A warning sign is posted at the AECL plant in Chalk River, Ont. on December 19 2007. Chalk River Laboratories, the Ontario facility that produces most of the medical isotopes used across North America, has been forced to unexpectedly interrupt its supply, triggering a temporary shortage.FRED CHARTRAND/The Canadian Press
The aging Chalk River nuclear reactor was back up and running on Saturday after an unplanned shut down which had triggered worries of a possible medical isotope shortage.
Atomic Energy of Canada Limited said repairs had to be made to the fuel rod flask – which fuels and de-fuels the reactor.
"The Fuel Rod Flask was returned to service during the evening of November 22," it said in a statement issued Saturday. "AECL has begun processing and will resume supplying molybdenum-99 to its customer, Nordion Inc., over the weekend."
Molybdenum-99 isotopes made by nuclear generators are used to obtain technetium isotopes, which are needed for a wide range of medical tests including diagnosing pulmonary embolisms — potentially fatal blood clots in the lung — or blockages in arteries that lead into the heart.
The Chalk River facility in Ontario is one of the world's largest producers of medical isotopes.
The shutdown took place at a time when two of the world's three other major producers were also out of operation, leading the president of the Canadian Association of Nuclear Medicine to issue a warning about a possible severe shortage if Chalk River remained down for a prolonged period.
The fact Chalk River is back on line should only mean a shortage for a couple of days next week, Dr. Norman Laurin said Saturday.
"Monday and Tuesday should be days that look very much like Friday, which is about 50 per cent of the normal availability, roughly and as early as, if not Wednesday, (then) Thursday we should be back to normal," Laurin said in an interview.
Production was stopped in early November at the South African Nuclear Energy Corp.'s reactor at Pelindaba, near Pretoria, after a leak was detected from the reactor.
And the Nuclear Research and Consultancy Group, which operates the Dutch production facility, announced Nov. 8 that it was shut down because of safety concerns.
It's not clear when either will be back in operation.