Section 0400-20-05-.82 - CONTROL OF ACCESS TO VERY HIGH RADIATION AREAS - IRRADIATORS(1) Each area in which there may exist radiation levels in excess of 500 rads (5 grays) in 1 hour at 1 meter from a radiation source3 that is used to irradiate materials shall meet the following requirements: 3 This rule applies to radiation from radiation sources that are used in non-self-shielded configuration. This rule does not apply to sources of radiation that are used in teletherapy, in radiography, or in completely self-shielded irradiators in which the source is both stored and operated within the same shielding radiation barrier and, in the designed configuration of the equipment, is always physically inaccessible to any individual and cannot create high levels of radiation in an area that is accessible to any individual.
(a) At least one authorized person who is familiar with the activity of the facility and is prepared to render or summon assistance shall be physically present when radiation is produced.(b) Each installation shall have primary barriers and/or secondary barriers sufficient to assure compliance with Rules 0400-20-05-.50, 0400-20-05-.55, 0400-20-05-.56 and 0400-20-05-.60 of these standards.(c) Each irradiation area shall be constructed so that persons within the area shall at all times be able to leave. Access control devices required by parts (h)2 through 4 of this paragraph shall not prevent an individual from leaving the area.(d) Devices and administrative procedures shall control each area to ensure that the area is clear of individuals prior to irradiation.(e) After any use of the radiation source and prior to the first individual's entry into the area, the area shall be surveyed to ensure that the radiation level in the area from the radiation source is below that at which an individual could receive a deep-dose equivalent in excess of 0.1 rem (1 mSv) in 1 hour.(f) Control Panel: 1. Only the operator at the control panel shall be able to activate an irradiator to create a radiation field in any area.2. The irradiator control panel shall be provided with a locking device to prevent unauthorized use. The locking device shall, when locked, make the irradiator incapable of creating a radiation field.3. The control panel and each entrance to an irradiation area shall have a device that gives a continuous indication of the radiation levels present in the area(s).4. All meters and controls on the irradiator control panel shall be identified and discernible.5. The operator shall have at the control panel a copy of operating and emergency procedures specific for that facility.(g) Warning Devices:1. Each area shall have devices that automatically generate conspicuously visible and audible alarm signals for at least five (5) seconds before irradiation begins. Following activation of these warning devices, there shall be a delay of not less than thirty (30) seconds before the irradiation may begin. The alarm signals shall be discernible in all irradiation areas. The alarm signals shall be sufficient to alert personnel in the area and to allow any individual in the area to reach and to operate the clearly identified emergency shut-off switches required in part (h)1 of this paragraph.2. Each area shall have visible flashing or rotating warning lights that operate when, and only when, radiation is being produced. Each entrance shall have a visible warning device that need not be flashing or rotating, but which operates when, and only when, radiation is being produced.(h) Control Devices: 1. Each area shall contain accessible emergency shut-off switches. Operation of an emergency shut-off switch shall prevent irradiation from occurring. These switches and their mode of operation shall be identified by a conspicuously posted sign adjacent to each switch. Shut-off switches shall include a manual reset at each switch that must be reset at the switch before the irradiator may be reactivated by the operator at the control panel.2. Each entrance or access point shall be equipped with interlocks. When any interlock is interrupted, broken, or tripped and before any opening into the area occurs, either:(i) The irradiator shall shut off automatically; or(ii) The radiation level within the area from the radiation source shall be reduced below that at which an individual could receive a deep-dose equivalent in excess of 0.1 rem (1 mSv) in 1 hour. After shut-off or reduction in output, restoring the irradiator to full operation shall be possible only from the control panel.
