(f) Control of access to very high radiation
areas--irradiators.
(1) This subdivision
applies to licensees or registrants with sources of radiation in
non-self-shielded irradiators. This subdivision does not apply to sources of
radiation that are used in teletherapy, in industrial radiography, or in
completely self-shielded irradiators in which the source of radiation is both
stored and operated within the same shielding radiation barrier and, in the
designed configuration of the irradiator, is always physically inaccessible to
any individual and cannot create a radiation level of five Gy (500 rad) or more
in one hour at one meter in an area that is accessible to any
individual.
(2) Each area in which
there may exist radiation levels in excess of five Gy (500 rad) in one hour at
one meter from a source of radiation that is used to irradiate materials shall
meet the following requirements:
(i) Each
entrance or access point shall be equipped with entry control devices which:
(a) function automatically to prevent any
individual from inadvertently entering a very high radiation area;
and
(b) permit deliberate entry
into the area only after a control device is actuated that causes the radiation
level within the area, from the source of radiation, to be reduced below that
at which it would be possible for an individual to receive a deep dose
equivalent in excess of one mSv (0.1 rem) in one hour; and
(c) prevent operation of the source of
radiation if it would produce radiation levels in the area that could result in
a deep dose equivalent to an individual in excess of one mSv (0.1 rem) in one
hour.
(ii) Additional
control devices shall be provided so that, upon failure of the entry control
devices to function as required by subparagraph (2)(i) of this subdivision:
(a) the radiation level within the area, from
the source of radiation, is reduced below that at which it would be possible
for an individual to receive a deep dose equivalent in excess of one mSv (0.1
rem) in one hour; and
(b)
conspicuous visible and audible alarm signals are generated to make an
individual attempting to enter the area aware of the hazard and at least one
other authorized individual, who is physically present, familiar with the
activity, and prepared to render or summon assistance, aware of the failure of
the entry control devices.
(iii) The licensee or registrant shall
provide control devices so that, upon failure or removal of physical radiation
barriers other than the sealed source's shielded storage container:
(a) the radiation level from the source of
radiation is reduced below that at which it would be possible for an individual
to receive a deep dose equivalent in excess of one mSv (0.1 rem) in one hour;
and
(b) conspicuous visible and
audible alarm signals are generated to make potentially affected individuals
aware of the hazard and the licensee or registrant or at least one other
individual, who is familiar with the activity and prepared to render or summon
assistance, aware of the failure or removal of the physical barrier.
(iv) When the shield for stored
sealed sources is a liquid, the licensee or registrant shall provide means to
monitor the integrity of the shield and to signal, automatically, loss of
shielding to a level at which it would be possible for an individual to receive
a deep dose equivalent in excess of one mSv (0.1 rem) in one hour.
(v) Physical radiation barriers that comprise
permanent structural components, such as walls, that have no credible
probability of failure or removal in ordinary circumstances need not meet the
requirements of subparagraphs (iii) and (iv) of this paragraph.
(vi) Each area shall be equipped with devices
that will automatically generate conspicuous visible and audible alarm signals
to alert personnel in the area before the source of radiation can be put into
operation and in time for any individual in the area to operate a clearly
identified control device, which must be installed in the area and which can
prevent the source of radiation from being put into operation.
(vii) Each area shall be controlled by use of
such procedures and devices as are necessary to ensure that the area is cleared
of personnel prior to each use of the source of radiation.
(viii) Prior to the first individual's entry
into each very high radiation area after any use of the source of radiation,
the area shall be checked by a radiation measurement. The area may not be used
unless the radiation level from the source of radiation in the area is below
that at which it would be possible for an individual to receive a deep dose
equivalent in excess of one mSv (0.1 rem) in one hour.
(ix) The entry control devices required in
subparagraph (i) of this paragraph shall have been tested for proper
functioning. (See section
16.14[h]
of this Part for recordkeeping requirements.)
(a) Testing shall be conducted prior to
initial operation with the source of radiation on any day, unless operations
were continued uninterrupted from the previous day; and
(b) Testing shall be conducted prior to
resumption of operation of the source of radiation after any unintentional
interruption; and
(c) The licensee
or registrant shall submit and adhere to a schedule for periodic tests of the
entry control and warning systems.
(x) The licensee or registrant shall not
conduct operations, other than those necessary to place the source of radiation
in safe condition or to effect repairs on controls, unless control devices are
functioning properly.
(xi) Entry
and exit portals that are used in transporting materials to and from the
irradiation area, and that are not intended for use by individuals, shall be
controlled by such procedures and devices as are necessary to physically
protect and warn against inadvertent entry by any individual through these
portals. Exit portals for irradiated materials shall be equipped to detect and
signal the presence of any loose radioactive material that is carried toward
such an exit and to automatically prevent loose radioactive material from being
carried out of the area.
(3) Licensees, registrants, or applicants for
licenses or registrations for sources of radiation within the purview of
paragraph (2) of this subdivision which will be used in a variety of positions
or in locations, such as open fields or forests, that make it impracticable to
comply with certain requirements of paragraph (2) of this subdivision, such as
those for the automatic control of radiation levels, may apply to the
Department for approval of alternative safety measures. Alternative safety
measures shall provide personnel protection at least equivalent to those
specified in paragraph (2) of this subdivision. At least one of the alternative
measures shall include an entry-preventing interlock control based on a
measurement of the radiation that ensures the absence of high radiation levels
before an individual can gain access to the area where such sources of
radiation are used.
(4) The entry
control devices required by paragraphs (2) and (3) of this subdivision shall be
established in such a way that no individual will be prevented from leaving the
area.