United States Nuclear Regulatory Commission - Protecting People and the Environment

U.S. Nuclear Regulatory Commission

Guidance for Posting Radiation Areas

HPPOS-066 PDR-9111210252

Title: Guidance for Posting Radiation Areas

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,


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:

a. Post, as a radiation area, the entrances to the

very large room or building.

b. 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


Regulatory references: 10 CFR 20.203, 10 CFR 20.1902

Subject codes: 4.2, 4.7

Applicability: Reactors

Page Last Reviewed/Updated Thursday, March 29, 2012