USA nuclear waste options undermined by politics

FOCUS: NUCLEAR WASTE MANAGEMENT

USA nuclear waste options undermined by politics

Nuclear energy in the USA generatesabout 2,000 metric tonne of used fuel each year, with a total of 84,000 metric tonne since the 1950s stored at more than 70 sites in 34 states. The country has yet to build a permanent disposal location for the spent fuel, despite the fact that a specific site for disposal on Federal Government owned land at Yucca Mountain, about 130km northwest of Las Vegas, Nevada, was written into Federal law in 1987.

The Nuclear Waste Policy Act of 1982 stated that the Federal Government would accept responsibility for spent nuclear fuel disposal from all civic energy production when a repository is operating. Politics and geological concerns, however, have prevented issuance of the licenses needed to start work on a permanent disposal facility at Yucca Mountain.

The Nuclear Energy Institute trade group said in May 2020 that taxpayers continue to pay some US$800 million annually because the Federal Government fails to meet disposal mandates. The funds pay for on-site storage of waste at reactor sites.

Plans to store 70,000 metric tonne of spent fuel at Yucca Mountain halted in 2010 when President Barack Obama canceled the project. Politicians from the State of Nevada have opposed the plan, further delaying construction. Some politicians at the County level have taken a more open-minded position. Meanwhile, spent nuclear fuel is currently stored temporarily in water-filled pools and above-ground dry storage facilities.

The area of Nevada has experienced some seismic activity, which naysayers of the Yucca Mountain facility say raises doubts about the safety of storing spent fuel at the site. The area experienced a 6.5 magnitude earthquake in May 2020, the third in the past two years within 150 miles of Yucca Mountain. Nevada officials have also gone so far as to challenge various assertions by the Federal Government about geology, hydrology and transportation risks associated with the project.

The site has two large tunnels excavated by the Department of Energy in the 1980s. The main tunnel is U-shaped and spans five miles x 25ft in diameter (about 8km x 7.6m) and the other is two miles long, branching off the main tunnel. The Yucca Mountain area is semiarid and has little surface water, with strong, low-permeability volcanic rock and with low levels of seismic activity. None of the earthquakes near the site damaged below ground facilities and the proposed repository has been designed to withstand much stronger seismic activity.

The proposed repository calls for a complex at about 1,000ft (300m) below the top of the mountain and about 1,000ft above an aquifer in the area (Fig 1). The mountain is formed of at least 6,000ft (1,800m) of volcanic tuff, which is volcanic ash compressed by gravity and intense heat to form solid rock. Below the tuff is carbonate rock formed from sediments laid down at the bottom of ancient seas that existed in the area. A mix of natural and engineered barriers would isolate the waste from the surrounding environment.

Fig 1. Proposed Yucca Mountain nuclear waste repository

“Because the Yucca Mountain site is considered unsafe for long term nuclear waste storage and disposal, and because there has been decades of bipartisan opposition, Yucca Mountain will never become the nuclear waste repository for the USA,” said Geoff Fettus, a senior attorney at the Natural Resources Defence Council nonprofit environmental advocacy group. He continued: “If leaders in Washington want to come up with a durable solution for radioactive waste, they need to start over and provide a durable framework that gives the EPA and State decision makers a say in where, how, and how much waste is stored at various sites.” Moving the permanent storage site from Yucca Mountain, however, would require an Act of Congress.

In this stalemate of national policy making, private companies in the USA have developed their own proposals including new temporary storage sites in New Mexico and Texas, which need a license for temporary nuclear waste storage for construction to start. Federal law however may need changing to allow for the Federal Government to own the waste and pay for development costs.

Holtec International has proposed an interim storage facility, known as HI-STORE, in southeastern New Mexico, about 35 miles from Carlsbad and about 12 miles from the existing Waste Isolation Pilot Plant (WIPP).

When Holtec began the application process, then-Governor of New Mexico Susana Martinez endorsed the project, which is now opposed by the current Governor, Michelle Lujan Grisham.

