This board in the health-safety operations office was updated by health-physicists with data from daily ionization dosimeters and other monitoring instruments to ensure that no one exceeded the legally permissible radiation exposure limits. Strict limits were imposed on the amount of radiation that employees could be exposed to over time. These limits were far below the levels that were considered to cause health risks. All personnel assigned to Plum Brook Reactor Facility were monitored for radiation exposure on a continuing basis by utilizing film badge dosimetry. The frequency of the individual readouts varied from monthly to quarterly depending on the job assignment. Since there was an inherent delay in this technology, it became necessary to have current daily estimates of exposure for personnel who routinely entered radiation areas. Lifetime exposure levels were also closely monitored through regular bioassay samples.
The Mock-Up Reactor (MUR) was a 100-kilowatt reactor installed in the reactor building to test experiments at low power before inserting them into the more powerful sixty-megawatt reactor. This allowed operators to determine the best location for the experiments and it also helped them understand the effects each loading scheme had on the neutron flux. Though much smaller and less powerful than the main Plum Brook reactor, the MUR required its own annual AEC/NRC license, and today has its own separate decommissioning plan.
For almost thirty years, the facility remained sealed and constantly monitored to ensure that no contamination escaped. However, aesthetic maintenance was not important, as shown by the peeling paint on the once shiny reactor dome.