Shutdown of the NRU Reactor
On November 18, 2007, AECL shut down the NRU reactor for what was intended to be 5 days of routine maintenance. During the shutdown, inspectors from Canada’s nuclear regulatory agency (Canadian Nuclear Safety Commission [CNSC]) discovered that AECL had been operating the reactor without upgraded emergency backup power systems for the reactor’s cooling pumps. The CNSC ordered the reactor to remain shut down until installation of these backup systems was completed.
The shutdown of the NRU caused shortages of Mo-99 in the United States and Canada, causing the cancellation of medical procedures and outcries from the medical community (see Ad Hoc Health Experts Working Group on Medical Isotopes, 2008). The Canadian Parliament passed a bill that allowed AECL to resume operation of the reactor for 120 days despite any conditions under the Nuclear Safety and Control Act relating to the installation of the emergency backup power systems.
NRU was restarted on December 16, 2007, with one of the two emergency backup systems for the cooling pumps installed; the second backup supply was installed shortly after the reactor began operating. MDS Nordion reported that it received the first batch of Mo-99 after the shutdown from AECL on December 19.
Once it became clear that NRU would have an extended shutdown (i.e., for more than a few days), Mo-99 producers in Europe and South Africa increased production of Mo-99 and took steps to distribute this isotope around the world to help offset supply disruptions (AIPES, 2007). In spite of this increased production, they were not able to replace all of the lost production.
Institut National des Radioéléments [IRE]) have agreements with multiple European reactors for target irradiation services (see Figure 3.1).
Until recently, the Canadian reactor operator Atomic Energy of Canada Limited (AECL) did not coordinate its reactor outage schedules with other reactor operators (Collier, 2008). However, after an extended shutdown in 2007 (discussed below and in Sidebar 4.1), the Canadian government announced that it was developing a new protocol for sharing information among reactor operators, isotope suppliers, and the medical establishment.
Unplanned reactor shutdowns can severely disrupt Mo-99 supplies, and these disruptions can have serious impacts on the quality of patient care. Supply disruptions can lead to the reduction of Tc-99m that is available for patient procedures. Some of these procedures can be rescheduled, but others, especially emergency procedures, cannot be postponed without potentially serious medical consequences. Such shutdowns have