobile at 126 miles per hour” (Source).
• NRC states that a majority of the spent fuel in the containers are in solid form. Even if an attack by suicide plane crash or rocket propelled grenade would penetrate the concrete and thick solid steel containers that result in a leak, the solid form of spent fuel would not likely be dispersed to an area beyond the ISFSI.
• NRC acknowledges the difficulty in assessing a potential attack, yet states that with the current threat conditions in the US, the threat of a malicious act on dry cask facilities is exceptionally low. If an attack were to occur, the local populace would be evacuated but the radiological risk to the populace would be relatively small.
Despite the ruling, the NRC has agreed to hear additional arguments from Mothers for Peace, but Diablo will proceed to construct its new storage area that covers the size of a football field and is able to hold 138 canisters. Additionally, there are at least one dozen more reactors already designing dry cask storage facilities similar to those at Diablo. Environmental activists will likely head to additional legal venues to urge further NRC assessments for each site. However, this would likely result in licensing delays and could further push the nation’s spent fuel storage to an unprecedented limited capacity.
Long Term Solution Delays Generate Interest for Alternative Methods
The US government had planned to initiate operations to geologically store spent fuel at Yucca Mountain in Nevada in 1996. However, after legal obstacles the project has been delayed until at least 2016. In January 2008, legislation was introduced in the US Senate to speed up efforts by limiting the safety requirement for the facility to 300 years rather than 1 million years. As Nevada politicians and activists continue to challenge the measure, Yucca Mountain would still only be an interim solution. By legislative mandate, the operation has set a maximum storage amount of 70,000 tons of dry cask storage. Experts claim that with that capacity limit, the repository would be full by roughly 2010 (Source).
With the nation’s nuclear industry maintaining steady momentum, reprocessing the spent fuel could also represent a future possibility. The reprocessing of the fuel, which is roughly 96 percent uranium, could present a potentially economic and practical incentive as the price of uranium ore continues to rise. However, critics allege such a process would be costly, time consuming, and carry a greater safety risk. Spent fuel rods would need to be dissolved into a highly radioactive, liquid form that is very difficult to contain.
As plans for Yucca Mountain continue to delay, nuclear reactor sites around the country will likely continue to design and implement dry cask storage units. While the above ground dry storage units represent a slighter softer target than hardened reactor plants, the robust design of dry cask containers, which hold small amounts of spent fuel in solid form, results in an overall low threat level to a reactor’s local populace.
