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Nuclear chemist says he is shocked at lack of a plan to deal with shortages caused by repeated reactor closings
There is more than one way to produce medical isotopes and the Canadian government should be exploring options that are safer and more reliable than nuclear reactors, one of Canada’s top nuclear chemists argues today in an essay in the journal Nature.
“Shockingly, there are no clear plans in place” for dealing with repeated closings of the aging reactors, including one in Canada, that create the essential radioactive material, writes Tom Ruth, who heads the positron emission tomography program at TRIUMF, Canada’s national laboratory for particle and nuclear physics.
But emerging research suggests it is possible to build accelerators that can produce the isotopes, Dr. Ruth says in his essay.
Accelerators cannot produce as much of the isotopes as nuclear reactors – one accelerator could supply just 5 per cent of world demand – “but this is outweighed by the advantage of using safer materials,” writes Dr. Ruth.
The isotopes – used in a wide variety of procedures from cancer diagnosis to heart monitoring – come from the decay of a chemical called molybdenum-99.
Nuclear reactors create the material by bombarding highly enriched uranium – the same sort of uranium that is used in nuclear weapons – with neutrons. Accelerators can achieve the same results by firing photons at a much safer type of uranium, writes Dr. Ruth.
TRIUMF, he says, recently held a workshop that concluded that the accelerators “could be built and routinely operated, and that several research projects should be initiated to verify that.”
Lisa Raitt, the federal Natural Resources Minister, said yesterday that she asked for an internal review of the research that the government has funded in the past year, including TRIUMF’s work looking at alternative methods to conventional medical-isotope production.
“Clearly, there is no quick or easy solution to guaranteeing the long-term global supply of medical isotopes,” Ms. Raitt said. “Our government is continuing to examine all potential options, as are other private- and public-sector parties with an interest in medical-isotope production.”
Dr. Ruth’s proposal comes after shutdowns at the aging Canadian nuclear reactor responsible for much of the world’s supply of medical isotopes have caused severe shortages, leading to delays in diagnosis and treatment.
This week it was revealed that the same 51-year-old reactor at Chalk River, Ont., suffered a contained leak of radioactive material in December and, according to published reports, may have been leaking water with low levels of radiation from a crack in a weld.
Despite the dangers posed by the facility, it is also critical to the health of many Canadians.
The Chalk River reactor and another unit in Petten, the Netherlands, which is currently out of service, produce 85 per cent of the world’s medical isotopes. The material cannot be stockpiled because it quickly loses its effectiveness.
If the Canadian government gave the green light to build an accelerator that could produce the isotopes, it would take about three years to build and would cost between $50-million (U.S.) and $125-million, writes Dr. Ruth. The average reactor costs between $500-million and $1-billion.
“The well-being of the citizens of the world requires significant involvement of both the private sector and governments at all levels,” he said. “Action is required before it is too late.”
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