Introduction to Health Physics: Fourth Edition - Ruang Baca FMIPA UB

RADIATION SAFETY GUIDES 409
TABLE 8-24. U.S. Environmental Protection Agency Radioactivity Limits for Drinking Water
RADIONUCLIDE CONCENTRATION LIMIT
Gross alpha, excluding Rn and U 15 pCi/L
Beta–gamma emitters 4 mrems/yr
Combined 226 Ra + 228 Ra 5 pCi/L
Tritium 20,000 dpm/L
90 Sr 8 pCi/L
Uranium, natural 30 μg/L
federal regulatory agencies that deal with radiation must issue regulations that are
compatible with those in the guides. Promulgation of radiation safety regulations is
the responsibility of the several regulatory agencies, including the EPA itself, which
regulates radioactive discharges into the atmosphere and into waters, establishes
drinking water standards, and regulates recovery and disposal of radioactive wastes
not regulated under the Atomic Energy Act. EPA regulations are published in Title
40, CFR (40 CFR 9, 141, 142). The EPA limits for radioactivity in drinking water are
listed above in Table 8-24.
Nuclear Regulatory Commission
According to the Atomic Energy Act, the AEC had two responsibilities. One was to
develop nuclear energy and useful applications for by-product materials. The second
was to regulate these activities so that they were carried out safely. Thus, a single
agency was charged with the duty to develop and promote nuclear energy and also to
regulate its safe use. Many persons in policymaking positions thought that these two
responsibilities were mutually incompatible and that there was an inherent conflict
of interest in carrying them out. To remedy this situation, the AEC was abolished in
1974 under the authority of the Energy Reorganization of 1974, and two new agencies
were established in its place. The development and promotion of nuclear energy was
assigned to the Energy Research and Development Administration (ERDA), which
later became the Department of Energy (DOE). Responsibility for radiation safety
in the use of source material, special nuclear material, and by-product material was
assigned to the Nuclear Regulatory Commission (NRC). The NRC’s regulations are
published in 10 CFR. The standards for protection against radiation are published
in Part 20 of these regulations, 10 CFR 20. A basic tenet of these safety regulations
is that the licensee must maintain strict control over all licensed sources at all times.
Dose Limits
A dose limit is the upper permissible bound for radiation dose; it is a dose level
that may not be exceeded. From 1957 until 1991, the AEC and then NRC radiation
safety regulations published in 10 CFR 20 were based on ICRP 2 recommendations
for radiation workers. To keep up with scientific and engineering advances, the
original regulations were amended numerous times. The publication of ICRP 26
in 1977 and ICRP 30 in 1979, which are based on “uniform risk” concept for fatal
radiogenic cancers and for serious hereditary effects rather than the “critical organ”
concept of ICRP 2, led to dose limits and calculational methodologies that differred
significantly from those used in 10 CFR 20. These changes in the philosophical basis
for dose limitation and in calculational methodology led to a need for revisions in
derived limits, such as the ALI (which was only implied in the former 10 CFR 20),