15A NCAC 11 .1604
Occupational Dose Limits for Adults:

What regulations are applicable?

Does the agency require establishment of Investigational (or ALARA) limits?

The agency requires that all licensees be familiar with the dose limits for occupationally exposed individuals.  This ensures that the licensee is aware of the limits and can apply the appropriate ALARA considerations.  Applicants for a radioactive materials or accelerator license need to provide this information in their application packages.

What regulations are applicable?

The licensee or applicant should consider the following regulations concerning occupational dose:

Not all of the above regulations will be applicable for all licensees.  This listing is provided to give applicants/licensees and example of the number of regulations which deal with occupational dose.  Simply put, approximately ¼ of the rules in Section .1600 deal with dose limits, recordkeeping and reporting doses in excess of the limits.  The applicant/licensee should review each of the above referenced regulations and determine which ones apply to your particular program.  Then each should be addressed in turn in the license application.

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Does the agency require establishment of Investigational (or ALARA) limits?

Whereas there is no specific regulation which requires the establishment of Investigational (ALARA) limits, the agency has always considered this to be a good health physics practice.  The establishment of   investigational limits demonstrates that the licensee will be routinely evaluating the exposure records of its employees and will have a set protocol/procedure to follow if an investigational limit is exceeded.

When defining the investigational dose limits, the licensee needs to define at least two (2) levels and derive a policy/procedure for use when either one is exceeded.  Remember that separate investigational levels for internal exposures need to be established based upon the Annual Limit of Intake (ALI).   The ALI's for all radionuclides may be found in Appendix B to 10 CFR Part 20.   The policy/procedure may include a simple letter to the employee stating that they have exceeded "Level I" and they should be aware of their current practices or an investigation procedure when an employee has exceeded "Level II." 

Investigational limits should always be reasonable and commensurate with the scope and extent of licensed activities.  The same "levels" for users of devices containing small amounts of radioactive materials and licensees who handle large amounts of unsealed materials should not be the same.   Many licensees  establish ALARA or Investigational Limits based on a percentage of the dose limits prescribed in 15A NCAC 11 .1604, .1610 or as a percentage of the ALI listed in Appendix B, 10 CFR Part 20.

The action(s) which will be taken if an employee exceeds these investigational limits should be clearly outlined within the policy statement.  Such actions include written notification by the RSO, review of job duties/responsibilities, investigations, etc.

The first step in this goal is for the appropriate staff (usually the RSO) to review and understand the monitoring report which the vendor supplies to the licensee.  Many vendors include an "investigational limit" in their reports.  The licensee must be familiar with the vendor's program and system to take full advantage of this service.