There is an underground repository for highly radioactive waste in the United States that few people are aware of. It’s important, because it’s an example of how we can handle highly radioactive spent fuel from nuclear power plants, including the dozen or so decommissioned nuclear plants like Maine Yankee, and finally resolve the controversy over nuclear waste.

Completed in 1999, the Waste Isolation Pilot Plant – known as WIPP – is our nation’s permanent disposal facility for waste with small quantities of long-lived radioactive materials that must be isolated from the human environment for tens of thousands of years. It is a labyrinth of tunnels and chambers situated in a bed of salt beneath the desert in southeastern New Mexico.

The facility has an excellent safety record. It’s proving that we can place radioactive materials in deep geological formations for permanent disposal. But that experience is not being recognized by Congress, which is failing to provide adequate funding for the planned repository at Yucca Mountain in Nevada. WIPP shows it can be done successfully.

What’s being disposed of at WIPP are the remnants of nuclear weapons production from the past half-century. These are materials that have small but highly toxic amounts of plutonium and similar materials – called transuranic wastes – that were generated and stored at nuclear weapons plants and national laboratories across the country, ranging from the Savannah River site in South Carolina to the Hanford Reservation in Washington state.

The Department of Energy oversees the operation of WIPP, and it’s understandably proud of its record. So far, there have been more than 5,000 truck shipments on interstate highways – 20 to 25 shipments a week – carrying containers of transuranic waste to WIPP. Altogether, the trucks have traveled more than 9 million miles – without a single release of radiation.

To date, 81,000 containers have been placed in the underground repository. When the shipments are completed – and that’s scheduled to happen in 2034 – the Energy Department will seal the repository.

Congress is now considering legislation that would begin to provide predictable funding for the Yucca Mountain project and address some of the snags that have delayed its development. The measure would also authorize construction of an interim storage facility for spent fuel at the Yucca Mountain site until the repository opens. Congress needs to take action now, because holding ponds for spent fuel at nuclear power plant sites are running out of storage capacity. Shifting the spent fuel to Yucca Mountain for long-term storage will enhance security and reduce the cost to electricity users of storing the spent fuel at nuclear plant sites.

Opponents of nuclear power claim that transporting spent fuel to Yucca Mountain is dangerous. But the experience with truck shipments to WIPP shows that canisters holding radioactive materials can be shipped long distances without harm to the public.

Recently, a National Academy of Sciences panel confirmed that shipping spent fuel by truck and rail to Yucca Mountain would be safe. In fact, over the past three decades, there have been more than 3,000 shipments of spent-nuclear fuel without a single radioactive episode.

Certainly it would be better to get rid of the more than 540 metric tons of spent fuel now in temporary storage at the Maine Yankee site. As pressure grows for cleaner energy, more nuclear power capacity will be needed in New England and elsewhere in the country. We are running out of affordable natural gas, and we need to turn to alternative sources that do not release global-warming gases. That means more nuclear power.

On pragmatic grounds, and because electricity users have already paid more than $24 billion for construction of the Yucca Mountain repository and deserve to see some results, the wise course is for Congress to end the years of indecision on the waste issue and pass the legislation that will lead to the completion of the repository.

Donald A. Grant, Ph.D., is R.C. Hill Professor and chair of the Mechanical Engineering Department at the University of Maine.