Plan) or (after the Fair Hydro Plan). Blackout of 2003 During the Northeast Blackout of 2003 three Bruce B units continued running at 60% reactor power and 0% grid electrical power. They were able to do so for hours, because they had steam bypass systems designed to de-couple the reactor output from the generator electrical output. The three units were reconnected to the grid within 5 hours. Bruce A and B stations were designed to operate indefinitely while disconnected from the grid. "Contrary to popular belief, the electrical generators of nuclear plants can follow the load demands of the electrical grid provided specific engineered systems to permit this mode of operation are included in the plant design." Cobalt-60 production Cobalt-60 (60Co) can be produced in a CANDU reactor by using adjuster rods made primarily out of 59Co (instead of the normal stainless steel), which is slowly transmuted into 60Co via neutron activation (59Co + n → 60Co). These now-intensely-radioactive cobalt-60 adjuster rods are then "harvested" (removed and replaced with fresh 59Co adjuster rods) after one to three years of use in the reactor during a routine reactor shutdown, and are later processed into sealed 60Co sources of varying intensities by Nordion. The Bruce nuclear power plant has been producing 60Co since the 1980s, and almost all of the world's supply of 60Co comes from various CANDU nuclear reactors, with Bruce being the single largest supplier. , Bruce supplied over 40% of the world's 60Co. This rose to over 50% by 2016, with Pickering supplying approximately another 20% of global demand. In 2016, Bruce extended their contract with Nordion for the continued supply of 60Co to cover the entire projected post-refurbishment life of the Bruce reactors, which are expected to operate until 2064. Bruce also began producing High Specific Activity (HSA) 60Co in 2016, which is designed for highly specialized medical uses such as cancer treatment and had been primarily produced at the NRU reactor for the past 60+ years (which was originally scheduled to be shut down in 2016, but will be kept online until 31 March 2018 due to the general worldwide lack of sufficient replacement medical isotope production capacity for several critical isotopes such as molybdenum-99). As the NRU produces over two-thirds of the world's HSA 60Co, Bruce's ability to supply HSA 60Co will become critical to help fill the immense production gap left by the NRU once