Molybdenum bottleneck resurfacesafter Canadian reactor shuts down

Backup plan kicks in to ensure supply

The nuclear medicine community in April received another reminderof the precarious nature of its supply of molybdenum-99, the rawmaterial for technetium-99m. The Canadian reactor that is themain source for the radioisotope was forced to shut down temporarilyon April 11, when a fuel rod became stuck.

The incident highlighted the fact that despite several yearsof attention to the problem, much of the world still relies ona single nuclear reactor for its supply of molybdenum-99. Thatreactor, at Chalk River Laboratories in Ontario, is operated byAtomic Energy of Canada, Ltd. (AECL), a Canadian government agency.It sells molybdenum-99 to Nordion International of Kanata, Ontario,which in turn distributes it to radiopharmaceutical supplierswho use it to develop technetium generator kits.

The Chalk River reactor was shut down for four days while thefuel rod problem was corrected, according to Ian Mumford, vicepresident of public affairs for Nordion. While it worked to bringthe reactor back on line, Nordion set in motion a backup plandesigned to prevent delays in deliveries of molybdenum-99. Thatplan relied on a nuclear reactor operated by IRE of Belgium tosupply Nordion's European customers while North American shipmentswere filled with molybdenum stock still on hand, Mumford said.

"The silver lining was that there was never any interruptionin supply to customers," Mumford said. "The backup planwas put into place and was acted on. That was encouraging forus."

Nuclear medicine physicians can be excused for feeling jittery,however. The April incident was not the first time the supplyof molybdenum has been imperiled. A labor dispute at Chalk Riverin 1992 also threatened molybdenum production before it was resolvedat the last minute (SCAN 8/12/92).

Efforts to develop a backup supply for molybdenum by buildinga new reactor have proceeded slowly. AECL was building a backupreactor to the Chalk River facility but stopped work on the projectdue to a contract dispute with Nordion (SCAN 11/17/93). The twosides are close to negotiating a settlement that will allow workon the reactor to resume, according to Mumford.

The U.S. Department of Energy is also hoping to create a domesticsupply of molybdenum-99 by dedicating a reactor at Sandia NationalLaboratories in Albuquerque, NM, to production of the radioisotope(SCAN 7/13/94).

The DOE is in the process of completing an environmental assessmentthat is required before the reactor can be converted to producingmolybdenum, according to Owen Lowe, head of the DOE's IsotopeProduction and Distribution Program. The DOE is examining publiccomment on the assessment to determine whether an environmentalimpact statement is required. Even if a statement is necessary,Lowe does not expect it to delay the conversion to moly production.

"We are projecting that we are on schedule for producingmolybdenum-99 in 1996," he said.

There are other potential sources of molybdenum that are rampingup their efforts, according to Carl Seidel, associate directorof technical affairs for Du Pont Radiopharmaceuticals. Seidelis also chairman of the Council on Radionuclides and Radiopharmaceuticals(CORAR), an industry group that deals with radioisotope supplyissues.

The Belgian IRE reactor is increasing its capacity to producemolybdenum, as is a Dutch reactor operated by Mallinckrodt Medical,according to Seidel.

"The short-term situation is still somewhat precariousbecause one reactor is still the major supplier," Seidelsaid. "In the next two years an adequate backup supply willbe available."