Of Great Service tells the story of the National Research Universal (NRU) reactor in Chalk River, Ontario and its historical role as one of Canada’s most important scientific and research facilities. One of the largest research reactors in the world, NRU was a landmark achievement in Canadian nuclear science and technology went it went into service on November 3, 1957 on the banks of the Ottawa River in Deep River, Ontario. For over 60 years, the reactor served Canadians as a supplier of industrial and medical radioisotopes used for the diagnosis and treatment of life-threatening diseases, as a major Canadian facility for neutron physics research, and to provide engineering research and development support for Canada’s fleet of nuclear power reactors. The documentary contains the stories, thoughts and memories of both past and present staff, and is an emotional story of the impact it has had on those who worked within it.