Section III - Discussion
III. DISCUSSION
10 CFR 835.202 requires, in part, that occupational exposures to
radiation "shall" be controlled so as not to exceed specified annual
limits. In addition, 10 CFR 835 requires that:
'Measures "shall" be taken to maintain radiation exposure in controlled
areas as low as is reasonably achievable through facility and equipment
design and administrative control. The primary methods used shall be
physical design features (e.g., confinement, ventilation, remote
handling, and shielding). Administrative controls and procedural
requirements "shall" be employed only as supplemental methods to control
radiation exposure' (10 CFR 835.1001(a)).
10 CFR 835.101 requires that: 'a DOE activity "shall" be conducted in
compliance with a documented radiation protection program (RPP)...", and
that "the content of each RPP "shall" be commensurate with the nature of
the activities performed and "shall" include formal plans and measures for
applying the as low as reasonably achievable (ALARA) process to
occupational exposure'.
10 CFR 835, the RCM, and DOE Orders, by necessity, must be generic to
cover the wide spectrum of facilities and activities within the DOE
complex. These primary documents often embrace and invoke the concepts,
requirements, and recommendations of secondary documents.
For the RGD program area the following documents have been invoked by
either DOE Order 5480.4, as amended, or the RCM:
-- 10 CFR 34, "Licenses for Radiography and Radiation Safety
Requirements for Radiographic Operations" (NRC, 1992);
-- ANSI N43.3, "American National Standard For General Radiation
Safety - Installations Using Non-Medical X-Ray and Sealed
Gamma-Ray Sources, Energies Up to 10 MeV" (Which updates ANSI
N543-1974) (ANSI, 1993);
-- ANSI N43.2, "Radiation Safety for X-Ray Diffraction and
Fluorescence Analysis Equipment" (ANSI, 1989a); and
-- ANSI N43.5, "Radiological Safety Standard for the Design of
Radiographic and Fluoroscopic Industrial X-Ray Equipment"
(Formerly called N537) (ANSI, 1989b).
When appropriate, these standards are cited with the specific section of
the standard enclosed in parentheses.
Requirements are defined in this IG for:
-- Radiation-generating devices;
-- analytical X-ray devices;
-- small accelerators used for radiography or other single
purpose applications;
-- radiation or electron generating devices that produce X-rays
incidentally;
-- sealed gamma-ray sources; and
-- sealed neutron sources.
Specific examples include: sealed photon or neutron emitting radioactive
sources; X-ray producing radiography equipment; research and analytical
X-ray or electron beam machines; sealed radioactive sources used as
irradiators; particle accelerators; neutron generators; Van de Graff
generators; electromagnetic pulse generators (if capable of producing
ionizing radiation); electron microscopes; electron arc welders;
microwave cavities that produce X-rays incidentally, and cabinet X-ray
machines used for security applications.
In general, all RGDs addressed may be classified as either devices that
must be electrically energized to produce ionizing radiation or sealed
radioactive sources consisting of encapsulated isotopes that emit
radiation continuously.
RGDs are used at DOE sites with a great variety of configurations and
operating characteristics and in a wide spectrum of applications. This
IG addresses RGDs used for industrial and research applications. RGDs
used for patient diagnostic or therapeutic medical applications are not
addressed. RCM 365.4 requires that medical RGDs be registered with the
cognizant regulatory agency which typically is a Federal, state or local
level authority. Requirements for medical uses are provided in DOE Order
5480.8A, as amended, "Contractor Occupational Medical Program" (DOE,
1992b).
To ensure individual safety from radiation, RGDs used at DOE sites
should be operated within an exempt shielded enclosure or installation.
These installations protect individuals by providing physical shielding
and/or controlling access to areas where RGDs are operated. All new RGD
installation designs and the modification of old RGD installations "shall"
consider radiological protection in their design objectives (10 CFR
835.1002 and RCM 128). Further guidance is provided in Section IV.B.2.,
"RGD Installation Design," of this IG.
Each installation provides different degrees of radiation protection. In
exempt shielded (including cabinet X-ray systems), shielded, and unattended
RGD installations, radiation protection is ensured primarily through the
use of physical barriers that include shielding and access controls.
Administrative controls are used in addition to physical controls to
prevent access to the RGD and controlled radiation areas during operation,
i.e., during beam activation or beam exposure.
Open installations, or "open air" installations, are used when the
specimen to be irradiated is too large for a shielded installation, when
a temporary setup is required, or when other operational constraints do
not permit using the RGD within a permanent enclosure. For open
installations, radiation protection is ensured primarily by the use of
posted perimeters, distance from the source to working individuals, and
continuous surveillance.
Analytical devices that are used for X-ray diffraction (typically low
energy) and fluorescence research applications are a subclass of either
exempt shielded or shielded installations. Analytical devices may use
either an open or shielded X-ray beam configuration. In the open-beam
systems, beam shutters, interlocks, distance, and shielding are used to
prevent radiation exposure above DOE mandated limits. In shielded
systems, the radiation source, sample, and detector (where needed) are
shielded in single or coupled enclosures that cannot be breached during
normal operations.
Small accelerators are also operated either within shielded enclosures
or "open air" configurations. Radiation protection requirements are
therefore similar to those designed for an RGD with a similar hazard.
RGDs that are commercially available, such as electron microscopes,
electron arc welders, industrial sources such as those used in density
and level gauges, and cabinet X-ray machines used for security
applications, "shall" be procured, categorized, inventoried, operated,
inspected and surveyed to ensure compliance with 10 CFR 835.1001 and
1003.