High-volume production of Mo-99 appears feasible with low-grade uranium

A National Research Council panel has concluded that commercial volumes of molybdenum-99 can be produced cost-effectively with low-enriched uranium. Mo-99 is the precursor of technetium-99m, a radioisotope used in most nuclear imaging procedures. The finding establishes a framework for weaning manufacturers of their reliance on nuclear bomb-grade uranium for Mo-99 production.

The 13-member Committee on Medical Isotope Production without Enriched Uranium determined that conversion to low-enriched uranium (LEU) is feasible without boosting production costs by more than 10%, a goal set by Congress when it ordered the committee's formation. The report found that conversion is possible at Chalk River, ON, and Petten, the Netherlands, the two main sources of Mo-99 used in the U.S. It also suggests, however, that generating the local political will to make conversions will be challenging.

Although expressing general support for the report, SNM president Robert W. Atcher, Ph.D., criticized the effort for not addressing physician concerns about isotope production.

"We are pleased by the prudent recommendations of the report and long-term view toward the potential conversion from high-enriched uranium (HEU)," he said in a release, "However, the information used for developing the economic impact is suspect. and the need for a reliable domestic isotope supply remains critical and is not addressed by this report, and continues to put patients at risk."

Formed by a unit of the National Academy of Sciences, the committee was asked to reconcile a conflict between the Energy Policy Act of 1992, which mandated an end to the use of HEU for medical isotope production, and the Energy Policy Act of 2005, which exempted HEU exports to Canada, the Netherlands, Belgium, France, and Germany to stave off potential shortages of Mo-99.

HEU is typically drawn from U.S. or Russian strategic stockpiles of decommissioned nuclear weapons. Its transportation across international borders has raised security concerns about a possible terrorist attack or accident.

The report concludes that the technical feasibility of conversion is not in question. An all-LEU system has operated in Argentina since 2002. An Argentine-designed and -built reactor near Sydney, Australia, will probably begin producing Mo-99 with LEU fuel and targets soon, and an all-LEU reactor is under construction near Cairo in Egypt.

The committee predicted that a 10% increase in the price of Mo-99 could provide substantial resources to help existing facilities convert to LEU with negligible effect on the cost of diagnostic imaging procedures. It also reported, however, that no evidence exists that large-scale producers are moving toward LEU-based production.

"There is a good reason that current large-scale producers have not yet converted to LEU-based production; namely, there is no good business reason at present for doing so," the committee members wrote.

They described how major producers could engineer conversion, however:

• Atomic Energy Canada Ltd., the semipublic corporation that oversees Canadian isotope production, was urged to remodel the now-shut down Maple 1 and Maple reactors at Chalk River. The committee reasoned that reconstruction – including even new reactor cores for the two troubled facilities -- can be finished by 2016, the new extended termination date for the National Research Universal Reactor at Chalk River that now serves as North America's main source of Mo-99.
• The Nuclear Research and Consultancy Group in the Netherlands was advised how to convert to LEU-based production at its High Flux Reactor in Petten in five years without waiting another two years for the completion of its planned replacement reactor at Pallas, the Netherlands.
• Operators of the Belgium Reactor 2 and the Osiris research reactors at Saclay Centre near Paris were informed that they could convert to LEU by adopting the same Mo-99 target designed under development for the HFR reactor and its Pallas replacement.

In South Africa, the committee found that NTP Radioisotopes will convert to LEU fuel for its reactor but does not plan to covert to LEU target for Mo-99 production. It learned little else about the company's intentions because the firm refused to participate in the study.

The committee identified four potential suppliers that are developing LEU-based systems to produce Mo-99 in the U.S. Missouri University Research Reactor intends to meet half of the domestic need for Mo-99. Other potential players include the Australian Nuclear Science and Technology Organization, the Argentine national commission of atomic energy, and nuclear reactor builder Babcock and Wilcox of Lynchburg, VA.

The FDA was urged to streamline regulator approvals of radiopharmaceuticals made with LEU-based Mo-99.

Congress was advised to encourage subsidies for the design and development of domestic production capabilities and to tighten regulations against the use of HEU-based pharmaceuticals and HEU export.

The report noted that opportunities may exist for the U.S. State Department to exert diplomatic pressure encouraging countries to convert.

"That would be the logical next step," said committee member Dr. Steve Larson, nuclear medicine director at Memorial Sloan Kettering Institute. "The committee saw no technical or economic reason that the conversion to LEU should not take place. I hope the companies simply get on with it."

For more information from the Diagnostic Imaging and Search Medica archives:

Isotope supply crash drives push for new moly sourcesNuclear medicine braces for effects of Petten reactor shutdownCanadian agency pulls plug on molybdenum reactorsSNM panel finds no easy path to expand molybdenum-99 supplies