United States Nuclear Regulatory Commission - Protecting People and the Environment

Guidance for Posting Radiation Areas

HPPOS-066 PDR-9111210252

See IE Information Notice No. 84-82 entitled as above and dated November 19, 1984. Posting only the entrance to a large room or building is inappropriate if most of the area is not a radiation area and only discrete areas are radiation areas. If discrete areas can reasonably be posted, they should be.

The health physics position was written in the context of 10 CFR 20.203, but it also applies to "new" 10 CFR 20.1902. A "radiation area" is defined in 10 CFR 20.202 (b) (2) as any area, accessible to personnel, in which radiation, originating in whole or in part within licensed material, exists at such levels that a major portion of the body could receive a dose greater than 5 millirem in 1 hour or greater than 100 millirem in 5 consecutive days. [Note: 10 CFR 20.1003 defines a radiation area as "an area, accessible to individuals, in which radiation levels could result in an individual receiving a dose equivalent in excess of 5 millirem (0.05 mSv) in 1 hour at 30 centimeters from the radiation source or from any surface that radiation penetrates."] The provisions of 10 CFR 20.203 (b) [or 10 CFR 20.1902 (a]) require that each radiation area be conspicuously posted with a sign or signs bearing the radiation caution symbol and the words: "CAUTION, RADIATION AREA."

Some power reactor licensees do not adequately post radiation areas in large buildings such as auxiliary buildings or reactor buildings. It has been argued that posting only the entrances to buildings and large areas meets the literal requirements for posting radiation areas in 10 CFR 203 (b) [or 10 CFR 20.1902 (a)].

However, in many cases this posting may fail to properly inform workers of radiological hazards in their work areas. In response to past requests for guidance from nuclear power reactor licensees concerning proper implementation of the posting requirements for radiation areas, the following NRC staff position was developed and transmitted to several power plant licensees.

The intent of 10 CFR 20.203 (b) [or 10 CFR 20.1902 (a)] is to alert personnel to the presence of radiation and to aid them in minimizing exposures. The circumstances of each situation must be evaluated to ensure that posting practices do not detract from this intent by 1) desensitizing personnel through overposting or (2) failing to sufficiently alert personnel to the presence and location of radiation areas.

Radiation area posting should warn individuals of specific radiological conditions in their immediate vicinity. It is counterproductive to post substantial areas which are not radiation areas. Since the regulations do not provide implementing details, such as whether a room or building containing a radiation area must be posted only at the entrance, or whether every discrete radiation area must be posted, the following should be used as guidance.

  1. Posting only the entrances to a very large room or building is inappropriate if most of the area is not a radiation area and only discrete areas or individual rooms (cubicles) actually meet the criteria for a radiation area.
  2. If discrete areas or rooms within a large area or building can be reasonably posted to alert individuals to radiation areas, these discrete areas or rooms should be posted individually.
  3. Items (1) and (2) above are not mutually exclusive.

Where much of a large area falls within the definition of a radiation area, but where smaller, discrete areas within that radiation area have radiation levels that are substantially above the general area levels, it may be appropriate and more informative to the workers to:

  1. Post, as a radiation area, the entrances to the very large room or building.
  2. Define (and alert workers to) discrete, smaller areas or rooms (within the larger, posted area) in which the radiation exposure rates are substantially higher than the predominant exposure rates of the larger, posted area.

Good posting programs focus on making the workers aware of their radiological environment so that the workers can minimize their exposure. By using an appropriate combination of posting and periodic worker awareness training, licensees can aid workers in minimizing their exposures.

Regulatory references: 10 CFR 20.203, 10 CFR 20.1902

Subject codes: 4.2, 4.7

Applicability: Reactors

Page Last Reviewed/Updated Monday, June 08, 2015