(A)105 CMR 120.229 applies to licensees with
sources of radiation in non-self-shielded irradiators. 105 CMR 120.229 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 high levels of
radiation in an area that is accessible to any individual.
(B) Each area in which there may exist
radiation levels in excess of five grays (500 rads) in one hour at one meter
from a source of radiation that is used to irradiate materials shall meet the
following requirements:
(1) 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 one millisievert (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 millisievert (0.1 rem)
in one hour.
(2)
Additional control devices shall be provided so that, upon failure of the entry
control devices to function as required by 105 CMR 120.229(B)(1):
(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
millisievert (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.
(3) The licensee 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 millisievert (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 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.
(4) When the shield for stored
sealed sources is a liquid, the licensee shall provide means to monitor the
integrity of the shield and to signal, automatically, loss of adequate
shielding.
(5) 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 105 CMR 120.229(B)(3) and
120.229(B)(4).
(6) 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.
(7) Each area shall be
controlled by use of such administrative procedures and such devices as are
necessary to ensure that the area is cleared of personnel prior to each use of
the source of radiation.
(8) Each
area shall be checked by a radiation measurement to ensure that, prior to the
first individual's entry into the area after any use of the source of
radiation, 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 millisievert (0.1 rem) in one hour.
(9) The entry control devices required in 105
CMR 120.229(B)(1) shall be tested for proper functioning.
See
105
CMR 120.270 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.
(b) Testing shall be conducted prior to
resumption of operation of the source of radiation after any unintentional
interruption.
(c) The licensee
shall submit and adhere to a schedule for periodic tests of the entry control
and warning systems.
(10) The licensee 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.
(11) 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 devices and administrative procedures 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 automatically to prevent loose radioactive
material from being carried out of the area.
(C) Licensees or applicants for licenses for
sources of radiation within the purview of 105 CMR 120.229(B) 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 105 CMR
120.229(B), such as those for the automatic control of radiation levels, may
apply to the Agency for approval of alternative safety measures. Alternative
safety measures shall provide personnel protection at least equivalent to those
specified in 105 CMR 120.229(B). 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.
(D) The entry control devices
required by 105 CMR 120.229(B) and (C) shall be established in such a way that
no individual will be prevented from leaving the area.
