Scientists in Canada have discovered that intense beams of light could generate isotopes for nuclear medicine and eliminate the security risks associated with making the medicines with weapons-grade uranium at the aging nuclear reactor in Chalk River, Ont.
Creating isotopes using light beams from "photo-fission" accelerators, instead of the 51-year-old Chalk River reactor, could also help salvage Canada's reputation in the nuclear world after several mishaps, according to a national task force report released Monday. If photo-fission works, the task force said that six accelerators could supply isotopes across North America, reported the StarPhoenix.
However, creating isotopes with light beams would be costly. According to the task force, constructing a photo-fission-producing accelerator would cost approximately $50 million to $125 million depending on the technology used.
The StarPhoenix reported that the task force, comprised of 24 physicists and nuclear medicine specialists from Canada and the United States, described photo fission as a promising alternative to the two aging nuclear reactors in Canada and Petten, the Netherlands, which now generate most of the world's medical isotopes.
The Chalk River reactor produces almost half the isotopes used in the world. It also generated an international crisis a year ago when the reactor was suddenly shut down over safety concerns, resulting in the cancellation of heart and cancer tests due to the isotope shortage.
The task force also noted that photo-fission eliminates the need for highly enriched uranium, which is used in targets that are irradiated inside the Chalk River reactor to make Molybdenum-99. The scientists said it should also be possible to make Moly-99 through photo-fission by bombarding natural uranium with streams of photons generated by an accelerator.
"We're proposing that instead of inserting a neutron (as occurs in the reactor when the uranium nucleus split to form Moly-99), you insert a photon," said Nigel Lockyer, task force co-chair and director of Triumf, the national particle and nuclear physics laboratory in Vancouver.
Another advantage is that the accelerators, which would be five to 10 meters long and powered by large amounts of electricity, can be turned on and off and do not generate radioactive waste, reported the StarPhoenix.