WHAT ARE THE ANNUAL RADIATION EXPOSURE LIMITS?
Annual Radiation Exposure Limits:
- Whole body, blood forming organs, gonads: 5,000mrem/year
- Lens of eye: 15,000 mrem/year
- Extremities and skin: 50,000 mrem/year
- Fetal: 500 mrem/gestation period
- General Public: 100 mrem/year
Based on USNRC Regulations, Title 10, Part 20, Code of Federal Regulations and adopted by many states. Certain states and other regulatory agencies may adhere to different limits.
WHAT IS ALARA?
ALARA is an acronym for "as low as is reasonably achievable." Used and defined by the NRC (Nuclear Regulatory Commission) and many other licensing agencies, an ALARA program’s objective is to reduce occupational exposures and doses to members of the public as far below the specified limits as is reasonably achievable by means of good radiation safety planning and practice.
The rules and regulations of the NRC require each licensee to “develop, document, and implement a radiation protection program…” And, each licensee “shall use, to the extent practical, procedures and engineering controls based upon sound radiation protection principles to achieve occupational doses and doses to members of the public that are as low as is reasonably achievable (ALARA).” (Code of Federal Regulations, Title 10, Chapter 20.1101, “Radiation Protection Programs.”)
In Title 10, Chapter 20.1003, “Definitions,” the NRC’s definition is:
“ALARA (acronym for "as low as is reasonably achievable") means making every reasonable effort to maintain exposures to radiation as far below the dose limits in this part as is practical consistent with the purpose for which the licensed activity is undertaken, taking into account the state of technology, the economics of improvements in relation to state of technology, the economics of improvements in relation to benefits to the public health and safety, and other societal and socioeconomic considerations, and in relation to utilization of nuclear energy and licensed materials in the public interest.“
WHAT IS ANSI/HPS N13.11?
ANSI/HPS N13.11 is the National Voluntary Laboratory Accreditation Program’s (NVLAP) proficiency testing standard for personnel dosimetry performance. The first version of the standard was written in 1983 through a joint-agency agreement between the U.S. Nuclear Regulatory Commission (NRC) and the National Institute of Standards and Technology (NIST), an agency of the U.S. Department of Commerce. The 1983 version established the accreditation criteria and processes to facilitate the NRC’s requirement that all dosimeters used by licensees must be processed and evaluated by an accredited laboratory (later codified in the U.S. Code of Federal Regulations as 10 CFR 20.1501). The standard served as the foundation for NVLAP’s Ionizing Radiation Dosimetry proficiency-testing program and was later modified by the Department of Energy for DOELAP.
ANSI/HPS N13.11 recently underwent some significant changes. The 2001 and 2009 revised standards are a result of the continuing effort by the Health Physics Society (HPS) and the American National Standard Institute (ANSI) to construct a standard that is acceptable to both the National Voluntary Laboratory Accreditation Program (NVLAP) and the Department of Energy Laboratory Accreditation Program (DOELAP).
A copy of ANSI/HPS N13.11-2009 is available for a fee from the Health Physics Society at hps.org.
Further information about NIST’s NVLAP program can be found at their website nist.gov.