Natural Resources Minister Greg Rickford said Friday that the National Research Universal reactor will remain in operation until 2018.
Rickford said the extension of the NRU is designed to help support global medical isotope demand between 2016 and 2018 should shortages occur.
He said Canadian Nuclear Laboratories will begin decommissioning the NRU after March 31, 2018. Routine production of molybdenum-99 from the NRU was to have ceased in 2016.
Molybdenum-99 isotopes are used to obtain technetium isotopes, which are needed for a wide range of medical tests including diagnosing potentially fatal blood clots in the lung.
Unexpected shutdowns of the reactor — which has been in operation since 1957 — have resulted in significant costs to taxpayers, including a $114 million investment in 2009 to return it to service.