(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 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 5 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 5 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;
(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 1 mSv (0.1 rem) in one hour; and
(c) when actuated, 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 1 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 (i) of this paragraph:
(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 1 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 as well as 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 1 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; as well as to make 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 1 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 will 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 1 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 as follows:
(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;
(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 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 commissioner 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 present 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.