The U.S. Nuclear Regulatory Commission (NRC) approved an updated “waste confidence” rule in mid-September that reflects the agency’s confidence that spent nuclear fuel (SNF) can be safely stored for at least 60 years beyond the closing date of any U.S. nuclear plant. Approval of this rule was required before the NRC can license any new reactors that will be required to store SNF on site indefinitely.

The NRC has been attempting to update its outdated waste confidence rule for several months but was sidetracked when the Obama administration decided to defund the Yucca Mountain nuclear waste repository that had been under development for more than two decades. For background on that decision and the implications for the nuclear power industry in the coming years, see “The U.S. Spent Nuclear Fuel Policy: Road to Nowhere,” May 2010 (available from our online archives at

The NRC’s revised waste confidence rule regarding dry cask storage is unambiguous: “if necessary, spent fuel generated in any reactor can be stored safely and without significant environmental impacts for at least 60 years beyond the licensed life for operation (which may include the term of a revised or renewed license) of that reactor in a combination of storage in its spent fuel storage basin and at either onsite or offsite independent spent fuel storage installations.”

The NRC memo continues with an optimistic comment on permanent storage of SNF: “Further, the commission believes there is reasonable assurance that sufficient mined geologic repository capacity will be available to dispose of the commercial high-level radioactive waste and spent fuel generated in any reactor when necessary.” The previous rule said the commission was confident that Yucca—or some other repository—would be open within 50 to 60 years of the time that any U.S. reactor closes (Figure 1).

1. Lifetime storage. Under new NRC guidelines, casks storing spent nuclear fuel at the Diablo Canyon Nuclear Power Plant, shown here, and other nuclear plants can be used for 60 years, and perhaps up to 120 years after the reactors are decommissioned. Source: NRC

In addition, the NRC directed its staff to conduct an in-depth review of existing SNF storage and shipping policies and to draft new rules that would allow onsite storage for more than 120 years. That directive has deep political overtones given that the NRC is expected to vote to support the DOE’s decision to withdraw the Yucca Mountain permit application. In June, a panel of NRC judges ruled that the DOE has no authority to withdraw the Yucca Mountain license application and the NRC has since asked the DOE to overrule the judge’s decision. Under the Nuclear Waste Policy Act, Yucca Mountain is designated as the nation’s SNF long-term repository, and the act requires the DOE to pursue licensing the facility. The highly anticipated decision is expected before year-end.

—Edited by Dr. Robert Peltier, PE