Radiation Hazard Level Designations

Because of the radiation levels produced by the equipment within the Proton Treatment Facility, there exists a need to restrict access to certain areas. These areas have been designated according to radiation exposure hazard levels. Appendix II shows where each radiation hazard area is located. The following is a list of definitions, some directly from the NRC, which delineate hazard levels within the Proton Treatment Facility:

Restricted Area means an area, access to which is limited by the licensee for the purpose of protecting individuals against undue risks from exposure to radiation and radioactive materials. Restricted area does not include areas used as residential quarters, but separate rooms in a residential building may be set apart as a restricted area.

Controlled Area means an area, outside a restricted area but inside the site boundary, access to which can be limited by the licensee for any reason.

Unrestricted Area means an area, access to which is neither limited nor controlled by the licensee.

Interlocked Area means an area which has been equipped with safety devices to prevent entry by any individual when the source of radiation within is producing, or has the potential to produce, a high radiation area.

High Radiation Area means an area, accessible to individuals, in which radiation levels could result in an individual receiving a dose equivalent in excess of 0.1 rem in 1 hour at 30 centimeters from the radiation source or from any surface that the radiation penetrates.

Radiation Area means an area, accessible to individuals, in which radiation levels could result in an individual receiving a dose equivalent in excess of 0.005 rem in 1 hour at 30 centimeters from the radiation source or from any surface that the radiation penetrates.

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