Section 9: Radiation Machines
A. General Safety Provisions
- A radiation producing machine is any device capable of producing ionizing radiation when the associated control devices are operated, except devices which produce radiation by the use of radioactive material.
- An enclosed system is a radiation producing machine which satisfies the requirements that all areas with exposure rates greater than .25 mR/hr are enclosed with an interlocked barrier. All others are considered closed systems.
- X-ray diffraction units, particle accelerators, and high voltage rectifiers operating above 10kV all fall into the category of radiation producing machines.
B. Texas Regulation of Radiation Machines
- This section provides special requirements for analytical x-ray equipment. The requirements of this section are in addition to, and not in substitution for, applicable requirements in other parts of these regulations.
- Analytical x-ray equipment means x-ray equipment used for x-ray diffraction, fluorescence analysis, or spectroscopy.
- Analytical x-ray system means a group of local and remote components utilizing x-rays to determine the elemental composition or to examine the micro structure of materials.
- Local components include those that are struck by x-rays such as radiation source housings, port and shutter assemblies, collimators, sample holders, cameras, goniometers, detectors, and shielding.
- Remote components include power supplies, transformers, amplifiers, readout devices, and control panels.
- Fail-safe characteristics mean a design feature which causes beam port shutters to close or otherwise prevents emergence of the primary beam, upon the failure of a safety or warning device.
- Normal operating procedures mean operating procedures for analytical purposes with shielding and barriers in place. These do not include maintenance but do include routine alignment procedures. Routine and emergency radiation safety considerations are part of the procedures.
- Open beam configuration means an analytical x-ray system in which an individual could accidentally place some part of his body in the primary beam path during normal operation.
- Primary beam means ionizing radiation which passes through an aperture of the source housing by a direct path from the x-ray tube located in the radiation source housing.
- Safety Device: A device which prevents the entry of any portion of an individual's body into the primary x-ray beam path or which causes the beam to be shut off upon entry into its path shall be provided on all open beam configurations. A registrant may apply to the RSO for an exemption for the requirement of a safety device. Such application shall include:
- a description of the various safety devices that have been evaluated.
- the reason each of the devices cannot be used. Shutters: On open beam configuration installed after the effective date of these regulations, each port on the radiation source housing shall be equipped with a shutter that cannot be opened unless a collimator or a coupling has been connected to the port.
- a description of the alternative methods that will be employed to minimize the possibility of an accidental exposure, including procedures to assure that operators and others in the area will be informed of the absence of safety devices.
- Warning Devices: Open beam configurations shall be provided with a readily discernible indication of
- x-ray tube status (ON-OFF) located near the radiation source housing, if the primary beam is controlled in this manner.
- shutter status (OPEN-CLOSED) located near each port on the radiation source housing, if the primary beam is controlled in this manner.
- Warning devices shall be labeled so that their purpose is easily defined. On equipment installed after the effective day of these regulations, warning devices shall have fail-safe characteristics.
- Ports: Unused ports on radiation machine sources housing shall be secured in the closed position in a manner which will prevent casual opening.
- Required Labeling
- CAUTION HIGH INTENSITY X-RAY BEAM or words having a similar intent on the x-ray source housing
- CAUTION RADIATION – THIS EQUIPMENT PRODUCES RADIATION WHEN ENERGIZED or words having a similar intent, near any switch that energized an x-ray tube
- Warning Lights
- An easily visible warning light labeled with the words X-RAY ON or words having a similar intent shall be located near any switch that energized an x-ray tube and shall be illuminated only when the tube is energized.
- On equipment installed after the effective day of these regulations, warning lights shall have fail-safe characteristics.
- Radiation Levels: The local components of an analytical x-ray system shall be located and arranged and shall include sufficient shielding or access control such that no radiation levels exist in any area surrounding the local component group which could result in a dose to an individual present therein in excess of regulatory limits. These levels shall be met at any specified tube rating.
- Surveys: Radiation surveys of all analytical x-ray systems sufficient to show compliance with state regulations shall be performed
- upon installation of the equipment.
- following any change in the initial arrangement, number, or type of local components in the system.
- following any maintenance requiring the disassembly or removal of a local component in the system.
- during the performance of maintenance and alignment procedures if the procedure requires the presence of a primary x-ray beam when any local component in the system is disassembled or removed.
- any time a visual inspection of the local components in the system reveals an abnormal condition.
- whenever personnel monitoring devices show a significant increase over the previous monitoring period or the readings are approaching the Radiation Protection Guides (radiation dose limits).
- Radiation survey measurements shall be completed on an annual basis.
- Posting: Each area or room containing analytical x-ray equipment shall be conspicuously posted with a sign or sign bearing the radiation symbol and the words "Caution-X-Ray Equipment" or words having a similar intent.
- Procedures: Normal operating procedures shall be written and available to all analytical x-ray equipment workers. No person shall be permitted to operate analytical x-ray equipment in any manner other than that specified in the procedures unless such person has obtained written approval of the Radiation Safety Officer.
- Bypassing: No person shall bypass a safety device unless such person has obtained the approval of the Radiation Safety Officer. When safety device has been bypassed, a readily discernible sign bearing the words "SAFETY DEVICE NOT WORKING" or words having a similar intent, shall be placed on the radiation source housing.
- Instruction: No person shall be permitted to operate or maintain analytical x-ray equipment unless such person has received instruction in and demonstrated competence as to
- identification of radiation hazards associated with the use of the equipment.
- significance of the various radiation warning and safety devices incorporated into the equipment, or the reasons they have not been installed on certain pieces of equipment and the extra precaution required in such cases.
- proper operating procedures for the equipment.
- radiation safety, including symptoms of an acute localized exposure.
- proper procedures for reporting an actual or suspected exposure.
- Personnel Monitoring: Finger dosimetric devices shall be provided to and shall be used by
- analytical x-ray equipment workers using systems having an open beam configuration and not equipped with a safety device.
- personnel maintaining analytical x-ray equipment if the maintenance procedures require the presence of primary x-ray beam when any local component in the analytical x-ray system is disassembled or removed.
C. Decommissioning of a Radiation Machine
- Decommission – when a registrant decides to terminate all activities involving a radiation machine authorized under the Radiation Safety Program
- The responsible user shall notify the Radiation Safety Officer when a radiation machine will no longer be used at Baylor University.
- The user and Radiation Safety Officer will determine disposition of the device.
- The Principal Investigator shall complete a Baylor University Equipment Release form as described in the Laboratory Equipment Decommissioning policy.
- A device may be transferred to another registered user following proper regulations for shipping and transfer.
- A device may be disposed of by first removing its capability of producing radiation. Deface all radiation signage prior to disposal.
The Radiation Safety Officer shall notify the Texas Department of State Health Services to ensure the University's registration is maintained current.
All records of decommissioning shall be maintained in the Department of EHS (RSO files).