The United States should plan to store spent nuclear fuel in cooling pools and concrete-and-steel casks for 100 years as it sorts out what should be done with it in the long term, according to a new study from MIT. Storing spent fuel temporarily, the study argues, is in some ways better than immediately transferring it into permanent underground storage at facilities like the proposed one at Yucca Mountain.
The report comes in the aftermath of the Fukushima nuclear-power-plant disaster in Japan, where stored fuel was a major source of radioactive material that escaped into the surrounding area. And it comes at a time when many are again worried about the vast amounts of nuclear waste piling up at power plants around the country.
When most nuclear plants were built in the United States, the plan was to reprocess the fuel, retrieving material that could be used to generate more electricity. As a result, plant designers included only enough storage space to deal with about a 10 years’ worth of fuel. When, for multiple reasons, the idea of reprocessing was abandoned, the federal government took on the obligation to dispose of the fuel itself—but so far it hasn’t done so. The question of what to do with spent fuel before sending it to permanent storage “has frankly been an afterthought,” says Ernest Moniz, director of MIT’s Energy Initiative and an author of the report. After decades of operation, many power plants have run out of room and are resorting to ad hoc approaches to deal with the spent fuel.
The report argues that a systematic program of moving spent fuel first into storage pools and then into large concrete-and-steel containers called dry casks at a central storage facility will have many advantages over the current disorganized approach, and also over moving it quickly to a permanent disposal site. Spent fuel contains large amounts of material that can be extracted through reprocessing technologies and then used to generate more electricity. At this point, when uranium is cheap, the authors say, doing so doesn’t make economic sense in the United States. But as technology progresses, reprocessing could become cheaper. Fuel stored in a central location in dry casks could easily be retrieved and reprocessed. In this scenario, spent fuel would go from being waste to being a large energy resource comparable to the strategic petroleum reserve, says Andrew Kadak, a research affiliate at MIT who worked on the MIT report. Storing the fuel in dry casks for several decades would also allow it to cool down to the point that it could be safely stored in a permanent disposal facility smaller and cheaper than those currently envisioned.
The lack of a clear plan for temporary fuel storage to date has created a situation in which large amounts of radioactive material are being stored in cooling pools at nuclear reactors, and such storage facilities are potentially vulnerable to natural disasters and terrorist attacks. At Fukushima, at least one cooling pool lost water, allowing the spent fuel to overheat and release radioactive materials. This has led some experts to call for spent fuel to be moved more quickly out of cooling pools in the United States and into dry casks that do not require water to keep cool, just naturally circulating air.
Others, including Kadak, counter that there will always be a need for cooling pools, since water cooling is important for removing heat from spent fuel that has recently been removed from a reactor. It takes about five years for the spent fuel to cool down enough to be stored in dry casks. (Moving sooner would be prohibitively expensive.) Moving out the old fuel will do little to make the water-cooling storage areas safer, he says, since this fuel is already cool enough that it doesn’t need water. He says what’s needed, instead of a push to move fuel into dry casks, is backup systems that can supply cooling water reliably, even if the pools leak and there is no power for pumping in water.
The report recommends $1 billion in research funding, an amount double the current funding for nuclear power, in part to ensure that nuclear waste can be stored safely for 100 years in dry casks.