As used in these regulations, each of the following terms shall
have the meaning assigned in this regulation:
(a) "Waste" means any low-level radioactive
waste that is acceptable for disposal in a land disposal facility. Low-level
radioactive waste shall mean radioactive waste that meets both of the following
conditions:
(1) Is not classified as any of
the following:
(A) High-level radioactive
waste;
(B) spent nuclear
fuel;
(C) "byproduct material," as
defined in paragraphs (2), (3), and (4) in the definition of "byproduct
material" in 10 CFR
20.1003, dated December 1, 2009;
(D) uranium or thorium tailings;
and
(E) transuranic waste;
and
(2) is classified as
low-level radioactive waste consistent with existing law and in accordance with
paragraph (a)(1) by the nuclear regulatory commission.
(b) "Waste-handling licensee" means any
person licensed to receive and store radioactive wastes before disposal, any
person licensed to dispose of radioactive waste, or any person licensed to both
receive and dispose of radioactive waste.
(c) "Wedge filter" means an added filter
effecting continuous, progressive attenuation of all or part of the useful
beam.
(d) "Week" means seven
consecutive days, starting on Sunday.
(e) "Weighting factor (wT) for an organ or
tissue (T)" means the proportion of the risk of stochastic effects resulting
from irradiation of that organ or tissue to the total risk of stochastic
effects when the whole body is irradiated uniformly. For calculating the
effective dose equivalent, the values of wT shall be as follows:
ORGAN OR TISSUE DOSE WEIGHTING FACTORS
| Organ or Tissue (T) |
wT
|
| Gonads |
0.25 |
| Breast |
0.15 |
| Red bone marrow |
0.12 |
| Lung |
0.12 |
| Thyroid |
0.03 |
| Bone surfaces |
0.03 |
| Remainder organs |
0.30a
|
| Whole body |
1.00b
|
a 0.30 results from 0.06 for each of the five
remainder organs that receive the highest doses, excluding the skin and the
lens of the eye.
b For the purpose of weighting the
external whole body dose in determining the total effective dose equivalent, a
single weighting factor, wT = 1.0, is specified. The use of other
weighting factors for external exposure may be approved by the secretary if the
licensee or registrant demonstrates that the effective dose to be received is
within the limits specified in these regulations.
(f) "Well bore" means a drilled hole in which
wireline service operations and subsurface tracer studies are
performed.
(g) "Well logging" means
the lowering and raising of measuring devices or tools that could contain
sources of radiation into well bores or cavities for the purpose of obtaining
information about the well or adjacent formations.
(h) "Wet-source-change irradiator" means an
irradiator whose sources are replaced underwater.
(i) "Wet-source-storage irradiator" means an
irradiator whose sources are stored underwater.
(j) "Whole body," for purposes of external
exposure, means the head and trunk, including the male gonads, and shall
include the arms above the elbow and the legs above the knee.
(k) "Wireline" means a cable containing one
or more electrical conductors that is used to raise and lower logging tools in
the well bore.
(l) "Wireline
service operation" means any evaluation or mechanical service that is performed
in the well bore using devices on a wireline.
(m) "Worker" means an individual, contractor,
or subcontractor engaged in work that is performed under a license or
registration, or both, issued by the department and that is controlled by a
licensee or registrant, or both. This term shall not include a specific
licensee or registrant.
(n)
"Working level (WL)" means any combination of short-lived radon daughters in
one liter of air that will result in the ultimate emission of 1.3E+5 MeV of
potential alpha particle energy. The short-lived radon daughters are the
following:
(1) For radon-222, the following:
(A) Polonium-218;
(B) lead-214;
(C) bismuth-214; and
(D) polonium-214; and
(2) for radon-220, the following:
(A) Polonium-216;
(B) lead-212;
(C) bismuth-212; and
(D) polonium-212.
(o) "Working-level month (WLM)"
means an exposure to one working level for 170 hours.
(p) "Written directive" means a written order
for a specific patient that is dated and signed by an authorized user before
the administration of a radiopharmaceutical or radiation and that contains any
of the following sets of information:
(1) For
any administration of quantities greater than 1.11 megabecquerels (30 iJiCi) of
sodium iodide I-125 or I-131, the radionuclide and dosage;
(2) for a therapeutic administration of a
radiopharmaceutical other than sodium iodide I-125 or I-131, the
radiopharmaceutical, dosage, and route of administration;
(3) for gamma stereotactic radiosurgery, the
target coordinates, collimator size, plug pattern, and total dose;
(4) for teletherapy, the total dose, dose per
fraction, treatment site, and overall treatment period;
(5) for high dose-rate remote afterloading
brachyther-apy, the radionuclide, treatment site, and total dose; or
(6) for all other brachytherapy, the
following information:
(A) Before
implantation, the radionuclide, number of sources, and source strengths;
and
(B) after implantation but
before completion of the procedure, the radionuclide, treatment site, and
either the total source strength and exposure time or the total dose.