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СКАЧАТЬ Commission (NRC), the Occupational Safety and Health Administration (OSHA), the Mine Safety and Health Administration (MSHA), and the Food and Drug Administration (FDA), issue specific regulations for those activities over which they have legal jurisdiction. The USNRC regulations are based on ICRP Publications 26 and 30 1,3, while OSHA regulations are based on ICRP Publication 2. The Department of Energy (DOE) has a mixture of ICRP recommendations that are promulgated in Title 10, Code of Federal Regulations (CFR), part 835.

      7.1 Nuclear Regulatory Commission

The NRC's task is to oversee the safe use of nuclear energy and its radioactive by‐products. The definition of by‐product materials was expanded in 2005 by amendments to the original Atomic Energy Act of 1954. To this end, it regulates the production, possession, and use of the following:

       Source materials. Uranium and thorium, and their ores containing at least 0.05% U or Th.

       Special nuclear material (SNM). Plutonium, 233U, and uranium enriched in 233U or 235U.

       Any material, except SNM, produced or made radioactive incident to making or using SNM.

       Radium sources.

       Material made radioactive in a particle accelerator.

       Sources of naturally occurring radioactive material.

      7.1.1 Primary Radiation Safety Standards (Dose Limits)

      For occupational exposure, the NRC's radiation safety standards are as follows:

       To limit stochastic effects. 5000 mrem (50 mSv) total effective dose in one year.

       To prevent deterministic effects. 50 000 mrem (500 mSv) in one year to any tissue except the lens of the eye, which is restricted to 15 000 mrem (150 mSv).

       To protect a conceptus. 500 mrem during the entire pregnancy.

       To protect individual members of the public. 100 mrem in one year.

      7.1.2 As Low as Reasonably Achievable

      It must be emphasized that these limits are maximum doses that may not be exceeded by design (except in special cases, such as a rescue operation following an accident). In practice, the ICRP recommends, and the regulatory agencies require, the application of the as low as reasonably achievable (ALARA) principle, which states that operations be designed so that the work is done in such a manner that the resulting dose is ALARA. NRC regulations require a licensee to demonstrate that the ALARA principle is being applied.

      7.1.3 Derived Radiation Safety Standards

      The primary annual dose limits include the sum of external doses and doses due to radionuclides within or on the surface of the body. To achieve the primary standard, secondary standards are prescribed, which establish an annual limit of intake (ALI) for all radionuclides in air and in potable water. The ALI is the maximum intake of radionuclide, either by inhalation or by ingestion, which results in the primary annual dose limit to the worker if radiation exposure were limited to that radionuclide taken in through that portal of entry. Thus, the ALI must be proportionally decreased if a worker is exposed to more than one radionuclide and/or external radiation.

      Tertiary limits are expressed as radionuclide concentrations in air and in water. In the case of occupational exposure to airborne radioactivity, the derived air concentration (DAC) is the inhalation ALI divided by the volume of air, 2400 m³, that the worker is assumed (according to the Reference Man model) to inhale during the course of a working year. Effluent limits to the air and to the water environments are derived in a similar manner using the dose limit for the public rather than the occupational dose limit.

      These standards are enforced through a system of licensing, inspection, and fines for violations. The NRC is authorized to delegate its licensing and inspection of by‐product material to Agreement States. An Agreement State is a state that has signed an agreement with the NRC to regulate the use of radioactive materials within that state to at least the same degree as the NRC. The state must show the NRC that it has the resources to meet this obligation. The agreement may be terminated if the state does not meet the NRC's criteria. At this time, 2018, there are 38 Agreement States.

      The NRC regulates some, but not all, naturally occurring radioactive materials that have been concentrated (²²⁶Ra) and all radionuclides produced in accelerators based on changes in the Atomic Energy Act in 2005. The NRC does not regulate the manufacture or use of radiation‐producing machines, such as X‐ray machines and particle accelerators.

      The NRC's regulations are published in Title 10, Code of Federal Regulations. To assist applicants for NRC licenses, or to assist licensees in complying with the regulations, the NRC publishes Regulatory Guides and NUREG documents. These guides describe procedures and methods that are acceptable to the NRC for the purpose of demonstrating compliance with the regulations.

      7.2 Occupational Safety and Health Administration

OSHA is a federal regulatory agency whose function is to assure safe workplaces. It does this by establishing occupational safety and health standards and by inspecting workplaces to determine whether they are in compliance with the regulations. Radiation exposure from all nonmining radiation sources that are not regulated by the NRC, such as X‐ray machines, are subject to OSHA regulation. Because of OSHA's limited resources, however, safety regulation of these radiation sources in Agreement States is left to the state. OSHA regulations are based on ICRP 2 recommendations. It should be noted that although OSHA is authorized to regulate and inspect to determine compliance with the regulations, it is not authorized to license any facility. OSHA's radiation regulations are found in 29 CFR 1910.1096.

      7.3 Mine Safety and Health Administration

      Radiation exposure in mines is regulated by MSHA, a federal regulatory agency located within the Department of Labor. MSHA's regulatory authority extends to underground and to surface mines, as well as to the mining infrastructure, such as ore‐processing facilities and tailings. In the case of uranium, MSHA shares mining health and safety responsibilities with the NRC. Contributions of uranium tailings to the off‐site environment are regulated by the EPA. MSHA's health and safety regulations are published in 30 CFR 57.

      7.4 Department of Energy

      Rather than being regulated by the NRC, federal law requires that the DOE establish its own radiation safety standards for its workers. These standards, which are consistent with EPA guidance to Federal agencies, are generally similar to the recommendations contained in ICRP 60 and 66, although the primary dose limits are the same as those given by the NRC. DOE radiation safety standards are published in 10 CFR 835.

8 PRINCIPLES OF RADIATION SAFETY

      The objective of health physics practice is to keep the radiation dose to the worker ALARA below the statutory limits. The practice of radiation protection is a special application of the control of the working environment by engineering means. In principle, if the potentially hazardous source cannot be eliminated, one must first try to isolate the source. If that is not sufficient, an attempt is made to control the environment to minimize the worker's exposure, and if that still is not good enough, the worker is isolated. The СКАЧАТЬ