Section II - Definitions
II. DEFINITIONS
accessible surface: Any surface to which access by any part of the
human body is possible without the use of tools or without the removal
of any part of the device.
as low as reasonably achievable (ALARA): The "approach" to radiation
protection to manage and control exposures (both individual and
collective) to the work force and to the general public to levels as low
as is reasonable, taking into account social, technical, economic,
practical, and public policy considerations. "ALARA is not a dose limit
but a process" which has the objective of attaining doses as far below
the applicable limits of 10 CFR 835 as is reasonably achievable.
attenuation: The reduction of the quantity of ionizing radiation upon
passage through matter, resulting from all types of interactions with
that matter.
cabinet X-ray system: An X-ray system with the X-ray tube installed in
an enclosure (hereinafter termed "cabinet") which, independently of
existing architectural structures except the floor on which it may be
placed, is intended to contain at least that portion of a material being
irradiated, provide radiation attenuation, and exclude individuals from
its interior during generation of X-radiation. Included are all the
X-ray systems designed primarily for inspection of carry-on baggage at
airline, railroad, and bus terminals, and in similar facilities. An
X-ray tube used within a shielded part of a building or X-ray equipment
which may temporarily or occasionally incorporate portable shielding is
not considered a cabinet X-ray system.
controlled area: Any area to which access is managed in order to
protect individuals from exposure to radiation and/or radioactive
material.
entrance or access point: Any location through which an individual
could gain access, in whole or in part, to areas controlled for the
purposes of radiation protection. This includes entry or exit portals
of sufficient size to permit human entry, irrespective of their intended
use.
fail-safe design: Despite any failure of equipment indicator or safety
components that can reasonably and realistically be anticipated, the
device is designed to protect individuals from exposure to radiation.
For example, if a light indicating "X-RAY ON" fails, the production of
X-rays will be prevented; or if a shutter status indicator fails, the
shutter will close.
flash X-ray unit: Any device that is capable of generating pulsed
X-rays.
interlock: A device for precluding access to an area of radiation
hazard by either preventing entry or by automatically removing the
hazard. One example is an electro-mechanical control mechanism that
interrupts the beam of ionizing radiation or shuts down the radiation
installation whenever the interlock is challenged.
irradiator: Any sealed radioactive material that has the potential to
create a radiation level exceeding 500 rads (5 grays) in 1 hour at 1
meter. As used in this IG, any sealed radioactive source operated
within the requirements of an RGD installation.
leakage radiation: All radiation, except the useful beam, coming from
the X-ray assembly or sealed radioactive source housing.
modification: Any alteration of the shielding configuration, device or
installation operating practices, or the replacement of the original RGD
(or component part thereof) with another that has not been previously
evaluated, inspected, surveyed, and documented by the Radiation
Protection Organization. This definition also includes the collocation
of additional or multiple unevaluated RGDs within a previously evaluated
installation.
normal operation: Operation under conditions as recommended by the
manufacturer of the RGD with recommended shielding and barriers in
place, and as specified in the operating procedures and requirements for
the RGD installation.
occupancy factor: Used during shielding design and analyses, the time
factor by which the workload or the dose or dose-rate should be
multiplied to correct for the degree of human habitability of the area
in question while the RGD is producing radiation.
occupied (occupiable) area: An area or location that may be physically
accessible by individuals (or body parts thereof) while a
radiation-generating device is in operation.
off-normal operation: An event or condition that adversely affects,
potentially affects, or indicates degradation in the safety, security,
environmental, or health-protection performance or operation of an RGD
installation. An "off-normal" event requires reporting in accordance
with DOE 5000.3B, "Occurrence Reporting and Processing of Operational
Information" (DOE, 1993c).
qualified expert: An individual having the knowledge, training, and
recognition of such by management to measure ionizing radiation, to
evaluate safety techniques, to design RGD installations, and to provide
advice on radiation protection requirements.
quality assurance: Actions that provide confidence that quality is
achieved. As used in this guide, the planned and systematic actions
necessary to provide adequate confidence that an installation or
component thereof will perform satisfactorily in service and in
compliance with DOE requirements.
radiation-generating device (RGD): Collective term for devices which
produce ionizing radiation, sealed sources which emit ionizing
radiation, small particle accelerators used for single purpose
applications which produce ionizing radiation (e.g., radiography), and
electron generating devices that produce X-rays incidentally.
radiography: Examination of the structure of materials by nondestructive
methods, using a RGD.
RGD Custodian: An individual who is trained and designated to maintain
cognizance over accountability and control of radiation-generating
devices assigned to him or her.
RGD installation: The sum of the radiation source (e.g., sealed
radioactive material or x-ray tube), the associated equipment and
component items, and the space in which they are located.
Four types of installations are defined as follows:
(1) exempt shielded installations are those designed to fully enclose
the specimen to be irradiated and to provide adequate shielding to
meet 10 CFR 835.1002(b);
(2) shielded installations are those designed to use the
room-within-a-room concept to limit access to the RGD beam and to
place more emphasis on distance as opposed to shielding for
radiation protection;
(3) open installations are those designed to accommodate a specimen
that is so large as to make an exempt shielded installation
impractical; and
(4) unattended installations are those designed for a specific purpose
and that do not require personnel in attendance for operation.
RGD Operator: An individual who is trained and deemed qualified by the
radiation protection organization and the RGD Custodian to use a
radiation-generating device.
sealed radioactive source: Any radioactive material that is contained
in a sealed capsule, sealed between layers of nonradioactive material,
or firmly fixed to a nonradioactive surface by electroplating or other
means. The confining barrier prevents dispersion of the radioactive
material under normal and most accidental conditions related to the use
of the source. For purposes of categorizing a sealed source as a RGD,
the radiation intensity of the unshielded source must equal or exceed
100 mrems (1 mSv) in 1 hour when measured at 30 centimeters from the
source.
shall: Within the context of this Guide, the word "shall" is used to
designate requirements from 10 CFR 835, the RCM, DOE Orders, and
secondary documents invoked by them.
shielding barrier: Any barrier of attenuating material used to reduce
radiation hazards. Used collectively as "shielding."
shielding barrier, primary: Any barrier sufficient to attenuate the
useful beam to the required radiation level.
shielding barrier, secondary: Any barrier sufficient to attenuate
leakage or scattered radiation to the required radiation level.
should and may: Within the context of this Guide, the words "should"
and "may" are used to represent optional program recommendations and
allowable alternatives, respectively. Deviations generally require no
specific approval or justification; however exceptions or deviations to
"should" provisions referenced directly from the RCM require specific
justification and approval in accordance with Article 113.3 of that
manual(i.e. RCM 113.3).
survey: An evaluation of the radiological conditions and potential
hazards incident to the production, use, transfer, release, disposal, or
presence of radioactive material or other sources of radiation. When
appropriate, such an evaluation includes a physical survey of the
location of radioactive material and measurements or calculations of
levels of radiation, or concentrations or quantities of radioactive
material present.
useful beam: That part of the primary and secondary radiation beam that
passes through the aperture, cone, or other device used for collimation.
workload: Used during the design of RGD shielding, a measure of the
intended amount of RGD use expressed in units of the output of the RDG
integrated over time; for example, milliampere-minutes per week for
X-ray generating devices operating below 4 MeV.