Dose Rate Survey
A dose rate survey should be performed anywhere workers are exposed to radiation levels that might result in radiation doses more than 10% of the occupational dose limits or where an individual is working in a dose rate of 2.5 mrem/hr or greater.
If exposure from radioactive material is a concern, dose rate surveys shall also ensure that the total effective dose equivalent to an individual member of the public is not able to exceed 100 mrem in a year and that the dose in any unrestricted area does not exceed 2 mrem in any one hour.
Work with ORS if you believe that your lab may be required to perform these types of surveys and you have questions.
Contamination surveys are required to be performed in sufficient areas to identify areas of radioactive contamination which may result in dose to workers or members of the public. Contamination surveys must seek to identify both fixed and removable contamination using appropriate detection equipment.
Contamination surveys should be performed:
- To evaluate the presence of radioactive material on unwanted surfaces including, but not limited to floors, laboratory furniture, and equipment;
- After a spill or contamination event;
- Post radioactive material use;
- After a change in the procedure or processes on which the radioactive material protocol is based;
- In unrestricted/public areas, in areas adjacent to restricted areas, and in all areas through which licensed materials are transferred or temporarily stored.
Below are the action levels for contamination surveys:
|Action Levels for Removable Surface Contamination
|Type of Emissions
|Betas & Gammas
|Radiation Use Area
|Non Radiation Use Area/ Unrestricted Area/ Public Area
|Action Levels for Portable Survey Meter Results
|Indistinguishable from background(1)
|3x background at 1cm(2)
- Exceeding action levels for personal contamination during a meter survey requires immediate action consistent with section F in the ORS Emergency Procedures.
- Exceeding action levels for surfaces during a meter survey requires prompt wipe tests to evaluate levels of removable contamination.
The frequency of surveys is not the same for all labs. Contact the health physicist assigned to your respective lab to get more specific guidance on minimum survey frequencies for your area(s).
A post-use surveys shall be performed at the end of each day, or after work with radioactive material has ceased for that day. Post-use surveys for unsealed alpha use labs shall be documented.
The frequency of routine contamination surveys shall be no less frequent than monthly. Certain permits that are considered to have an “elevated” risk may also be required to have a more frequent contamination survey requirement, (weekly, daily). A monthly survey requirement, as the name implies, are required for every room approved for unsealed radioactive material every calendar month in which unsealed radioactive material was used or stored in that room. Its recommended to schedule those at the start of each month to enable float should a delay occur. There should be a total of 12 surveys performed per calendar year at a minimum, with one occurring and dated for each month of the year.
No Possession Statement
The routine periodic contamination survey need not be performed if radioactive material has not been possessed and/or stored (e.g., no radioactive samples, no stock vials, no waste) in a laboratory since that laboratory was last surveyed. If radioactive material has not been possessed within the room(s) since the last routine periodic survey a “No Possession Statement” may be marked on the survey map with name and date of individual performing the evaluation. This is an optional selection on all survey diagrams/room maps provided by ORS.