Members of the public can be exposed to minute amounts of radioactive material from emissions from NFS process air stacks and from effluents that are discharged into the Nolichucky River after processing in NFS' treatment facility.

Airborne Pathway - To make the most accurate possible estimates of potential exposure to a member of the public, NFS safety professionals use data for wind speed and direction, in combination with data continuously collected from the air stacks, to estimate maximum dose that a person that is off-site could receive. This theoretical person is called the “maximally exposed individual,” or MEI. The location of the MEI varies depending on wind direction and the relative contributions from the various air stacks. In reality, there is no real person that can receive the exposure attributed to the MEI in a given year, but it is a conservative and regulator-accepted way to demonstrate that dose to the public is being maintained below the applicable limit.

The following chart provides recent data on dose to the MEI from the airborne pathway:

Waterborne Pathway - To make the most accurate possible estimates of potential exposure to a member of the public NFS safety professionals use data for flow in the Nolichucky River, in combination with data collected for all liquids discharged to the river, to estimate maximum dose that a person that is off-site could receive. This theoretical person is called the “maximally exposed individual,” or MEI. The MEI for the waterborne pathway is a person that drinks water directly from the river at the nearest drinking water intake point. This MEI is a conservative and regulator-accepted way to demonstrate that dose to the public is being maintained below the applicable limit.

The following chart provides recent data on dose to the MEI from the waterborne pathway:

The materials NFS works with emit a low-level of penetrating radiation, some of which makes it to the facility fence line. Unlike the air and water pathways (see above) exposure to a member of the public from this direct radiation can only come from spending time near NFS’ fences. In order to monitor and assure control over this source of radiation, NFS places monitoring devices on the fence in multiple locations surrounding the site. The highest value from these devices is used to derive a potential exposure to a person that is literally occupying a position at the fence line (which NFS controls and does not allow a person to occupy for any extended period of time for security reasons). Data from the highest monitoring location varies, but typically provides an estimated exposure potential of less than 5 mrem for a given year. It is expected that, with the completion of an on-going project to add new security fences around the NFS facility over the next couple of years, this already low exposure potential will become even lower. NFS’ monitoring method is a conservative and regulator-accepted way to demonstrate that dose potential to the public is being maintained below the applicable limit.

NFS complies with both State of Tennessee and Federal regulatory dose limits. The State limit is 100 mrem for a year. The Federal limit is also 100 mrem for a year, except for radioactivity from sources that are involved in commercial nuclear fuel manufacture, for which a limit of 25 mrem in a year applies. NFS BLEU Prep Facility and BLEU Complex are involved in the production of materials used in commercial power reactors, and are therefore subject to the lower 25 mrem limit.

In addition to the direct effluent measurements already discussed, NFS samples air, water, vegetation, soil and river/creek sediments, looking for traces of radioactivity that might indicate the presence of radioactivity from NFS sources.

NFS Scientists Taking Samples
Water
Air
Soil
Sediments/Silt
Vegetation