(24) Category 2 quantity of radioactive material--A
quantity of radioactive material meeting or exceeding the category
2 threshold but less than the category 1 threshold in accordance with §336.357(z)
of this title (relating to Physical Protection of Category 1 and Category
2 Quantities of Radioactive Material). This is determined by calculating
the ratio of the total activity of each radionuclide to the category
2 threshold for that radionuclide and adding the ratios together.
If the sum is equal to or exceeds 1, the quantity would be considered
a category 2. Category 2 quantities of radioactive material do not
include the radioactive material contained in any fuel assembly, subassembly,
fuel rod, or fuel pellet.
(25) Class--A classification scheme for inhaled material
according to its rate of clearance from the pulmonary region of the
lung. Materials are classified as D, W, or Y, which applies to a range
of clearance half-times: for Class D (Days) of less than ten days,
for Class W (Weeks) from 10 to 100 days, and for Class Y (Years) of
greater than 100 days. For purposes of the rules in this chapter, "lung
class" and "inhalation class" are equivalent terms.
(26) Collective dose--The sum of the individual doses
received in a given period of time by a specified population from
exposure to a specified source of radiation.
(27) Committed dose equivalent (HT , 50 ) (CDE)--The dose equivalent to organs or
tissues of reference (T) that will be received from an intake of radioactive
material by an individual during the 50-year period following the
intake.
(28) Committed effective dose equivalent (HE ,50 ) (CEDE)--The
sum of the products of the weighting factors applicable to each of
the body organs or tissues that are irradiated and the committed dose
equivalent to each of these organs or tissues.
(29) Compact--The Texas Low-Level Radioactive Waste
Disposal Compact established under Texas Health and Safety Code, §403.006
and Texas Low-Level Radioactive Waste Disposal Compact Consent Act,
Public Law Number 105-236 (1998).
(30) Compact waste--Low-level radioactive waste that:
(A) is generated in a host state or a party state;
or
(B) is not generated in a host state or a party state,
but has been approved for importation to this state by the compact
commission under §3.05 of the compact established under Texas
Health and Safety Code, §403.006.
(31) Compact waste disposal facility--The low-level
radioactive waste land disposal facility licensed by the commission
under Subchapter H of this chapter (relating to Licensing Requirements
for Near-Surface Land Disposal of Low-Level Radioactive Waste) for
the disposal of compact waste.
(32) Constraint (dose constraint)--A value above which
specified licensee actions are required.
(33) Critical group--The group of individuals reasonably
expected to receive the greatest exposure to residual radioactivity
for any applicable set of circumstances.
(34) Curie (Ci)--See §336.4 of this title (relating
to Units of Radioactivity).
(35) Declared pregnant woman--A woman who has voluntarily
informed the licensee, in writing, of her pregnancy and the estimated
date of conception. The declaration remains in effect until the declared
pregnant woman withdraws the declaration in writing or is no longer
pregnant.
(36) Decommission--To remove (as a facility) safely
from service and reduce residual radioactivity to a level that permits:
(A) release of the property for unrestricted use and
termination of license; or
(B) release of the property under restricted conditions
and termination of the license.
(37) Deep-dose equivalent (Hd )
(which applies to external whole-body exposure)--The dose equivalent
at a tissue depth of one centimeter (1,000 milligrams/square centimeter).
(38) Demand respirator--An atmosphere-supplying respirator
that admits breathing air to the facepiece only when a negative pressure
is created inside the facepiece by inhalation.
(39) Depleted uranium--The source material uranium
in which the isotope uranium-235 is less than 0.711%, by weight, of
the total uranium present. Depleted uranium does not include special
nuclear material.
(40) Derived air concentration (DAC)--The concentration
of a given radionuclide in air which, if breathed by the "reference
man" for a working year of 2,000 hours under conditions of light
work (inhalation rate of 1.2 cubic meters of air/hour), results in
an intake of one ALI. DAC values are given in Table I, Column 3, of §336.359(d)
of this title (relating to Appendix B. Annual Limits on Intake (ALI)
and Derived Air Concentrations (DAC) of Radionuclides for Occupational
Exposure; Effluent Concentrations; Concentrations for Release to Sanitary
Sewerage).
(41) Derived air concentration-hour (DAC-hour)--The
product of the concentration of radioactive material in air (expressed
as a fraction or multiple of the derived air concentration for each
radionuclide) and the time of exposure to that radionuclide, in hours.
A licensee shall take 2,000 DAC-hours to represent one, equivalent
to a committed effective dose equivalent of 5 rems (0.05 sievert).
(42) Discrete source--A radionuclide that has been
processed so that its concentration within a material has been purposely
increased for use for commercial, medical, or research activities.
(43) Disposal--With regard to low-level radioactive
waste, the isolation or removal of low-level radioactive waste from
mankind and mankind's environment without intent to retrieve that
low-level radioactive waste later.
(44) Disposable respirator--A respirator for which
maintenance is not intended and that is designed to be discarded after
excessive breathing resistance, sorbent exhaustion, physical damage,
or end-of-service-life renders it unsuitable for use. Examples of
this type of respirator are a disposable half-mask respirator or a
disposable escape-only Self-Contained breathing apparatus.
(45) Distinguishable from background--The detectable
concentration of a radionuclide is statistically different from the
background concentration of that radionuclide in the vicinity of the
site or, in the case of structures, in similar materials using adequate
measurement technology, survey, and statistical techniques.
(46) Diversion--The unauthorized movement of radioactive
material subject to §336.357 of this title (relating to Physical
Protection of Category 1 and Category 2 Quantities of Radioactive
Material) to a location different from the material's authorized destination
inside or outside of the site at which the material is used or stored.
(47) Dose--A generic term that means absorbed dose,
dose equivalent, effective dose equivalent, committed dose equivalent,
committed effective dose equivalent, total organ dose equivalent,
or total effective dose equivalent. For purposes of the rules in this
chapter, "radiation dose" is an equivalent term.
(48) Dose equivalent (HT )--The
product of the absorbed dose in tissue, quality factor, and all other
necessary modifying factors at the location of interest. The units
of dose equivalent are the rem and sievert (Sv ).
(49) Dose limits--The permissible upper bounds of radiation
doses established in accordance with the rules in this chapter. For
purposes of the rules in this chapter, "limits" is an equivalent
term.
(50) Dosimetry processor--An individual or organization
that processes and evaluates individual monitoring devices in order
to determine the radiation dose delivered to the monitoring devices.
(51) Effective dose equivalent (HE )--The
sum of the products of the dose equivalent to each organ or tissue
(HT ) and the weighting factor (wT ) applicable to each of the body organs or
tissues that are irradiated.
(52) Embryo/fetus--The developing human organism from
conception until the time of birth.
(53) Entrance or access point--Any opening through
which an individual or extremity of an individual could gain access
to radiation areas or to licensed radioactive materials. This includes
portals of sufficient size to permit human access, irrespective of
their intended use.
(54) Environmental Radiation and Perpetual Care Account--An
account in the general revenue fund established for the purposes specified
in the Texas Health and Safety Code, §401.306.
(55) Escorted access--Accompaniment while in a security
zone by an approved individual who maintains continuous direct visual
surveillance at all times over an individual who is not approved for
unescorted access.
(56) Exposure--Being exposed to ionizing radiation
or to radioactive material.
(57) Exposure rate--The exposure per unit of time.
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