Medical isotope production using the 1957-built NRU reactor experienced two forced outages due to safety concerns (December 2007) and a heavy water leak (May 14, 2009). The production from the NRU reactor represents a significant fraction of the worlds medical isotope supply and the disruptions has caused a worldwide shortage. Due to maintenance requirements from the aging NRU reactor and the failure of the MAPLE 1 & 2 reactor projects, the long term production of medical isotopes at Chalk River has become uncertain. The NRU reactor at Chalk River will be decommissioned in 2018.