3. Additional control devices shall be provided so that, upon failure of the interlocks to function as required by part 2 of this subparagraph: (i) The radiation level within the area from the radiation source shall be reduced below that at which an individual could receive a deep-dose equivalent in excess of 0.1 rem (1 mSv) in 1 hour; and(ii) Conspicuously visible and audible alarm signals shall be generated that make the following persons aware of the hazard and of the failure of the interlocks: (I) Any individual attempting to enter the area; and(II) The individual required to be present in subparagraph (a) of this paragraph.4. Interlocks shall not be used to shut off the irradiator except in an emergency or during testing.5. Interlocks shall be bypassed only to test, adjust, maintain, and/or rearrange equipment. A conspicuous indication of the bypassed condition shall be made at the control panel. This subparagraph does not authorize the operation of an irradiator with warning devices, interlocks, emergency shut-off switches or other control devices that are incapable of proper operation.6. Activities in which interlocks are bypassed as permitted under part 5 of this subparagraph shall be: (i) Authorized only by the radiation safety officer;(ii) Performed only for a specified time;(iii) Recorded, showing: (II) Length of time bypassed,(III) Reason for bypassing, and(IV) Signature of the individual installing and removing the bypass. These records shall be maintained for inspection by the Division; and
(iv) Performed at low power and current, if possible.7. No individual shall be permitted to enter an area, the access of which is controlled by interlocks, while such interlocks are bypassed as permitted in part 5 of this subparagraph, unless such individual is utilizing personnel monitoring equipment that shall give an audible indication when a dose rate of 0.015 rem (0.15 mSv) per hour is exceeded. The personnel monitoring equipment referred to in this part is in addition to that required elsewhere in these standards. Calibration requirements in paragraph (2) of Rule 0400-20-05-.70 shall also apply to such personnel monitoring equipment.8. The licensee or registrant shall provide control devices so that, upon failure or removal of physical radiation barriers other than a sealed source's shielded storage container: (i) The radiation level within the area from the radiation source shall be reduced below that at which an individual could receive a deep-dose equivalent in excess of 0.1 rem (1 mSv) in 1 hour; and(ii) Conspicuously visible and audible alarm signals shall be generated that make the following persons aware of the hazard and of the failure or removal of the physical barrier: (I) Any individual attempting to enter the area; and(II) The individual required to be present in subparagraph (a) of this paragraph.9. When the shield for the stored sealed source(s) is a liquid, the licensee shall provide means to monitor the integrity of the shield and to signal, automatically, loss of adequate shielding.10. Physical radiation barriers that comprise permanent structural components, such as walls, which have no credible probability of failure or removal in ordinary circumstances need not meet the requirements of part 8 of this subparagraph.(i) There shall be available at each facility portable radiation monitoring equipment that is operable and has been calibrated for the radiations being produced by the facility. Such equipment shall be tested for operation and calibrated at intervals not to exceed 3 months and after each instrument servicing or repair. A note shall be attached to each instrument showing the latest calibration date. Records of calibration shall be maintained for inspection by the Division.(j) The interlock and emergency shut-off systems required in subparagraph (h) of this paragraph shall be separate electrical circuits and/or mechanical systems.(k) Electrical circuit diagrams of the irradiator and the associated interlock and emergency shut-off systems shall be kept current and on file at each irradiator facility.(l) The access control and warning devices required in subparagraphs (g) and (h) of this paragraph shall have been tested for proper functioning (see Rule 0400-20-05-.138 for recordkeeping requirements).1. Unless irradiation was continued uninterrupted from the previous day, testing shall be conducted prior to daily initiation of irradiation;2. After any unintended interruption, testing shall be conducted prior to resumption of irradiation; and3. The licensee or registrant shall submit and adhere to a schedule for periodic tests of the access control and warning systems.(m) The licensee or registrant shall not conduct operations, other than those necessary to place the radiation source in safe condition or to effect repairs on controls, unless control and warning devices are functioning properly.(n) Portals used in transporting only materials to and from the irradiation area shall be controlled by devices and administrative procedures that warn and physically protect individuals from inadvertent entry. Exit portals shall be equipped to: 1. Detect and signal the presence of any loose radiation sources being carried toward such an exit; and2. Automatically prevent loose radiation sources from being carried out of the area.(o) Licensees, registrants or applicants may apply to the Division for approval of alternative safety measures for irradiators, provided:1. The irradiator is within the purview of this rule;2. The irradiator will be used in a variety of positions or locations (such as open fields or forests) that make it impractical to comply with certain requirements of subparagraph (h) of this paragraph (such as automatic control of radiation levels);3. Any alternative safety measures shall provide a degree of personnel protection at least equivalent to those specified in this rule;4. At least one of the alternative measures shall include an access-preventing interlock control based on a measurement of the radiation. This interlock control shall ensure that no individual can gain access to the area in which an individual could receive a deep-dose equivalent in excess of 0.1 rem (1 mSv) in 1 hour at 30 centimeters from the radiation source or any surface that the radiation penetrates.Tenn. Comp. R. & Regs. 0400-20-05-.82
Original rule filed February 22, 2012; effective May 22, 2012.Authority: T.C.A. §§ 68-202-201 et seq., and 4-5-201 et seq.