The HI-STORE consolidated interim storage facility, or CISF, would occupy 288 acres and stand less than 2ft above ground, storing up to 100,000 metric tonne of spent fuel about 40ft (12m) underground (Fig 2). The project would cost about $3 billion in capital investments, with construction expected to start as soon as late 2022. Opponents say such a facility would not be ready until 2048 at the earliest.

Fig 2. Rendering of the proposed Holtec facility

Credit: Holtec

Interim Storage Partners, a joint venture of Waste Control Specialists and Orano CIS, has proposed a site in Andrews County, Texas, on the border with New Mexico. The facility would store an eventual total of 40,000 metric tonne of spent fuel on 332 acres. The site is atop a 600ft (180m) thick bed of red clay that is ten times less permeable than concrete and limits any horizontal groundwater travel to about 1ft (30cm) per 1,000 years.

Like the Holtec facility, the project has faced political opposition. Local residents and officials have spoken out against the planned site because nuclear waste would be transported to the facility on local railways. But the area has stored low-level nuclear waste since 2012.

Former Texas Governor and former USA Energy Secretary Rick Perry has long supported interim nuclear waste storage in the State. The current Governor of Texas, Greg Abbott, has voiced opposition to more spent fuel at the site.

A previous attempt by Private Fuel Storage for an interim storage site on Goshute tribal lands about 45 miles from Salt Lake City, Utah, was abandoned in 2012. The Goshute people sought $3 billion for the project. Local politicians and Utah residents opposed the project. The USA Bureau of Indian Affairs declined toapprove the lease agreement and the USA Bureau of Land Managementrefused a project needed to transport waste to the site.

Final environmental impact statements for the Holtec and Interim Storage Partners concepts in New Mexico and Texas are expected from the USA Nuclear Regulatory Commission (NRC) in Summer 2021. Opposition groups argue that the plans violate Federal law by possibly making the Federal Government own the nuclear waste before operation of a permanent repository.

The NRC continues to move towards providing licenses for 40 years for the Holtec and Interim Storage Partners facilities, with an opportunity to renew the licenses in 40-year increments. The NRC states that the USA Congress could change the law in the meantime to allow spent fuel to be stored in locations other than Yucca Mountain, making the proposals legal.

Fig 3. Proposal for disposal in deep horizontal directional drilling boreholes

Credit: Deep Isolation

As an alternative to tunnel and cavern repositories, a startup company, Deep Isolation, has a proposal to dispose of nuclear waste, contained in canisters, in deep directional drilling horizontal boreholes.

The corrosion-resistant canisters would be placed into carbon steel-encased boreholes and sent about a mile underground and then up to two miles horizontally (Fig 3). The horizontal section of the boreholes would be about 18in diameter and the canisters about 18ft long x 13in diameter. A 3,300ft long disposal section would hold about 150 canisters, with an array of 10 parallel disposal sections, holding a total of 1,500 pressurized water reactor assemblies, which would accommodate the waste produced by a 1,000 MWe nuclear power plant during 30 years of operation.

The horizontal section of the boreholes could extend for up to two miles in sedimentary, igneous or metamorphic host rocks. These repositories could be installed at or near commercial reactor sites or at regional repositories in different locations. The company has raised $14 million of private investment and has signed agreements with NAC International, Schlumberger and Bechtel to develop the technology.

Potential sites would be identified through a stakeholder and community engagement process. After a community has shown interest in moving forward, a sitespecific study of the geology, hydrology, geochemical and seismic activities of a potential host site would follow. Once the necessary license, permits and agreements with the community and State Governments are in place, placement of waste canisters in drilled boreholes could start within a few years.

While the borehole technology is considered a promising alternative to cavern repositories, the Deep Isolation team would need an Act of Congress to allow for alternatives to Yucca Mountain to be licensed.

By Wade Tyler Millward, USA Correspondent, TunnelTalk

References

• Waste management at Yucca Mountain – TunnelTalk, May 2002