Government Regulation of Radiation & Exposure

May 27th, 2015 | By Mirion Technologies

Given the risks and the public concerns involved, there are many government agencies and regulations dealing with radioactive materials and exposures. Governing everything from production of medical isotopes to monitoring for the transportation of terrorist material, these agencies help keep the danger to the public from radiation as low as possible.

*NRC Resident Inspectors perform Inspections at the Nuclear Power Plants by Nuclear Regulatory Commission, used under CC BY 2.0*

DIFFERENT AGENCIES AND WHAT THEY REGULATE

(NRC, DHS, FTA, ETC)

In the US, there are many agencies at work. For the nuclear power industry, the primary regulatory agency is the NRC, or Nuclear Regulatory Commission. They monitor existing plants and their emissions, they provide licensing for new plants, and oversee the handling and disposal of nuclear waste material. One of the key aspects of what the NRC does is dictate the limits of exposure to the public, along with other guidelines and limitations on the nuclear industry to ensure that safety standards are met.

*The United States Nuclear Regulatory Commissiion (NRC) is tasked with monitoring and regulating US nuclear power plants*

Other agencies involved include the Department of Homeland Security, which coordinates with various state agencies and organizations to provide radiation security for facilities and events. The Federal Transit Administration also is involved, dictating the means by which radioactive material may be shipped and how it must be labeled and placarded.

OCCUPATIONAL VS NON OCCUPATIONAL LIMITS

For the nuclear industry, the NRC, among other things, dictates exposure limits to both workers dealing with radioactive material, called the occupationally exposed, and the general public, or non-occupationally exposed. For an occupationally exposed worker, such as someone at a nuclear power plant or in nuclear medicine at a hospital (if they’re licensed by the NRC), the limit is 5 rem a year. Surprisingly, while most nuclear power workers never receive anywhere close to that amount, some workers in the medical field, such as those working with X-ray fluoroscopy machines, are amongst the highest occupationally exposed workers. Pregnant women who are occupationally exposed may choose to (but are not required to) declare their pregnancy and receive lower dose limits throughout the term of the pregnancy.

For members of the public, the annual limit from the NRC (which is matched by the EPA for areas not covered by NRC guidelines) is 100 mrem. Licensed facilities have to have programs in place to limit exposure, and be able to demonstrate that procedures are in place that members of the public would not be exceeding those levels.

HAZMAT TEAMS & OTHER AGENCIES THAT PERFORM LOCAL SURVEYS

Some states and municipalities have departments that are equipped to deal with radioactive material. Either as part of a local fire department, a stand-alone hazmat team, or a larger state emergency management agency, these groups are equipped to perform radiological surveys of areas suspected of having radioactive contamination, be it from an automobile accident involving shipment of sources, to a suspected terrorist incident.

*A Hazmat team performs a survey of a train car for traces of radioactive contamination*

It’s generally recommended to contact one of these agencies if there’s a suspected issue with radioactive contamination or exposure. Given the complexity of attaining and interpreting the data, and the necessity of following procedures to ensure accuracy, it’s better to contact these groups who have the equipment and training before attempting, as an individual, to purchase and use detection equipment in such a case.

System Selection Guide

Mirion offers guidance with selections to meet your needs, based on application, software and hardware.

Spectrum Analysis

Radioactive decay occurs randomly in time, so the measurement of the number of events detected in a given time period is never exact, but represents an average value with some uncertainty. Better average values can be obtained by acquiring data over longer time periods.

Neutron Detection and Counting

Neutrons have mass but no electrical charge. Because of this they cannot directly produce ionization in a detector, and therefore cannot be directly detected. This means that neutron detectors must rely upon a conversion process where an incident neutron interacts with a nucleus to produce a secondary charged particle. These charged particles are then directly detected and from them the presence of neutrons is deduced.

Gamma and X-Ray Detection

The choice of a particular detector type for an application depends upon the X-ray or gamma energy range of interest and the application’s resolution and efficiency requirements.