Task Force recommends dramatic technology shift for medical isotope production

A task force assembled by TRIUMF is telling the federal government to give serious consideration to experimental photo-fission technology for the production of medical isotopes. Photo fission uses low-enriched uranium and small, relatively inexpensive accelerators as opposed to the aging NRU nuclear reactor at Chalk River which is high cost, high maintenance and requires weapons-grade, highly enriched uranium.

The task force on Alternatives for Medical-Isotope Production was struck at the request of Natural Resources Canada to assess Canada's current capabilities for producing medical isotopes, technically known as molybdenum-99 or Mo-99. The request followed the crisis in Mo-99 production stemming from last year's shutdown of the NRU, Atomic Energy of Canada Ltd's 52-year-old nuclear reactor. The NRU produces approximately half of the world's supply of Mo-99, which is sold by MDS Nordion.

The task Force was also asked to compare and contrast the accelerator and nuclear reactor technologies, develop a "realistic option" for accelerator-based production, identify next steps and examine opportunities for enhancing Canada's economic competitiveness by going the accelerator route.

TRIUMF has incorporated the development of photo fission technology in its new five-year plan, which is now complete and will be presented next March to the National Research Council (TRIUMF's main funder). It includes the development of superconducting radio frequency (SRF) technology to facilitate the development of high-power electron beams essential for the photo fission option.

"That's the big thrust of our five-year plan," says Dr Nigel Lockyer, TRIUMF's director and co- convener of the task force. "SRF will enable us to go to high current and makes photo fission more real … TRIUMF is proposing to be a test bed to prove that the solution is possible"

While photo fission-produced Mo-99 has several distinct advantages over the current nuclear reactor method, it does require massive amounts of electricity and heat build-up. SRF could offer a solution to solving this problem but more research is required, prompting the task force to recommend the formation of a steering group to oversee "a strong and focused R&D program … to validate the use of a photo-fission accelerator for production of significant quantities of high-quality Mo-99." The recommendation calls for a public-private partnership to fund the R&D program with a recommendation on the use of the technology within three to four years.

"We're proud that this is a not a solution proposed by anyone else. The photo fission approach is unique and the confluence of accelerator technology we're already working on. TRIUMF has a significant nuclear medicine program," says Lockyer.

Reaction by MDS Nordion to the task force findings is best described as cautiously optimistic. In an email response to questions from RE$EARCH MONEY, MDS says it supports "all viable efforts to improve long-term isotope supply".

"This particular method (accelerator-driven photo fission) is early in the development cycle but shows some theoretical capability," says the Kanata ON-based company. "We remain open to considering all proposals and reviewing them against our strategies to meet the needs of the nuclear medicine community, customers and patients."

MDS makes it clear, however, that it still prefers the MAPLE reactors which were terminated earlier this year, sparking a $1.6-billion lawsuit by Nordion against AECL and the government.

In the absence of MAPLE reactors to replace the NRU, photo fission based reactors offer a potentially viable alternative if the technology can be perfected. A single multi-megawatt machine could supply all of the Canadian market or 5-7% of the North American market, meaning several would have to be operated simultaneously, preferably in co-location with irradiation and processing facilities and generator plants.

Making photo fission even more attractive is the cost — between $50 million and $125 million per accelerator depending upon the technology selected. A downside of the technology is the necessity of making the production facilities narrowly focused, eliminating the additional R&D uses currently possible with the NRU.

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