1. (1) The Division may grant a written exemption from specific requirements of this chapter if the applicant or registrant demonstrates, to the Division’s satisfaction, achievement of radiation protection, through other means, equivalent to that required by Chapters 0400-20-04 through 0400-20-08 or Chapters 0400-20-10 through 0400-20-12.
2. (2) Each Registrant and/or Licensee shall provide personnel monitoring devices calibrated for the radiations and energies of radiation produced by the fusion machine and used as required by Rules 0400-20-05-.70 and 0400-20-05-.71.
3. (3) Each installation shall be provided with such primary barriers and/or secondary barriers as are necessary to assure compliance with Rules 0400-20-05-.50, 0400-20-05-.55, 0400-20-05-.56, and 0400-20-05-.60.

4. (4) Controls and safety devices.

   1. (a) Only the fusion machine operator at the control panel shall be able to activate a fusion machine to create a radiation field in any area in which an individual could receive a dose in excess of two millirems per hour.
   2. (b) All entrances into a target room or other high radiation areas shall be provided with interlocks.
   3. (c) The interlock system and the emergency cut-off shall be separate electrical circuits and/or mechanical systems.
   4. (d) When any interlock is interrupted, broken, or tripped, either the fusion machine shall shut off automatically or the radiation level within the room will be reduced to an average of not more than two millirems per hour and a maximum of 10 millirems per hour at a distance of one meter in any direction from any accessible surface of the fusion machine system. After shut-off or reduction in output, it shall be possible to restore the fusion machine to full operation only from the control panel. Radiation levels produced by radioactive materials shall not be considered as the radiation levels to be reduced by such controls.
   5. (e) Interlocks shall not be used to shut off the fusion machine except in an emergency or during testing.
   6. (f) Emergency shut-off switches shall be located within the high radiation areas so as to be accessible to individuals therein within the warning period. These switches and their mode of operation shall be identified by a conspicuously posted sign adjacent to the switch. These switches shall be capable of automatically causing the fusion machine to either shut off or reduce the radiation level to an average of not more than two millirems per hour and a maximum of 10 millirems per hour at a distance of one meter in any direction from any accessible surface of the fusion machine system. These shut-off switches shall include a manual reset at each switch, which must be reset at the switch before the fusion machine may be restarted by the fusion machine operator at the control panel. Radiation levels produced by radioactive material shall not be considered as the radiation levels to be reduced by such control.
   7. (g) All locations designated as high radiation areas shall be equipped with visual flashing or rotating warning lights that operate when, and only when, radiation is being produced. Each entrance to such area shall have a visual warning device, which need not be flashing or rotating, but operates when, and only when radiation is being produced.
   8. (h) Each high radiation area shall have an audible warning device which shall be activated for at least five seconds prior to the possible creation of such high radiation area. Following the activation of the audible warning device, there shall be a delay of not less than 30 seconds before the high radiation area may be produced. Such warning device shall be discernible in all high radiation and radiation areas.
   9. (i) All meters and controls on the fusion machine control console shall be identified and discernible.
   10. (j) The fusion machine control panel shall be provided with a locking device to prevent use by unauthorized individuals. Such locking device shall, when locked, make the fusion machine incapable of creating a radiation field in any areas in which an individual could receive a dose in excess of two millirems per hour.
   11. (k) 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 three months and after each instrument servicing and 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.
   12. (l) There shall be present at the control panel and at entrances to all high radiation areas a device that shall give a continuous indication of the radiation levels present in the target or areas.
   13. (m) Electrical circuit diagrams of the fusion machine and the associated interlock systems shall be kept current and on file at each fusion machine facility.
   14. (n) All high radiation areas shall be so constructed that persons within the area may at all times be able to escape.

5. (5) Operation.

   1. (a) Only fusion machine operators qualified as required under Rule 0400-20-14-.19 shall be allowed to unlock and operate the control panel of a fusion machine.
   2. (b) Interlocks may be bypassed only to test, adjust, maintain, and/or rearrange equipment provided a conspicuous indication of such condition is made at the control panel. This subparagraph does not authorize the operation of a fusion machine with the high radiation area warning devices or emergency shut off switches incapable of proper operation.

   3. (c) Activities in which interlocks are bypassed as permitted under subparagraph (b) of this paragraph shall:

      1. 1. Only be authorized by the radiation safety officer;
      2. 2. Only be performed for a specific time;
      3. 3. Be recorded showing the date, length of time bypassed, reason for bypassing, and signed by the individual installing and removing the bypass. These records shall be maintained for inspection by the Division; and
      4. 4. Be performed at low power and current, if possible.
   4. (d) 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 subparagraph (b) of this paragraph, unless such individual is utilizing personnel monitoring equipment that will give an audible indication when a dose rate of 15 millirems per hour is exceeded. The personnel monitoring equipment referred to in this paragraph is in addition to that required elsewhere in these rules. Calibration requirements of subparagraph (4)(k) of Rule 0400-20-09-.17 shall also apply to such personnel monitoring equipment.
   5. (e) The fusion machine operator shall have at the control panel a copy of the operating and emergency procedures.

Authority: T.C.A. §§ 4-5-201, et seq.; 68-202-101, et seq.; and 68-202-201, et seq. Administrative History: New rules filed March 11, 2026; effective June 9, 2026.