InfrastructureNext-generation nuclear fuel may be too hot to handle: report
It sounded like a good idea: Enrich the uranium used to power nuclear reactors further so that operators will be able to extract more electricity from a given amount of fuel; trouble is, burn-up rates above a certain point would violate U.S. Nuclear Regulatory Commission’s safety standards unless new methods were devised for packaging the fuel
New high-efficiency nuclear fuel meant to burn longer and stronger may prove unstable in an emergency and hard to dispose of, according experts cited in a report published Wednesday. By further enriching the uranium used to power nuclear reactors, operators have been able to extract more electricity from a given amount of fuel, a measure expressed in gigawatt-days per tonne of uranium (GWd/tU). Ramping up fuel efficiency has worked especially well in the pressurised water and boiling water reactors used in the United States and elsewhere. The objective has been to extract more power from fuel and produce less radioactive waste, one of the most vexing problems associated with nuclear energy. A new generation of nuclear plants in the United States and Britain is poised to use reactors designed for “burn-up rates” of 60 GWd/tU, according to the New Scientist, which canvassed experts. “At these rates, uranium fuel rods should burn for around a year longer than today’s best burn-up fuel,” the magazine said.
There is a problem, though: Tests conducted by Michael Billone at Argonne National Laboratory in Illinois, and presented last month at a conference in Washington, D.C., showed that burn-up rates above 45 GWd/tU would violate U.S. Nuclear Regulatory Commission’s (NRC) safety standards unless new methods were devised for packaging the fuel, the magazine reported.
A sudden loss of cooling water — as happened during the partial meltdown of a reactor core in 1979 at Three Mile Island in Pennsylvania — would pose such a danger, according to the simulations. The U.S. nuclear energy’s Electric Power Research Institute says that such a loss of coolant is not possible in modern reactors, but the NRC has still launched a three-year review of its safety standards. “We are actively preparing to revise NRC’s safety criteria to account for the burn-up effect,” a commission spokesman told New Scientist. Disposal is also a potential problem because the new, high-efficiency fuel is up to 50 percent more radioactive than fuel currently in use, thus generating far more heat during storage.
